defmodule Image do @moduledoc """ `Image` is based upon the fabulous [vix](https://hex.pm/packages/vix) library that provides a [libvips](https://www.libvips.org) wrapper for Elixir. `Image` is intended to provide well-documented common image processing functions in an idiomatic Elixir functional style as a layer above the very comprehensive set of functions in `Vix` and `libvips`. In a very simple image resizing [benchmark](https://github.com/kipcole9/image/blob/main/bench/image_resize.exs), `Image` is approximately 2 to 3 times faster than `Mogrify` and uses about 5 times less memory. """ alias Vix.Vips.{Operation, MutableImage} alias Vix.Vips.Image, as: Vimage alias Image.{Exif, Xmp, Complex, Options, Color, Interpretation, BlendMode} alias Image.Options.{Resize, Thumbnail, Compose, Open, ChromaKey} alias Image.Math alias Image.Draw alias Evision.Constant import Image.Color, only: :macros @typedoc """ A 512 bit binary hash of an image. Useful for comparing the similarity of two images. See `Image.dhash/1` and `Image.hamming_distance/2`. """ @type image_hash :: binary() # Default radius of rounded corners @default_round_corner_radius 50 # Standard size of an avatar image, at least for # this library @default_avatar_size 180 # When pixelating an image resize to this scale # the scale up by the inverse using nearest_neighbour # scaling @pixelate_scale 0.05 # The default sigma applied to a gaussian blur. # Used by blur/3 and feather/2 @default_blur_sigma Options.Blur.default_blur_sigma() # if the ratio between width and height differs # by less than this amount, consider the image # to be square @square_when_ratio_less_than 0.0 # The percent from absolute black and # absolute white in autolevel/1 @level_trim_percent 0.3 @typedoc """ The valid sources of image data when opening an image. """ @type image_data :: Path.t() | File.Stream.t() | binary() @typedoc """ Represents either in image, or a color that is used to fill a new image """ @type image_or_color :: Vimage.t() | Color.t() @typedoc """ The valid rendering intent values. For all functions that take an optional intent parameter the default is `:perceptual`. ## Perceptual Intent Perceptual rendering is used to process photographic type images. This intent processes the colors so that the output reproduction is pleasing. This process tends to change the color from the original, so no guarantee the reproduction will be accurate against the original. ## Relative Intent Relative colorimetric changes all the colours out of gamut to the nearest colour in gamut, so many colours change to the same one. It DOES NOT change colours in gamut. Perceptual changes ALL the colours in the image in a proportional way so that they lie in the output device gamut. ## Saturation Intent Saturation moves in-gamut colors toward the edge of the destination gamut for maximum saturation and impact. This intent will make an image more colorful by using the full gamut of the destination device. This intent cares not for the genuine representation of color. ## Absolute Intent Absolute rendering attempts to reproduce all colors numerically (destination = source). This can cause unexpected results if the source gamut is larger than the destination. """ @type render_intent :: :perceptual | :relative | :saturation | :absolute @typedoc """ Error messages returned by `libvips` Typically a string. """ @type error_message :: term() @typedoc """ A pixel is represented as a list of number values or a single number (which is then assumed to be the value for all bands). The number of list elements is determined by the colorspace interpretations. For example: * `RGB` colorspace would be represented by a list of three floats like `[0.0, 0,0, 0.0]` for black. * `CMYK` colorspace would be represented by a list of four floats. * A `PNG` image can be in any appropriate colorspace but may also have an `alpha` band and therefore have three, four or five floats in a list to represent the pixel. """ @type pixel :: [number()] | number() @typedoc """ Image orientation. """ @type aspect :: :landscape | :portrait | :square @typedoc """ A composition is a 2-tuple defining an image and the options which describe how to compose this image on a base image. """ @type composition :: {Vimage.t(), composition_options} @typedoc """ When composing an image on a base image, these options drive how the composition proceeds. * `:x` describes the absolute `x` offset on the base image where this image will be placed. If this option is set to `:left`, `:center` or `:right` then the `x` position will be calculated relative to the base image. If `:x` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dx`. * `:y` describes the absolute `y` offset on the base image where this image will be placed. If this option is set to `:top`, `:middle` or `:bottom` then the `y` position will be calculated relative to the base image. If `:y` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dy`. * `:dx` describes the relative offset used to calculate the `x` value. `:dx` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:x_baseline` option. If `:x` is also specified then `:x` is first calculated, then `:dx` is added to it. In this case, `:x_baseline` is ignored. * `:dy` describes the relative offset used to calculate the `y` value. `:dy` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:y_baseline` option. If `:y` is also specified then `:y` is first calculated, then `:dy` is added to it. In this case, `:x_baseline` is ignored. * `:blend_mode` is the `t:Image.BlendMode.t/0` used when composing this image over its base image. The default is `:over` which is appropriate for most use cases. * `:x_baseline` establishes the baseline on the previously composed image from which `:dx` is calculated. The default is `:right`. * `:y_baseline` establishes the baseline on the previously composed image from which `:dy` is calculated. The default is `:bottom`. """ @type composition_options :: [ {:x, non_neg_integer() | nil | :left | :center | :right}, {:y, non_neg_integer() | nil | :top | :middle | :bottom}, {:dx, integer()}, {:dy, integer()}, {:blend_mode, Image.BlendMode.t()}, {:x_baseline, nil | :left | :center | :right}, {:y_baseline, nil | :top | :middle | :bottom} ] @typedoc """ The data type of the image, using the same type definitions as `t:Nx.Type.t/0`. """ @type format :: {:u | :s | :f | :c | :bf, 8 | 16 | 32 | 64 | 128} @doc """ Guards whether the given struct is an image type either `Vix.Vips.Image` or `Vix.Vips.MutableImage`. """ defguard is_image(image_type) when image_type in [Vimage, MutableImage] @doc """ Guards whether the coordinates can be reasonably interpreted as a bounding box. `left` and `top` when positive are relative to the left and top of the image respectively. When negative they are relative to the right and bottom of the image. """ @doc subject: "Guard" defguard is_box(left, top, width, height) when is_integer(left) and is_integer(top) and is_integer(width) and is_integer(height) and width > 0 and height > 0 @doc """ Guards whether a number can be reasonably interpreted as a size (as in size of a crop or mask) """ @doc subject: "Guard" defguard is_size(size) when is_integer(size) and size > 0 @doc """ Guards whether a term might be reasonably interpreted as an image pixel. """ @doc subject: "Guard" defguard is_pixel(value) when is_number(value) or is_list(value) @doc """ Guards whether a value is a percentage as representeed by a float between `-1.0` and `1.0`. """ @doc subject: "Guard" defguard is_percent(value) when is_float(value) and value >= -1.0 and value <= 1.0 @doc """ Guards whether a value is a positive percentage as representeed by a float greater than `0.0` and less than or equal to `1.0`. """ @doc subject: "Guard" defguard is_positive_percent(value) when is_float(value) and value > 0.0 and value <= 1.0 @doc """ Create a new image of the given dimensions. ### Arguments Either `width` and `height` OR `image` should be provided. * `width` is the image width as an integer. * `height` is the image height as an integer. * `image` is an image from which the `width`, `height` are derived. * `options` is a keyword list of options. ### Options * `:color` defines the color of the image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. * `:bands` defines the number of bands (channels) to be created. The default is the number of bands of `:color` option or if `:color` is an integer then the default value is `3`. * `:format` defines the format of the image. The default is `{:u, 8}`. * `:interpretation` defines the interpretation of the image. The default is `:srgb`. ### Returns * `{:ok, image}` or * `{:error, reason}` ### Notes * Either `width` and `height` OR `image` should be provided as arguments but NOT both. ### Examples # 100x100 pixel image of dark blue slate color iex> {:ok, _image} = Image.new(100, 100, color: :dark_slate_blue) # 100x100 pixel green image, fully transparent iex> {:ok, _image} = Image.new(100, 100, color: [0, 255, 0, 1], bands: 4) """ @doc subject: "Load and save" @spec new(width :: pos_integer(), height :: pos_integer()) :: {:ok, Vimage.t()} | {:error, error_message()} def new(width, height) when is_integer(width) and is_integer(height) and width > 0 and height > 0 do new(width, height, []) end @spec new(image :: %Vimage{}, options :: Options.New.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def new(%Vimage{} = image, options) do {width, height, bands} = Image.shape(image) options = Keyword.put_new(options, :bands, bands) new(width, height, options) end @doc subject: "Load and save" @spec new(width :: pos_integer(), height :: pos_integer(), options :: Options.New.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def new(width, height, options) when is_integer(width) and is_integer(height) and width > 0 and height > 0 do with {:ok, options} <- Options.New.validate_options(options) do {:ok, pixel} = Vix.Vips.Operation.black!(1, 1, bands: options.bands) |> Image.Math.add!(options.color) |> Operation.cast(options.format) {:ok, image} = Operation.embed(pixel, 0, 0, width, height, extend: :VIPS_EXTEND_COPY) Operation.copy(image, interpretation: options.interpretation, xres: options.x_res, yres: options.y_res, xoffset: options.x_offset, yoffset: options.y_offset ) end end @doc """ Return a new image of the given dimensions and background color or raise an exception. ### Arguments Either `width` and `height` OR `image` should be provided. * `width` is the image width as an integer. * `height` is the image height as an integer. * `image` is an image from which the `width`, `height` re derived. * `options` is a keyword list of options. ### Options * `:bands` defines the number of bands (channels) to be created. The default is `3`. * `:color` defines the color of the image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. * `:format` defines the format of the image. The default is `{:u, 8}`. * `:interpretation` defines the interpretation of the image. The default is `:srgb`. ### Returns * `{:ok, image}` or * `{:error, reason}` ### Notes * Either `width` and `height` OR `image` should be provided as arguments but NOT both. ### Examples # 100x100 pixel image of dark blue slate color iex> {:ok, _image} = Image.new(100, 100, color: :dark_slate_blue) # 100x100 pixel green image, fully transparent iex> {:ok, _image} = Image.new(100, 100, color: [0, 255, 0, 1], bands: 4) """ @doc subject: "Load and save" @spec new!(width :: pos_integer(), height :: pos_integer()) :: Vimage.t() | no_return() def new!(width, height) when is_integer(width) and is_integer(height) and width > 0 and height > 0 do case new(width, height) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @spec new!(image :: %Vimage{}, options :: Options.New.t()) :: Vimage.t() | no_return() def new!(%Vimage{} = image, options) do case new(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc subject: "Load and save" @spec new!(width :: pos_integer(), height :: pos_integer(), options :: Options.New.t()) :: Vimage.t() | no_return() def new!(width, height, options) when is_integer(width) and is_integer(height) and width > 0 and height > 0 do case new(width, height, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Create a new image of the same shape as the provided image. The function creates a new image with the same width, height and bands as the image argument. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` from which the new images `width` and `height` and ` bands` will be derived. * `options` is a keyword list of options. ### Options * `:bands` defines the number of bands (channels) to be created. The default is the number of bands in `image`. * `:color` defines the color of the image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. * `:format` defines the format of the image. The default is `{:u, 8}`. * `:interpretation` defines the interpretation of the image. The default is `:srgb`. ### Returns * `{:ok, image}` or * `{:error, reason}` """ @doc subject: "Load and save", since: "0.1.13" @spec new(image :: %Vimage{}) :: {:ok, Vimage.t()} | {:error, error_message()} def new(%Vimage{} = image) do new(image, []) end @doc """ Return a new image of the same shape as the provided image or raise an exception. The function creates a new image with the same width, height and bands as the image argument. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` from which the new images `width` and `height` and ` bands` will be derived. * `options` is a keyword list of options. ### Options * `:bands` defines the number of bands (channels) to be created. The default is the number of bands in `image`. * `:color` defines the color of the image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. * `:format` defines the format of the image. The default is `{:u, 8}`. * `:interpretation` defines the interpretation of the image. The default is `:srgb`. ### Returns * `{:ok, image}` or * `{:error, reason}` """ @doc subject: "Load and save", since: "0.1.13" def new!(%Vimage{} = image) do case new(image, []) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Opens an image file or stream for image processing. ### Arguments * `image_path_or_stream_or_binary` is the file system path to an image file or a `t:File.Stream.t/0` or any `t:Enumerable.t/0`. It can also be any binary `.jpg`, `.png` or `.webp` image. * `options` is a keyword list of options. The default is `[access: :sequential]` for all images except images derived from binary image data. ### Options The available options depend upon the image type. #### All image types * `:access` is the file access mode, either `:random` or `:sequential`. The default is `:random`. When `:sequential`, `Image` (via `Vix`) is able to support streaming transformations and optimise memory usage more effectively. However `:sequential` also means that some operations cannot be completed because they would require non-sequential access to the image. In these cases, `:random` access is required. * `:fail_on` sets the error level at which image loading and decoding will stop. The default is `:none`. Each error state implies all the states before it such that `:error` implies also `:truncated`. #### JPEG image options * `:shrink` is an integer factor in the range `1..16` by which the image is reduced upon loading. This is an optimization that can result in improved performance and reduced memory usage if the image is being loaded with the intent to resize it to smaller dimensions. The default value is `1` meaning no shrink-on-load. * `:autorotate` is a boolean value indicating if the image should be rotated according to the orientation data stored in the image metadata. The default is `false`. #### WEBP options * `:scale` will scale the image on load. The value is a number greater than `0` and less than or equal to `1024` with a default of `1` meaning no scaling on load. Numbers less than `1.0` scale the image down so that a scale of `0.5` will halve the image size on load. * `:page` indicates the first page to be loaded. The value is in the range `0..100_000` with a default value of `0`. This parameter is useful on animated images. * `:pages` indicates the number of pages to load. The value must be between `-1` and `100_000`. The default value is `1`. A value of `-1` would load all the available pages which is useful if you want to keep the animation of the input image. #### TIFF options * `:autorotate` is a boolean value indicating if the image should be rotated according to the orientation data stored in the image metadata. The default is `false`. * `:page` indicates the first page to be loaded. The value is in the range `0..100_000` with a default value of `0`. This parameter is useful on animated images. * `:pages` indicates the number of pages to load. The value must be between `-1` and `100_000`. The default value is `1`. A value of `-1` would load all the available pages which is useful if you want to keep the animation of the input image. #### PNG options * There are no PNG-specific image loading options. #### GIF options * `:page` indicates the first page to be loaded. The value is in the range `0..100_000` with a default value of `0`. This parameter is useful on animated images. * `:pages` indicates the number of pages to load. The value must be between `-1` and `100_000`. The default value is `1`. A value of `-1` would load all the available pages which is useful if you want to keep the animation of the input image. ### Returns * `{:ok, image}` or * `{:error, message}` """ @doc subject: "Load and save" @spec open(path_or_stream_or_binary :: image_data(), options :: Open.image_open_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def open(path_or_stream_or_binary, options \\ []) # JPEG signature def open(<<0xFF, 0xD8, 0xFF, _::binary>> = image, options) do from_binary(image, options) end # PNG signature png = quote do <<0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, _::size(32), "IHDR", _::binary>> end def open(unquote(png) = image, options) do from_binary(image, options) end # WEBP signature def open(<<"RIFF", _::size(32), "WEBP", _::binary>> = image, options) do from_binary(image, options) end # GIF87a signature def open(<<0x47, 0x49, 0x46, 0x38, 0x37, 0x61, _::binary>> = image, options) do from_binary(image, options) end # GIF89a signature def open(<<0x47, 0x49, 0x46, 0x38, 0x39, 0x61, _::binary>> = image, options) do from_binary(image, options) end # TIF little endian def open(<<0x49, 0x49, 0x2A, 0x00, _::binary>> = image, options) do from_binary(image, options) end # TIF big endian def open(<<0x4D, 0x4D, 0x00, 0x2A, _::binary>> = image, options) do from_binary(image, options) end def open(image_path, options) when is_binary(image_path) do with {:ok, options} <- Options.Open.validate_options(options) do image_path |> String.split("[", parts: 2) |> do_open(options) end end def open(%File.Stream{line_or_bytes: bytes} = image_stream, options) when is_integer(bytes) do with {:ok, options} <- Options.Open.validate_options(options) do options = loader_options(options) Vix.Vips.Image.new_from_enum(image_stream, options) end end def open(%Stream{} = image_stream, options) do with {:ok, options} <- Options.Open.validate_options(options) do options = loader_options(options) Vix.Vips.Image.new_from_enum(image_stream, options) end end def open(%File.Stream{}, _options) do {:error, "File stream must be specify the number of bytes to read. " <> "It should be opened as File.stream!