pdfcraft_filters::encode_jbig2 stores each distinct mark of a 1-bit
image (8-connected black pixels, at most 256 a side) once, as a symbol
in a symbol dictionary, and places its exact copies with an immediate
lossless text region that refers to it. Larger marks, and in a second
plan marks that occur once, go to a generic region over their box. It
keeps whichever of that and the generic coding (encode_jbig2_generic,
unchanged) is smaller. Only exact copies share a symbol, so the stream
decodes to the same bits.
Written from the JBIG committee's ISO/IEC 14492 Final Committee Draft:
6.4 and 6.5 (text region and symbol dictionary decoding), 7.2, 7.4.2
and 7.4.3 (segment headers and syntax) and Annex A (the integer coders,
checked against its worked example and Table A.1).
On six pages of rendered 300 dpi text the output is 28% of the generic
coding's size and 17% of Group 4's, at about 100 ms a page; hayro-jbig2
and Poppler (pdfimages) both decode it to the original bits. Scans,
whose copies of a letter are seldom identical, gain little: that needs
refinement coding. A dictionary shared between pages (/JBIG2Globals)
is a further step.
The optimizer's Monochrome Images > JBIG2 (lossless) and doc_optimize
mono jbig2 use it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P6yUtvWGPsJpMLyh6pxSXG
pdfcraft_filters::encode_jbig2_generic writes 1-bit rows as a JBIG2
stream for JBIG2Decode (embedded organisation: a page information
segment and an immediate lossless generic region, no globals): template
0 with its nominal AT pixels, typical prediction, and the MQ arithmetic
coder (mq.rs), written from the JBIG committee's ISO/IEC 14492 Final
Committee Draft. The coder reproduces its Annex H.2 test sequence byte
for byte; output round-trips through hayro-jbig2, and Poppler renders
it the same as the original.
The optimizer's Monochrome Images gets JBIG2 (lossless) beside CCITT
Group 4 (still the default), doc_optimize mono jbig2; a document below
PDF 1.4 gets /Version /1.4 in its catalog. On 300 dpi text JBIG2 is
about a third smaller than Group 4.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BfMGHQNgdq5yf5tKZHGR3z
pdfcraft_filters::encode_g4 encodes packed 1-bit rows as Group 4 (ITU-T
T.6, /K -1) through the fax crate (MIT, already in the tree via tiff),
with rows capped at 32,767 samples so its 16-bit positions can't
overflow; round trips are checked against hayro-ccitt.
The optimizer (Settings::mono, CCITT G4 by default, so Reduce File Size
too) re-encodes a 1-bit image of one colour component, or an image
mask, stored with no filter or general-purpose ones, when that is
smaller as stored. The samples decode to the same bits, so colour
space, decode array and masks stay. PDF Optimizer gets a Monochrome
Images row and doc_optimize a mono option. optimize.mono-compression
goes from planned to partial (JBIG2 and monochrome downsampling not
yet).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BfMGHQNgdq5yf5tKZHGR3z
ROADMAP.md: kept both progress lines.
crates/optimize/README.md: PR's decoder sentence plus the target-version section from main.
Cargo.lock: auto-merged.
Conflicts: ATTRIBUTION.toml: took main's side (hashes recomputed after the merges). crates/optimize/src/lib.rs, crates/automation/src/lib.rs, tools.rs: Settings and tool schema keep object_streams (#3227) and lzw_to_flate (#4181); doc_optimize description names both options. crates/optimize/tests/optimize.rs: both sides' imports and tests kept.
Optimize decoded DCT images with the generic JPEG decoder, which converts
three components from YCbCr to RGB whenever the JPEG itself doesn't say
otherwise, and then dropped /DecodeParms. An RGB JPEG stored untransformed
(/ColorTransform 0 and no Adobe marker) therefore came out in other colours
when recompressed, resampled or merged from strips.
The samples are now read with the colour transform ISO 32000-2 §7.4.8
gives them: an Adobe APP14 marker's flag, else /ColorTransform (default 1).
Untransformed samples are taken as stored, and the result is written as a
plain YCbCr JPEG (or Flate), which needs no /DecodeParms. When the marker
and /ColorTransform disagree, a value is out of range, the parameters are
not paired with the filter as §7.4 pairs them, or the decoder reads the
components otherwise (named R, G and B), the image is left as it is.
The tests draw each image with PdfCraft's renderer before and after
Optimize: RGB JPEGs with and without an Adobe marker under each
/ColorTransform, CMYK JPEGs (still left alone) and JPEG strips merged into
one picture.
