Part of #641: Image Trace: Create Strokes

Advanced › Create: Fills and/or Strokes, with Stroke (the widest line, px).
With Strokes, each colour's 8-connected parts no wider than the stroke width
(chamfer distance transform) trace as open centre lines instead of filled
outlines: the line is thinned to one pixel (Zhang-Suen with each removal
re-checked, so two-pixel lines survive; staircase corners dropped), its
skeleton becomes runs between ends and junctions (junction pixels merged,
spurs pruned, runs through two-way junctions joined, rings closed), and each
run is simplified and fitted with curves. The stroke width is the line's mean
width (pixels over length). Traced lines get round caps and joins in the
document. Without Fills, wider areas become 1 px stroked outlines.
`imageTrace.make` takes fills, strokes and strokeWidth, and refuses neither
fills nor strokes and a non-positive width.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ROADMAP.md

@@ -4,7 +4,7 @@ VectorCraft is a clean-room, open-source, pure-Rust reimplementation of the Adob
 
 This file tracks **how far we are and what's left**. Time estimates are wall-clock hours of continuous Claude Opus 5.5 agent work (including builds and the CI gate), given both for **one agent** and for **4–6 parallel agents** on disjoint crates. They are counted from the remaining work (see [Parity estimate](#parity-estimate)), calibrated against measured throughput, and updated as work lands.
 
-_Last updated: 2026-10-09 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated
+_Last updated: 2026-10-09 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated
 
 ## Where we are
 
@@ -143,9 +143,9 @@ grade by behaviour against `plan/illustrator/`, not by whether a menu item exist
 - **Type:** Text Wrap, Type on a Path effects (Rainbow/Skew/3D Ribbon/Stair Step/Gravity) and Options (Flip, Align to Path, Spacing; OK keeps the type where it is), type on a path's start, centre and end brackets (Selection and Direct Selection drag them to set where the type runs, slide it along its path and, across the path, flip it: #429), Character and Paragraph Styles (override-preserving redefine), paragraph attributes per paragraph (alignment, indents, spacing, hyphenation, hanging punctuation, tab stops, paragraph style, direction, mojikumi and leading model; the Paragraph, Tabs and Paragraph Styles panels act on the paragraphs the Type tool's selection or caret touches, Return continues the paragraph's style, threads and SVG keep them), Area Type Options (rows/columns/inset/first baseline, vertical Align Top/Center/Bottom/Justify per row/column, reflowing non-rectangular frames and text wrap), threaded text across any closed shapes, Fit Headline, the Every-line Composer for justified and ragged text (paragraph-wide breaks for an even rag, Single-line per object from the Paragraph panel menu or `text.setFormat {composer}`). Area type resizes like Illustrator's type areas: a bounding-box handle drag (Selection tool) or Area Type Options Width/Height size the frame and the text reflows at its size (threads too); Direct Selection drags a frame corner or edge (`text.reshapeArea`). Point type still scales. Auto Size: the frame height follows the text after every edit, in the same undo step (rectangular frames of horizontal type in one row; columns get the least height that holds them; a height set by hand or threading turns it off), and the "Auto Size New Area Type" preference gives it to new area type. Shrink Text to Fit (beyond Illustrator): overflowing area type scales its sizes, leading and baseline shifts down by the largest factor (in 0.1 pt steps of the first run, down to a minimum percentage) that fits, at layout time so every export sees it. `text.areaOptions` and `document.inspect` report overflow and the shrink factor. The Selection tool shows the type widget beside selected type's bounding box (hollow on point type, filled on area type); double-clicking it converts between them (Type › Convert To Area Type / Convert To Point Type), keeping the text and its styles in place. Variable fonts list every named instance as a style of their family (Figtree Light to Black and their italics, Bahnschrift, Segoe UI Variable), and the instance chosen is shaped, drawn, outlined and measured at its axis settings; PDF and SVG embed it as that instance. Variation axis sliders are not done. Beyond Illustrator: inline graphics (`text.insertInline`, Type ▸ Insert Inline Symbol) set a document symbol in a run of type as one character that flows, wraps and justifies like a glyph (InDesign-style inline objects, e.g. mana symbols in card rules text): sized to a multiple of the font size, centred on the cap height, opening up tall lines, following Redefine Symbol; a character of its run's size for Character Alignment and Top-to-Top leading, placed by the bidi reordering in right-to-left text (a neutral U+FFFC); drawn on the canvas, kept as live text plus a `<use>` in SVG and as vector art in PDF; Backspace removes it whole. Hebrew and Arabic are laid out right to left with the Unicode bidirectional algorithm (embedded Latin and numbers keep their direction, lines put in visual order after wrapping) in point, area and path type, with caret, selection and arrow keys in visual order; each paragraph's direction comes from its first strong character unless Paragraph Direction sets it (Paragraph panel with Show Indic Options, `text.setFormat {direction}`), and new type aligns to the start of its direction. SVG export outlines right-to-left text. Font Size and Leading are combo boxes in the Character and Properties panels (Font Size in the Control bar too, beside the Character link, font family and style): type, step with ↑/↓ or the spinner, scrub the label, or pick a preset (6–72 pt, shown in the type unit; Leading also Auto), each pick one undo step; Kerning and Tracking list -100…200; a size, leading, kerning or tracking the selected text doesn't share shows blank (#458).