(path, options, bytes) where bytes " <> "is the number of bytes to read on each iteration."} end defp do_open([path], options) do if File.exists?(path) do options = build_option_string(options) Vimage.new_from_file(path <> options) else {:error, :enoent} end end defp do_open([path, open_options], options) do if File.exists?(path) do open_options = String.trim_trailing(open_options, "]") options = build_option_string(open_options, options) Vimage.new_from_file(path <> options) else {:error, :enoent} end end defp loader_options(options) do "[" <> Enum.map_join(options, ",", fn {k, v} -> "#{k}=#{v}" end) <> "]" end @doc """ Returns an image created from an in-memory binary representation of an image. The binary must be a complete formatted image such as that returned from `File.read!/1`. ### Arguments * `binary` is a binary representation of a formatted image * `options` is a keyword list of options. See `Image.open/2` for the list of applicable options. ### Returns * `{:ok, image}` or * `{:error, reason}` """ @doc subject: "Load and save", since: "0.7.0" @spec from_binary(binary :: binary(), options :: Open.image_open_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def from_binary(binary, options \\ []) when is_binary(binary) do with {:ok, options} <- Options.Open.validate_options(options) do options = Keyword.delete(options, :access) Vimage.new_from_buffer(binary, options) end end @doc """ Returns an image created from an in-memory binary representation of an image or raises an exception. The binary must be a complete formatted image such as that returned from `File.read!/1`. ### Arguments * `binary` is a binary representation of a formatted image * `options` is a keyword list of options. See `Image.open/2` for the list of applicable options. ### Returns * `image` or * raises an exception. """ @doc subject: "Load and save", since: "0.25.0" @spec from_binary!(binary :: binary(), options :: Open.image_open_options()) :: Vimage.t() | no_return() def from_binary!(binary, options \\ []) when is_binary(binary) do case from_binary(binary, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Opens an image file for image processing returning an image or raising an exception. ### Arguments * `image_path` is the file system path to an image file. * `options` is a keyword list of options. See `Image.open/2`. ### Returns * `image` or * raises an exception. """ @doc subject: "Load and save" @spec open!(image_path :: Path.t(), options :: Options.Open.image_open_options()) :: Vimage.t() | no_return() def open!(image_path, options \\ []) do case open(image_path, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, {reason, image_path} end end @doc """ Write an image to a file, a stream, an enumerable or to memory. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `image_path` is the file system path to an image file. It may also be a stream created with `File.stream!/3` or with `Stream.resource/3`, a `t:Plug.Conn.t/0` if `Plug` is configured or lastly, it can also be `:memory` in which case the image is written to a binary. * `options` is a keyword list of options. The default is `[]`. ### Options The available options depends on the type of image file being opened. #### All image types * `:strip_metadata` is a boolean indicating if all metadata is to be stripped from the image. The default is `false`. * `:background` is the background value to be used for any transparent areas of the image. Jpeg does not support alpha bands so a color value must be assigned. * `:quality` which influences image compression and is a integer in the range `1..100`. The default for most image formats is `75`. For PNG files it is the compression amount with a default of `60`. For HEIF files the default is `50`. ### Streaming images and :memory images * `:suffix` must be specified so that the image is written in the correct format. For example: `suffix: ".jpg"`. #### JPEG images * `:progressive` is a boolean indicating if the image should be interleaved rather than baseline. Progressive has the advantage of perceived time for the initial image load and the cost of multiple decoding passes on the client. For many applications `:progressive` is to be preferred but validation of this assumption for specific use cases is required. * `:minimize_file_size` is a boolean indicating whether to apply a number of techniques to minimise the file size of the jpeg file at the cost of additional time to save the image. All metadata will also be removed. * `:icc_profile` indicates the icc profile to be attached to the output image. The value may be an inbuilt profile (`:none`, `:srgb`, `:cmyk`, `:p3`), the name of an icc profile in the systems profile directory or a full path to an icc profile file. The default is to use the icc profile of the input image if there is one. #### PNG images * `:progressive` which has the same meaning and values as for JPEG images. * `:minimize_file_size` is a boolean indicating whether to apply a number of techniques to minimise the file size of the `png` file at the cost of additional time to save the image. All metadata will also be removed. * `:effort` is an integer to adjust the level of CPU effort to reduce the file size. The value must be in the range `1..10`, the default is `7`. * `:icc_profile` indicates the icc profile to be attached to the output image. The value may be an inbuilt profile (`:none`, `:srgb`, `:cmyk`, `:p3`), the name of an icc profile in the systems profile directory or a full path to an icc profile file. The default is to use the icc profile of the input image if there is one. #### WEBP images * `:minimize_file_size` is a boolean which is most useful on animated `WebP`. It enables mixed encoding and optimise the file for minimum size at the cost of additional time to save the image. All metadata will also be removed. Using this parameter on a non-animated `webp` file will only remove the metadata as `:strip_metadata` would do. * `:effort` is an integer to adjust the level of CPU effort to reduce the file size. The value must be in the range `1..10`, the default is `7`. * `:icc_profile` indicates the icc profile to be attached to the output image. The value may be an inbuilt profile (`:none`, `:srgb`, `:cmyk`, `:p3`), the name of an icc profile in the systems profile directory or a full path to an icc profile file. The default is to use the icc profile of the input image if there is one. #### GIF options * `:interframe_maxerror` Maximum inter-frame error for transparency. The value must be in the range `0..32`. The default is `0`. By increasing this value, the encoder will try to take advantage from temporal redundancy between neighboring frames by enabling higher compression rates. * `:effort` is an integer to adjust the level of CPU effort to reduce the file size. The value must be in the range `1..10`, the default is `7`. #### HEIF images * `:compression` is the compression strategy to be applied. The allowable values are `:hevc`, `:avc`, `:jpeg` and `:av1`. The default is `:hevc`. * `:effort` is an integer to adjust the level of CPU effort to reduce the file size. The value can be in the range `1..10`, the default is `5`. * `:minimize_file_size` is a boolean indicating whether to apply a number of techniques to minimise the file size of the `heif` file at the cost of additional time to save the image. All metadata will also be removed. ### Returns * `{:ok, image}` (or `{:ok, binary}` is the destination is `:memory`) or * `{:error, reason}` """ if match?({:module, _module}, Code.ensure_compiled(Plug)) do @spec write( image :: Vimage.t(), image_path :: Path.t() | Plug.Conn.t() | Enumerable.t() | File.Stream.t() | :memory, options :: Options.Write.image_write_options() ) :: {:ok, Vimage.t()} | {:ok, binary()} | {:error, error_message()} else @spec write( image :: Vimage.t(), image_path :: Path.t() | Enumerable.t() | File.Stream.t() | :memory, options :: Options.Write.image_write_options() ) :: {:ok, Vimage.t()} | {:ok, binary()} | {:error, error_message()} end @doc subject: "Load and save" def write(image, image_path, options \\ []) def write(%Vimage{} = image, image_path, options) when is_binary(image_path) do with {:ok, options} <- Options.Write.validate_options(image_path, options) do image_path |> String.split("[", parts: 2) |> write_path(image, options) end end if match?({:module, _module}, Code.ensure_compiled(Plug)) do def write(%Vimage{} = image, %Plug.Conn{} = conn, options) do with {:ok, options} <- Options.Write.validate_options(options, :require_suffix) do {suffix, options} = Keyword.pop(options, :suffix) options = suffix <> loader_options(options) result = image |> Vimage.write_to_stream(options) |> Enum.reduce_while(conn, fn chunk, conn -> case Plug.Conn.chunk(conn, chunk) do {:ok, conn} -> {:cont, conn} {:error, :closed} = error -> {:halt, error} end end) with %Plug.Conn{} <- result do {:ok, image} end end end end def write(%Vimage{} = image, %module{} = stream, options) when module in [File.Stream, Stream] do with {:ok, options} <- Options.Write.validate_options(options, :require_suffix) do case write_stream(image, stream, options) do :ok -> {:ok, image} other -> other end end end def write(%Vimage{} = image, :memory, options) do with {:ok, options} <- Options.Write.validate_options(options, :require_suffix) do {suffix, options} = Keyword.pop(options, :suffix) options = suffix <> loader_options(options) Vimage.write_to_buffer(image, options) end end defp write_stream(image, stream, options) do {suffix, options} = Keyword.pop(options, :suffix) options = suffix <> loader_options(options) image |> Vimage.write_to_stream(options) |> Stream.into(stream) |> Stream.run() rescue e in Vix.Vips.Image.Error -> {:error, e.message} end defp write_path([image_path], image, options) do options = build_option_string(options) case Vimage.write_to_file(image, image_path <> options) do :ok -> {:ok, image} other -> other end end defp write_path([image_path, open_options], image, options) do write_options = String.trim_trailing(open_options, "]") options = build_option_string(write_options, options) case Vimage.write_to_file(image, image_path <> options) do :ok -> {:ok, image} other -> other end end @doc """ Write an image to a file, a stream, an enumerable or to memory returning the image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `image_path` is the file system path to an image file. It may also be a stream created with `File.stream!/3` or with `Stream.resource/3`. Lastly, it can also be `:memory` in which case the image is written to a memory buffer. * `options` is a keyword list of options. See `Image.write/2`. ### Returns * `image` (or a binary is the destination is `:memory`) or * raises an exception. """ @doc subject: "Load and save" @spec write!( image :: Vimage.t(), image_path_or_stream :: Path.t() | Plug.Conn.t() | Enumerable.t() | File.Stream.t(), options :: Options.Write.image_write_options() ) :: Vimage.t() | binary() | no_return() def write!(%Vimage{} = image, image_path, options \\ []) do case write(image, image_path, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, {reason, image_path} end end @doc """ Convert an image into an enumerable stream. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:buffer_size` is the size in bytes for each chunk in the stream being written. Some services, like AWS S3, require a minimum 5 MiB per chunk to be delivered and this option can be used to satisfy that requirement. For additional options see `Image.write/3`. ### Returns * An `t:Enumerable.t/0` suitable for streaming to an external service such as S3, Minio or any other enumerable consumer. ### Example In this example an image is opened, resized and then streamed into AWS S3: "some/image.jpg" |> Image.open!() |> Image.resize!(200) |> Image.stream!(suffix: ".jpg", buffer_size: 5_242_880) |> ExAws.S3.upload("images", "some_object_name.jpg") |> ExAws.request() Since AWS S3 requires multipart uploads to be 5MiB per chunk, we specify the `:buffer_size` option to `Image.stream!/2`. """ @doc subject: "Load and save" @spec stream!(Vimage.t(), options :: Options.Write.image_write_options()) :: Enumerable.t() def stream!(%Vimage{} = image, options \\ []) do with {:ok, options} <- Options.Write.validate_options(options, :require_suffix) do {suffix, options} = Keyword.pop(options, :suffix) {buffer_size, options} = Keyword.pop(options, :buffer_size, :unbuffered) options = suffix <> loader_options(options) stream = Vimage.write_to_stream(image, options) if buffer_size == :unbuffered || buffer_size == 0 do stream else buffer!(stream, buffer_size) end else {:error, reason} -> raise Image.Error, reason end end # Rebuffers a stream into chunks of a minimum size. # This is useful when streaming to AWS S3 which requires # a minimum 5 MiB chunk size for multi-part uploads. defp buffer!(stream, buffer_size) do chunker = fn bin, acc -> acc_size = IO.iodata_length(acc) if IO.iodata_length(bin) + acc_size >= buffer_size do size = buffer_size - acc_size <> = bin {:cont, IO.iodata_to_binary([acc, chunk]), [rest]} else {:cont, [acc, bin]} end end final = fn [] -> {:cont, []} acc -> {:cont, IO.iodata_to_binary(acc), []} end Stream.chunk_while(stream, [], chunker, final) end @doc """ Scans the condition image cond and uses it to select pixels from either the then `if_image` or the `else_image`. Non-zero means copy a pixel from `if_image`, `0` means copy a pixel from `else_image`. ### Arguments * `condition_image` is any image. Typically it is an image formed by the relation operations such as `Image.Math.greater_than/2`. * `if_image_or_color` is either an `t:Vimage.t/0` or a `t:Image.Color.t/0`. If a color is provided then an image is constructed with the same shape as `condition_image` filled with the provided color. * `else_image_or_color` is either an `t:Vimage.t/0` or a `t:Image.Color.t/0`. If a color is provided then an image is constructed with the same shape as `condition_image` filled with the provided color. ### Notes Any image can have either 1 band or `n` bands, where `n` is the same for all the non-1-band images. Single band images are then effectively copied to make n-band images. Images `if_image` and `else_image` are cast up to the smallest common format. The `condition_image` is cast to `{:u, 8}`. If the images differ in size, the smaller images are enlarged to match the largest by adding zero pixels along the bottom and right. The output image is calculated pixel by pixel as: (condition_image / 255) * if_image + (1 - condition_image / 255) *`else_image` """ @doc subject: "Operation", since: "0.13.0" @spec if_then_else( condition_image :: Vimage.t(), if_image :: image_or_color(), else_image :: image_or_color() ) :: {:ok, Vimage.t()} | {:error, error_message()} def if_then_else(%Vimage{} = condition_image, %Vimage{} = if_image, %Vimage{} = else_image) do Operation.ifthenelse(condition_image, if_image, else_image) end def if_then_else(%Vimage{} = condition_image, if_color, else_image_or_color) when is_color(if_color) do with {:ok, [hex: _hex, rgb: if_color]} <- Color.rgb_color(if_color), {:ok, if_image} <- new(condition_image, color: if_color) do if_then_else(condition_image, if_image, else_image_or_color) end end def if_then_else(%Vimage{} = condition_image, if_image_or_color, else_color) when is_color(else_color) do with {:ok, [hex: _hex, rgb: else_color]} <- Color.rgb_color(else_color), {:ok, else_image} <- new(condition_image, color: else_color) do if_then_else(condition_image, if_image_or_color, else_image) end end @doc """ Automatically determine the chroma key color of an image. The top left 10x10 pixels of the flattened image are averaged to produce a color sample that can then be used by `Image.chroma_mask/2`, `Image.chroma_key/2` and `Image.trim/2`. ### Argument * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * An RGB color as a three-element list of integers. """ # Original python code # this will be an RGB triple eg. [10, 10, 240] # key_colour = [i.avg() for i in foreground.crop(0, 0, 10, 10).bandsplit()] @doc subject: "Operation", since: "0.13.0" @spec chroma_color(image :: Vimage.t()) :: Color.t() def chroma_color(%Vimage{} = image) do with {:ok, flattened} <- maybe_flatten(image), {:ok, cropped} <- Image.crop(flattened, 0, 0, 10, 10) do for i <- band_range(cropped) do Operation.avg!(image[i]) |> round() end end end defp maybe_flatten(image) do if has_alpha?(image) do flatten(image) else {:ok, image} end end defp max_band_index(image) do Image.bands(image) - 1 end defp band_range(image) do 0..max_band_index(image) end @doc """ Return a chroma-based masked image. Chroma masking is the process of removing a background color from an image and returning the remaining content as an alpha mask. The masking is done in the LCh color space since it's perceptually more uniform. The returned mask in reverted to the interpretation of the original image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options There are two masking strategies available: the thresholding strategy (default) and the color range strategy. #### Threshold strategy * `:color` is an RGB color which represents the the chroma key to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:auto` in which the average of the top left `10x10` pixels of the image is used. * `:threshold`is a positive integer to indicate the threshold around `:color` when calculating the mask. The default is `20`. #### Color range strategy * `:greater_than` is an RGB color which represents the upper end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. * `:less_than` is an RGB color which represents the lower end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. """ # Original python code for thresholding from: https://github.com/libvips/libvips/discussions/3097#discussioncomment-3892994 # threshold = 20 # mask = ((foreground - key_colour) ** 2).bandmean() > (3 * threshold ** 2) @doc subject: "Operation", since: "0.13.0" @spec chroma_mask(image :: Vimage.t(), options :: ChromaKey.chroma_key_options() | map()) :: {:ok, Vimage.t()} | {:error, error_message()} def chroma_mask(image, options \\ []) def chroma_mask(%Vimage{} = image, options) when is_list(options) do alias Image.Math with {:ok, options} <- Options.ChromaKey.validate_options(options) do chroma_mask(image, options) end end def chroma_mask(%Vimage{} = image, %{color: color, threshold: threshold}) do alias Image.Math color = maybe_calculate_color(image, color) image |> Math.subtract!