Part of #868: PDFs saved with the reference app's editing data open from it, as .ai files do

A PDF saved with the reference app's editing data keeps that data in
streams named AIPDFPrivateData1, AIPDFPrivateData2, ..., where a .ai
file uses AIPrivateData1, AIPrivateData2, .... illustrator_data read
only the .ai names, so such a PDF opened like any other PDF: plain
groups opened ungrouped, and hidden objects and guides were missing. The
import gave no warning that the PDF's editing data went unread.

illustrator_data now reads the AIPDFPrivateData streams when the file
has no AIPrivateData1, and the PDF opens from its editing data as a .ai
file does. editingData: false still opens it like any other PDF.
has_private_data still looks for AIPrivateData keys only.

layered_ai also returns whether it read the layers. When it did, art
reaching past a PDF's page opens whole, and through_editing_data drops
the PDF importer's note that such art was clipped (PAST_PAGE_NOTE, now
public) as it drops the off-artboard note. When it didn't, both notes
stay. On main, a .ai whose editing data can't be decoded or has no
layers opened from its PDF part without the off-artboard note.

testkit::ai::pdf writes the .ai file of testkit::ai::ai with the PDF
key names. The editing-data tests open it as a PDF, and the import fuzz
test opens the damaged sample as a PDF too.

Docs: the document.open params, docs/mcp.md,
docs/file-format-parity.md, docs/gaps.md (G9: the export direction of
#868 remains), one evidence line in docs/target-app-parity.md, and #868
moved from layer structure to editing data in the File formats row of
docs/target-app-parity.md and in docs/roadmap.md.

docs/file-format-parity.md

@@ -46,7 +46,7 @@ private editing data. VectorCraft:
 
