ExPdfium.Bitmap (ExPdfium v0.4.2)

A raw pixel bitmap — produced by ExPdfium.render_page/3 (a rendered page) or ExPdfium.image_data/3 (a decoded embedded image).

data is a raw pixel buffer. format records the byte order and channel count so consumers can interpret it: :rgba/:bgra (4 channels), :bgrx (4, with a padding byte), :bgr (3), or :gray (1). render_page/3 yields :rgba (default) or :bgra; an image decoded with image_data/3 keeps its native pdfium format. With width, height, and stride (bytes per row), the buffer feeds directly into e.g. Vix.Vips.Image.new_from_binary/5 — or use to_vix/1, which reads format and hands back a correctly-interpreted image (band count + BGR→RGB), so you don't have to branch on the channel order yourself.

Summary

Types

format()

t()

Functions

to_vix(bitmap)

Convert this bitmap into a correctly-interpreted Vix.Vips.Image.

Types

format()

@type format() :: :rgba | :bgra | :bgrx | :bgr | :gray

t()

@type t() :: %ExPdfium.Bitmap{
  data: binary(),
  format: format(),
  height: non_neg_integer(),
  stride: non_neg_integer(),
  width: non_neg_integer()
}

Functions

to_vix(bitmap)

@spec to_vix(t()) :: {:ok, struct()} | {:error, :vix_not_loaded | :vix_failed}

Convert this bitmap into a correctly-interpreted Vix.Vips.Image.

Reads format so the caller doesn't have to: it sets the right band count and reorders pdfium's native BGR channel order into RGB (:bgr, :bgrx, :bgra), drops the padding byte of :bgrx, and passes :rgba/:gray straight through. Row stride padding is stripped first. The result is ready for the rest of a Vix/Image pipeline (resize, Image.write_to_file/2, …):

{:ok, bmp} = ExPdfium.image_data(doc, 0, 2)
{:ok, img} = ExPdfium.Bitmap.to_vix(bmp)
:ok = Vix.Vips.Image.write_to_file(img, "out.png")

Vix is an optional dependency. If it isn't in your project, this returns {:error, :vix_not_loaded} (add {:vix, "~> 0.39"} to your deps). Returns {:error, :vix_failed} if libvips rejects the buffer.