Changelog

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All notable changes to PaperForge will be documented in this file.

The format is based on Keep a Changelog, and this project follows Semantic Versioning.

0.2.0 - 2026-07-26

Added

Document configuration

  • Added document-level configuration through PaperForge.new/1.
  • Added the :compress document option.
  • Enabled Flate stream compression by default.
  • Added support for disabling compression with PaperForge.new(compress: false).
  • Added the :pdf_version document option with "1.7" as the default.
  • Added validation for unsupported document options.
  • Added validation for invalid compression and PDF version values.

Stream compression

  • Added PaperForge.Compression.
  • Added stream compression using the PDF /FlateDecode filter.
  • Added support for streams with zero, one, or multiple filters.
  • Added automatic insertion of the /Filter entry in stream dictionaries.
  • Added compression support for page content streams.
  • Preserved JPEG image data without recompressing it.
  • Added tests that decompress Flate streams and verify their actual commands.

Fonts

  • Added a built-in font registry.
  • Added automatic reuse of fonts already registered in a document.
  • Added on-demand font registration when pages are compiled.
  • Added sequential font resource names such as /F1, /F2, and /F3.
  • Added support for the 14 standard PDF Type 1 fonts:
    • Helvetica
    • Helvetica Bold
    • Helvetica Oblique
    • Helvetica Bold Oblique
    • Times Roman
    • Times Bold
    • Times Italic
    • Times Bold Italic
    • Courier
    • Courier Bold
    • Courier Oblique
    • Courier Bold Oblique
    • Symbol
    • Zapf Dingbats
  • Added font family and style metadata.
  • Added support for WinAnsi and built-in font encodings.
  • Added PaperForge.Font.definition_to_dictionary/1.
  • Added built-in font metrics.
  • Added text-width measurement through PaperForge.TextMetrics.
  • Added tests for font registration, font reuse, unsupported fonts, and consecutive font resource names without relying on fixed object IDs.

Text layout

  • Added text alignment:
    • Left
    • Center
    • Right
  • Added optional text width for alignment calculations.
  • Added automatic text measurement using built-in font metrics.
  • Added PaperForge.TextWrapper.
  • Added automatic word wrapping.
  • Added support for explicit newline characters.
  • Added configurable line height.
  • Added long-word splitting when a word exceeds the available width.
  • Added PaperForge.Graphics.TextBox.
  • Added multiline text boxes.
  • Added optional text-box height limits.
  • Added line-count and overflow information from text-box layout.
  • Added support for text-box alignment.
  • Added support for text-box fill color.
  • Added support for selecting built-in fonts by atom.

Page coordinates and margins

Images

  • Added JPEG image support.
  • Added support for non-interlaced 8-bit grayscale, RGB, grayscale-alpha, and RGBA PNG images.
  • Added JPEG signature validation.
  • Added PNG signature validation.
  • Added JPEG marker parsing without decoding image pixels.
  • Added PNG IHDR and IDAT parsing without decoding image pixels.
  • Added extraction of:
    • Width
    • Height
    • Bits per component
    • Number of color components
    • Color space
  • Added support for:
    • Grayscale JPEG images
    • RGB JPEG images
    • CMYK JPEG images
    • Grayscale PNG images
    • RGB PNG images
    • Grayscale PNG images with alpha
    • RGBA PNG images
  • Added PDF image XObjects using /DCTDecode.
  • Added PNG image XObjects using /FlateDecode and PNG predictor decode parameters.
  • Added PNG transparency support using PDF soft masks (/SMask).
  • Optimized PNG parsing to avoid unnecessary per-pixel reconstruction when the PNG can be inserted directly into the PDF.
  • Added CMYK decode arrays for compatible JPEG images.
  • Added PaperForge.Image.
  • Added PaperForge.ImageRegistry.
  • Added SHA-256-based image deduplication.
  • Added sequential image resource names such as /Im1 and /Im2.
  • Added image loading from:
    • File paths
    • JPEG binaries
    • PNG binaries
  • Added automatic aspect-ratio preservation.
  • Added image sizing using:
    • Original dimensions
    • Width only
    • Height only
    • Explicit width and height
  • Added PaperForge.Graphics.Image.
  • Added PDF image drawing using the cm and Do operators.
  • Added page-level image operations through PaperForge.Page.image/3.
  • Added tests for RGB, grayscale, CMYK, invalid, truncated, duplicated, and distinct JPEG image handling.
  • Added tests for RGB, grayscale, grayscale-alpha, RGBA, invalid, truncated, deduplicated, and unsupported PNG image handling.
  • Added PNG parsing benchmarks and large-image tests.

Page resources

  • Added PaperForge.PageResources.
  • Added centralized page resource management.
  • Added automatic font resource dictionaries.
  • Added automatic image XObject dictionaries.
  • Added resource deduplication within pages.
  • Added support for pages containing multiple fonts and images.

Metadata and string encoding

  • Added PaperForge.StringEncoding.
  • Added automatic PDF string encoding selection.
  • Added literal PDF strings for compatible text.
  • Added UTF-16BE encoding for Unicode metadata.
  • Added Unicode support for:
    • Title
    • Author
    • Subject
    • Keywords
    • Creator
    • Producer
  • Added creation-date metadata.
  • Added modification-date metadata.
  • Added PDF date serialization for:
  • Added timezone-offset serialization for DateTime metadata.
  • Added metadata option validation.
  • Added omission of empty metadata values.
  • Added tests for Latin-1 and UTF-16BE metadata serialization.