(color) |> Math.pow!(2) |> Operation.bandmean!() |> Math.greater_than!(3 * threshold ** 2) |> wrap(:ok) end def chroma_mask(%Vimage{} = image, %{greater_than: greater_than, less_than: less_than}) do with {:ok, greater} <- Image.Math.greater_than(image, greater_than), {:ok, less} = Image.Math.less_than(image, less_than), {:ok, color_mask} = Image.Math.boolean_and(greater, less), {:ok, mask} = Vix.Vips.Operation.bandbool(color_mask, :VIPS_OPERATION_BOOLEAN_AND) do Vix.Vips.Operation.invert(mask) end end defp maybe_calculate_color(image, :auto), do: chroma_color(image) defp maybe_calculate_color(_image, color), do: color @doc """ Return a chroma-based masked image or raises an exception. Chroma masking is the process of removing a background color from an image and returning the remaining content as an alpha mask. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options There are two masking strategies available: the thresholding strategy (default) and the color range strategy. #### Threshold strategy * `:color` is an RGB color which represents the the chroma key to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:auto` in which the average of the top left `10x10` pixels of the image is used. * `:threshold`is a positive integer to indicate the threshold around `:color` when calculating the mask. The default is `20`. #### Color range strategy * `:greater_than` is an RGB color which represents the upper end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. * `:less_than` is an RGB color which represents the lower end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. """ @doc subject: "Operation", since: "0.13.0" @spec chroma_mask!(image :: Vimage.t(), options :: ChromaKey.chroma_key_options()) :: Vimage.t() | no_return() def chroma_mask!(%Vimage{} = image, options \\ []) do case chroma_mask(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Chroma key an image. Chroma keying is the process of removing a background color from an image resulting in a foreground image that may be composited over another image. If the image already has an alpha band then the image is flattened before adding the image mask as a new alpha band. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options There are two masking strategies available: the thresholding strategy (default) and the color range strategy. #### Threshold strategy * `:color` is an RGB color which represents the the chroma key to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:auto` in which the average of the top left `10x10` pixels of the image is used. * `:threshold` is a positive integer to indicate the threshold around `:color` when calculating the mask. The default is `20`. #### Color range strategy * `:greater_than` is an RGB color which represents the upper end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. * `:less_than` is an RGB color which represents the lower end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. """ @doc subject: "Operation", since: "0.13.0" @spec chroma_key(image :: Vimage.t(), options :: ChromaKey.chroma_key_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def chroma_key(%Vimage{} = image, options \\ []) do with {:ok, options} <- Options.ChromaKey.validate_options(options), {:ok, mask} <- chroma_mask(image, options) do image = if has_alpha?(image), do: Operation.flatten!(image), else: image Operation.bandjoin([image, mask]) end end @doc """ Chroma key an image and return an image or raise an exception. Chroma keying is the process of removing a background color from an image resulting in a foreground image that may be composited over another image. If the image already has an alpha band then the image is flattened before adding the image mask as a new alpha band. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options There are two masking strategies available: the thresholding strategy (default) and the color range strategy. #### Threshold strategy * `:color` is an RGB color which represents the the chroma key to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:auto` in which the average of the top left `10x10` pixels of the image is used. * `:threshold` is a positive integer to indicate the threshold around `:color` when calculating the mask. The default is `20`. #### Color range strategy * `:greater_than` is an RGB color which represents the upper end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. * `:less_than` is an RGB color which represents the lower end of the color range to be masked. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. """ @doc subject: "Operation", since: "0.13.0" @spec chroma_key!(image :: Vimage.t(), options :: ChromaKey.chroma_key_options()) :: Vimage.t() | no_return() def chroma_key!(%Vimage{} = image, options \\ []) do case chroma_key(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Applies a gaussian blur to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:sigma` is the `float` size of the mask to use. A larger number makes the image more blurry. A range between `1.0` and `10.0` is normally appropriate. The default is `#{@default_blur_sigma}`. * `:min_amplitude` is a `float` that determines the accuracy of the mask. The default is `0.2`. A smaller number will generate a larger, more accurate mask, ### Returns * `{:ok, blurred_image}` or * `{:error reason}` """ @doc subject: "Operation", since: "0.13.0" @spec blur(image :: Vimage.t(), options :: Options.Blur.blur_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def blur(%Vimage{} = image, options \\ []) do with {:ok, options} <- Options.Blur.validate_options(options) do Operation.gaussblur(image, options.sigma, "min-ampl": options.min_amplitude) end end @doc """ Applies a gaussian blur to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:sigma` is the `float` size of the mask to use. A larger number makes the image more blurry. A range between `1.0` and `10.0` is normally appropriate. The default is `#{@default_blur_sigma}`. * `:min_amplitude` is a `float` that determines the accuracy of the mask. The default is `0.2`. A smaller number will generate a larger, more accurate mask, ### Returns * `blurred_image` or * raises an exception. """ @doc subject: "Operation", since: "0.13.0" @spec blur!(image :: Vimage.t(), options :: Options.Blur.blur_options()) :: Vimage.t() | no_return() def blur!(%Vimage{} = image, options \\ []) do case blur(image, options) do {:ok, blurred_image} -> blurred_image {:error, reason} -> raise Image.Error, reason end end @doc """ Feather (blur the edges) of an image mask. Applies a gaussian blur to a one-band image or the alpha band of a multi-band image that can be used to smooth the blending of one image into another. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` that is either a single band image or an image with an alpha band. * `options` is a keyword list of options. ### Options * `:sigma` is the `float` size of the mask to use. A larger number makes the image more blurry. A range between `1.0` and `10.0` is normally appropriate. The default is `#{@default_blur_sigma}`. * `:min_amplitude` is a `float` that determines the accuracy of the mask. The default is `0.2`. A smaller number will generate a larger, more accurate mask, ### Returns * `{:ok, blurred_mask_image}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.13.0" @spec feather(image :: Vimage.t(), options :: Options.Blur.blur_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def feather(%Vimage{} = image, options \\ []) do with {:ok, options} <- Options.Blur.validate_options(options) do cond do has_alpha?(image) -> {image, alpha} = split_alpha(image) {:ok, feathered} = feather(alpha, options) Operation.bandjoin([image, feathered]) bands(image) == 1 -> margin = options.sigma * 2 crop!(image, margin, margin, width(image) - 2 * margin, height(image) - 2 * margin) |> Operation.embed!(margin, margin, width(image), height(image)) |> blur!(options) |> wrap(:ok) true -> {:error, "Image has no alpha band and is not a single band image"} end end end @doc """ Feather (blur the edges) of an image mask returning an image or raising an exception. Applies a gaussian blur to a one-band image or the alpha band of a multi-band image that can be used to smooth the blending of one image into another. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` that is either a single band image or an image with an alpha band. * `options` is a keyword list of options. ### Options * `:sigma` is the `float` size of the mask to use. A larger number makes the image more blurry. A range between `1.0` and `10.0` is normally appropriate. The default is `#{@default_blur_sigma}`. * `:min_amplitude` is a `float` that determines the accuracy of the mask. The default is `0.2`. A smaller number will generate a larger, more accurate mask, ### Returns * `{:ok, blurred_mask_image}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.13.0" @spec feather!(image :: Vimage.t(), options :: Options.Blur.blur_options()) :: Vimage.t() | no_return() def feather!(%Vimage{} = image, options \\ []) do case feather(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Add an alpha band to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `alpha_image` is any single-band image that will be added as an alpha image to `image` OR * `:color` which defines the color of the alpha image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. ### Note If `color` is provided then the alpha layer determines the level of transparency of `image`. White (RGB color 255) means that `imaage` will be opaque. Black (the default, RGB 0) means that `image` will be transparent. Other colors will determine the level of transparency between the two. ### Returns * `{:ok, image_with_added_alpha_band}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.13.0" @spec add_alpha(image :: Vimage.t(), alpha_image :: Vimage.t() | Image.Color.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def add_alpha(%Vimage{} = image, %Vimage{} = alpha_image) do cond do has_alpha?(image) -> {:error, "Image already has an alpha band"} bands(alpha_image) > 1 -> {:error, "Alpha image has more than one band"} true Vix.Vips.Operation.bandjoin([image, alpha_image]) end end def add_alpha(%Vimage{} = image, color) when Color.is_color(color) do with {:ok, color} <- Color.validate_color(color), {:ok, alpha_image} <- Image.new(image, bands: 1, color: color) do add_alpha(image, alpha_image) end end @doc """ Add an alpha band to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `alpha_image` is any single-band image that will be added as an alpha image to `image` OR * `:color` which defines the color of the alpha image. This can be specified as a single integer which will be applied to all bands, or a list of integers representing the color for each band. The default is `0`, meaning black. The color can also be supplied as a CSS color name as a string or atom. For example: `:misty_rose`. See `Image.Color.color_map/0` and `Image.Color.rgb_color/1`. ### Note If `color` is provided then the alpha layer determines the level of transparency of `image`. White (RGB color 255) means that `imaage` will be opaque. Black (the default, RGB 0) means that `image` will be transparent. Other colors will determine the level of transparency between the two. ### Returns * `image_with_added_alpha_band` or * raises an exception. """ @doc subject: "Operation", since: "0.13.0" @spec add_alpha!(image :: Vimage.t(), alpha_image :: Vimage.t() | Image.Color.t()) :: Vimage.t() | no_return() def add_alpha!(%Vimage{} = image, alpha_image) do case add_alpha(image, alpha_image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Split an image to separate the alpha band from the other image bands. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{image_bands_without_alpha, alpha_band}` or * `{:image_bands, nil}` if there is not alpha band detected. """ @doc subject: "Operation", since: "0.13.0" @spec split_alpha(image :: Vimage.t()) :: {bands :: Vimage.t(), alpha :: Vimage.t() | nil} def split_alpha(%Vimage{} = image) do if has_alpha?(image) do alpha_band = image[alpha_band(image)] image = Operation.extract_band!(image, 0, n: Image.bands(image) - 1) {image, alpha_band} else {image, nil} end end @doc """ Compose two images together to form a new image. ### Arguments * `base_image` is any `t:Vix.Vips.Image.t/0`. * `overlay_image` is any `t:Vix.Vips.Image.t/0` that will be composed over the top of `base_image`. It can also be a list of `t:composition/0`s that allow for multiple images to be composed in a single call. * `options` is a keyword list of options. ### Options for a single overlay image * `:blend_mode` is the manner in which the two images are composited. See `t:Image.BlendMode.t/0`. The default is `:over` which is the most common blend mode. * `:x` is the offset (0-based) from the *left* of the `base_image` where the `overlay_image` will be placed. It may also be one of the keywords `:left`, `:right` or `:center`. The default is `:center`. * `:y` is the offset (0-based) from the *top* of the `base_image` where the `overlay_image` will be placed. It may also be one of the keywords `:top`, `:bottom` or `:middle`. The default is `:middle`. ### Composition list options When `overlay_image` is an `image_list`, each entry in the list is either a `t:Vix.Vips.Image.t/0` or a `t:composition/0`. A composition supports the specification of how a particular image is composed onto the base image. * `:x` describes the absolute `x` offset on the base image where this image will be placed. If this option is set to `:left`, `:center` or `:right` then the `x` position will be calculated relative to the base image. If `:x` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dx`. * `:y` describes the absolute `y` offset on the base image where this image will be placed. If this option is set to `:top`, `:middle` or `:bottom` then the `y` position will be calculated relative to the base image. If `:y` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dy`. * `:dx` describes the relative offset used to calculate the `x` value. `:dx` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:x_baseline` option. If `:x` is also specified then `:x` is first calculated, then `:dx` is added to it. In this case, `:x_baseline` is ignored. * `:dy` describes the relative offset used to calculate the `y` value. `:dy` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:y_baseline` option. If `:y` is also specified then `:y` is first calculated, then `:dy` is added to it. In this case, `:x_baseline` is ignored. * `:blend_mode` is the `t:Image.BlendMode.t/0` used when composing this image over its base image. The default is `:over` which is appropriate for most use cases. * `:x_baseline` establishes the baseline on the previously composed image from which `:dx` is calculated. The default is `:right`. * `:y_baseline` establishes the baseline on the previously composed image from which `:dy` is calculated. The default is `:bottom`. ### Returns * `{:ok, composed_image}` or * `{:error, reason}` ### Examples # Compose images over a base image using # absolute coordinates from the base image # to place each overlay image. #=> {:ok, image} = Image.compose(base_image, polygon, x: :middle, y: :top) #=> {:ok, image} = Image.compose(image, explore_new, x: 260, y: 200) #=> {:ok, image} = Image.compose(image, places, x: 260, y: 260) #=> {:ok, image} = Image.compose(image, blowout, x: 260, y: 340) #=> {:ok, image} = Image.compose(image, start_saving, x: 260, y: 400) # Compose images over a base image # using a composition list and coordinates # that are either absolute with respect to the # base image or relative to the previously # composed image. #=> Image.compose(base_image, [ ..> {polygon, x: :center, y: :top}, ..> {explore_new, y_baseline: :top, x_baseline: :left, dx: 20, dy: 200}, ..> {places, dy: 10}, ..> {blowout, dy: 20}, ..> {start_saving, dy: 50} ..> ]) """ @doc subject: "Operation" @spec compose(base_image :: Vimage.t(), overlay_image :: Vimage.t(), options :: Keyword.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def compose(base_image, overlay_image_or_images, options \\ []) def compose(%Vimage{} = base_image, %Vimage{} = overlay_image, options) do x = Keyword.get(options, :x, :center) y = Keyword.get(options, :y, :middle) blend_mode = Keyword.get(options, :blend_mode) with {:ok, blend_mode} <- Image.BlendMode.validate_blend_mode(blend_mode) do {x, y} = xy_offset(base_image, overlay_image, x, y) Operation.composite2(base_image, overlay_image, blend_mode, x: x, y: y) end end @spec compose(base_image :: Vimage.t(), image_list :: [Vimage.t(), ...], options :: Keyword.