M11: say redaction and export don't read Group 4 yet; Reduce File Size's descriptions

- Redaction doesn't decode CCITT, so a mark over part of an image the
  optimizer stored as Group 4 removes the whole image (nothing leaks),
  and Export ▸ Images refuses it. The optimize README and the
  mono-compression parity note say so. Later PRs of this stack add both
  (#4335 export, #4384 redaction).
- doc_reduce's description, Engine::reduced_bytes and docs/cli-batch.md
  now list the black-and-white step; docs/target-app-parity.md's
  optimize row gives the measured counts and no longer lists CCITT as
  missing; the M11 milestone row lists it as done.

From reviews with the pdfcraft-review skill.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P6yUtvWGPsJpMLyh6pxSXG

crates/automation/src/tools.rs

@@ -1332,7 +1332,7 @@ pub fn tools() -> Vec<ToolDef> {
             }),
             &["from"],
         )),
-        t("doc_reduce", "Reduce file size", "Write a smaller copy of the document to `path` with Acrobat's Reduce File Size choices: images above 225 ppi downsampled to 150 ppi and JPEG-compressed (medium quality), thumbnails dropped, identical fonts and images merged, unused objects dropped, compressed object streams. If the copy wouldn't be smaller, nothing is written and `written` is false. The open document is unchanged.")
+        t("doc_reduce", "Reduce file size", "Write a smaller copy of the document to `path` with Acrobat's Reduce File Size choices: colour and grey images above 225 ppi downsampled to 150 ppi and JPEG-compressed (medium quality), black-and-white images stored as CCITT Group 4 whenever that is smaller, thumbnails dropped, identical fonts and images merged, unused objects dropped, compressed object streams. If the copy wouldn't be smaller, nothing is written and `written` is false. The open document is unchanged.")
             .cmd("optimize.reduce")
             .with(schema(json!({ "doc": doc(), "path": { "type": "string" } }), &["doc", "path"])),
         t("doc_initial_view", "Initial view", "Read or change how the document opens (Document Properties ▸ Initial View) and its reading options: navigation (page, bookmarks, pages, attachments, layers), layout (default, single, continuous, two_up, two_up_continuous, two_up_cover, two_up_continuous_cover), magnification (default, actual, fit_page, fit_width, fit_height, fit_visible, or a percentage), page, window options (fit_window, center_window, full_screen, display_title), interface options (hide_menubar, hide_toolbar, hide_window_ui), language and binding (left, right). Only the given ones change; returns the result. Undoable.").with(schema(

crates/engine/src/session/files.rs

@@ -68,10 +68,11 @@ impl Session {
         if pdf { Ok(bytes.clone()) } else { self.convert_to_pdf(name, bytes).map(|(_, pdf)| pdf) }
     }
 
-    /// Reduce File Size: Acrobat's defaults (images above 225 ppi to 150 ppi, JPEG medium
-    /// quality; thumbnails dropped), identical resources merged, unused objects dropped, objects
-    /// packed into compressed object streams. Returns the bytes and how many objects were
-    /// merged. The open document is not changed (Acrobat saves the reduced copy as a new file).
+    /// Reduce File Size: Acrobat's defaults (colour and grey images above 225 ppi to 150 ppi,
+    /// JPEG medium quality; black-and-white stored as CCITT Group 4 whenever smaller; thumbnails
+    /// dropped), identical resources merged, unused objects dropped, objects packed into
+    /// compressed object streams. Returns the bytes and how many objects were merged. The open
+    /// document is not changed (Acrobat saves the reduced copy as a new file).
     pub fn reduced_bytes(&self, id: DocId) -> Result<(Arc<Vec<u8>>, usize), EditError> {
         let (bytes, report) = self.optimized_bytes(id, &optimize::Settings::default(), &[])?;
         Ok((bytes, report.merged))

crates/optimize/README.md

@@ -41,7 +41,8 @@ let report = optimize_with_progress(&mut doc, &settings, &mut |stage| keep_going
   space, decode array and masks stay. Group 4 wins on scans, whose ragged edges defeat Flate;
   on clean computer-drawn 1-bit art Flate can be smaller, and the image then stays. Not yet:
   JBIG2, monochrome downsampling, inline images, soft masks and `/Mask` images, and rows wider
-  than 32,767 samples.
+  than 32,767 samples. Redaction doesn't decode Group 4 yet: a mark over part of an image stored
+  this way removes the whole image (nothing leaks), and Export ▸ Images can't export one.
 - **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

docs/cli-batch.md

@@ -27,7 +27,8 @@ new engine importers become available here automatically. Without `convert`,
 only `.pdf` inputs are processed. Unsupported extensions are reported as skipped.
 
