Files
pdfcraft/crates/optimize
3908a03aa6 Optimizer: Audit space usage counts images PrintCraft added as images (#3)
Content added with Edit ▸ Add content records its image in the content stream's dictionary
(/PCAdded /Image). The audit claimed a page's content streams before its resources and
followed that reference, so an added image's bytes were reported as Content Streams and
Images showed 0 % (a 1.9 MB picture read as 99.9 % content). Resources are now claimed
first, so whatever a content stream's dictionary points at keeps its own category.

Co-authored-by: storybored379 <storybored379@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-04 13:24:06 -04:00
..

printcraft-optimize

Layer L4: the PDF Optimizer (execution plan M11.1; Acrobat's Reduce File Size and Optimize PDF ▸ Advanced optimization).

let report = optimize(&mut doc, &Settings::default())?;   // Reduce File Size's choices
  • Images: the effective resolution of each image is measured where pages draw it (the CTM through form XObjects; the smallest over all uses). Colour and grayscale images above a threshold are resampled with a bicubic (Catmull-Rom) filter to a target resolution and stored as JPEG (Acrobat's quality steps) or ZIP; soft masks are resampled with their image. An image is replaced only if the result is smaller. Left alone: CMYK and other colour spaces, image masks, decode arrays, more than 8 bits, JPEG 2000, JBIG2 and CCITT.
  • Discard objects: thumbnails, alternate images, document tags, print settings.
  • Clean up: Flate for streams with no filter.

The engine runs Remove Hidden Information (printcraft-redact) for the user-data categories, then this, then merges identical objects and writes a full, compressed save. JPEG decoding and encoding and resampling come from the image crate.