 - **Interface languages, vertical type:** VectorCraft ▸ Language (or Preferences ▸ User Interface) picks Automatic (the system locale) or a registered language, persisted as `interfaceLanguage`. Translations come from per-language catalogs (`i18n/*.tsv`): Traditional and Simplified Chinese, Japanese, Spanish (neutral international Spanish, for every `es-*` locale), French (every `fr-*` locale), Italian (every `it-*` locale) and Russian (every `ru-*` locale) cover the whole interface, Czech and Brazilian Portuguese every menu label, Brazilian Portuguese the shell's `tl!` literals too (tested); Spanish, French, Italian and Russian also translate status-bar and error messages as they are shown (`@msg` templates, every message literal tested; the messages themselves stay English for agents); untranslated text stays English. Japanese and Chinese glyphs come from the craft-fonts build input (release builds) or the installed fonts, Czech, Spanish, French, Italian and Russian ones from the bundled UI fonts. The web app follows the browser's languages (or `?lang=`). The Basic toolbar's Type button holds Vertical Type in its flyout. Vertical Type, Vertical Area Type and Vertical Type on a Path create vertical text (columns right to left, upright CJK glyphs and marks with `vert` alternates, Latin and longer numbers on their side, two- and three-digit numbers set as tate-chu-yoko in one em of the column (kept whole when justified), upright glyphs centred on the column (tracked or justified too), point type's anchor on the first column's centre line); kinsoku (the strict set) applies to horizontal and vertical Japanese, and justified Japanese lines spread their room between characters (not inside Latin words); Paragraph panel › Mojikumi Set (shown with Preferences › Type › Show East Asian Options, `text.setFormat {mojikumi}`): None or Line-end Punctuation Half Width (new type's default, as in Illustrator; older documents and imported text keep None) shares one half-em space between consecutive punctuation, sets a closing mark ending a line half width and an opening bracket starting a wrapped line flush with its start, and puts a quarter em between Japanese and Latin letters or digits; Paragraph panel menu › Top-to-Top / Bottom-to-Bottom Leading measures leading from em box top to top (area type's first line touches the frame) or from baseline to baseline (new type in a Japanese interface starts top to top, with em box centre character alignment, #432); Paragraph panel menu › Burasagari None / Regular / Force (`text.setFormat {burasagari: "none"|"standard"|"forced"}`) hangs an East Asian comma or full stop (、。，．､｡) ending an area type line outside it, Regular (new type's default) when it doesn't fit and Force always (the rest of the line then fills the measure; closing brackets and Latin punctuation don't hang); Character panel menu › Character Alignment (with the East Asian options; `text.setFormat` or `text.setRangeStyle {charAlign}`) lines characters smaller than the largest on their line up on the Roman baseline, the em box top/right, centre or bottom/left, or the ICF (ideographic character face) top/right or bottom/left, from the font's BASE table or, without one, the average ink box of some ideographs and kana; Type ▸ Type Orientation switches existing text; caret, selection, hit testing and arrow keys follow the writing direction. Vertical text exports to PDF as real text and to SVG as outlines.
 - **Transparency:** opacity masks (clip/invert/disable/link), exported as SVG `<mask>` and PDF soft masks.