 - `optimize` uses Reduce File Size settings: JPEG quality 60, resampling to 150 ppi
-  above 225 ppi, plus the existing document cleanup. `--ppi` (9–1600) sets the target
+  above 225 ppi (black-and-white images stored as CCITT Group 4 when smaller), plus the
+  existing document cleanup. `--ppi` (9–1600) sets the target
   and a threshold of 1.5 times that value; `--quality` (1–100) sets JPEG quality.
   These settings can lose image detail. A candidate that is not smaller retains
   the bytes entering that step. This is not an images-only or lossless preset.

docs/roadmap.md

@@ -196,7 +196,7 @@ total matches the parity estimate.
 | M8 | Security + redaction | 100–180 | 68% | 15–30 | Done: opening protected documents, permissions, Protect Using Password, Remove security; redaction (mark text/areas/pages, Search & Redact with patterns, apply removing glyphs, image pixels, vectors, XObject content, annotations and fields, verification, full rewrite on save); Remove hidden information and Sanitize.<br>Done since: redaction codes (U.S. FOIA and Privacy Act sets as overlay text, in Redaction properties and `redact_mark`). Redaction cleans indirect and form structure references, preserving surviving form tags. Redaction retires inherited resource dictionaries, so a parent `/Pages` can't keep a removed XObject reachable; unredacted pages are left untouched. Image redaction removes alternate images and unsupported masks only on affected images. Changed marked-content spans lose replacement descriptions; untouched spans keep theirs. Hidden-text cleanup retires unused named descriptions across inherited/shared page and form resources (64 focused tests and scoped Rust 1.96 Clippy/wasm checks pass; publication CI pending). The redaction audit counts a filled cover that hides half of any one word of a long line (#2662), applied or not. Phone-pattern redaction also matches labelled Italian geographic numbers with `+39` and a slash after the area code (#3205 follow-up); unlabelled international slash numbers remain unsupported. Missing: certificate security, custom redaction code sets and pattern locales, DCT re-encoding |
 | M9 | Signatures (PAdES, validation) | 160–280 | 60% | 40–70 | Done: new `sign` crate (DER, X.509, CMS, PKCS #12 on RustCrypto; aws-lc-rs for RSA private keys); PAdES B-B signing (visible, invisible, existing fields, certification with DocMDP); validation with trust store and changes-after-signing classification; self-signed digital IDs; Signatures panel, message bar, sign dialogs; agent tools. Checked with pdfsig and OpenSSL.<br>Done since: macOS Keychain and Windows Current User Personal store signing (software-backed CNG keys), certificate viewer, signed documents protected from rewrites, page validation overlays separate from original signature artwork (baked Not Verified captions remain; #79 open), snapshot tabs that reuse instead of multiplying. Missing: timestamps (B-T), LTV (DSS, OCSP, CRL), FieldMDP, smart cards, PKCS #11 |
 | M10 | OCR, create, export, print | 200–350 | 33% | 120–215 | Done: create from blank/text/PNG/JPEG/TIFF (multi-page)/GIF/BMP; export PNG/JPEG/TIFF and text; Print (Acrobat's sizing, n-up, booklet, poster, comments & forms, preview, the CUPS and Windows spoolers, print-ready PDF).