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def compose(%Vimage{} = base_image, image_list, _options) when is_list(image_list) do width = Image.width(base_image) height = Image.height(base_image) zipped = Enum.reduce_while(image_list, {0, 0, width, height, []}, fn %Vimage{} = image, {prev_x, prev_y, prev_width, prev_height, acc} -> build_composition(image, prev_x, prev_y, prev_width, prev_height, acc, Map.new()) {%Vimage{} = image, options}, {prev_x, prev_y, prev_width, prev_height, acc} -> build_composition(image, prev_x, prev_y, prev_width, prev_height, acc, Map.new(options)) end) case zipped do {:error, reason} -> {:error, reason} {_x, _y, _height, _width, list} -> {overlay_images, x_list, y_list, blend_modes} = unzip_composition(list) Operation.composite([base_image | overlay_images], blend_modes, x: x_list, y: y_list) end end defp build_composition(image, prev_x, prev_y, prev_width, prev_height, acc, options) do import Compose, only: [get_x: 6, get_y: 6] options = Map.merge(Compose.default_composit_options(), options) with {:ok, x} <- get_x(image, prev_x, prev_width, options.x, options.dx, options.x_baseline), {:ok, y} <- get_y(image, prev_y, prev_height, options.y, options.dy, options.y_baseline), {:ok, blend_mode} <- BlendMode.validate_blend_mode(options.blend_mode) do {:ok, [image, x, y, blend_mode]} end |> accumulate_compositions(image, acc) end defp unzip_composition(list) do Enum.reduce(list, {[], [], [], []}, fn [image, x, y, blend_mode], {images, xs, ys, blend_modes} -> {[image | images], [x | xs], [y | ys], [blend_mode | blend_modes]} end) end defp accumulate_compositions(composition, image, acc) do case composition do {:ok, composition} -> [_image, x, y | _rest] = composition {:cont, {x, y, Image.width(image), Image.height(image), [composition | acc]}} {:error, reason} -> {:halt, reason} end end @doc """ Compose two images together to form a new image or raise an exception. ### Arguments * `base_image` is any `t:Vix.Vips.Image.t/0`. * `overlay_image` is any `t:Vix.Vips.Image.t/0` that will be composed over the top of `base_image`. * `options` is a keyword list of options. ### Options * `:blend_mode` is the manner in which the two images are composited. See `t:Image.BlendMode.t/0`. The default is `:over` which is the most common blend mode. * `:x` is the offset (0-based) from the *left* of the `base_image` where the `overlay_image` will be placed. It may also be one of the keywords `:left`, `:right` or `:center`. The default is `:center`. * `:y` is the offset (0-based) from the *top* of the `base_image` where the `overlay_image` will be placed. It may also be one of the keywords `:top`, `:bottom` or `:middle`. The default is `:middle`. ### Composition list options When `overlay_image` is an `image_list`, each entry in the list is either a `t:Vix.Vips.Image.t/0` or a `t:composition/0`. A composition supports the specification of how a particular image is composed onto the base image. * `:x` describes the absolute `x` offset on the base image where this image will be placed. If this option is set to `:left`, `:center` or `:right` then the `x` position will be calculated relative to the base image. If `:x` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dx`. * `:y` describes the absolute `y` offset on the base image where this image will be placed. If this option is set to `:top`, `:middle` or `:bottom` then the `y` position will be calculated relative to the base image. If `:y` is nil (the default) then the image will be placed according to the relative offset of the previously composed image using `:dy`. * `:dx` describes the relative offset used to calculate the `x` value. `:dx` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:x_baseline` option. If `:x` is also specified then `:x` is first calculated, then `:dx` is added to it. In this case, `:x_baseline` is ignored. * `:dy` describes the relative offset used to calculate the `y` value. `:dy` is an integer offset from the edge of the previously composed image. Which edge is determined by the `:y_baseline` option. If `:y` is also specified then `:y` is first calculated, then `:dy` is added to it. In this case, `:x_baseline` is ignored. * `:blend_mode` is the `t:Image.BlendMode.t/0` used when composing this image over its base image. The default is `:over` which is appropriate for most use cases. * `:x_baseline` establishes the baseline on the previously composed image from which `:dx` is calculated. The default is `:right`. * `:y_baseline` establishes the baseline on the previously composed image from which `:dy` is calculated. The default is `:bottom`. ### Returns * `composed_image` or * raises an exception ### Examples # Compose images over a base image using # absolute coordinates from the base image # to place each overlay image #=> base_image ..> |> Image.compose!(polygon, x: :middle, y: :top) ..> |> Image.compose!(explore_new, x: 260, y: 200) ..> |> Image.compose!(places, x: 260, y: 260) ..> |> Image.compose!(blowout, x: 260, y: 340) ..> |> Image.compose!(start_saving, x: 260, y: 400) # Compose images over a base image # using a composition list and coordinates # that are either absolute with respect to the # base image or relative to the previously # composed image #=> base_image ..> |> Image.compose!([ ..> {polygon, x: :center, y: :top}, ..> {explore_new, y_baseline: :top, x_baseline: :left, dx: 20, dy: 200}, ..> {places, dy: 10}, ..> {blowout, dy: 20}, ..> {start_saving, dy: 50} ..> ]) """ @doc subject: "Operation" @spec compose!(base_image :: Vimage.t(), overlay_image :: Vimage.t(), options :: Keyword.t()) :: Vimage.t() | no_return() def compose!(base_image, image_or_image_list, options \\ []) def compose!(%Vimage{} = base_image, %Vimage{} = overlay_image, options) do case compose(base_image, overlay_image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @spec compose!(base_image :: Vimage.t(), image_list :: [Vimage.t(), ...], options :: Keyword.t()) :: Vimage.t() | no_return() def compose!(%Vimage{} = base_image, image_list, options) when is_list(image_list) do case compose(base_image, image_list, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Create a meme image from a base image and one or two lines of text. The size of the text is determined by the size of the base image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` over which the meme text will be composed. * `headline` is the top line of the meme text. * `options` is a keyword list of options. ### Options * `:text` is the second line of text at the bottom of the meme image. The default is `""`. * `:text_size` is the size of the bottom text in points. The default is calculated proportional to the size of the image. * `:headline_size` is the size of the headline text in points. The default is calculated proportional to the size of the image. * `:font` is the name of the font family to be applied. The default is `Impact`. * `:font_file` is the path name to a font file that will be loaded. The default is `:default` which will load the included `Impact` font if the font family is `Impact`. If the font family is not `Impact` and the `:font_file` is `:default` then the font displayed is resolved by the underlying operating system. If `:font_file` is a string, then it is expected to be a valid font file. If `:font_file` is set to a path then the `:font` option should also be set to the correct font name. * `:weight` is the font weight to be rendered. The options are `:ultralight`, `:light`, `:normal`, `:bold`, `:ultrabold`, and `:heavy`. The default `:bold`. * `:transform` determines how the text is presented. The options are `:upcase`, `:downcase`, `:capitalize` and `:none`. The default is `:upcase`. * `:color` is an RGB color of the text. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:white`. * `:outline_color` is an RGB color of the text outline. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:black`. * `:margin` is the width of the margin in pixels. The margin is applied to both the left and right sides of the image. The default is calculated proportional to the size of the image. """ @doc subject: "Generator", since: "0.13.0" @spec meme(image :: Vimage.t(), headline :: String.t(), options :: Options.Meme.meme_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def meme(%Vimage{} = image, headline, options \\ []) when is_binary(headline) do with {:ok, options} <- Options.Meme.validate_options(image, options), {:ok, width} <- text_box_width(image, options), {:ok, headline} <- text_overlay(headline, options.headline_size, width, options), {:ok, text} <- text_overlay(options.text, options.text_size, width, options) do image |> compose!(headline, headline_location(image, headline)) |> compose(text, text_location(image, text)) end end @doc """ Return a meme image from a base image and one or two lines of text or raise an exception. The size of the text is determined by the size of the base image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` over which the meme text will be composed. * `headline` is the top line of the meme text. * `options` is a keyword list of options. ### Options * `:text` is the second line of text at the bottom of the meme image. The default is `""`. * `:text_size` is the size of the bottom text in points. The default is calculated proportional to the size of the image. * `:headline_size` is the size of the headline text in points. The default is calculated proportional to the size of the image. * `:font` is the name of the font family to be applied. The default is `Impact`. If the font family name is `"Impact"` then the included `unicode.impact.ttf` font file will also be loaded. This ensures that the `Impact` font is available on all systems. * `:font_file` is the path name to a font file that will be loaded. The default is `:default` which will load the included `Impact` font if the font family is `Impact`. If the font family is not `Impact` and the `:font_file` is `:default` then the font displayed is resolved by the underlying operating system. If `:font_file` is a string, then it is expected to be a valid font file. If `:font_file` is set to a path then the `:font` option should also be set to the correct font name. * `:weight` is the font weight to be rendered. The options are `:ultralight`, `:light`, `:normal`, `:bold`, `:ultrabold`, and `:heavy`. The default `:bold`. * `:justify` is a boolean indicating if the headline and text are to be justified. If `true` then space is added between words so that both edges of each line are aligned with both margins. The default is `false`. * `:transform` determines how the text is presented. The options are `:upcase`, `:downcase`, `:capitalize` and `:none`. The default is `:upcase`. * `:color` is an RGB color of the text. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:white`. * `:outline_color` is an RGB color of the text outline. The color can be an integer between `0..255`, a three-element list of integers representing an RGB color or an atom representing a CSS color name. The default is `:black`. * `:margin` is the width of the margin in pixels. The margin is applied to both the left and right sides of the image. The default is calculated proportional to the size of the image. """ @doc subject: "Generator", since: "0.13.0" @spec meme!(image :: Vimage.t(), headline :: String.t(), options :: Options.Meme.meme_options()) :: Vimage.t() | no_return() def meme!(%Vimage{} = image, headline, options \\ []) when is_binary(headline) do case meme(image, headline, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end defp text_box_width(image, %{margin: margin}) do {:ok, width(image) - 2 * margin} end defp text_overlay("", _size, _width, _options) do Operation.black(1, 1) end defp text_overlay(text, size, width, %{font: font} = options) do text = "" <> transform(text, options.transform) <> "" font = "#{font} #{size}" text_options = [font: font, width: width, align: :VIPS_ALIGN_CENTRE] |> maybe_add_fontfile(options[:fontfile]) with {:ok, {text, _}} <- Operation.text(text, text_options) do outline(text, options) end end @doc false def maybe_add_fontfile(options, nil) do options end def maybe_add_fontfile(options, font_file) do Keyword.put(options, :fontfile, font_file) end defp outline(image, %{color: color, outline_color: outline_color} = options) do radius = round(options.headline_size / 10) width = width(image) + 2 * radius height = height(image) + 2 * radius {:ok, text} = Operation.embed(image, radius, radius, width, height) {:ok, circle_mask} = Operation.black!(radius * 2 + 1, radius * 2 + 1) |> Math.add!(128) |> Draw.circle(radius, radius, radius, fill: true, color: :white) {:ok, outlined} = text |> Operation.morph!(circle_mask, :VIPS_OPERATION_MORPHOLOGY_DILATE) |> blur(sigma: 0.5, min_amplitude: 0.1) {:ok, background_text} = outlined |> new!(color: outline_color, bands: 3) |> bandjoin!(outlined) |> Operation.copy(interpretation: :VIPS_INTERPRETATION_sRGB) {:ok, foreground_text} = text |> new!(color: color, bands: 3) |> bandjoin!(text) |> Operation.copy(interpretation: :VIPS_INTERPRETATION_sRGB) compose(background_text, foreground_text) end defp transform(text, :none), do: text defp transform(text, :capitalize), do: String.capitalize(text) defp transform(text, :upcase), do: String.upcase(text) defp transform(text, :downcase), do: String.downcase(text) defp bandjoin!(a, nil), do: a defp bandjoin!(a, b), do: Operation.bandjoin!([a, b]) @headline_distance_from_top 0.03 @text_distance_from_bottom 0.03 defp headline_location(image, text) do x = ((width(image) - width(text)) / 2) |> round() y = (height(image) * @headline_distance_from_top) |> round() [x: x, y: y] end defp text_location(image, text) do x = ((width(image) - width(text)) / 2) |> round() y = (height(image) - height(text) - height(image) * @text_distance_from_bottom) |> round() [x: x, y: y] end @doc """ Returns the filename for an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * The pathname from which the image was opened or `nil` if there is no associated path. This can happen in the case of a streamed image or an image created from a memory buffer. """ @doc subject: "Image info" @spec filename(image :: Vimage.t()) :: Path.t() | nil def filename(%Vimage{} = image) do Vix.Vips.Image.filename(image) rescue e in RuntimeError -> if e.message == "null_value" do nil else reraise e, __STACKTRACE__ end end @doc """ Returns the EXIF data for an image as a map. Only a subset of EXIF data is returned but its a substantial subset. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `{:ok, exif_map}` where `exif_map` is a map of selected EXIF data. * `{:error, reason}` """ @doc subject: "Metadata" @spec exif(Vimage.t()) :: {:ok, map()} | {:error, error_message()} def exif(%Vimage{} = image) do with {:ok, exif_blob} <- Vimage.header_value(image, "exif-data"), <<"Exif"::binary, 0::16, exif::binary>> <- exif_blob do exif |> Exif.extract_exif() |> wrap(:ok) else false -> {:error, "Invalid Exif data"} other -> other end end @doc """ Returns the XMP data for an image as a keyword list. Only a selected set of XMP data is returned. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `{:ok, xmp_map}` where `xmp_map` is a map of selected XMP data. """ @doc subject: "Metadata" @spec xmp(Vimage.t()) :: {:ok, map()} def xmp(%Vimage{} = image) do with {:ok, xmp_blob} <- Vimage.header_value_as_string(image, "xmp-data"), {:ok, xmp_binary} <- Base.decode64(xmp_blob) do xmp_binary |> SweetXml.parse(dtd: :none) |> Xmp.extract_xmp() |> wrap(:ok) end end @doc """ Returns the width of an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * The image width as an integer. """ @doc subject: "Image info" @spec width(image :: Vimage.t()) :: pos_integer() def width(%Vimage{} = image) do Vimage.width(image) end @doc """ Returns the height of an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * The image height as an integer. """ @doc subject: "Image info" @spec height(image :: Vimage.t()) :: pos_integer() def height(%Vimage{} = image) do Vimage.height(image) end @doc """ Return the number of bands in an image. A band is sometimes referred to as a channel. Note than bands are 0-indexed. That is, the first band is band 0, the second band is band 1 and so on. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * An integer number of bands in the image. """ @doc subject: "Image info" @spec bands(image :: Vimage.t()) :: pos_integer() def bands(%Vimage{} = image) do Vimage.bands(image) end @doc """ Returns the shape of an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * The image shape as a tuple of `{width, height, bands}`. """ @doc subject: "Image info", since: "0.9.0" @spec shape(image :: Vimage.t() | MutableImage.t()) :: {width :: pos_integer(), height :: pos_integer(), bands :: pos_integer()} def shape(%image_type{} = image) when is_image(image_type) do {width(image), height(image), bands(image)} end @doc """ Returns the image interpretation. The interpretation is how `Image` understands the image date. For example, `:srgb` or `:cmyk` or `:bw`. For most common web applications, the interpretation will be `:srgb`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * The image interpretation as an atom. ### Notes * See also `Image.Interpretation.known_interpretations/0` """ @doc subject: "Image info", since: "0.9.0" @spec interpretation(image :: Vimage.t()) :: Image.Interpretation.t() def interpretation(%Vimage{} = image) do image |> Vix.Vips.Image.interpretation() |> Image.Interpretation.decode_interpretation() end @doc """ Returns the data type of the image pixels. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * The image type as a tuple in the same format as `t:Nx.Type.t/0`. For example `{:u, 8}` for a common `:srgb` image. """ @dialyzer {:nowarn_function, {:type, 1}} @doc subject: "Image info", since: "0.9.0" @spec type(image :: Vimage.t()) :: Image.BandFormat.t() def type(%Vimage{} = image) do Image.BandFormat.nx_format(image) end @doc """ Flip an image horizontally or vertically. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `direction` is either `:horizontal` or `:vertical`. ### Returns * `{:ok, flipped_image}` or * `{:error, reason}` """ @doc subject: "Operation" @spec flip(image :: Vimage.t(), direction :: :vertical | :horizontal) :: {:ok, Vimage.t()} | {:error, error_message()} def flip(%Vimage{} = image, :vertical) do Operation.flip(image, :VIPS_DIRECTION_VERTICAL) end def flip(%Vimage{} = image, :horizontal) do Operation.flip(image, :VIPS_DIRECTION_HORIZONTAL) end def flip(%Vimage{} = _image, direction) do {:error, "Invalid flip direction. Must be :vertical or :horizontal. Found #{inspect(direction)}"} end @doc """ Flip an image horizontally or vertically returning a flipped image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `direction` is either `:horizontal` or `:vertical`. ### Returns * `flipped_image` or * raises an exception. """ @doc subject: "Operation" @spec flip!(image :: Vimage.t(), direction :: :vertical | :horizontal) :: Vimage.t() | no_return() def flip!(%Vimage{} = image, direction) do case flip(image, direction) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Resize an image. If the intent is to thumbnail an image then `Image.thumbnail/3` is recommended since it applies a very efficient downsizing algorithm for that use case. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `scale` is a float scale factor. * `options` is a keyword list of options. ### Options * `:centre` is a boolean indicating whether to use the centre downsampling convention. The default is `false`. * `:interpolate` defines which resampling kernel to apply. The options are `:nearest`, `:linear`, `:cubic`, `:mitchell`, `:lanczos2` or `:lanczos3` (the default). ### Returns * `{:ok, resized_image}` or * raises an exception """ @doc subject: "Resize", since: "0.13.0" @spec resize(Vimage.t(), scale :: number(), options :: Resize.resize_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def resize(%Vimage{} = image, scale, options \\ []) when scale >= 0 do with {:ok, options} <- Resize.validate_options(options) do Operation.resize(image, scale, options) end end @doc """ Resize an image or raise an exception. If the intent is to thumbnail an image then `Image.thumbnail/3` is recommended since it applies a very efficient downsizing algorithm for that use case. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `scale` is a float scale factor. * `options` is a keyword list of options. ### Options * `:centre` is a boolean indicating whether to use the centre downsampling convention. The default is `false`. * `:interpolate` defines which resampling kernel to apply. The options are `:nearest`, `:linear`, `:cubic`, `:mitchell`, `:lanczos2` or `:lanczos3` (the default). ### Returns * `resized_image` or * raises an exception """ @doc subject: "Resize", since: "0.14.0" @spec resize!(Vimage.t(), scale :: number(), options :: Resize.resize_options()) :: Vimage.t() | no_return() def resize!(%Vimage{} = image, scale, options \\ []) when scale >= 0 do case resize(image, scale, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Pixelates an image. Pixelation is the process of reducing the image resolution while retaining the image dimensions. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `scale` is the scale factor to apply to the image when it is pixelated. This means that one "pixel" is `image width * scale`. The default is `#{@pixelate_scale}`. ### Returns * `{:ok, pixelated_image}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.14.0" @spec pixelate(image :: Vimage.t(), scale :: number()) :: {:ok, Vimage.t()} | {:error, error_message()} def pixelate(%Vimage{} = image, scale \\ @pixelate_scale) when is_number(scale) and scale > 0 do image |> resize!(scale) |> resize(1 / scale, interpolate: :nearest) end @doc """ Pixelates an image or raise an exception. Pixelation is the process of reducing the image resolution while retaining the image dimensions. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `scale` is the scale factor to apply to the image when it is pixelated. This means that one "pixel" is `image width * scale`. The default is `#{@pixelate_scale}`. ### Returns * `{:ok, pixelated_image}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.14.0" @spec pixelate!(image :: Vimage.t(), scale :: number()) :: Vimage.t() | no_return() def pixelate!(%Vimage{} = image, scale \\ @pixelate_scale) when is_number(scale) and scale > 0 do case pixelate(image, scale) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Thumbnail an image to fit or fill a bounding box. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` or a pathname to an image file. * `length` is the integer length of the longest side of the resulting image after resizing. It c an also be of the form "x". That is, a string with the width and height separated by an `x`. The `` may be omitted in which case it is the same as providing an integer length. * `options` is a keyword list of options. ### Options * `:crop` determines if the strategy is "resize to fit" (crop is `:none`) or "resize to fill" (when the crop option is not `:none`). The value may be one of `:none`, `:center`, `:entropy`, `:attention`, `:low` or `:high`. The default is `:none`. See also `t:Image.Options.Crop.crop_focus/0`. * `:height` - Size to this height. Default is to maintain the image aspect ratio unless `resize: :force` is set. If `resize; :force` is set then the default `:height` is the height of `image`. * `:fit` sets the `:crop` and `:resize` options to align with the CSS [object-fit](https://www.w3schools.com/css/css3_object-fit.asp) property. Note that using the `:fit` option overwrites the options `:crop` and `:resize`. Since options are processed in the order in which they are presented, `:crop` and `:resize` may still be force set if they are after the `:fit` option. `:fit` takes one of the following values: * `:fill` - the image is resized to fill the given dimension. If necessary, the image will be stretched or squished to fit. This is the same as setting `resize: :force`. Note that is `:height` is not specified it will be the same height as `image`. * `:contain` - the image keeps its aspect ratio, but is resized to fit within the given dimension. This is the same as setting `crop: :none` and `resize: :both`. * `:cover` - the image keeps its aspect ratio and fills the given dimensions. The image will be clipped to fit. Clipping will default to `:center` unless `:crop` is already set to a value other than `:none`. This is the same as setting `crop: :center` (if `:crop` is not already set) and `resize: :both`. * `:autorotate` is a boolean indicating if the image should be autorotated based upon the image metadata. The default is `true`. * `:intent` indicates the rendering intent. The default is `:relative`. See also `t:Image.render_intent/0`. * `:export_icc_profile` indicates the icc profile to be attached to the resized image. The value may be an inbuilt profile (`:srgb`, `:p3` or `:cmyk`), the name of an icc profile in the systems profile directory or a full path to an icc profile file. The default is to export the icc profile of the resized image if there is one. * `:import_icc_profile` indicates the icc profile to be attached to the input image. The value may be an inbuilt profile (`:srgb`, `:p3` or `:cmyk`), the name of an icc profile in the systems profile directory or a full path to an icc profile file. The default is to use the icc profile of the input image if there is one. * `:linear` is a boolean indicating of the image should be resized in linear space. The default `false`. Shrinking is normally done in sRGB colourspace. Set linear to shrink in linear light colourspace instead. This can give better results, but can also be far slower, since tricks like JPEG shrink-on-load cannot be used in linear space. * `:resize` determines if an image may be only upsized, only downsized, both or a forced aspect ratio is applied. The value may be one of `:up`, `:down`, `:both` or `:force`. The default is `:both`. ### Returns * `{:ok, thumbnailed_image}` or * `{:error, reason}` """ @doc subject: "Resize" @spec thumbnail(Vimage.t(), length :: pos_integer(), options :: Thumbnail.thumbnail_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def thumbnail(image_or_path, length, options \\ []) def thumbnail(%Vimage{} = image, length, options) when is_size(length) do with {:ok, options} <- Thumbnail.validate_options(options) do Operation.thumbnail_image(image, length, options) end end @spec thumbnail(Path.t(), length :: pos_integer(), options :: Thumbnail.thumbnail_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def thumbnail(image_path, length, options) when is_binary(image_path) and is_size(length) do with {:ok, options} <- Thumbnail.validate_options(options), {:ok, _path} <- file_exists?(image_path) do Operation.thumbnail(image_path, length, options) else {:error, _reason} = error -> error end end @spec thumbnail( Vimage.t() | Path.t(), dimensions :: binary(), options :: Thumbnail.thumbnail_options() ) :: {:ok, Vimage.t()} | {:error, error_message()} def thumbnail(image_or_path, dimensions, options) when is_binary(dimensions) do with {:ok, length, options} <- Thumbnail.validate_dimensions(dimensions, options) do thumbnail(image_or_path, length, options) end end @doc """ Thumbnail an image to fit or fill a bounding box returning an image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` or a pathname to an image file. * `length` is the integer length of the longest side of the resulting image after resizing. It c an also be of the form "x". That is, a string with the width and height separated by an `x`. The `` may be omitted in which case it is the same as providing an integer length. * `options` is a keyword list of options. See `Image.thumbnail/3`. ### Returns * `image` or * raises an exception. """ @doc subject: "Resize" @spec thumbnail!(Vimage.t(), length :: pos_integer(), options :: Thumbnail.thumbnail_options()) :: Vimage.t() | no_return() def thumbnail!(image_or_path, length, options \\ []) def thumbnail!(%Vimage{} = image, length_or_dimensions, options) do case thumbnail(image, length_or_dimensions, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @spec thumbnail!(Path.t(), length :: pos_integer(), options :: Thumbnail.thumbnail_options()) :: Vimage.t() | no_return() def thumbnail!(image_path, length, options) when is_binary(image_path) and is_size(length) do with {:ok, options} <- Thumbnail.validate_options(options), {:ok, _path} <- file_exists?(image_path) do Operation.thumbnail!(image_path, length, options) else {:error, :enoent} -> raise Image.Error, {:enoent, image_path} end end @spec thumbnail!( Vimage.t() | Path.t(), dimensions :: binary(), options :: Thumbnail.thumbnail_options() ) :: Vimage.t() | no_return() def thumbnail!(image_or_path, dimensions, options) when is_binary(dimensions) do with {:ok, length, options} <- Thumbnail.validate_dimensions(dimensions, options) do thumbnail!(image_or_path, length, options) end end @doc """ Make a circular image intended to be used as an avatar image. The image is resized, a circular mask is applied and all metadata is removed from the image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `size` is the diameter of the resulting image after resizing. The default value is `#{@default_avatar_size}`. * `options` is a keyword list of options. See `Image.resize/3` for the valid options. ### Returns * `{:ok, avatar_image}` or * `{:error, reason}` """ @doc subject: "Generator" @spec avatar(Vimage.t(), size :: pos_integer(), options :: Options.Avatar.avatar_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def avatar(image, size \\ @default_avatar_size, options \\ []) def avatar(%Vimage{} = image, size, options) when is_size(size) do with {:ok, options} <- Options.Avatar.validate_options(options) do {:ok, image} = Operation.thumbnail_image(image, size, options) circular_mask_and_remove_meta(image) end end def avatar(image_path, size, options) when is_binary(image_path) and is_size(size) do with {:ok, options} <- Options.Avatar.validate_options(options), {:ok, image_path} = file_exists?(image_path) do {:ok, image} = Operation.thumbnail(image_path, size, options) circular_mask_and_remove_meta(image) end end defp circular_mask_and_remove_meta(image) do {:ok, image} = circle(image) remove_metadata(image) end @doc """ Make a circular image intended to be used as an avatar image returning an image or raising an exception. The image is resized, a circular mask is applied and all metadata is removed from the image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `size` is the diameter of the resulting image after resizing. The default value is `#{@default_avatar_size}`. * `options` is a keyword list of options. See `Image.resize/3` for the valid options. ### Returns * `avatar_image` or * raises an exception. """ @doc subject: "Generator" @spec avatar!(Vimage.t(), size :: pos_integer(), options :: Options.Avatar.avatar_options()) :: Vimage.t() | no_return() def avatar!(%Vimage{} = image, size \\ @default_avatar_size, options \\ []) do case avatar(image, size, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Crop an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `left` is the top edge of crop area as an integer or a float in the range `-1.0..1.0`. If `left` is an integer it is the absolute number of pixels. If `left` a float is fraction of the width of the image. If `left` is positive it is relative to the left edge of the image. If it is negative it is relative to the right edge of the image. * `top` is the top edge of crop area as an integer or a float in the range `-1.0..1.0`. If `top` is an integer it is the absolute number of pixels. If `top` is a float is fraction of the height of the image. If `top` is positive it is relative to the top edge of the image. If it is negative it is relative to the bottom edge of the image. * `width` is the width of area remaining as a positive integer or float in the range `0.0..1.0`. If `width` is an integer it is the absolute nunber of pixels. If `width` is a float it is the fraction of the original image width. * `height` is the width of area remaining as a positive integer or float in the range `0.0..1.0`. If `height` is an integer it is the absolute nunber of pixels. If `height` is a float it is the fraction of the original image height. ### Notes * `left` is 0-indexed. That is, the leftmost edge of the image starts at `0`. * `top` is 0-indexed. That is, the topmost edge of the image starts at `0`. ### Returns * `{:ok, cropped_image}` or * `{:error, reason}` """ @doc subject: "Resize" @spec crop(Vimage.t(), integer(), integer(), pos_integer(), pos_integer()) :: {:ok, Vimage.t()} | {:error, error_message()} def crop(%Vimage{} = image, left, top, width, height) when is_box(left, top, width, height) and left >= 0 and top >= 0 do Operation.extract_area(image, left, top, width, height) end def crop(%Vimage{} = image, left, top, width, height) when is_box(left, top, width, height) and left < 0 and top >= 0 do left = width(image) + left - width Operation.extract_area(image, left, top, width, height) end def crop(%Vimage{} = image, left, top, width, height) when is_box(left, top, width, height) and left >= 0 and top < 0 do top = height(image) + top - height Operation.extract_area(image, left, top, width, height) end def crop(%Vimage{} = image, left, top, width, height) when is_box(left, top, width, height) and left < 0 and top < 0 do left = width(image) + left - width top = height(image) + top - height Operation.extract_area(image, left, top, width, height) end def crop(%Vimage{} = image, left, top, width, height) do with {left, top, width, height} <- Options.Crop.normalize_box(dims(image), left, top, width, height) do crop(image, left, top, width, height) end end defp dims(%Vimage{} = image) do {width(image), height(image)} end @doc """ Crop an image returning a cropped image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `left` is the left edge of extract area as a positive integer. * `top` is the top edge of extract area as an integer. If `top` is positive it is relative to the top of the image. If it is negative it is relative to the bottom of the image. * `width` is the width of extract area as a positive integer. * `height` is the height of extract area as a positive integer. ### Returns * `cropped_image` or * raises an exception. """ @doc subject: "Resize" @spec crop!(Vimage.t(), integer(), integer(), pos_integer(), pos_integer()) :: Vimage.t() | no_return def crop!(%Vimage{} = image, left, top, width, height) do case crop(image, left, top, width, height) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Normalize an image by expanding the luninance of an image to cover the full dynamic range. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, normalized_image}` or * `{:error, reason}`. """ @doc subject: "Operation", since: "0.23.0" @min_luminance 1.0 @max_luminance 99.0 @spec normalize(image :: Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def normalize(%Vimage{} = image) do with {:ok, lab_image} <- to_colorspace(image, :lab) do luminance = lab_image[0] min = Operation.percent!(luminance, @min_luminance) max = Operation.percent!(luminance, @max_luminance) normalize_if_possible(image, lab_image, luminance, min, max) end end defp normalize_if_possible(image, lab_image, luminance, min, max) when abs(max - min) > 1 do without_alpha_band(image, fn image -> original_interpretation = interpretation(image) chroma = Operation.extract_band!(lab_image, 1, n: 2) f = 100.0 / (max - min) a = -(min * f) luminance |> Operation.linear!([f], [a]) |> bandjoin!(chroma) |> to_colorspace(original_interpretation) end) end defp normalize_if_possible(image, _lab_image, _luminance, _min, _max) do image end @doc """ Normalize an image by expanding the luninance of an image to cover the full dynamic range. Raises an exception on error. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `normalized_image` or * raises an exception. """ @doc subject: "Operation", since: "0.23.0" @spec normalize!(image :: Vimage.t()) :: Vimage.t() | no_return() def normalize!(%Vimage{} = image) do case normalize(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Scales each band of an image to fit the full dynamic range. Unlike `Image.normalize/1`, each band is scaled separately. The function finds the image histogram, searches for thresholds which will select #{inspect(@level_trim_percent)}% and #{inspect(1 - @level_trim_percent)}% of pixels in each image band, then rescales the image so that those pixel values become `0` and `255`. The scaling is performed in the `:srgb` color space but the image is converted back to its original color space after levelling. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, auto_levelled_image}` or * `{:error, reason}`. """ # Implemented based upon https://stackoverflow.com/questions/59666277/remove-color-cast-using-libvips @doc subject: "Operation", since: "0.23.0" @spec autolevel(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def autolevel(%Vimage{} = image) do use Image.Math with_colorspace(image, :srgb, fn image -> bands = image |> Operation.hist_find!() |> split_bands() low = Enum.map(bands, &level_percent(&1, @level_trim_percent)) high = Enum.map(bands, &level_percent(&1, 100 - @level_trim_percent)) scale = for {h, l} <- Enum.zip(high, low), do: 255.0 / (h - l) scaled = (image - low) * scale image = Operation.cast!(scaled, :VIPS_FORMAT_UCHAR) {:ok, image} end) end @doc """ Scales each band of an image to fit the full dynamic range. Unlike `Image.normalize/1`, each band is scaled separately. Raises an exception on error. The function finds the image histogram, searches for thresholds which will select #{inspect(@level_trim_percent)}% and #{inspect(1 - @level_trim_percent)}% of pixels in each image band, then rescales the image so that those pixel values become `0` and `255`. The scaling is performed in the `:srgb` color space but the image is converted back to its original color space after levelling. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `auto_levelled_image` or * raises an exception. """ @doc subject: "Operation", since: "0.23.0" @spec autolevel!(Vimage.t()) :: Vimage.t() | no_return() def autolevel!(%Vimage{} = image) do case autolevel(image) do {:ok, leveled} -> leveled {:error, reason} -> raise Image.Error, reason end end defp level_percent(hist, percentage) do use Image.Math norm = hist |> Operation.hist_cum!() |> Operation.hist_norm!() {:ok, {_c, r, _other}} = Operation.profile(norm > width(norm) * percentage / 100) Operation.avg!