-- **Advanced art:** live Blends (steps/distance/smooth colour, editable spine, anchor-targeted Blend tool, faithful interpolation, knockout), Envelope Distort (warp/mesh/top object, Reset, full Envelope Options, mesh handles, Edit Contents; type, images, symbols, gradients, patterns and appearance distorted everywhere), Liquify tools with options and pen pressure, Puppet Warp with rotating pins, Perspective Grid with presets, movable planes and projected type (choosing a perspective tool shows the grid; Hide Grid hides it with the tool still chosen), Gradient Mesh, Shape Builder (stroke-only open paths and lines cut the regions they cross and enclose regions of their own; filled open paths count as closed; erase mode while Alt/Option is held: a minus pointer, red highlights of what will go, a click or drag deletes the regions touched, the pieces of open lines and the edges (outline pieces between the points where paths meet, opening their paths there) it passes over, one undo step, `shapeBuilder.merge {erase}` and `shapeBuilder.regions` edges over MCP), Live Paint (every path an edge, open lines included), Image Trace (12 presets, colour layers traced in parallel; a trace past two million anchor points or an image over 64 megapixels is refused with advice rather than running out of memory, and a selection too large to outline shows its bounds (#525); Object › Image Trace › Make and Make and Expand trace at once with the Default preset, #543; with an image selected the Control bar and the Properties panel show Image Trace, whose arrow traces with any preset, Mask (`object.maskImage`: a clipping path on the image's outline, selected so its handles crop), Crop Image and Embed or Unembed in place of Fill and Stroke; with an Image Trace object selected, its Preset (choosing another traces again), the Image Trace panel and Expand, plus Release in Properties; the View modes are not done), pattern swatches with pattern editing mode, live Repeat (radial/grid/mirror).
+- **Advanced art:** live Blends (steps/distance/smooth colour, editable spine, anchor-targeted Blend tool, faithful interpolation, knockout), Envelope Distort (warp/mesh/top object, Reset, full Envelope Options, mesh handles, Edit Contents; type, images, symbols, gradients, patterns and appearance distorted everywhere), Liquify tools with options and pen pressure, Puppet Warp with rotating pins, Perspective Grid with presets, movable planes and projected type (choosing a perspective tool shows the grid; Hide Grid hides it with the tool still chosen), Gradient Mesh, Shape Builder (stroke-only open paths and lines cut the regions they cross and enclose regions of their own; filled open paths count as closed; erase mode while Alt/Option is held: a minus pointer, red highlights of what will go, a click or drag deletes the regions touched, the pieces of open lines and the edges (outline pieces between the points where paths meet, opening their paths there) it passes over, one undo step, `shapeBuilder.merge {erase}` and `shapeBuilder.regions` edges over MCP), Live Paint (every path an edge, open lines included), Image Trace (12 presets, colour layers traced in parallel; a trace past two million anchor points or an image over 64 megapixels is refused with advice rather than running out of memory, and a selection too large to outline shows its bounds (#525); Object › Image Trace › Make and Make and Expand trace at once with the Default preset, #543; with an image selected the Control bar and the Properties panel show Image Trace, whose arrow traces with any preset, Mask (`object.maskImage`: a clipping path on the image's outline, selected so its handles crop), Crop Image and Embed or Unembed in place of Fill and Stroke; with an Image Trace object selected, its Preset (choosing another traces again), the Image Trace panel and Expand, plus Release in Properties; Advanced › Create: Fills and/or Strokes, where lines up to the Stroke width trace as stroked centre lines (distance transform, thinning, a skeleton graph with spurs pruned, curve fitting; one width per line; without Fills, wider areas become stroked outlines), part of #641; the View modes are not done), pattern swatches with pattern editing mode, live Repeat (radial/grid/mirror).
 - **Paint and appearance (M3):**
-  - **Swatches:** names follow the colour model and are unique; Swatch Options (process/spot, Global, Gray/RGB/HSB/CMYK/Web, live preview); editing a global or spot swatch recolours every linked fill, stroke and text run in one undo step; multi-select and delete with confirmation; New Swatch and New Color Group dialogs (a group from the selected artwork's colours); swatches in colour groups convert, separate and count like any other. The Swatches panel selects ranges and whole groups, has a find field, and drags swatches to reorder, regroup or paint art; Add Used Colors, Select All Unused, Merge, Ungroup and Sort by Kind; a CMYK document keeps applied colours in CMYK. Swatch libraries: nine generated colour libraries and five gradient libraries in a library panel, saved and loaded as `.vcswatches`, `.gpl` or CSS. Tints of global and spot colours ("Name 40%") stay linked and separate as a percentage of their plate. Spot colours can be defined in Lab (Spot Colors options). A built-in [Registration] swatch prints on every plate.