<br>Done since: embedded/72/custom DPI choices for image imports; export all images; OCR (searchable image for pages, ranges and multiple files); single-sided cut-and-stack imposition with cut marks, through Print and doc_print; architectural/ANSI/large ISO sheet presets, Match page at 100% and PDF-scale preview (#599 follow-up); Create PDF from multiple files (PDFs, images and text, edited as pages in the grid); OCR can also read pictures on pages that have text, without adding that text twice (#1028). Model staging fetches SHA-256-verified ONNX detection/recognition files after the upstream RTEN URL brownout; runtime discovery prefers complete ONNX pairs per directory, then complete legacy RTEN pairs, without mixing formats or changing directory precedence. Done since: Word invoice export uses borderless inferred tables, floating positioned text/artwork only where text overlaps an image or is rotated, and per-page sizes, covered by synthetic invoice automation regressions (#773); printing on the web through the browser's print dialog, sheets drawn by PdfCraft (gap 4). Lossless image export applies per-component Decode, including Indexed mapping (#1201 partial). Existing 16-bit precision and color-management limits remain. #3532 partial: vector printing retains existing appearances with absent Subtype through a print-owned Form copy; source artwork stays unchanged. #3120: Office export reads form XObjects 50 levels deep, as the renderer does, and up to 50 000 a page; pages past that are listed in `truncated_pages`. Word table cells use the grid columns they span, including cells after a merged cell. Done since: text in a table slot covered by another cell's span remains as paragraph text in Word, HTML, RTF and PowerPoint. Missing: OCR languages beyond Latin, editable-text OCR output, full Office layout fidelity/import. Done since: dotted-leader contents entries stay in separate complete paragraphs (#1757) #2156 candidate: last selected print paper persists across sessions; other print preferences unchanged. Image export applies soft-mask Decode opacity intervals before resizing, including indirect entries and inverted ranges. Vector printing gives annotation appearances unoccupied XObject names so existing page artwork survives. |
-| M11 | Optimize, preflight, PDF/A/X/UA, print production | 200–350 | 18% | 80–140 | Done: new `optimize` crate: Reduce File Size and the PDF Optimizer (images measured where drawn, bicubic downsampling, JPEG/ZIP recompression only when smaller, discard objects and user data, Flate clean-up, resource merging, object streams). Target-version compatibility is partial: newer content is not detected or converted. Content stream boundaries preserve comments, split operands and graphics state when image fragments merge. Image downsampling includes page-local `/UserUnit` scaling when measuring physical resolution. Done since: reject invalid image and soft-mask dimensions with checked sizing (#2178). Missing: fonts and transparency panels, space audit, preflight, PDF/A/X/UA |
+| M11 | Optimize, preflight, PDF/A/X/UA, print production | 200–350 | 18% | 80–140 | Done: new `optimize` crate: Reduce File Size and the PDF Optimizer (images measured where drawn, bicubic downsampling, JPEG/ZIP recompression only when smaller, discard objects and user data, Flate clean-up, resource merging, object streams). Target-version compatibility is partial: newer content is not detected or converted. Content stream boundaries preserve comments, split operands and graphics state when image fragments merge. Image downsampling includes page-local `/UserUnit` scaling when measuring physical resolution. Done since: reject invalid image and soft-mask dimensions with checked sizing (#2178); black-and-white images stored losslessly as CCITT Group 4 when smaller. Missing: fonts and transparency panels, space audit, preflight, PDF/A/X/UA |
