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cyfung1031andClaude Haiku 5.5
be94112c8e
* cos: decode only the first filter of a stream, strictly Stream::decoded_first_filter_strict decodes the outer filter of a chain and leaves the rest of the chain encoded, within a caller bound. The optimizer uses it to remove an ASCII85 or ASCIIHex wrapper without inflating the inner data. Co-Authored-By: Claude Haiku 5.5 <[email protected]> * optimize: strip redundant ASCII wrappers from filtered streams A stream whose filter array starts with ASCII85Decode or ASCIIHexDecode loses that outer layer when the serialized replacement is smaller. The inner encoded bytes are kept exactly, and the decoded stream is unchanged. Streams with DecodeParms, image, object stream, or Crypt filters are left alone, as are streams whose wrapper fails strict decoding. Co-Authored-By: Claude Haiku 5.5 <[email protected]> * optimize: document redundant ASCII-wrapper cleanup Co-Authored-By: Claude Haiku 5.5 <[email protected]> --------- Co-authored-by: Claude Haiku 5.5 <[email protected]>
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; for streams with an outer ASCII85 or ASCIIHex
layer, that layer is removed when the result is smaller (the inner filters keep their encoded
bytes). Streams with
/DecodeParms, images and object streams are left alone.
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.