.ai import: template layers and ruler guides open as they were set

The editing data's layer options set a template layer from the flag four
places after the colour index. The colour index of nine-operand options,
and the colour index and dimming percentage of eleven and twelve operand
options, are read from their own places (they were read one place later).

A straight (N) * guide path directly on a layer that runs across the
whole canvas, or from edge to edge of one artboard, opens as a ruler
guide on that layer (an artboard guide of that artboard); other guide
paths stay guide paths. Guides scale with the document when its editing
data is in the units of a UserUnit page, and an EPS that keeps only its
first artboard keeps only that artboard's guides.

Fixes #779

docs/file-format-parity.md

@@ -92,7 +92,7 @@ the app's own editing copy of a file (an EPS after its `%%EOF`, a `.ai`'s `AIPri
 |---|---|---|---|---|
 | VectorCraft `.vectorcraft` / `.vctemplate` | — | yes | yes | lossless JSON, versioned, save down to v1; property-tested round trips (`format/tests/prop_format.rs`); documents with a lot of path data are written as compact JSON, about a fifth of the size (#1492); a save falls back to a plain fsync and to writing elsewhere and copying in when the folder refuses the usual steps (#1625, #1649, part of #1620; not confirmed on a real network share); the size limits on embedded data also apply to files read from memory (#1783), and saving over a private file on Unix leaves no readable temporary copy beside it (#1778); a dynamic symbol's type (`dynamic` on the symbol) and an instance's appearance changes to its art (`symbol_overrides`, each path at most 64 deep, counted against the object budget) are written only when set, so documents without them save as before (#4938) |
 | Illustrator template `.ait` | open, save | yes | PDF-compatible only, from Save as Template (`.vctemplate` stays its default) | New from Template opens a saved `.ait` untitled with its layers and art (`tests_pdfedit.rs`) |
-| Illustrator `.ai` | open, save | yes (PDF-compatible + editing-data structure, File Info) | PDF-compatible, or legacy version 7 (layers and groups) | see above; no real-file corpus |
+| Illustrator `.ai` | open, save | yes (PDF-compatible + editing-data structure with template layers and ruler guides, File Info) | PDF-compatible, or legacy version 7 (layers and groups) | see above; no real-file corpus |
 | PDF | open, place, save | yes (layers, masks, editable text, security, overprint, File Info from the XMP packet and the document information dictionary; Crop To › Trim takes the bleed box as the document's bleed) | yes (presets, PDF/X-1a/3/4, layers, marks and bleed, ICC, fast web view, 1.3+) | fuzzed import; shared guarded writer and windowed reader ([pdf-backend.md](pdf-backend.md)), metadata, incomplete-content and dependency-source regressions; PDF text opens where the file draws it, glyph by glyph (#722: kerning or none, spacing per character, text rise as baseline shift, vertical writing, justified text boxes); alpha soft masks drawn as images import with the mask (#1551); a clip only counts as covering the page when its shape does (#1542); a PDF another app copied pastes as editable vector art (#1499); letter-spaced type on a path keeps its length and its glyph-by-glyph stroke comes in as one text object (#1586, #1585); a crafted name tree with shared nodes no longer takes exponential time on open (#1781); fonts named with hyphens (`Noto-Sans-Bold`) or with a composite font's CMap (`Name-Identity-H`) find the installed family; invisible text (rendering mode 3: a scanned page's recognized text) opens as type with no fill or stroke and saves back as invisible, searchable text (#2675); PDF/X-1a and X-3 flattening in a CMYK document keeps CMYK inks where it rasterizes (#2160) |
 | EPS | open, place, save | yes (own PostScript L3 interpreter, Illustrator EPS editing data structure) | yes (L2/L3, TIFF previews) | CID-keyed CJK type not read; #505; images encoded with `CCITTFaxDecode` (ITU-T T.4 Group 3 and T.6 Group 4, with `K`, `Columns`, `Rows`, `EndOfBlock`, `EndOfLine`, `EncodedByteAlign` and `BlackIs1`) draw, and damaged data keeps the rows decoded before its first damaged row; Type 42 (TrueType) fonts set type at its size (#1553); a clip only counts as covering the page when its shape does (#1542); an EPS another app copied pastes as editable vector art (`clipboard.importEps`, #1499); a stitched shading keeps its hard colour changes on import (#1654); CMYK images, CMYK JPEGs included, keep their ink amounts on import, as from PDF, and the pixels a `MaskColor` or `ImageType 3` mask hides become a grayscale opacity mask; ruzstd 0.9.1 for compressed editing data (#1807, RUSTSEC-2026-0344) |
 | PostScript `.ps` | open, place | yes (the EPS reader reads its first page; `.epsf` files open and place as EPS) | via Print to PostScript | `tests_epsimport.rs` |