 ### Illustrator's private editing data
 
-the app's own editing copy of a file (an EPS after its `%%EOF`, a `.ai`'s `AIPrivateData` streams, Zstandard or zlib, the EPS's in ASCII85) is not documented as a whole. VectorCraft reads its structure: layers and sublayers (names, order, visibility, lock, printing, preview, dimming, colour), groups as they were nested, compound paths, clipping groups and layer clipping, object names, hidden and locked objects, fills and strokes (grey, CMYK, RGB, named and spot colours, spot colours defined in Lab with their Lab values (#1032), global process colours as global swatches at their tint), linear and radial gradients, pattern fills with their patterns as pattern swatches (#1025), opacity, blend modes, isolation and knockout, embedded images with their alpha channel, guides, and every artboard where it is. An object with several fills or strokes, effects or a brush comes in as its drawn look (a group named after it). Type is made from the file's text document, whole and editable, shown or not: point type, area type (a story in several frames as threaded type) and type on a path, with its characters, fonts, size, leading, tracking, scaling, baseline shift, fill and stroke (grey, RGB or CMYK), alignment, indents and paragraph spacing; the page's drawing of it (often in pieces) is left out. Where the text document can't say (a frame of another kind, or a document that doesn't agree with the page), type that shows comes from the page into its text object's place (no group around it), and hidden type is left out with a note. Kerning, underline and the other character and paragraph options aren't read yet. A `.ai` saved without PDF compatibility (a placeholder page) opens from its editing data alone, its point type, area type and type on a path made from the text document. Symbols, pattern fills whose pattern it can't read, placed files and anything else it doesn't read make the file come in as its page (on a layer that doesn't show, they are left out of that layer), with a warning saying what. The layers' art is also compared with the page (by lightness, so colours written as their CMYK equivalents compare alike, and by whether a pixel is inked at all); the page is used when they differ by more than 5%, where one draws an object the other doesn't (away from type, whose lines may be laid out afresh), and when an EPS whose page is its art's box has art printed outside it (#735). An EPS whose page is its art's box keeps that page when it comes in through its layers, not the editing data's artboard, and a text object counts as drawn by the page by its colours, not only its lightness, so a red stroke stacked over a dark red one stays (#1102). `textAs: "outlines"` opens a `.ai` whose type shows from its PDF part, which has the outlines; `editingData: false` opens any of them as its page or PDF part only, for print pipelines (#735). A file whose import left something out (hidden text, art or layers) is never written over by an export or Save As to its own path unless `acknowledgeLoss: true` (`convert --replace-lossy`), so the original keeps what the document lacks. Where a `.ai` can't be read that way (or its layers are turned off in the import options), we read its PDF-compatible part, so Illustrator-only live objects arrive as appearance, and plain groups arrive ungrouped: that part draws each object on its own and marks only layers, clipping groups and groups with opacity, blending or a mask (those come back). Art outside the artboards isn't in that part at all (Illustrator's PDF part leaves it out), so it doesn't open; the import says so in a note (#472). Its pages still go where the editing data puts the artboards (a grid stays a grid), with the art on each, when it has as many artboards as pages, of the same sizes (#1068). That part also has no paragraphs: area type is written line by line, and comes back as area type only where its font is installed and lays the lines out with the same breaks, else as a point type object per line (#508). Art off the page that a PDF does draw opens on the pasteboard.
+the app's own editing copy of a file (an EPS after its `%%EOF`, a `.ai`'s `AIPrivateData` streams, a PDF's `AIPDFPrivateData` streams when it was saved with the editing data (#868), Zstandard or zlib, the EPS's in ASCII85) is not documented as a whole. VectorCraft reads its structure: layers and sublayers (names, order, visibility, lock, printing, preview, dimming, colour), groups as they were nested, compound paths, clipping groups and layer clipping, object names, hidden and locked objects, fills and strokes (grey, CMYK, RGB, named and spot colours, spot colours defined in Lab with their Lab values (#1032), global process colours as global swatches at their tint), linear and radial gradients, pattern fills with their patterns as pattern swatches (#1025), opacity, blend modes, isolation and knockout, embedded images with their alpha channel, guides, and every artboard where it is. An object with several fills or strokes, effects or a brush comes in as its drawn look (a group named after it). Type is made from the file's text document, whole and editable, shown or not: point type, area type (a story in several frames as threaded type) and type on a path, with its characters, fonts, size, leading, tracking, scaling, baseline shift, fill and stroke (grey, RGB or CMYK), alignment, indents and paragraph spacing; the page's drawing of it (often in pieces) is left out. Where the text document can't say (a frame of another kind, or a document that doesn't agree with the page), type that shows comes from the page into its text object's place (no group around it), and hidden type is left out with a note. Kerning, underline and the other character and paragraph options aren't read yet. A `.ai` saved without PDF compatibility (a placeholder page) opens from its editing data alone, its point type, area type and type on a path made from the text document. Symbols, pattern fills whose pattern it can't read, placed files and anything else it doesn't read make the file come in as its page (on a layer that doesn't show, they are left out of that layer), with a warning saying what. The layers' art is also compared with the page (by lightness, so colours written as their CMYK equivalents compare alike, and by whether a pixel is inked at all); the page is used when they differ by more than 5%, where one draws an object the other doesn't (away from type, whose lines may be laid out afresh), and when an EPS whose page is its art's box has art printed outside it (#735). An EPS whose page is its art's box keeps that page when it comes in through its layers, not the editing data's artboard, and a text object counts as drawn by the page by its colours, not only its lightness, so a red stroke stacked over a dark red one stays (#1102). `textAs: "outlines"` opens a `.ai` whose type shows from its PDF part, which has the outlines; `editingData: false` opens any of them as its page or PDF part only, for print pipelines (#735). A file whose import left something out (hidden text, art or layers) is never written over by an export or Save As to its own path unless `acknowledgeLoss: true` (`convert --replace-lossy`), so the original keeps what the document lacks. Where a `.ai` can't be read that way (or its layers are turned off in the import options), we read its PDF-compatible part, so Illustrator-only live objects arrive as appearance, and plain groups arrive ungrouped: that part draws each object on its own and marks only layers, clipping groups and groups with opacity, blending or a mask (those come back). Art outside the artboards isn't in that part at all (Illustrator's PDF part leaves it out), so it doesn't open; the import says so in a note (#472). Its pages still go where the editing data puts the artboards (a grid stays a grid), with the art on each, when it has as many artboards as pages, of the same sizes (#1068). That part also has no paragraphs: area type is written line by line, and comes back as area type only where its font is installed and lays the lines out with the same breaks, else as a point type object per line (#508). Art off the page that a PDF does draw opens on the pasteboard.
 