+  - **Swatches:** names follow the colour model and are unique; Swatch Options (process/spot, Global, Gray/RGB/HSB/CMYK/Web, live preview); editing a global or spot swatch recolours every linked fill, stroke and text run in one undo step; multi-select and delete with confirmation; New Swatch and New Color Group dialogs (a group from the selected artwork's colours); swatches in colour groups convert, separate and count like any other. The Swatches panel selects ranges and whole groups, has a find field, and drags swatches to reorder, regroup or paint art; Add Used Colors, Select All Unused, Merge, Ungroup and Sort by Kind; a CMYK document keeps applied colours in CMYK. Swatch libraries: nine generated colour libraries and five gradient libraries in a library panel, saved as `.vcswatches`, `.gpl` or CSS, and loaded from `.vcswatches`, `.gpl` and swatch exchange (`.ase`) files (RGB, CMYK, Lab and Gray; global, spot and process; groups). Tints of global and spot colours ("Name 40%") stay linked and separate as a percentage of their plate. Spot colours can be defined in Lab (Spot Colors options). A built-in [Registration] swatch prints on every plate.
   - **Colour:** a Color Picker (colour field, H/S/B/R/G/B channel slider, HSB/RGB/Lab/CMYK fields, hex, web-only snapping, out-of-gamut correction); the Color panel follows each colour's own model and Alt-click paints the other proxy; proxies look through groups and show "?" for mixed paint; Invert, Complement, Apply Last Color (`,`) and Apply Last Gradient (`.`) keep the colour model; every paint command feeds the recent colours. The Color Guide has 21 harmony rules, Steps and Variation options and Limit to Library. Adjust Color Balance (its Global mode shifts tints) and Saturate preview live; Edit Colors and Recolor also reach meshes, images and patterns. Recolor Artwork has colour reduction, five recolour methods, presets, Limit to Library, a colour-wheel Edit tab and Edit Color Group; a local Color Themes panel saves five-colour themes. Fill/Stroke chips open swatch and mixer popovers (the Properties panel has the Control bar's Fill and Stroke chips, Stroke link and weight spinner, with nothing selected too), panels have Illustrator's Window menu keys (Align Shift+F7, Transform Shift+F8, Pathfinder Cmd+Shift+F9, Layers F7, Character Cmd+T…; every panel can be given one in Edit › Keyboard Shortcuts), and Eyedropper Options pick up and apply chosen attributes (Alt and Shift+Alt, image pixels). Fills and strokes can overprint (Attributes panel, Overprint Black options), and CMYK documents blend in inks on screen, in PDF and when flattening. Document Color Mode converts the art, symbols, pattern tiles and swatches through the colour settings: Gray stays Gray, RGB greys separate into four-colour greys and a rich black as Illustrator does, or go on the black plate only with `grays: "black"` (also for `document.open {colorMode}`).
   - **Gradients:** lossless, validated gradient params; gradients follow rotate, reflect, shear, non-uniform scale and distortions; the Gradient tool edits the fill or stroke of the active proxy, type included; an interactive on-canvas annotator (move, length/angle, rotate, add/move/delete/duplicate stops, midpoints, a stop popover, Delete and arrow keys). The Gradient panel has the Fill/Stroke proxy, a gradient-swatch dropdown with Save to Swatches, midpoint locations, Alt-drag to copy or swap stops, swatch drops on the ramp and a stop eyedropper; copied appearances and graphic styles place gradients on each target's own bounds; gradient handles snap and honour Constrain Angle. Gradient stops stay linked to global and spot swatches. Freeform gradients (points and lines) are edited on the canvas; radial gradients have an extent ellipse, an aspect handle and an off-centre focal point (SVG `fx`/`fy`, PDF two-point radials). A stroke's gradient runs within, along or across it. Object ▸ Expand turns gradients into N objects or a gradient mesh.