docs/target-app-parity.md

@@ -1069,6 +1069,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     A `.ai` or EPS opened from its editing data with one object on a shown layer that the reader can't read (an unknown operator inside a group, a pattern fill whose pattern it doesn't have, a symbol instance, a placed file without a usable preview) keeps its layers and groups: in that object's place, its layer gets a group of the page's objects inside the object's box, named after it, with a warning that lists what came in as the page's art and an export or Save As to its own path asking first (`acknowledgeLoss`). The file still opens from its page or PDF part when no box can be found, when live art or another unread object shares the page art inside it, when the object spans two artboards, or when the page art doesn't carry the object's transparency (#4806; `crates/eps/src/import/tests_native.rs`, `crates/engine/src/cmd/fileio/tests_aiimport.rs`).
     PDF export and `.ai` saves write a page with a side longer than 14,400 pt with a `UserUnit` (PDF 1.6), its longer side divided by 14,400 and rounded up to the next thousandth, so that no side is longer than 14,400 units (ISO 32000-1, Annex C.2); in PDF 1.3 to 1.5 files and PDF/X files such a page is written in points.
     Placed (linked) files in a `.ai`'s editing data come in as linked images in their place, each showing the low-resolution preview the file keeps of it until its file is found or relinked in the Links panel (a file found next to the document or at its path is read as the document opens). A file with them no longer falls back to its PDF part, so its guides, sublayers and hidden objects open (#1264; `crates/eps/src/import/ai/tests.rs`, `crates/engine/src/tests/links.rs`). In a file opened that way, a gradient with stops in the middle runs its whole ramp across its shape and a gradient object no longer passes its fill to the next path (#1390); text objects with an appearance keep their own text and frame, type of hidden layers stays hidden, and type on later artboards lands on its text objects (#1391); area type whose frame is too short for a line of the fallback font shows its first line, the frame made taller with a warning in the open result (#1392).
+    `.ai` and EPS editing-data import keeps template layers, and opens canvas and artboard ruler guides as ruler guides on their layers; guide objects stay editable guide paths (#779; `crates/eps/src/import/ai/tests.rs`, `crates/eps/src/import/tests_native.rs`).
     A `.ai` saved without PDF compatibility (its PDF part only a placeholder page) is placed and pasted from its editing data, as it opens: File › Place places the art of the layers that show on the first artboard (`file.place`'s `page` places another one), and Paste of it as PDF data (`clipboard.importPdf`) takes every object. `document.open` with `pages` naming every page of such a file opens it the same way (`crates/engine/src/cmd/fileio/tests_aiimport.rs`).
   - 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; grayscale TIFFs with an alpha channel or other extra channels place, relink and open, the alpha as the image's transparency (#1466 in part; CCITT Group 3 and planar files with extra channels are not read); 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).
   - The Open and Place dialogs list PostScript `.ps` files and `.epsf` files. A `.ps` file opens and places through the EPS reader (its first page), also when its header is only `%!`, as the `ps` format, which exports don't write (Print to PostScript does); an `.epsf` file opens and places as EPS. Copied in a file manager, these files paste as EPS, and `clipboard.importEps` also reads PostScript whose header is only `%!` (`crates/engine/src/cmd/fileio/tests_epsimport.rs`).