 | M12 | Accessibility, compare, measure, search, XFA | 200–380 | 30% | 90–160 | Done: new `a11y` crate with the Accessibility Checker (all 32 rules, report, Fix/Skip/Explain, options dialog and results panel, agent tools). Locatable figure, annotation and form findings highlight their page bounds. Character encoding accepts Identity-H/V with Adobe CJK collections and predefined CJK CMaps independently (#3673); per-glyph validation and embedded-font extraction remain separate.<br>Done since: 2D distance, perimeter and area measurements with persistent viewport calibration, snapping, live information and CSV export; a bounded, text-only auto-tag proposal tool for one page. Marking a figure decorative rewrites only that stream (#1324). An XFA radio item whose value contains a space is written back unchanged (#1319). Done since: #2569: Growable multiline XFA text reflows after edits, with undo/redo, save/reopen and print coverage; oversized fields still become read-only page text. Structured-data synchronization warnings retain accepted whitespace without relayout from stale data. Done since: #2572: Every repeated page-master button resolves its own field to the shared XFA click script, including print buttons. Done since: #2570: Dynamic XFA rich-text fields carry exData/maxLength into AcroForm MaxLen for reported and enforced Unicode character limits, retained after save/reopen. Done since: #2589: Active XFA skips PDF-container fallback scripts while retaining requested messages and saved scripts; ordinary/static/unlaid-out documents and explicit console/field calls keep their existing behavior. Missing: writing proposed tags and parent tree, field autotag, visual Tags/Order/Content panels, Reading Order tool, compare, geospatial/3D measurement, search index, XFA<br>Reading colours: pending page backgrounds follow the configured colour (#2059). |
 | M13 | Automation (MCP, Action Wizard, CLI) + AI providers | 60–120 | 45% | 25–45 | Done: MCP resources (document info, text, page images); headless tool table (123 tools incl. signing, optimizing, initial view, links, stamps, data exchange, comment review, forms authoring and scripts, redaction, sanitize, print, add content), opt-in MCP server over stdio, CLI `run`/`tools` (closed stdout pipes exit cleanly), UI control channel with drag. Missing: Action Wizard, AI providers<br>Done since: CLI run and MCP reject missing, empty, repeated and option-valued --root arguments before any tool/script execution or MCP initialization. A single-hyphen directory name remains valid; synthetic CLI regressions preserve a would-be overwritten file. `text_find` also caps the per-page match ranges it materializes at the remaining result limit plus one continuation match. CLI robustness scans visit each directory once through overlapping roots and symlink aliases. |
 | M12 | Accessibility, compare, measure, search, XFA | 200–380 | 30% | 90–160 | Done: new `a11y` crate with the Accessibility Checker (all 32 rules, report, Fix/Skip/Explain, options dialog and results panel, agent tools). Locatable figure, annotation and form findings highlight their page bounds. Character encoding accepts Identity-H/V with Adobe CJK collections and predefined CJK CMaps independently (#3673); per-glyph validation and embedded-font extraction remain separate.<br>Done since: 2D distance, perimeter and area measurements with persistent viewport calibration, snapping, live information and CSV export; a bounded text-only auto-tag proposal tool; text-only Apply writes marked content, paragraph tags and a parent tree, then opens the Tags panel for review. Missing: mixed-content and field autotag, heading/list/table/figure classification, Order/Content panels, Reading Order tool, compare, geospatial/3D measurement, search index, XFA<br>Done since: CLI info, text and render use dynamic XFA layout pages, with synthetic count/text/pixel and copy-permission regressions (#1645).<br>Reading colours: pending page backgrounds follow the configured colour (#2059). |

