SVG export: mask and filter regions cover the art they apply to

Opacity masks, inverted and unclipped masks, and knockout groups were
written with mask and filter regions of 200,000 x 200,000 units around
the origin. CairoSVG draws each mask into an image of its region's size
and stops with "out of memory", so a file with any of them did not
open; Firefox drew inverted masks wrong and WebKit drew knockout groups
and inverted masks wrong.

Each region now covers what the masked or knocked-out art paints: its
visual box grown by its raster effects, brush art and members' reach,
the mask art's box, and in a scaled symbol instance its strokes and
effects at their own size. A mask whose art reaches past its object
still comes back whole on import.

docs/file-format-parity.md

@@ -286,7 +286,7 @@ Names in the editing data that aren't UTF-8 (layers, objects, artboards, colors,
 | PDF | open, place, save | yes (authored ActualText in editable import, #6165; 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+; objects' URLs as link annotations, not in PDF/X) | 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); an image mask (`/ImageMask true`) painted in a solid color opens as a grayscale image colorized by that color, a spot color keeping its swatch and tint, so Fill and Recolor Artwork reach it, and the same mask painted again in another color keeps that color (#6313); an image in a Separation space opens as a grayscale image of its tints colorized by its ink at 100 % (a spot swatch, a process plate or Registration), its soft mask as its opacity mask (#6314); a DeviceN image of one colorant opens the same way, and one of process plates only (the ink `None` may be among them) opens in CMYK with each colorant's tint in its plate (#6348)  PDF export keeps harakat and zero-advance Noto Arabic dot glyphs in one compatible batch per layout line, with per-glyph vertical offsets (#6309). `crates/pdf/src/tests/realtext.rs` (`mark_text_*`) checks decoded cluster mappings, mixed Arabic/Latin/digits, contour placement against outline export, vertical columns, differing path rotations and PDF/X-1a/3/4. Editable-text import preserves authored ActualText separately (#6165), with cross-line/style layout limits; separately styled or differently rotated clusters and external viewer search/copy remain outside this export-only evidence. |
 | EPS | open, place, save | yes (own PostScript L3 interpreter, Illustrator EPS editing data structure) | yes (L2/L3, TIFF previews) | CIDFonts the file doesn't carry not drawn, but for those over a predefined Unicode CMap (`UniJIS-UCS2-H`), set as type in the font of the CIDFont's name; name-keyed fonts in a FontSet set as type by name; #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); an embedded Type 1 font's encrypted part is read for its glyphs, which space its type, outline it and draw glyphs without a character, in plain and composite fonts; a Type 42 font that carries its TrueType font gives each code its character by its glyph name or, for names that say nothing (`/g12`), by the glyph's entry in the font's own character map, spaces its type by its own widths and draws glyphs that stand for no character from its outlines; the show operators' spacing along the baseline (`ashow`, `widthshow`, `xshow`, `yshow`, `xyshow`, and the moves of `kshow`'s procedure, run between each two characters) is kept on live type as tracking, so type in a font that isn't installed keeps the file's line lengths (spacing that moves characters off the baseline, as `yshow`, `xyshow` or a `kshow` procedure can, places each character as its own text object); composite (Type 0) fonts with the 8/8 mapping, as PDF-to-PostScript converters write two-byte fonts, draw a Type 42 descendant's glyphs from the TrueType outlines it carries and an embedded Type 1 descendant's from its charstrings, and set other descendants' characters as type at the composite font's size (other mappings are still set as type in the font of their name); CID-keyed fonts (`composefont`, `FMapType` 9 over a CMap built with the CIDInit operators or `Identity-H`/`Identity-V`; `bfchar` and `bfrange` mappings give a base-font descendant its codes or glyph names) draw the glyphs of the Type 0 CIDFonts (Type 1 charstrings in their `StartData` binary data or `GlyphDirectory`) and Type 2 CIDFonts (TrueType glyphs through `CIDMap`) they carry, and the CID-keyed fonts of a FontSet's Compact Font Format data (Type 2 charstrings); 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); sampled functions (type 0) interpolate between their samples, multilinearly or by cubics with `Order 3`, and a sampled axial or radial gradient has a stop at each sample; a gradient the page paints as a row of abutting one-colour strips (as Level 2 writers draw smooth shades) imports as one linear gradient, without the seams the strips leave when each is drawn alone; 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` |
-| SVG / SVGZ | open, place, save | yes | yes (SVG Options, Preserve Editing, symbols, filters, rich text) | strongest format; tests in `crates/svg/tests`; text on a path follows basic shapes as their SVG 2 equivalent paths (#1527); CSS transforms and the `font` shorthand (#1565), percentage lengths in symbols (#1596), Inkscape flowed text as area type (#1568) and Inkscape pages as artboards (#1601) import; an unsupported filter is named in its warning (#1598); an artboard exported on its own (Export As with Use Artboards, Export for Screens, Asset Export) has the artboard's name as `<title>`, Save the document's (#3544); attributes in other applications' XML namespaces (`plotter:pen="2"`) kept on their objects from import to export, as `data-*` attributes are (`crates/svg/tests/it/foreign_attributes.rs`); simple shapes export as `<rect>`, `<circle>`, `<ellipse>`, `<line>`, `<polygon>` and `<polyline>` where they draw the same as the path (#4652, `crates/svg/tests/it/basic_shapes.rs`) |
+| SVG / SVGZ | open, place, save | yes | yes (SVG Options, Preserve Editing, symbols, filters, rich text) | strongest format; tests in `crates/svg/tests`; text on a path follows basic shapes as their SVG 2 equivalent paths (#1527); CSS transforms and the `font` shorthand (#1565), percentage lengths in symbols (#1596), Inkscape flowed text as area type (#1568) and Inkscape pages as artboards (#1601) import; an unsupported filter is named in its warning (#1598); an artboard exported on its own (Export As with Use Artboards, Export for Screens, Asset Export) has the artboard's name as `<title>`, Save the document's (#3544); attributes in other applications' XML namespaces (`plotter:pen="2"`) kept on their objects from import to export, as `data-*` attributes are (`crates/svg/tests/it/foreign_attributes.rs`); simple shapes export as `<rect>`, `<circle>`, `<ellipse>`, `<line>`, `<polygon>` and `<polyline>` where they draw the same as the path (#4652, `crates/svg/tests/it/basic_shapes.rs`); the regions of exported masks and filters (opacity masks, inverted masks, knockout groups) cover the art they apply to (`crates/svg/tests/it/blend_export.rs`) |
 | DXF | open, export | yes | yes (R12–2018) | R13–2018 closed SPLINE flags and control-point closure on import verified (#1299); circular cubic paths export as native CIRCLE/ARC where stroke semantics permit; R12 weighted strokes remain POLYLINE while non-circular curves keep the existing fallback (`crates/cad/src/tests.rs`); [Autodesk group 70](https://help.autodesk.com/cloudhelp/2024/ENU/AutoCAD-DXF/files/GUID-E1F884F8-AA90-4864-A215-3182D47A9C74.htm). DXF 2000–2018 LAYOUT objects write the paper image origin as 148/149 (was a stray 158), the shade plot codes (2004+) and the model type flag, and the plot style placeholder carries no subclass marker (#3085; structure test `r2000_and_later_files_have_the_structure_cad_apps_require`, checked with ezdxf's audit; not yet confirmed in Autodesk Fusion). CNC preset and VCarve QA remain open |
 | DWG | open, export | no | no | no open spec; DXF instead |
 | EMF / WMF | open, export | yes | yes | an oversized embedded PNG or JPEG is refused from its header, before any pixels are decoded (#1776) |