4dafbfc325
Deleting an image with Edit a PDF removes its Do operation, but the image stays in the page's /Resources /XObject, so every full rewrite (Reduce file size, Optimize PDF) carried its data along: a page left blank still weighed the whole picture. Clean Up now drops image and form XObjects from a page's own resources when their name is written in no stream the document still uses. Shared and inherited resources are left alone, and if any stream can't be read the way a viewer would read it, nothing is removed: viewers look names up through parent resources, so only a name written nowhere is safe to drop. doc_optimize reports unused_xobjects. Co-authored-by: Andrew Taylor <andrew.taylor@tayeng.com> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com> |
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| Cargo.toml | ||
| README.md | ||
README.md
pdfcraft-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
// Or with progress: called before each image and the clean-up; `false` cancels.
let report = optimize_with_progress(&mut doc, &settings, &mut |stage| keep_going)?;
- 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 (pdfcraft-redact) for the user-data categories,
then this, then merges identical objects and writes a full, compressed save
(pdfcraft_engine::optimizer::OptimizeJob, which the UI runs on a worker thread with a
progress bar). JPEG decoding and
encoding and resampling come from the image crate.