 ## Format by format
 

docs/gaps.md

@@ -64,10 +64,11 @@ from G14 and the budget run of G15: **~170–270 h** one agent, ~50–80 h wall
 ## G9 Illustrator `.ai` and EPS files from real users
 
 - **Missing:** faithful layer and group structure from the editing data in real files (#951: 109 layers instead
-  of 14; #868: round trip with Illustrator 2018 loses layers and groups), guides and non-printing construction
+  of 14), guides and non-printing construction
   lines (#779), open speed on large files (#758), legacy type in `.ai` files in PostScript form (those without
   their prolog open since #1027), live effects, brushes and symbols as live objects (#637; pattern fills and global colours are read since #1025). Writing Illustrator's own editing data is out of scope
-  (undocumented); Save As `.ai` stays PDF-compatible.
+  (undocumented); Save As `.ai` stays PDF-compatible, and Illustrator 2018 opens such a file without its layers and
+  groups (#868).
 - **Evidence:** the issues above; 28 of the 350 issues are about `.ai`/EPS (about 22 people, the most common single
   format theme), 20 fixed, and the 8 open ones are about structure (layers, guides, speed, live objects), not missing
   art. No real-file `.ai` corpus (users' files may be used locally, never committed).

docs/mcp.md

@@ -496,7 +496,8 @@ pattern fills, placed files or anything else the reader doesn't read on a layer
 different from its page, opens as before: an EPS as its printed page, a `.ai` file from its PDF content (where plain
 groups open ungrouped), with a warning saying why. Layers look different when they draw an object the page doesn't (or
 miss one it draws), and, for an EPS whose page is the box of its art, when they print art outside it. With
-`textAs: "outlines"` a `.ai` file whose type shows opens from its PDF content, which has the type's outlines.
+`textAs: "outlines"` a `.ai` file whose type shows opens from its PDF content, which has the type's outlines. A PDF
+saved with Illustrator's editing data holds it in `AIPDFPrivateData` streams and opens from it as a `.ai` file does.
 
 The document then has what the file's page doesn't print: hidden objects and layers, layers that don't print, guides and
 the art outside the artboards, as the app that wrote the file shows them. Exports and `artboard.fitToArt` leave out the

docs/roadmap.md

@@ -23,13 +23,13 @@ Checked 2026-10-10 from the code, tests and open issues; no workflow fails, so V
 | Set type: point and area type, Character and Paragraph styles, threading, outlines | yes | type core 80%; styles, threading, Create Outlines and font matching tested ([type-parity.md](type-parity.md)); hyphenation and justification options missing (not blocking) | 0 |
 | Organise layers and artboards and export assets (Export for Screens, SVG, PNG, PDF per artboard) | yes | Layers panel rework, Artboards panel and tool, Export for Screens and Asset Export done; ghost borders in some Asset Export output (#983) | 0 |
 | Print production: CMYK and spot colour, bleed and marks, PDF/X out, separations preview | yes | PDF/X-1a/3/4, presets, marks and bleed, ICC output intent, Separations Preview, Print with PostScript output | 0 |
-| Exchange files with Illustrator users: open their `.ai`/EPS/PDF, hand back a file they can open | partial (doesn't block alpha) | `.ai`, EPS and PDF open as editable art, but real files can get the wrong layer structure (#951, #868) and lose guides (#779); Save As `.ai` is PDF-compatible, which Illustrator opens without its own editing data. This is the beta main-format gap ([gaps.md](gaps.md) G9) | 10–20 (for beta) |
+| Exchange files with Illustrator users: open their `.ai`/EPS/PDF, hand back a file they can open | partial (doesn't block alpha) | `.ai`, EPS and PDF open as editable art, but real files can get the wrong layer structure (#951) and lose guides (#779); Save As `.ai` is PDF-compatible, which Illustrator opens without its own editing data (#868). This is the beta main-format gap ([gaps.md](gaps.md) G9) | 10–20 (for beta) |
 