(r) end @doc """ Trims an image to the bounding box of the non-background area. Any alpha is flattened out, then the image is median-filtered, all the row and column sums of the absolute difference from background are calculated in a single pass. Then the first row or column in each of the four directions where the sum is greater than threshold gives the bounding box that is used to define the crop area. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:background` is the color to be considered the background color. The default is automatically detected by averaging the pixels at the top left of the image. * `:threshold` is the integer threshold (or color similarity) that is applied when determining the bounds of the non-background area. The default is `10`. The default value means only a small color background color range is considered. Increasing the threshold value maybe required. ### Returns * `{:ok, cropped_image}` which is the image cropped to the bounding box of the non-background area. * `{:error, reason}`. Reason may be `:uncropped` which means the image was considered to be only the background color. """ @doc subject: "Resize", since: "0.23.0" @spec trim(image :: Vimage.t(), options :: Options.Trim.trim_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def trim(%Vimage{} = image, options \\ []) do with {:ok, options} <- Options.Trim.validate_options(options) do background = maybe_calculate_color(image, options.background) threshold = options.threshold case Vix.Vips.Operation.find_trim(image, background: background, threshold: threshold) do {:ok, {_left, _top, 0, 0, _other}} -> {:error, :uncropped} {:ok, {left, top, width, height, _other}} -> Image.crop(image, left, top, width, height) error -> error end end end @doc """ Trims an image to the bounding box of the non-background area. Any alpha is flattened out, then the image is median-filtered, all the row and column sums of the absolute difference from background are calculated in a single pass. Then the first row or column in each of the four directions where the sum is greater than threshold gives the bounding box that is used to define the crop area. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:background` is the color to be considered the background color. The default is automatically detected by averaging the pixels at the top left of the image. * `:threshold` is the integer threshold (or color similarity) that is applied when determining the bounds of the non-background area. The default is `10`. The default value means only a small color background color range is considered. Increasing the threshold value maybe required. ### Returns * `cropped_image` which is the image cropped to the bounding box of the non-background area or * raises an exception. """ @doc subject: "Resize", since: "0.23.0" @spec trim!(image :: Vimage.t(), options :: Options.Trim.trim_options()) :: Vimage.t() | no_return() def trim!(%Vimage{} = image, options \\ []) do case trim(image, options) do {:ok, trimmed} -> trimmed {:error, reason} -> raise Image.Error, reason end end @doc """ Flatten an alpha layer out of an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, flattened_image}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.23.0" @spec flatten(image :: Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def flatten(%Vimage{} = image) do Vix.Vips.Operation.flatten(image) end @doc """ Flatten an alpha layer out of an image or raises an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `flattened_image` or * raises an exception """ @doc subject: "Operation", since: "0.23.0" @spec flatten!(image :: Vimage.t()) :: Vimage.t() | no_return() def flatten!(%Vimage{} = image) do case flatten(image) do {:ok, flattened} -> flattened {:error, reason} -> raise Image.Error, reason end end @doc """ Dilate an image mask, adding a pixels to the edge of the mask. Mask is used in the sense of an image on a transparent background. The results on other image types is undefined. The added pixels are the same color as the edge pixels in the mask. ### Note Dilate works for any non-complex image type, with any number of bands. The input is expanded by copying edge pixels before performing the operation so that the output image has the same size as the input. Edge pixels in the output image are therefore only approximate. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `pixels` is a positive integer number of pixels to dilate. The default is `1`. ### Returns * `{:ok, dilated_mask}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.23.0" @spec dilate(image :: Vimage.t(), pixels :: pos_integer) :: {:ok, Vimage.t()} | {:error, error_message} def dilate(image, pixels \\ 1) when is_integer(pixels) and pixels > 0 do Enum.reduce_while(1..pixels, {:ok, image}, fn _pixel, {:ok, image} -> {:cont, Vix.Vips.Operation.rank(image, 3, 3, 8)} _pixel, {:error, reason} -> {:halt, {:error, reason}} end) end @doc """ Dilate an image mask, adding a pixels to the edge of the mask or raising an exception. Mask is used in the sense of an image on a transparent background. The results on other image types is undefined. The added pixels are the same color as the edge pixels in the mask. ### Note Dilate works for any non-complex image type, with any number of bands. The input is expanded by copying edge pixels before performing the operation so that the output image has the same size as the input. Edge pixels in the output image are therefore only approximate. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `pixels` is a positive integer number of pixels to dilate. The default is `1`. ### Returns * `dilated_mask` or * raises an exception """ @doc subject: "Operation", since: "0.23.0" @spec dilate!(image :: Vimage.t(), pixels :: pos_integer) :: Vimage.t() | no_return() def dilate!(%Vimage{} = image, pixels \\ 1) when is_integer(pixels) and pixels > 0 do case dilate(image, pixels) do {:ok, dilated} -> dilated {:error, reason} -> raise Image.Error, reason end end @doc """ Erode an image mask, removing pixels from the edge of the mask. Mask is used in the sense of an image on a transparent background. The results on other image types is undefined. ### Note Erode works for any non-complex image type, with any number of bands. The input is expanded by copying edge pixels before performing the operation so that the output image has the same size as the input. Edge pixels in the output image are therefore only approximate. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `pixels` is a positive integer number of pixels to dilate. The default is `1`. ### Returns * `{:ok, eroded_mask}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.23.0" @spec erode(image :: Vimage.t(), pixels :: pos_integer) :: {:ok, Vimage.t()} | {:error, error_message} def erode(image, pixels \\ 1) when is_integer(pixels) and pixels > 0 do Enum.reduce_while(1..pixels, {:ok, image}, fn _pixel, {:ok, image} -> {:cont, Vix.Vips.Operation.rank(image, 3, 3, 0)} _pixel, {:error, reason} -> {:halt, {:error, reason}} end) end @doc """ Erode an image mask, removing pixels from the edge of the mask or raising an exception. Mask is used in the sense of an image on a transparent background. The results on other image types is undefined. ### Note Erode works for any non-complex image type, with any number of bands. The input is expanded by copying edge pixels before performing the operation so that the output image has the same size as the input. Edge pixels in the output image are therefore only approximate. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `pixels` is a positive integer number of pixels to dilate. The default is `1`. ### Returns * `eroded_mask` or * raises an exception """ @doc subject: "Operation", since: "0.23.0" @spec erode!(image :: Vimage.t(), pixels :: pos_integer) :: Vimage.t() | no_return() def erode!(%Vimage{} = image, pixels \\ 1) when is_integer(pixels) and pixels > 0 do case erode(image, pixels) do {:ok, eroded} -> eroded {:error, reason} -> raise Image.Error, reason end end @doc """ Rotate an image clockwise (to the right) by a number of degrees. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `angle` is a `float` number of degrees to rotate in a clockwise direction. * `options` is a keyword list of options. ### Options * `:idy` is the vertical input displacement which defaults to `0.0` * `:idx` is the horizontal input displacement which defaults to `0.0` * `:ody` is the vertical output displacement which defaults to `0.0` * `:odx` is the horizontal output displacement which defaults to `0.0` * `:background` is the background color to be used for filling the blank areas of the image. The background is specified as a list of 3 or 4 float values depending on the image color space. ## Notes The displacement parameters cause the image canvas to be expanded and the image displaced, relative to the top left corner of the image, by the amount specified. The rules defining how the image canvas is expanded is not known to the author of `Image`. Experimentation will be required if you explore these options. ### Returns * `{:ok, rotated_image}` or * `{:error, reason}` """ @doc subject: "Operation" @spec rotate(image :: Vimage.t(), angle :: float(), options :: Options.Rotate.rotation_options()) :: {:ok, Vimage.t()} | {:error, error_message()} def rotate(%Vimage{} = image, angle, options \\ []) when is_number(angle) do with {:ok, options} <- Options.Rotate.validate_options(options) do Operation.rotate(image, angle, options) end end @doc """ Rotate an image clockwise (to the right) by a number of degrees. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `angle` is a `float` number of degrees to rotate in a clockwise direction. * `options` is a keyword list of options. See `Image.rotate/3`. ## Notes The displacement parameters cause the image canvas to be expanded and the image displaced, relative to the top left corner of the image, by the amount specified. The rules defining how the image canvas is expanded is not known to the author of `Image`. Experimentation will be required if you explore these options. ### Returns * `rotated_image` or * raises an exception. """ @doc subject: "Operation" @spec rotate!(image :: Vimage.t(), angle :: float(), options :: Options.Rotate.rotation_options()) :: Vimage.t() | no_return() def rotate!(%Vimage{} = image, angle, options \\ []) when is_number(angle) do case rotate(image, angle, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Rotate an image based upon the orientation information in an image's EXIF data. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, {auto_rotated_image, flags}}` or * `{:error, reason}` ### Flags Two flags are returned indicating what action was taken: * `:flip` which is a boolean indicating if the image was flipped or not and * `:angle` through which the image was rotated. This value will be one of `0`, `90`, `180` or `270` representing the degrees of rotation. """ @doc subject: "Operation" @spec autorotate(image :: Vimage.t()) :: {:ok, {Vimage.t(), Keyword.t()}} | {:error, error_message()} def autorotate(%Vimage{} = image) do case Operation.autorot(image) do {:ok, {image, flags}} -> {:ok, {image, decode_rotation_flags(flags)}} other -> other end end @rotation_encoding %{ VIPS_ANGLE_D0: 0, VIPS_ANGLE_D90: 90, VIPS_ANGLE_D180: 180, VIPS_ANGLE_D270: 270 } defp decode_rotation_flags(flags) do angle = Keyword.fetch!(flags, :angle) angle = Map.fetch!(@rotation_encoding, angle) Keyword.put(flags, :angle, angle) end @doc """ Rotate an image based upon the orientation information in an image's EXIF data. Returns a potentially rotated image or raises and exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `auto_rotated_image` or * raises an exception. """ @doc subject: "Operation" @spec autorotate!(image :: Vimage.t()) :: Vimage.t() | no_return() def autorotate!(image) do case autorotate(image) do {:ok, {image, _flags}} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Adds a concentric ripple effect to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, image_with_ripple}` or * `{:error, reason}` """ @dialyzer {:nowarn_function, {:ripple, 1}} @doc subject: "Operation" @spec ripple(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def ripple(%Vimage{} = image) do use Image.Math width = width(image) height = height(image) # this makes an image where pixel (0, 0) (at the top-left) has value [0, 0], # and pixel (image.width, image.height) at the bottom-right has value # [image.width, image.height] {:ok, index} = Operation.xyz(width, height) # make a version with (0, 0) at the centre, negative values up and left, # positive down and right center = index - [width / 2, height / 2] # to polar space, so each pixel is now distance and angle in degrees {:ok, polar} = Complex.polar(center) # scale sin(distance) by 1/distance to make a wavey pattern d = 10_000 * sin!(polar[0] * 3) / (1 + polar[0]) # and back to rectangular coordinates again to make a set of vectors we can # apply to the original index image {:ok, joined} = Operation.bandjoin([d, polar[1]]) {:ok, rectangular} = Complex.rectangular(joined) index = index + rectangular # finally, use our modified index image to distort the input! Operation.mapim(image, index) end @doc """ Adds a concentric ripple effect to an image returning an image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `image_with_ripple` or * raises an exception. """ @dialyzer {:nowarn_function, {:ripple!, 1}} @doc subject: "Operation" @spec ripple!(Vimage.t()) :: Vimage.t() | no_return() def ripple!(%Vimage{} = image) do case ripple(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Apply a circular mask to an image. The returned image has an alpha band masking the circular image. As a result, it is best saved to a format, like `.png` that supports alpha transparency. Note that `.jpg` files do not support alpha transparency. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, circular_image}` or * `{:error, reason}` """ @doc subject: "Mask" @spec circle(Vimage.t(), Keyword.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def circle(%Vimage{} = image, _options \\ []) do width = width(image) height = height(image) size = min(width, height) {:ok, mask} = mask(:circle, size, size) Operation.bandjoin([image, mask]) end @doc """ Apply a circular mask to an image returning an image or raising an exception. The returned image has an alpha band masking the circular image. As a result, it is best saved to a format, like `.png` that supports alpha transparency. Note that `.jpg` files do not support alpha transparency. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `circular_image` or * raises an exception. """ @doc subject: "Mask" @spec circle!(Vimage.t(), Keyword.t()) :: Vimage.t() | no_return() def circle!(%Vimage{} = image, options \\ []) do case circle(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Apply rounded corners to an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:radius` is the desired corner radius. The default is #{@default_round_corner_radius}. ### Returns * `{:ok, rounded_corner_image}` or * `{:error, reason}` """ @doc subject: "Generator" @spec rounded(Vimage.t(), Keyword.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def rounded(%Vimage{} = image, options \\ []) do options = Keyword.put_new(options, :radius, @default_round_corner_radius) width = width(image) height = height(image) {:ok, mask} = mask(:rounded_corners, width, height, options) Operation.bandjoin([image, mask]) end @doc """ Apply rounded corners to an image. Returns an image or raises an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. ### Options * `:radius` is the desired corner radius. The default is #{@default_round_corner_radius}. ### Returns * `rounded_corner_image` or * raises an exception. """ @doc subject: "Mask" @spec rounded!(Vimage.t(), Keyword.t()) :: Vimage.t() | no_return() def rounded!(%Vimage{} = image, options \\ []) do case rounded(image, options) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end # Create an image mask (alpha transparency) that can # then be applied to an image. # At some point this will become a public API. defp mask(type, width, height, options \\ []) defp mask(:circle, diameter, diameter, _options) do centre = div(diameter, 2) svg = """ """ {:ok, {circle, _flags}} = Operation.svgload_buffer(svg) Operation.extract_band(circle, alpha_band(circle)) end defp mask(:rounded_corners, width, height, options) do radius = Keyword.get(options, :radius, @default_round_corner_radius) svg = """ """ {:ok, {mask, _flags}} = Operation.svgload_buffer(svg) Operation.extract_band(mask, alpha_band(mask)) end @doc """ Minimize metadata by keeping only the artist and copyright (if available). Removing metadata from an image can greatly reduce the overall size of an image. The proportional reduction is most noticeable with smaller images which are very common in web applications. Removing all metadata is a common option however with intellectual property concerns in mind this function will keep the artist and copyright fields if they exist in the original image. On a 1000x500px image exported from Adobe Lightroom with metadata intact, removing the metadata results in am approximately 50% saving in file size due to the removal of most EXIF and all IPTC and XMP metadata. Note that the minimized metadata is only materialized when the minimized image is saved to a file. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `{:ok, image_with_minimal_metadata}` or * `{:error, reason}` """ @doc subject: "Metadata" @spec minimize_metadata(image :: Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def minimize_metadata(%Vimage{} = image) do with {:ok, exif} <- exif(image), {:ok, image} <- remove_metadata(image) do Vimage.mutate(image, fn mut_img -> :ok = Exif.put_metadata(mut_img, :copyright, exif.copyright) :ok = Exif.put_metadata(mut_img, :artist, exif.artist) end) end end @doc """ Minimize metadata by keeping only the artist and copyright (if available). See also `Image.minimize_metadata/1`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * ` image_with_minimal_metadata` or * raises an exception. """ @doc subject: "Metadata" @spec minimize_metadata!(image :: Vimage.t()) :: Vimage.t() | no_return() def minimize_metadata!(%Vimage{} = image) do case minimize_metadata(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @metadata_fields %{ exif: "exif-data", xmp: "xmp-dataa", iptc: "iptc-data" } @metadata_names Map.keys(@metadata_fields) @doc """ Remove metadata from an image returning an updated image or raising an exception. This can significantly reduce the size of an image file. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `fields` is a list of metadata field names as strings. The default is all known field names. There are some special field names interpreted by `Image` to simplify metadata removal these are: * `:exif` which means remove all [EXIF](https://en.wikipedia.org/wiki/Exif) metadata * `:iptc` which means remove all [IPTC](https://en.wikipedia.org/wiki/IPTC_Information_Interchange_Model) metadata * `:xmp` which means remove all [xmp](https://en.wikipedia.org/wiki/Extensible_Metadata_Platform) data ## Notes * The available field names (ie. metadata fields) in an image can be returned with a call to `Vix.Vips.Image.header_field_names/1`. * Errors removing metadata fields is not propagated into the return for this function. Errors might occur when attempting to remove metadata fields that do not exist in the image. ### Returns * `{:ok, image_without_metadata_fields}` or * `{:error, reason}` """ @doc subject: "Metadata" @spec remove_metadata(Vimage.t(), list(binary() | atom())) :: {:ok, Vimage.t()} | {:error, error_message()} def remove_metadata(image, fields \\ []) def remove_metadata(image, field) when not is_list(field) do remove_metadata(image, List.wrap(field)) end def remove_metadata(image, []) do {:ok, fields} = Vimage.header_field_names(image) remove_metadata(image, fields) end def remove_metadata(%Vimage{} = image, fields) when is_list(fields) do Vimage.mutate(image, fn mut_img -> Enum.each(fields, &remove_meta(mut_img, &1)) end) end @doc """ Remove metadata from an image returning an image or raising an exception. This can significant;y reduce the size of an image file. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `fields` is a list of metadata field names as strings. The default is all known field names. There are some special field names interpreted by `Image` to simplify metadata removal these are: * `:exif` which means remove all [EXIF](https://en.wikipedia.org/wiki/Exif) metadata * `:iptc` which means remove all [IPTC](https://en.wikipedia.org/wiki/IPTC_Information_Interchange_Model) metadata * `:xmp` which means remove all [xmp](https://en.wikipedia.org/wiki/Extensible_Metadata_Platform) data ## Notes * The available field names (ie. metadata fields) in an image can be returned with a call to `Vix.Vips.Image.header_field_names/1`. * Errors removing metadata fields is not propagated into the return for this function. Errors might occur when attempting to remove metadata fields that do not exist in the image. ### Returns * `image_without_metadata_fields` or * raises an exception. """ @doc subject: "Metadata" @spec remove_metadata!(Vimage.t(), list(binary() | atom())) :: Vimage.t() | no_return() def remove_metadata!(image, fields \\ []) do case remove_metadata(image, fields) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end defp remove_meta(image, field) when is_atom(field) and field in @metadata_names do field = Map.fetch!(@metadata_fields, field) remove_meta(image, field) end defp remove_meta(image, field) do MutableImage.remove(image, field) end @y_band 1 @doc """ Create an image gradient of the same size as the given image. The gradient will interpolate from the `start` value to the `finish` value. The default `start` value is black with 100% transparency. The default `finish` value is black with 100% opacity. `start` and `finish` are given as an `rgb` triplet or quadruplet list of integers between `0` and `255`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `:start is an `rgb` triplet or quadruplet list of numbers between `0` and `255`. * `:finish is an `rgb` triplet or quadruplet list of numbers between `0` and `255`. ### Returns * `{:ok, gradient_image}` or * `{:error, reason}` ### Example # transparent_black and opaque_black are the default # start and finish values transparent_black = [0, 0, 0, 0] opaque_black = [0, 0, 0, 255] {:ok, gradient} = Image.linear_gradient(image, transparent_black, opaque_black) """ @dialyzer {:nowarn_function, {:linear_gradient, 1}} @dialyzer {:nowarn_function, {:linear_gradient, 2}} @dialyzer {:nowarn_function, {:linear_gradient, 3}} @start_color [0, 0, 0, 0] @finish_color [0, 0, 0, 255] @doc subject: "Generator" @spec linear_gradient(Vimage.t(), start :: Color.rgb_color(), finish :: Color.rgb_color()) :: {:ok, Vimage.t()} | {:error, error_message()} def linear_gradient(%Vimage{} = image, start \\ @start_color, finish \\ @finish_color) do use Image.Math width = width(image) height = height(image) {:ok, xyz} = Operation.xyz(width, height) {:ok, y} = Operation.extract_band(xyz, @y_band) # the distance image: 0 - 1 for the start to the end of the gradient d = y / height # and use it to fade the quads ... we need to tag the result as an RGB # image (d * finish + (1 - d) * start) |> Operation.copy(interpretation: :VIPS_INTERPRETATION_sRGB) end @doc """ Create an image gradient of the same size as the given image. Returns the gradient image or raises and exception. The gradient will interpolate from the `start` value to the `finish` value. The default `start` value is black with 100% transparency. The default `finish` value is black with 100% opacity. `start` and `finish` are given as an `rgb` triplet or quadruplet list of integers between `0` and `255`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `:start is an `rgb` triplet or quadruplet list of numbers between `0` and `255`. * `:finish is an `rgb` triplet or quadruplet list of numbers between `0` and `255`. ### Returns * `gradient_image` or * raises an exception. ### Example # transparent_black and opaque_black are the default # start and finish values transparent_black = [0, 0, 0, 0] opaque_black = [0, 0, 0, 255] gradient = Image.linear_gradient!(image, transparent_black, opaque_black) """ @dialyzer {:nowarn_function, {:linear_gradient!, 1}} @dialyzer {:nowarn_function, {:linear_gradient!, 2}} @dialyzer {:nowarn_function, {:linear_gradient!, 3}} @doc subject: "Generator" @spec linear_gradient!(Vimage.t(), start :: Color.rgb_color(), finish :: Color.rgb_color()) :: Vimage.t() | no_return() def linear_gradient!(%Vimage{} = image, start \\ @start_color, finish \\ @finish_color) do case linear_gradient(image, start, finish) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Returns a radial gradient as an image. This image might then be composited over another image. ### Arguments * `width` is the width of the gradient in pixels. * `height` is the height of the gradient in pixels. * `options` is a keyword list of options. The default is `[]`. ### Options * `:start` is the color from which the gradient starts in the center of the image. * `:finish` is the color at which the gradient finishes at the end of the gradient. * `:feather` is the slope of the gradient. That it, how quickly the gradient moves from the `:start` color to the `:finish` color. The valid range is `1..10` representing the smallest amount of feather (harshest transition) to the largest amount of feather (smoothest transition). ### Returns * `{:ok, gradient_image}` or * `{:error, reason}` """ @dialyzer {:nowarn_function, {:radial_gradient, 2}} @dialyzer {:nowarn_function, {:radial_gradient, 3}} @doc subject: "Generator", since: "0.6.0" @spec radial_gradient(width :: pos_integer(), height :: pos_integer(), options :: Keyword.t()) :: {:ok, %Vimage{}} | {:error, error_message()} def radial_gradient(width, height, options \\ []) do use Image.Math # Lab colors, not RGB # Since rgba 0 for transparency means # transparent, and 1 means opaque we # transition from black to white start = [0, 0, 0] finish = [100, 0, 0] max = max(width, height) # Take a number 1..10 feather = Keyword.get(options, :feather, 1) # Range of 0.5 to 3 -> probably linear radius = Keyword.get(options, :radius, 2) x = Operation.xyz!(width, height) - [width / 2, height / 2] d = (x[0] ** 2 + x[1] ** 2) ** 0.5 / (2 ** (feather * 0.05) * max / radius) out = d * finish + (d * -1 + 1) * start Operation.copy(out, interpretation: :VIPS_INTERPRETATION_LAB) end @doc """ Returns the dominant color of an image as an RBG triplet value in an integer list. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `options` is a keyword list of options. The default is `[]`. ### Options * `:bins` is an integer number of color frequency bins the image is divided into. The default is `10`. ### Returns * `[r, g, b]` """ @max_band_value 256 @doc subject: "Image info", since: "0.3.0" @spec dominant_color(Vimage.t(), Keyword.t()) :: Color.rgb_color() def dominant_color(%Vimage{} = image, options \\ []) do bins = Keyword.get(options, :bins, 10) bin_size = @max_band_value / bins midpoint = bin_size / 2 {:ok, histogram} = Operation.hist_find_ndim(image, bins: bins) {v, x, y} = Image.Math.maxpos(histogram) {:ok, pixel} = Operation.getpoint(histogram, x, y) z = Enum.find_index(pixel, &(&1 == v)) r = x * bin_size + midpoint g = y * bin_size + midpoint b = z * bin_size + midpoint [round(r), round(g), round(b)] end @doc """ Returns the histogram for an image. The histogram is returned as a `t:Vimage.t/0` that is a 255 by 255 image the same numbers of bands as the source image. ### Argument * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, histogram_image}` or * `{:error, reason}` ### Notes The returned image is is organized as a 256x256 pixel image with the same number of bands as the original image. Each pixel on the image returns the count of pixels in the original image that are in that 1/256th part of the image. """ @doc subject: "Operation", since: "0.3.0" @spec histogram(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def histogram(%Vimage{} = image) do image |> Operation.hist_find!() |> Operation.hist_norm() end @doc """ Returns the pixel value at the given image location. The returned pixel is a list of numbers where the length of the list is equal to the number of bands in the image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `x` is an integer offset from the top left of the image along the `x` (width) axis. The number must be in the range `0..width - 1`. * `y` is an integer offset from the top left of the image along the `y` (height) axis. The number must be in the range `0..height - 1`. ### Returns * `{:ok, pixel_value}` or * `{:error, reason}` """ @doc subject: "Operation", since: "0.3.0" @spec get_pixel(Vimage.t(), non_neg_integer(), non_neg_integer()) :: {:ok, Color.rgb_color()} | {:error, error_message()} def get_pixel(%Vimage{} = image, x, y) do Operation.getpoint(image, x, y) end @doc """ Mutate an image with through the given function. This funcation is a convenience wrapper around `Vix.Vips.Image.mutate/2`. """ @doc subject: "Operation", since: "0.7.0" @spec mutate(Vimage.t(), (Vix.Vips.MutableImage.t() -> any())) :: {:ok, Vimage.t()} | {:error, error_message()} def mutate(%Vimage{} = image, fun) when is_function(fun, 1) do Vimage.mutate(image, fun) end @doc """ Converts an image to the given colorspace. Available colorspaces are returned from `Image.Interpretation.known_interpretations/0`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `colorspace` is any known colorspace. See `Image.Interpretation.known_interpretations/0` for a list of the known colorspaces. ### Returns * `{;ok, image_in_new_colorspace}` or * `{:error, reason}` ### Example Image.to_colorspace(image, :bw) """ @doc subject: "Color" @spec to_colorspace(Vimage.t(), Interpretation.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def to_colorspace(%Vimage{} = image, colorspace) do with {:ok, colorspace} <- Interpretation.validate_interpretation(colorspace) do Vix.Vips.Operation.colourspace(image, colorspace) end end @doc """ Converts an impage to the given colorspace returning an image or raising an exception. Available colorspaces are returned from `Image.Interpretation.known_interpretations/0`. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `colorspace` is any known colorspace. See `Image.Interpretation.known_interpretations/0` for a list of the known colorspaces. ### Returns * `image_in_new_colorspace` or * raises an exception ### Example Image.to_colorspace!(image, :bw) """ @doc subject: "Color" @spec to_colorspace!(Vimage.t(), Interpretation.t()) :: Vimage.t() | no_return() def to_colorspace!(%Vimage{} = image, colorspace) do case to_colorspace(image, colorspace) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Convert image to polar coordinates. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, image_in_polar_coordinates}` or * `{:error, reason}` """ @dialyzer {:nowarn_function, {:to_polar_coordinates, 1}} @doc subject: "Operation" @spec to_polar_coordinates(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def to_polar_coordinates(%Vimage{} = image) do use Image.Math width = width(image) height = height(image) xy = Operation.xyz!(width, height) xy = xy - [width / 2.0, height / 2.0] scale = min(width, height) / width xy = xy * 2.0 / scale {:ok, index} = Complex.polar(xy) index = index * [1.0, height / 360.0] Operation.mapim(image, index) end @doc """ Convert image to polar coordinates returning an image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `image_in_polar_coordinates` or * raises an exception. """ @dialyzer {:nowarn_function, {:to_polar_coordinates!, 1}} @doc subject: "Operation" @spec to_polar_coordinates!(Vimage.t()) :: Vimage.t() | no_return() def to_polar_coordinates!(%Vimage{} = image) do case to_polar_coordinates(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Convert image to rectangular coordinates. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ## Notes Roundtrip to polar and back to rectangular coordinates displays some image distortion, likely due to rounding errors in float arithmetic. Further study is required. ### Returns * `{:ok, image_in_rectangular_coordinates}` or * `{:error, reason}` """ @dialyzer {:nowarn_function, {:to_rectangular_coordinates, 1}} @doc subject: "Operation" @spec to_rectangular_coordinates(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def to_rectangular_coordinates(%Vimage{} = image) do use Image.Math width = width(image) height = height(image) xy = Operation.xyz!(width, height) xy = xy * [1.0, 360.0 / height] {:ok, index} = Complex.rectangular(xy) scale = min(width, height) / width index = index * scale / 2.0 index = index + [width / 2.0, height / 2.0] Operation.mapim(image, index) end @doc """ Convert image to rectangular coordinates returning an image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ## Notes Roundtrip to polar and back to rectangular coordinates displays some image distortion, likely due to rounding errors in float arithmetic. Further study is required. ### Returns * `image_in_rectangular_coordinates` or * raises an exception. """ @dialyzer {:nowarn_function, {:to_rectangular_coordinates!, 1}} @doc subject: "Operation" @spec to_rectangular_coordinates!(Vimage.t()) :: Vimage.t() | no_return() def to_rectangular_coordinates!(%Vimage{} = image) do case to_rectangular_coordinates(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end if match?({:module, _module}, Code.ensure_compiled(Nx)) do @doc """ Converts an image into an [Nx](https://hex.pm/packages/nx) tensor. ### Arguments * `image` is any `t:Vimage.t/0` * `options` is a keyword list of options ### Options * `:shape` determines how the tensor is shaped. The valid values are: * `:whb` or `:whc` which leaves the tensor unchanged with the underlying data in `width, height, bands` shape. This is the default action. * `:hwc` or `:hwb` which reshapes the tensor to `height, width, channels` which is commonly use for machine learning models. ### Returns * An `t:Nx.Tensor.t/0` tensor suitable for use in the `Nx` library. ### Example iex> {:ok, image} = Vix.Vips.Operation.black(3, 3) iex> Image.to_nx(image, backend: Nx.BinaryBackend) {:ok, Nx.tensor([[[0], [0], [0]], [[0], [0], [0]], [[0], [0], [0]]], type: {:u, 8}, names: [:width, :height, :bands], backend: Nx.BinaryBackend)} """ @dialyzer {:nowarn_function, {:to_nx, 1}} @dialyzer {:nowarn_function, {:to_nx, 2}} @doc subject: "Matrix", since: "0.5.0" @spec to_nx(image :: Vimage.t(), options :: Keyword.t()) :: {:ok, Nx.Tensor.t()} | {:error, error_message()} def to_nx(%Vimage{} = image, options \\ []) do {to_shape, options} = Keyword.pop(options, :shape) with {:ok, tensor} <- Vix.Vips.Image.write_to_tensor(image), {:ok, shape, names} <- maybe_reshape_tensor(tensor, to_shape) do %Vix.Tensor{data: binary, type: type} = tensor binary |> Nx.from_binary(type, options) |> Nx.reshape(shape, names: names) |> wrap(:ok) end end @dialyzer {:nowarn_function, {:maybe_reshape_tensor, 2}} defp maybe_reshape_tensor(%Vix.Tensor{shape: shape, names: names}, nil), do: {:ok, shape, names} defp maybe_reshape_tensor(%Vix.Tensor{shape: shape, names: names}, :whb), do: {:ok, shape, names} defp maybe_reshape_tensor(%Vix.Tensor{shape: shape, names: names}, :whc), do: {:ok, shape, names} defp maybe_reshape_tensor(%Vix.Tensor{} = tensor, :hwb), do: maybe_reshape_tensor(tensor, :hwc) defp maybe_reshape_tensor(%Vix.Tensor{shape: {width, height, bands}}, :hwc) do {:ok, {height, width, bands}, [:height, :width, :channels]} end defp maybe_reshape_tensor(_tensor, shape) do {:error, "Invalid shape. Allowable shapes are :whb, :whc, :hwc and :hwb. Found #{inspect(shape)}"} end @doc """ Converts an [Nx](https://hex.pm/packages/nx) tensor into an image. ### Arguments * `tensor` is any three dimensional `t:Nx.Tensor.t/0`. * `options` is a keyword list of options. For valid options see `Nx.from_binary/2`. ### Returns * `{:ok, image}` or * `{:error, reason}` ### Notes In order to convert a tensor into an image it must satisfy these constraints: * It must have three dimensions. * It must have a tensor type that is compatible with `libvips` (most tensors will satisfy this requirement other than tensors whose type is complex). * The names of the axes must be `[:width, :height, any_other]` or `[:height, :width, any_other]`. ### Example iex> {:ok, image} = Vix.Vips.Operation.black(3, 3) iex> {:ok, tensor} = Image.to_nx(image) iex> {:ok, _image_2} = Image.from_nx(tensor) """ @doc subject: "Matrix", since: "0.5.0" @spec from_nx(tensor :: Nx.Tensor.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def from_nx(tensor) when is_struct(tensor, Nx.Tensor) do with {:ok, tensor_format} <- Image.BandFormat.image_format_from_nx(tensor) do case Nx.shape(tensor) do {width, height, bands} when bands in 1..5 -> binary = Nx.to_binary(tensor) Vix.Vips.Image.new_from_binary(binary, width, height, bands, tensor_format) shape -> shape_error(shape) end end end # TODO Needs to respect the image type when doing the # color channel order conversion (ie when its an RGB-A etc etc) # Same for interpretation (not every image is srgb!) if Code.ensure_loaded?