docs/target-app-parity.md

@@ -208,7 +208,7 @@ full parity in that area.
 | H Digital signatures | 45 | 23 | 10 | 62.2% | 45% | 40–70 | PAdES B-B signing and validation (PKCS #12, macOS Keychain, Windows store with PIN prompts), certification, encrypted documents, certificate usage checks; B-T, LTV, OCSP/CRL with caller-supplied evidence. Missing: PKCS #11 and smart cards outside Windows, timestamp-server preferences, online revocation fetching, FieldMDP and field locking, OS trust store, EU Trusted Lists, compare signed version |
 | I Scan and OCR | 26 | 5 | 2 | 23.1% | 15% | 40–75 | Searchable image (ocrs, Latin script without accents) on pages, ranges and many files. Missing: every other language (#744 Dutch; accents, CJK, Cyrillic, Arabic), editable-text output, deskew, rotation, despeckle, camera images beyond straightening (found or placed corners): orientation, clean-up, MRC compression, scanners |
 | J Create and export | 34 | 12 | 3 | 39.7% | 25% | 55–100 | Create from images, multipage TIFF, text, clipboard, blank, many files at once; export PNG/JPEG/TIFF, text, RTF; Word and HTML partial. Missing: Office/HTML/web/PostScript to PDF, Excel and PowerPoint export, Word layout fidelity (#773), SVG/XML/EPS/PS/JPEG 2000 export, accessible text |
-| K Optimize and standards | 58 | 15 | 10 | 34.5% | 20% | 65–115 | Reduce File Size and the Optimizer (images, discards, clean-up, space audit); PDF/A-2b/3b verify and convert (partial). Missing: Preflight (profiles, fixups, reports), PDF/A-1/4 and a/u levels, PDF/X, PDF/UA, PDF/E, PDF/VT, transparency flattening, font unembedding, monochrome JBIG2/CCITT |
+| K Optimize and standards | 58 | 17 | 11 | 38.8% | 20% | 65–115 | Reduce File Size and the Optimizer (images, discards, clean-up, space audit); PDF/A-2b/3b verify and convert (partial). Missing: Preflight (profiles, fixups, reports), PDF/A-1/4 and a/u levels, PDF/X, PDF/UA, PDF/E, PDF/VT, transparency flattening, font unembedding, monochrome JBIG2 and downsampling |
 | L Print | 39 | 15 | 1 | 39.7% | 35% | 30–55 | Acrobat's sizing, n-up, booklet, poster, comments & forms, preview, print-ready PDF, CUPS on macOS/Linux, the Windows spooler (#756) and the browser's print dialog on the web. Missing: print as image, PostScript, all print-production tools (output preview, separations, ink manager, printer marks, colour conversion) |
 | M Accessibility | 61 | 38 | 1 | 63.1% | 30% | 40–70 | Accessibility Checker (all 32 rules, report, fixes), alternate text, title and language. Missing: autotag, Tags/Order/Content panels, Reading Order tool, artifact marking, table editor, Read Out Loud, full keyboard operation of the app, screen-reader audit |
 | N Automation, preferences, misc | 75 | 20 | 5 | 30.0% | 35% | 25–45 | CLI, MCP, UI control channel, 141 automation tools, Action Wizard (run, create), compare (text, visual, report, side by side, Text/Visual filter). Missing: most Preferences pages, Acrobat's finer compare filters, Action Wizard management, custom commands, AI providers, rich media/3D, hosted web app |

parity/acrobat-features.toml

@@ -7385,7 +7385,7 @@ status = "partial"
 commands = ["optimize.advanced", "optimize.reduce"]
 tools = ["doc_optimize", "doc_reduce"]
 evidence = ["crates/filters/src/ccitt.rs::bitmaps_round_trip", "crates/filters/src/ccitt.rs::a_page_of_text_like_marks_round_trips_and_shrinks", "crates/filters/src/ccitt.rs::what_it_cannot_encode_is_an_error", "crates/optimize/tests/optimize.rs::black_and_white_images_become_ccitt_group_4", "crates/automation/tests/it/automation.rs::doc_optimize_stores_black_and_white_images_as_ccitt_group_4", "crates/ui-egui/tests/it/create.rs::the_pdf_optimizer_dialog_saves_an_optimized_copy"]
-notes = "CCITT Group 4, lossless: PDF Optimizer ▸ Images ▸ Monochrome Images (on by default, so Reduce File Size does it too; doc_optimize mono) stores a 1-bit image of one colour component (grey, indexed, a separation) or an image mask, kept with no filter or general-purpose ones, as Group 4 when that is smaller as stored; the samples decode to the same bits, so colour space, decode array and masks stay. Group 4 wins on scans; on clean computer-drawn 1-bit art Flate can be smaller, and the image then stays. Not yet: JBIG2 (lossless or lossy, which Adobe's help says beats CCITT for monochrome), monochrome downsampling, inline images, soft masks and /Mask images, rows wider than 32,767 samples."
+notes = "CCITT Group 4, lossless: PDF Optimizer ▸ Images ▸ Monochrome Images (on by default, so Reduce File Size does it too; doc_optimize mono) stores a 1-bit image of one colour component (grey, indexed, a separation) or an image mask, kept with no filter or general-purpose ones, as Group 4 when that is smaller as stored; the samples decode to the same bits, so colour space, decode array and masks stay. Group 4 wins on scans; on clean computer-drawn 1-bit art Flate can be smaller, and the image then stays. Not yet: JBIG2 (lossless or lossy, which Adobe's help says beats CCITT for monochrome), monochrome downsampling, inline images, soft masks and /Mask images, rows wider than 32,767 samples. Redaction doesn't decode Group 4 yet (a mark over part of such an image removes it whole; nothing leaks), and Export ▸ Images can't export one."
 
 [[feature]]
 id = "optimize.only-if-smaller"