 ## Current focus
 
 1. **Interaction-fidelity pass** (G1) by tool, from [ui-parity.md](ui-parity.md): Pen and Curvature, Direct
    Selection, smart guides and snapping first. 60–90 h, parallel by tool.
-2. **`.ai` files from real users** (G9): layer structure (#951, #868), guides (#779). 10–20 h.
+2. **`.ai` files from real users** (G9): layer structure (#951), guides (#779). 10–20 h.
 3. **Launch and stability** (G10): the Windows and Linux start-up reports. 20–35 h.
 4. **Core-tool bugs** (G11): Shape Builder regions (#937), Asset Export borders (#983). 8–15 h.
 5. **Raster effects** (G2) continue alongside: Artistic (Film Grain done; 14 left), Sketch, then the Effect Gallery. 23–39 h.

docs/target-app-parity.md

@@ -83,7 +83,7 @@ dominate; 3D, graphs and automation are specialist). They sum to 105. Feature de
 | Layers, artboards, document setup | 5 | 78% | 30.0's artboard locking and colours and managing artboards from the canvas, Layers panel row context menus and Collect for Export | 5–8 | estimated (lowered from 82%: target moved) |
 | View & navigation | 3 | 70% | New View/Edit Views, multiple windows and Arrange, Snap to Glyph | 9–14 | estimated |
 | Guides, grids, smart guides, snapping, rulers | 3 | 80% | 30.0's tangent and perpendicular snapping and its snapping panel, "intersect" smart guides, global/video rulers, distance readouts while drawing | 4–7 | estimated (lowered from 85%: target moved) |
-| File formats | 6 | 75% | `.ai` files open with a flattened or wrong layer structure in real cases (#951, #868), guides lost (#779), no writing of Illustrator's editing data, FreeHand/CorelDRAW/DWG/HEIC/JPEG 2000 import, 3D export; see [file-format-parity.md](file-format-parity.md) | 10–20 | estimated (lowered from 85%: open issues) |
+| File formats | 6 | 75% | `.ai` files open with a flattened or wrong layer structure in real cases (#951), guides lost (#779), no writing of Illustrator's editing data (#868), FreeHand/CorelDRAW/DWG/HEIC/JPEG 2000 import, 3D export; see [file-format-parity.md](file-format-parity.md) | 10–20 | estimated (lowered from 85%: open issues) |
 | Export for Screens, Asset Export, slices, Save for Web | 3 | 85% | anti-aliasing ghost borders (#983), TIFF in Export for Screens (30.2) | 2–4 | estimated |
 | Print, colour management, separations, flattener | 3 | 80% | print preview fidelity | 2–4 | estimated |
 | Automation (Actions, Variables, scripting, batch) | 3 | 60% | a scripting surface (Illustrator: JavaScript/ExtendScript), Batch, image and graph variables, dataset import/export | 8–14 | estimated |
@@ -484,6 +484,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
 - **Files (M4):**
   - `.vectorcraft` (lossless JSON, compressed, atomic saves, save down to v1), Save As with a format chooser, Save a Copy, Revert, templates, Data Recovery after a crash (browser tabs hold their copies with Web Locks too, so a background tab's copies are never taken for a crash's, and a tab repairs copies another removed when it resumes: #367), background save and export. The desktop app writes its warnings and errors (graphics adapter, a lost graphics device, panics the guard recovered from) to standard error and to `logs/vectorcraft.log` next to the preferences, the two previous runs kept and each file capped at 16 MiB, so a launch without a terminal still leaves something to attach to a bug report (#465).
   - SVG/SVGZ in and out with SVG Options, Preserve Editing, symbols, filters, rich text and physical units (SVG type under a transform or `viewBox` scale opens at the size it draws at, the scale moved into its size, leading, baseline shift and strokes, a stretch, skew or rotation kept as its transform: #396; a top-level group with a clip path, such as a clipped Inkscape layer, opens as a layer with a clipping mask, its name kept: #420; hidden objects written hidden on Save and `convert`, and `data-*` attributes kept as the objects' own data: #522; top-level groups open as layers named from `data-name`, else the id, also when one more group (a transform on all the art, a `<switch>`) wraps them, hidden ones hidden, and a file whose art sits loose under a root `<svg>` with an id (or `data-name`), as one-layer exports write it, opens with its one layer named from it; nested groups stay groups, except the sublayers VectorCraft writes, marked `data-vc-layer`, and