(Evision) do @doc """ Converts an `Image` image to an [Evision]() image. Note that only images with 3 bands can be transferred to `eVision`. ### Arguments * `image` is any `t:Vimage.t/0` * `convert_to_bgr` is a boolean indicating if the color order should be converted from `RGB` to `BGR` which is the normal channel layout for OpenCV. The default is `true`. ### Returns * `{:ok, evision_image}` ### Notes * `Image` images have the shape `{width, height, bands}` whereas `Evision` images have the shape `{height, width, bands}` so this function transposes the dimensions to match. * `Image` data is arranged as `rgb` data elements whereas `Evision` requires the data to be in `bgr` order. This function also reorders the data appropriately. """ @dialyzer {:nowarn_function, {:to_evision, 2}} @doc subject: "Matrix", since: "0.9.0" def to_evision(%Vimage{} = image, convert_to_bgr \\ true) do with {:ok, tensor} <- to_nx(image), {width, height, bands} <- validate_transferable_image(image), %Evision.Mat{} = mat <- Evision.Mat.from_nx(tensor, {height, width, bands}), %Evision.Mat{} = mat <- Evision.Mat.last_dim_as_channel(mat) do mat = if convert_to_bgr, do: Evision.cvtColor(mat, Constant.cv_COLOR_RGB2BGR()), else: mat {:ok, mat} end end @doc """ Converts to an `Image` image from an `Evision.Mat` image. ### Arguments * `evision_image` is any `Evision.Mat` image. ### Returns * `{:ok, image}` ### Notes * `Image` images have the shape `{width, height, bands}` whereas `Evision` images have the shape `{height, width, bands}` so this function transposes the dimensions to match. * `Image` data is arranged as `rgb` data elements whereas `Evision` requires the data to be in `bgr` order. This function also reorders the data appropriately. """ @dialyzer {:nowarn_function, {:from_evision, 1}} @doc subject: "Matrix", since: "0.9.0" def from_evision(%Evision.Mat{} = evision_image) do with %Evision.Mat{} = mat <- Evision.cvtColor(evision_image, Constant.cv_COLOR_BGR2RGB()) do tensor = Evision.Mat.to_nx(mat) case Nx.shape(tensor) do {_, _, bands} when bands in 1..5 -> {height, width, bands} = Nx.shape(tensor) tensor |> Nx.reshape({width, height, bands}, names: [:height, :width, :bands]) |> from_nx() shape -> shape_error(shape) end end end end defp shape_error(shape) do {:error, "The tensor must have the shape {height, width, bands} with bands between" <> "1 and 5. Found shape #{inspect(shape)}"} end end @doc """ Returns a 512-bit difference hash as a binary. Image hashes can be used to compare the similarity of images. See `Image.hamming_distance/2`. dhash is generates a "difference hash" for a given image -- a perceptual hash based on Neal Krawetz's dHash algorithm in a [Hacker Factor](http://www.hackerfactor.com/blog/index.php?/archives/529-Kind-of-Like-That.html) blog entry. The code is adapted from the Ruby implementation in [dhash-vips](https://github.com/Nakilon/dhash-vips). ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `{:ok, 512-bit binary}` or * `{:error, reason}` """ @dialyzer {:nowarn_function, {:dhash, 1}} @dialyzer {:nowarn_function, {:dhash, 2}} @doc subject: "Metadata", since: "0.6.0" @spec dhash(image :: Vimage.t()) :: image_hash() def dhash(%Vimage{} = image, hash_size \\ 8) when is_integer(hash_size) and hash_size > 0 do alias Image.Math {:ok, convolution} = Image.Matrix.image_from_matrix([[1, -1]]) image |> pixelate_for_hash(hash_size) |> Operation.cast!(:VIPS_FORMAT_INT) |> Operation.conv!(convolution) |> crop!(1, 0, hash_size, hash_size) |> Math.greater_than!(0) |> Math.divide!(255) |> Operation.cast!(:VIPS_FORMAT_UCHAR) |> Vimage.write_to_binary() end defp pixelate_for_hash(%Vimage{} = image, hash_size) do image |> thumbnail!(hash_size + 1, height: hash_size, resize: :force) |> Operation.flatten!() |> to_colorspace!(:bw) |> Operation.extract_band!(0) end @doc false def convert_binary_to_hash(binary) do for <>, reduce: <<>> do acc -> <<_rest::bitstring-7, bit::bitstring>> = <> <> end end @doc """ Returns the hamming distance of two images or two image hashes. A [hamming distance](https://en.wikipedia.org/wiki/Hamming_distance) gives an indication of the similarity of two images. In general, a hamming distance of less than `10` indicates that the images are very similar. A distance of less than `20` suggests the images are quite similar. Any other distance suggests the images have little in common. ### Arguments * `image_1` is any `t:Vix.Vips.Image.t/0` * `image_2` is any `t:Vix.Vips.Image.t/0` Alternatively, both arguments may be image hashes returned by `Image.dhash/1`. Both arguments must be of the same type. ### Returns * `{:ok, hamming_distance}` where hamming distance is a positive integer or * `{:error, reason}`. """ @doc subject: "Operation", since: "0.6.0" @spec hamming_distance(image_1 :: Vimage.t(), image_2 :: Vimage.t()) :: {:ok, non_neg_integer()} | {:error, error_message()} def hamming_distance(%Vimage{} = image_1, %Vimage{} = image_2) do with {:ok, hash_1} <- dhash(image_1), {:ok, hash_2} <- dhash(image_2) do hamming_distance(hash_1, hash_2) end end @spec hamming_distance(image_hash(), image_hash()) :: {:ok, non_neg_integer()} | {:error, error_message()} def hamming_distance(hash_1, hash_2) when is_binary(hash_1) and is_binary(hash_2) do hash_1 |> :crypto.exor(hash_2) |> count_ones() |> wrap(:ok) end defp count_ones(binary) when is_binary(binary) do for(<>, do: bit) |> Enum.sum() end # Prebuilt binaries may not have this function because # libvips may not have the dependencies required. if Code.ensure_loaded?(Vix.Vips.Operation) && function_exported?(Vix.Vips.Operation, :fwfft!, 1) do @doc """ Returns the fast fourier transform (fft) of the given image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `{:ok, fft_image}` or * `{:error, reason}` ### Example Image.fft(image) """ @doc subject: "Operation" @spec fft(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def fft(%Vimage{} = image) do image |> to_colorspace!(:bw) |> Operation.fwfft!() |> Operation.wrap!() |> Operation.abs() end @doc """ Returns the fast fourier transform (fft) of the given image returning an image or raising an exception. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `fft_image` or * raises an exception ### Example Image.fft!(image) """ @doc subject: "Operation" @spec fft!(Vimage.t()) :: Vimage.t() | no_return() def fft!(%Vimage{} = image) do case fft(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Attempts top determine the distance from the perpendicular for a given image. The principle is that rotating the image by the skew angle should return an image in the upright position. The results are very image sensitive and perfect results are not guaranteed. The algorithm is an implementation of [this stackoverflow post](https://stackoverflow.com/questions/52474645/improve-a-picture-to-detect-the-characters-within-an-area/52502597#52502597). ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `skew_angle` which is a float number of degrees the image is tilted from the upright. #### Example skew_angle = skew_angle(image) Image.rotate(image, skew_angle) """ @dialyzer {:nowarn_function, {:skew_angle, 1}} @doc subject: "Operation" @spec skew_angle(Vimage.t()) :: float() def skew_angle(%Vimage{} = image) do {_columns, rows, []} = image |> fft!() |> to_rectangular_coordinates!() |> Operation.project!() {_v, _x, y} = rows |> Operation.gaussblur!(10.0) |> Image.Math.maxpos() # and turn to an angle in degrees we should counter-rotate by 270 - 360 * y / height(rows) end end @doc """ Convert an image into a mask. Takes an image, extracts its alpha channel which holds the opacity information and inverts the content. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `{:ok, mask}` or * `{:error, reason}` """ @doc subject: "Mask" @spec convert_to_mask(Vimage.t()) :: {:ok, Vimage.t()} | {:error, error_message()} def convert_to_mask(%Vimage{} = image) do if alpha_band = alpha_band(image) do {:ok, mask} = Operation.extract_band(image, alpha_band) Operation.invert(mask) else {:error, "Image has no alpha band"} end end @doc """ Convert an image into a mask returning an image or raising an exception. Takes an image, extracts its alpha channel which holds the opacity information and inverts the content. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * `mask` image or * raises an exception """ @doc subject: "Mask" @spec convert_to_mask!(Vimage.t()) :: Vimage.t() | no_return() def convert_to_mask!(%Vimage{} = image) do case convert_to_mask(image) do {:ok, image} -> image {:error, reason} -> raise Image.Error, reason end end @doc """ Split the image into a list of its component bands. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` ### Returns * a list of single band images extracted from `image`. """ @doc subject: "Split and join", since: "0.13.0" @spec split_bands(Vimage.t()) :: [Vimage.t()] def split_bands(%Vimage{} = image) do for i <- 0..max_band_index(image), do: image[i] end @doc """ Returns a boolean based upon whether a given image has an alpha band. The determination is a heuristic so certainty cannot be guaranteed. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * `true` or `false` """ @doc subject: "Image info" @spec has_alpha?(Vimage.t()) :: boolean() def has_alpha?(%Vimage{} = image) do Vimage.has_alpha?(image) end @doc """ Returns the band number of the alpha channel of an image, or nil if it doesn't have one. The determination is a heuristic so certainty cannot be guaranteed. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Returns * An integer in the range `1..4` depending on the image interpretation. Returns `nil` if there is no alpha band. The integer is a 0-based offset and can therefore be directly used to access the band. For example `image[alpha_band(image)]`. """ @doc subject: "Split and join" @spec alpha_band(Vimage.t()) :: 1..4 | nil def alpha_band(%Vimage{} = image) do if has_alpha?(image) do Vimage.bands(image) - 1 else nil end end @doc """ Execute a function over the image without its alpha band (if any) ensuring the alpha band is replaced when the function returns. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. * `fun` is any 1-arity function that is required to return `{:ok, image}` or `{:error, reason}`. ### Returns * `{:ok, image}` or * `{:error, reason}` """ @spec without_alpha_band(Vimage.t(), (Vimage.t() -> {:ok, Vimage.t()} | {:error, error_message})) :: {:ok, Vimage.t()} | {:error, error_message} def without_alpha_band(%Vimage{} = image, fun) when is_function(fun, 1) do {without_alpha, alpha} = split_alpha(image) case fun.(without_alpha) do {:ok, image} -> {:ok, bandjoin!(image, alpha)} {:error, reason} -> {:error, reason} end end def with_colorspace(image, colorspace, fun) do original_colorspace = interpretation(image) with {:ok, converted} <- to_colorspace(image, colorspace) do case fun.(converted) do {:ok, image} -> to_colorspace(image, original_colorspace) other -> other end end end # The iTerm2 Image Preview protocol is: # ESC ] 1337 ; File = [arguments] : base-64 encoded file contents ^G # Decimal 27 @esc <<0x1B>> # Decimal 7 @ctrl_g <<0x07>> @default_max_width "1000" @max_width_env_key "IMAGE_PREVIEW_MAX_WIDTH" @doc """ Outputs an inline preview of an image to an iTerm2 terminal. Only iTerm2 terminal windows are supported. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` or a tuple of the form `{:ok, image}`. ### Returns * The `image` parameter as provided with the side effect of emitting an image preview on an iTerm terminal. ### Notes * The function `Image.p/1` is delegated to this function. * The maximum width of the preview can be set by the environment variable `#{@max_width_env_key}`. The default is `1_000` pixels wide. If the width of the image is greater than the maximum it will be resized to the maximum width for the preview. * Intended to be used as shortcut in `iex`. It can be included in an `.iex.exs` file: # .iex.exs import_if_available(Image, only: [preview: 1]) """ @doc subject: "Display", since: "0.13.0" @spec preview(Vimage.t() | {:ok, Vimage.t()}) :: Vimage.t() | {:ok, Vimage.t()} | {:error, error_message()} def preview(%Vimage{} = image) do with {:ok, "iTerm2"} <- supported_terminal(System.get_env("LC_TERMINAL")) do {prelude, epilog} = get_prelude_epilog_for_term(System.get_env("TERM")) {:ok, image} = maybe_resize_to_fit(image, shape(image)) with {:ok, binary} <- Vix.Vips.Image.write_to_buffer(image, ".png") do encoded_image = Base.encode64(binary, padding: true) bin_size = byte_size(binary) head = prelude <> "]1337;File=size=#{bin_size};inline=1:" IO.write(head <> encoded_image <> epilog) image end end end def preview({:ok, %Vimage{} = image}) do {:ok, preview(image)} end @doc """ Outputs an inline preview of an image to an iTerm2 terminal. Only iTerm2 terminal windows are supported. Delegates to `Image.preview/1` ### Arguments * `image` is any `t:Vix.Vips.Image.t/0`. ### Notes * The function `Image.p/1` is delegated to this function. * The maximum width of the preview can be set by the environment variable `#{@max_width_env_key}`. The default is `1_000` pixels wide. If the width of the image is greater than the maximum it will be resized to the maximum width for the preview. * Intended to be used as shortcut in `iex`. It can be included in `.iex.exs` file: # .iex.exs import_if_available(Image, only: [p: 1]) """ @doc subject: "Display", since: "0.13.0" @spec p(Vimage.t()) :: Vimage.t() | {:error, error_message()} def p(image) do preview(image) end defp supported_terminal("iTerm2" = terminal) do {:ok, terminal} end defp supported_terminal(terminal) do {:error, "Unsupported terminal #{inspect(terminal)}. iTerm2 is required for inline image display."} end defp get_prelude_epilog_for_term("screen" <> _rest) do {@esc <> "Ptmux;" <> @esc <> @esc, @ctrl_g <> @ctrl_g <> "\\\r\n"} end defp get_prelude_epilog_for_term(_term) do {@esc, @esc <> "\\" <> "\r\n"} end defp maybe_resize_to_fit(image, {width, _height, _bands}) do max_width = @max_width_env_key |> System.get_env(@default_max_width) |> String.to_integer() if width > max_width do thumbnail(image, max_width) else {:ok, image} end end @doc """ Returns the number of operating system threads available for use by `libvips`. By default the number of threads will be the number of cores in the system. Since image processing is CPU intensive it may be appropriate to reduce the number of threads to be available to reduce the risk of CPU starvation for other workloads. See `Image.put_concurrency/1`. """ @doc subject: "Configuration" @spec get_concurrency :: pos_integer() def get_concurrency do Vix.Vips.concurrency_get() end @doc """ Sets the number of available threads for use by `libvips`. By default this is the same as the number of cores in the system. Reducing this number may prevent CPU starvation for other workloads. ### Arguments * `concurrency` is a positive integer denoting the maximum number of threads that `libvips` will use for concurrency. ### Returns * `{:ok, updated_concurrency}` """ @doc subject: "Configuration" @spec put_concurrency(pos_integer()) :: pos_integer() def put_concurrency(concurrency) when is_integer(concurrency) and concurrency > 0 do :ok = Vix.Vips.concurrency_set(concurrency) get_concurrency() end @doc """ Returns the aspect of an image. ### Arguments * `image` is any `t:Vix.Vips.Image.t/0` * `options` is a keyword list of options ### Options * `:square_ratio` indicates when an image is to be considered square. It is a floating point indicator of the ratio between the width and height below which the image is considered square. The default is `0.0` meaning that the dimensions must be exactly equal in order for the image to be considered square. ### Returns * Either `:landscape`, `:portrait` or `:square`. ### Example iex> puppy = Image.open!(Path.expand("test/support/images/puppy.webp")) iex> Image.aspect(puppy, square_ratio: 0.05) :landscape """ @doc subject: "Image info" @spec aspect(Vimage.t()) :: aspect() def aspect(%Vimage{} = image, options \\ []) do square_ratio = Keyword.get(options, :square_ratio, @square_when_ratio_less_than) width = Image.width(image) height = Image.height(image) ratio = abs(1.0 - width / height) cond do ratio <= square_ratio -> :square width > height -> :landscape height > width -> :portrait end end @doc """ Returns the version of `libvips` in operation. """ @doc subject: "Configuration" @spec vips_version :: {:ok, Version.t()} def vips_version do Vix.Vips.version() |> Version.parse() end ### Helpers defp wrap(item, atom) do {atom, item} end defp build_option_string(options, other_options) do "[" <> options <> "," <> join_options(other_options) <> "]" end defp build_option_string(options) do "[" <> join_options(options) <> "]" end defp join_options(options) do Enum.map_join(options, ",", fn {k, v} -> "#{k}=#{v}" end) end defp file_exists?(path) do if File.exists?(path, [:raw]), do: {:ok, path}, else: {:error, :enoent} end defp xy_offset(%Vimage{} = _image, _overlay, x, y) when is_number(x) and is_number(y) do {x, y} end defp xy_offset(%Vimage{} = base_image, %Vimage{} = overlay, x, y) do x = offset_from(x, Image.width(base_image), Image.width(overlay)) y = offset_from(y, Image.height(base_image), Image.height(overlay)) {x, y} end # Used for x offset defp offset_from(:left, _base_size, _overlay_size), do: 0 defp offset_from(:right, base_size, overlay_size), do: base_size - overlay_size defp offset_from(:center, base_size, overlay_size), do: div(base_size, 2) - div(overlay_size, 2) # Used for y offset defp offset_from(:top, _base_size, _overlay_size), do: 0 defp offset_from(:bottom, base_size, overlay_size), do: base_size - overlay_size defp offset_from(:middle, base_size, overlay_size), do: div(base_size, 2) - div(overlay_size, 2) defp offset_from(other, _base_size, _overlay_size) do raise ArgumentError, """ Invalid offset position #{inspect(other)}. Valid positions are :left, :right, :middle, :top, :bottom, :center """ end @doc false def validate_transferable_image(image) do case shape(image) do {width, height, bands} when bands == 3 -> {width, height, bands} other -> {:error, "Only images with three bands can be transferred to eVision. " <> "Found an image of shape #{inspect(other)}"} end end @doc false def bumblebee_configured? do Enum.reduce_while([Nx, EXLA, Bumblebee], true, fn mod, flag -> case Code.ensure_compiled(mod) do {:module, _module} -> {:cont, flag} _other -> {:halt, false} end end) end @doc false def evision_configured? do match?({:module, _module}, Code.ensure_compiled(Evision)) end end