Part of #1201.
* M11: merge image fragments, and the Standard and Mobile optimizer presets
Some PDF printers draw a page picture as thousands of images one pixel row
high (one real page: 3,300 strips, 4.3 MB). The optimizer works image by
image, a one-row image can't be resampled, and every JPEG strip carries its
own headers, so Reduce File Size saved 2 bytes on it.
- pdfcraft-optimize `fragments` (Settings::merge_fragments, on by default):
runs of `q … cm /Im Do Q` drawing upright 8-bit grey or RGB images in one
colour space, sharing their left and right edges and stacked edge to edge
(at least four, nothing else drawn between them; or, failing that, the
rows drawn one under the other up to a gap) become one lossless image at
their finest resolution. The image settings then resample it, and Clean
Up drops the strips. A page whose content can't be read back exactly is
left alone.
- Presets as in Acrobat's Settings menu: Standard (Reduce File Size's
choices) and Mobile (images above 144 ppi to 96 ppi, JPEG high). The PDF
Optimizer dialog has a Settings menu (Custom once an option changes) and
a Merge image fragments box; doc_optimize takes preset and
merge_fragments and reports merged_images and fragments_merged.
- A progress stage for the merge; four new strings in all 21 catalogs.
On the real page: Standard/Reduce 4.3 MB → 231 KB, Mobile → 161 KB, with
a rendering closer to the original than Acrobat's Mobile result (147 KB).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* Refresh catalog hashes after merging main
---------
Co-authored-by: magdale76 <16279778+magdale76@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
* 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 <noreply@anthropic.com>
* 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 <noreply@anthropic.com>
* optimize: document redundant ASCII-wrapper cleanup
Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Haiku 5.5 <noreply@anthropic.com>
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>
Office scanners write the default decode array (/Decode [0 1 0 1 0 1]) on their page
images. Reduce skipped every image with a decode array, so a scan stayed the same
size. The default array is now treated as absent; any other array still skips the
image.
Reduce also saved its copy even when it wasn't smaller, reported as "-N% smaller".
It now saves nothing and says the file is already as small as it can be made;
doc_reduce returns "written": false. Optimize PDF still saves (what it discards
may matter more than the size) but says "not smaller".
Co-authored-by: Andrew Taylor <andrew.taylor@tayeng.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
* M11: Optimize PDF and Reduce File Size run in the background with a progress bar
Advanced optimization and Reduce File Size did all their work on the UI
thread, so on a large file the window stopped repainting until they were
done and looked as if it had crashed.
- pdfcraft-optimize: optimize_with_progress reports each image and the
clean-up; returning false stops with OptimizeError::Cancelled.
- engine: Session::optimize_job captures a copy of the document and the
choices; OptimizeJob::run reports each OptimizeStage (removing user data,
images, cleaning up, merging, writing), stops on request with
EditError::Cancelled and turns a panic into an error so a worker always
reports back. optimized_bytes is the job run in place.
- ui: both commands run the job on a worker thread (inline in tests and on
the web), like OCR and Export. A card at the bottom centre shows the
stage ("Optimizing... image 14 of 40"), a bar that eases towards the
fraction with a light sweeping across it, the percentage and Cancel;
notices stack above it. A second run is refused while one is going. The
control channel's state includes the progress.
The headless doc_optimize and doc_reduce tools stay synchronous. New
strings are translated for es, fr, ja, zh-hans, zh-hant.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* Clippy: as_chunks in the signature image background test (follow-up to #355)
#360 switched the image test to as_chunks; #355 added another chunks_exact(4)
in the background test, which clippy's chunks_exact_to_as_chunks rejects.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* Optimize: report a failed worker spawn instead of waiting forever
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
The app, crates, binaries, bundle id, packaging, icons, screenshots and docs are now
PdfCraft / pdfcraft (repo storytold/pdfcraft). On first launch the desktop app moves the
PrintCraft settings and crash-recovery folders to the new name, and both apps read settings
saved under the old storage key, so upgrades keep recent files, preferences and unsaved work.
The signing test fixtures keep their PrintCraft subject names (they are binary).
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
- js: `host()` returns a script error instead of panicking when the host state is missing.
- optimize, a11y: the graphics-state stack is read with `last`/`last_mut` instead of `expect`.
- fonts: the standard-14 ASCII map is built from `u8`, which can't fail.
- filters: zlib encoding into a `Vec` keeps the standard's narrow, documented `expect` exception.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