Public API

Testing

  • Expanded document graph tests.
  • Added tests for document compression and PDF version configuration.
  • Added tests for unsupported document options.
  • Added tests for invalid compression values.
  • Added tests for compressed PDF output.
  • Added tests for uncompressed PDF output.
  • Added tests for font reuse and additional font registration.
  • Added tests for JPEG and PNG parsing, image registration, image deduplication, and image scaling.
  • Added tests for top-left and bottom-left coordinate compilation.
  • Added tests for margins and text-box layout behavior.
  • Added tests that verify every xref offset points to the beginning of its object.
  • Added a structural round-trip style writer test covering multiple pages, fonts, repeated images, metadata, compression, resources, and xref offsets.
  • Updated writer tests so they no longer assume compressed stream contents are visible as plain text.
  • Updated document tests to use explicit PDF reference fields.
  • Restored compilation with --warnings-as-errors.

Changed

  • Changed the default page content stream behavior to use Flate compression.
  • Changed document creation to accept configuration options.
  • Changed document creation so only the page tree and catalog are created initially.
  • Changed font creation to register standard Type 1 fonts only when used.
  • Changed the next automatically allocated object identifier to start after the initial page tree and catalog objects.
  • Changed page compilation to register fonts and images dynamically.
  • Changed page image compilation to detect supported image formats before registering image XObjects.
  • Changed page compilation to flow through PaperForge.PageCompiler.
  • Changed page resource generation to use PaperForge.PageResources.
  • Changed text rendering to use registered font resource names instead of a hardcoded font resource.
  • Changed text positioning to support page margins and configurable origins.
  • Changed metadata values to use automatic PDF string encoding.
  • Changed JPEG files to be embedded directly as PDF image streams.
  • Changed the document structure to use explicit reference field names:
    • root_reference
    • pages_reference
    • info_reference
  • Changed tests to validate behavior and structure rather than relying on compressed stream contents or fixed internal assumptions.
  • Changed page streams to select filters from the document configuration.
  • Changed multiline text rendering to use text wrapping and layout metrics.

Fixed

  • Fixed duplicate @doc warnings for multi-clause PaperForge.add_page/2.
  • Fixed the missing PaperForge.Font.definition_to_dictionary/1 function.
  • Fixed JPEG bitstring matching by pinning payload_length.
  • Fixed compilation under mix compile --warnings-as-errors.
  • Fixed font resource reuse across pages.
  • Fixed repeated image embedding by deduplicating JPEG binaries.
  • Fixed repeated image embedding by deduplicating PNG binaries.
  • Fixed image aspect-ratio calculations when only one dimension is provided.
  • Fixed top-left coordinate conversion for box-shaped operations.
  • Fixed page resource dictionaries for multiple fonts and image XObjects.
  • Fixed metadata encoding for characters outside simple PDF literal-string ranges.
  • Fixed stream filter serialization for compressed page content.
  • Fixed tests that referenced removed or renamed document fields.
  • Fixed tests that expected uncompressed text while compression was enabled.

Internal

  • Added PaperForge.PageCompiler as the central page operation compiler.
  • Added separate registries for fonts and images.
  • Added normalized built-in font definitions.
  • Added font metric tables.
  • Added dedicated modules for:
    • Compression
    • Coordinates
    • Margins
    • Font registration
    • Image registration
    • JPEG parsing
    • PNG parsing
    • Page compilation
    • Page resources
    • String encoding
    • Text measurement
    • Text wrapping
    • Text boxes
    • Image drawing
  • Continued using iodata for PDF command and document construction.
  • Kept PDF object references separate from indirect object values.

0.1.0 - 2026-07-26

Added

  • Initial PaperForge project structure
  • Pure Elixir PDF generation without external rendering tools
  • PDF primitive serialization for:
    • Null values
    • Booleans
    • Integers
    • Floating-point numbers
    • Names
    • Literal strings
    • Arrays
    • Dictionaries
    • Indirect references
    • Streams
  • Indirect PDF object representation
  • PDF object references with generation numbers
  • PDF stream support with automatic byte-length calculation
  • Internal document object graph
  • Automatic PDF object ID allocation
  • Document catalog generation
  • PDF page tree generation
  • Multi-page document support
  • Cross-reference table generation
  • PDF trailer and startxref generation
  • Binary PDF output
  • File-writing API
  • Built-in Helvetica font support using WinAnsiEncoding
  • A3, A4, A5, Letter, Legal, and custom page sizes
  • Portrait and landscape page orientations
  • Text drawing with:
    • Position
    • Font size
    • Fill color
  • Line drawing with:
    • Start and end coordinates
    • Stroke color
    • Configurable line width
  • Rectangle drawing with:
    • Stroke
    • Fill
    • Stroke color
    • Fill color
    • Configurable line width
  • Circle drawing using cubic Bézier curves
  • RGB color support
  • 8-bit RGB color helpers
  • Grayscale color support
  • Basic PDF metadata:
    • Title
    • Author
    • Subject
    • Keywords
    • Creator
    • Producer
  • Example documents for text, multiple pages, and graphics
  • Unit tests for the PDF serializer, document graph, pages, and writer

Technical details

  • Uses iodata internally to reduce unnecessary binary concatenation
  • Produces traditional PDF cross-reference tables
  • Uses generation 0 for newly generated indirect objects
  • Uses native PDF coordinates with the origin at the bottom-left corner
  • Isolates graphic operations using the PDF q and Q operators