Inkscape sublayers, which open as sublayers in their layer's colour: #372); PDF and PDF-compatible `.ai` in and out (layers, with hidden ones kept hidden with their art and nested ones as sublayers, on pages of up to 64 million operators, art whose layer can't be told going to a hidden, non-printing layer rather than showing or printing: #419; strokes kept live, a fill and a stroke of one outline as one object; a type object's stroke written as each glyph's outline stroked back on the type, so it stays one editable object; lines wrapped in a frame (each wrapped line ending in a space, one left edge, leading and font) back as one area type object, left aligned or justified with its paragraph spacing, where laying it out breaks the lines where the file does; glyphs set apart by gaps wider than a space (a barcode's digit groups) keeping their places; layers stacked as the pages mark them even when one first paints on a later page, art ending a layer's marked content or a clip closing in a later layer kept in its own layer, and layers with no art kept empty: #508; art reaching past a plain PDF's page clipped to its crop box, as PDF viewers show it, each such object in a clip group of its own (a PDF-compatible `.ai` opens whole: #675); a `.ai` on its trim boxes with the bleed boxes round them as the document's bleed, as Crop To › Trim opens a PDF (#1266); masks, editable text with type set along a curve coming back as type on a path, each artboard's art on its own page only, an `.ai`'s white page under its layers left out rather than coming in as art, spot colours, presets, security, marks and bleed, ICC output intents, raster effects, subset fonts, PDF/X, PDF layers, overprint, page thumbnails, fast web view, PDF 1.3). CMYK images keep their ink amounts from PDF import (and from placed CMYK TIFFs) to PDF export: a CMYK JPEG passes through unchanged, others stay CMYK (DeviceCMYK, or ICC-based CMYK in PDF/X-3/X-4) unless the Output settings convert them; the canvas shows them through the working CMYK profile (#320). A masked CMYK image (`/SMask`, `/Mask` or a colour key) keeps its inks too, its alpha coming in as a greyscale opacity mask.
+    A PDF saved with Illustrator's editing data opens through it as a PDF-compatible `.ai` does, with its layers and groups and with art reaching past its page unclipped; such a PDF holds the data in `AIPDFPrivateData` streams (part of #868).
   - EPS and DXF in and out, EMF/WMF in and out; PNG (with PNG-8), JPEG, WebP, GIF, TIFF, BMP, Targa and layered PSD export; PSD and PSB files open and place, linked or embedded, as their merged image in every colour mode and depth (#918). EPS import runs a PostScript Level 3 interpreter written from the PostScript Language Reference: resource categories and `resourceforall`, local and global VM (`currentglobal`/`setglobal`/`gcheck`), `clipsave`/`cliprestore`, subarrays and substrings that share storage, the standard dictionaries in `systemdict`, `dictstack`, `internaldict`, executable filters and strings, `load` by any key, `//name` immediate names, `token`, `execform`, user paths, `cshow`, `rootfont`, `cachestatus`, colour rendering and halftone queries, file `status` and data read with `flushfile`, and `pdfmark` marks dropped (Discord feedback, #466, #469, #474). Masked images (`ImageType 3` in its three interleavings) and reusable streams are read, and an image's several data sources are read in turn, as the reference defines (procedures that read one file get their own rows: such images came in banded, #498). `restore` puts dictionaries back as they were at the `save`, so programs that count their saves in a dictionary read to their end (part of #505). Tiling patterns come in as pattern swatches, uncoloured ones too; Type 3 fonts' glyphs as their outlines, spaced by `ashow`/`widthshow`/`xshow`/`kshow`; mesh and function-based shadings (types 1, 4–7) as gradient meshes; sampled functions (type 0) and Flate/LZW predictors are read. It is tested with programs written from the specification in the ways common generators use these features; Inkscape/cairo EPS files open as vectors. When a file's PostScript still can't be read, it opens as its TIFF preview, its Windows metafile preview (as vectors) or its EPSI preview, and the warning (in the status bar, `document.open`/`app.open`/MCP `open_file` replies and `vectorcraft-cli info`) names the error, the operator that raised it and the procedures it ran in. Legacy PostScript `.ai` files (Illustrator 3–8, written with the prolog that defines their operators) keep their groups and nested groups (`u` … `U`), between and inside clipping groups; EPS and EMF/WMF import nest clips (and groups) at most 128 deep, so a hostile file can't exhaust the stack. DXF TEXT justified Fit or Aligned spans its two points (stretched, or scaled as a whole). PDF export writes type as real, searchable text in embedded subset fonts by default, as Illustrator's PDF presets do (Convert Text to Outlines is an option; printer's marks stay shapes), so text-heavy PDFs stay small (#733). DXF export writes each fill as its outlines followed by its hatch, so laser and cutter software, which skips hatches, gets filled art and type too (#546).
   - Affinity documents in (AF.1–AF.4): `.af` (Affinity 3) and `.afdesign`/`.afphoto`/`.afpub` (Affinity 1 and 2, container versions 8–12) open and place as editable art: layers and sublayers, groups (pass-through or isolated), artboards (with their names and backgrounds) and Publisher pages side by side, curves with live corners, parametric shapes (rectangles with corner radii, ellipses, polygons, stars, pies, triangles, trapezoids), compound shapes, solid/linear/elliptical gradient fills and strokes (weight, dashes, alignment, scale-with-object), clipping by nesting, vector and pixel masks, artistic and frame text with fonts, sizes, tracking, leading and alignment, placed images (their original JPEG/PNG) and pixel layers (8/16-bit RGB, CMYK), opacity, visibility, locking and blend modes, at the document's resolution in points. Effects, adjustments, brushes and pressure profiles, transparency gradients, master pages, symbol instances (imported as their cached picture), special shapes (cloud, heart, cog…, imported as ellipses) and Affinity-only blend modes are named in the import warning. A file whose native data can't be read opens as its embedded preview with the reason, and that preview can't be placed. Save never writes back over the Affinity file and there is no Affinity export. AF.4 adds Affinity 3 artboard recognition and actual-outline clipping, source-backed JPEG/PNG raster tiles, Unicode text-run recovery, stored fallback/exact installed fonts, OpenType feature flags and compound-geometry limits. 51 public CC0/MIT/Apache-2.0 files (33 current `.af`), pinned and sha256-verified (`cargo xtask corpus --affinity`), test native retention and every-board native/SVG/PDF/PSD output for current files; selected files compare their saved thumbnails. No Affinity reopen or independent paired PSD oracle was available; [source audit and complex-font gaps](affinity-validation.md); [scope, provenance and limits](../crates/affinity/README.md).
   - Placed documents: File › Place of a `.vectorcraft` file links to it by default (`file.place`'s `link`): one locked object showing an artboard of the document (or its art's bounds), read the way placing it without Link reads it, its symbols, patterns and images kept apart from the document's; without Link (or from bytes, not a file) it is an editable copy as before. It stays vectors in every output (SVG, PDF, EPS, EMF, DXF), and so do placed documents inside it, read from their own files up to 8 levels deep (documents that place each other stop there). On screen they draw from bitmaps cached per file and zoom step, shared by every copy and made in the background (a placeholder until ready), so a sheet of them redraws in about a millisecond; exports and prints draw them exactly. Like linked images, a save keeps only a preview of each (JPEG when opaque) unless Include Linked Files; output, and zooming past the preview, read the file again, falling back to the preview with a warning when it is gone or changed. Saves for older versions write them as plain art. Links check, update, relink, Update Links on open, Link Info (the artboard's size), Placement Options, Break Link (also Embed, Object › Expand: the editable copy placing without Link gives, its resources joining the document), Edit Original (the document in a new tab) and the Links panel cover them; saving a document updates the open documents that place it. The native format (v4) keeps data of 8 KB or more after the JSON instead of base64 in it.