   - **Strokes:** one stroke-geometry module shared by the canvas, SVG, PDF and Outline Stroke; dotted lines (zero-length dashes draw dots or squares); arrowheads with hollow outlines, tip-on-end or extend-past-end alignment and one opacity for line and head. SVG and PDF export arrowheads, width profiles, brushes and aligned strokes exactly as the canvas draws them; Outline Stroke and the live Outline Stroke effect outline every stroke item as drawn (dashes, heads, profiles, alignment); dashes can be fitted to corners and path ends; width profiles carry through dashes, and their corners take the join. The Stroke panel edits type's character strokes, follows the stroke units (its weight presets are round values in that unit: `0.25 mm`, `0.0625 in`, `1 px`, #426; fields show four decimals in mm, cm and inches, three in points), shows mixed values blank and opens from the Control bar. A width profile library, thirty more arrowheads, and Width Point Edit with multi-select and discontinuous points. Visual bounds and clicks cover the whole painted stroke. Scale Strokes & Effects, Scale Corners and Use Preview Bounds work everywhere, and new art inherits stroke options, a graphic style or the whole last appearance.
@@ -158,7 +158,7 @@ grade by behaviour against `plan/illustrator/`, not by whether a menu item exist
 - **Fonts:** a font is found by any of its names (family and style in every language of its name table, legacy family/style pairs, PostScript name), so documents from other apps open with the font they name; Find Font and `text.fonts` say for each font whether it was found exactly, by another name, substituted or missing, and how many glyphs are missing. PDF and `.ai` import brings Japanese text back as live type: CID fonts without a ToUnicode map read through the standard CMaps, vertical columns (WMode 1) as vertical type, letter spacing as tracking; a glyph is live type only when the installed font (in the closest style of its family) draws the same glyph, and text in a font that isn't installed comes in as live type shown in the fallback font until the font is installed (exports that draw it — PDF, EPS, EMF/WMF, raster, SVG outlines or embedded fonts — warn that they wrote the fallback font; `textAs: outlines` keeps the PDF's embedded glyphs).
 - **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; 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; 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).
+  - 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; 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).
   - 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. 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).
   - 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.
   - Place and the Links panel, Package, File Info, Print with print presets, PostScript output and print tiling, slices and Save for Web, Export for Screens and Asset Export, CSS Properties, PNG/PDF/SVG/text clipboard flavours; files copied in a file manager paste as art (SVG, PDF, EMF/WMF, bitmaps) on every desktop platform, and Linux/Wayland reads the compositor's clipboard (#398); on Linux the Paste menu checks the clipboard off the UI thread, so an X11 owner that never answers can't freeze the window (#510); screenshots and other copied pictures paste as embedded images at the view centre everywhere, the web included (#457).
@@ -215,7 +215,7 @@ about 1–1.5 agent-hours each, so the other rows (estimated on the older scale)
 | Type core | 9 | 80% | Middle Eastern features beyond bidi layout and Paragraph Direction (Character Direction, digit types, kashidas, the Middle Eastern composers, editable bidirectional SVG text, a split caret where directions meet); Hyphenation… and Justification… options (Every-line Composer for justified and ragged text, per object, is done; it is tuned by eye, not yet compared side by side with Illustrator; mixed type sizes in a paragraph still break single-line), Optical Margin Alignment, paragraph spacing limit for vertically justified area type, hidden characters, paragraph attributes in the Type tool's copy and paste (the characters keep their styles, the paragraphs take the destination's), mixed-value display in the Paragraph panel for a selection across differing paragraphs, Transform Again after a type-area resize (it scales the type), partial selection of type-area anchors by marquee | 14–19 |
 | Type advanced | 4 | 50% | CJK composition for vertical type (ruby, mojikumi beyond Line-end Punctuation Half Width — the other sets (and their paragraph-start bracket and indent rules), kinsoku sets and the Mojikumi Settings dialog —, proportional vertical metrics, manual tate-chu-yoko), variable font axis sliders (named instances are styles), tab leaders, spell check (open dictionary), Touch Type, Retype; vertical point/area/path type and Type Orientation have initial support (beyond parity, not scored: inline symbols in text) | 20–28 |
 | Symbols, blends, envelopes, Repeat, perspective | 5 | 88% | symbol libraries (original), dynamic symbols, envelope Anti-Alias/Preserve Shape output and warp point editing, brush interpolation in blends (M8 fidelity pass done) | 5–8 |
-| Image Trace, graphs, image tools | 3 | 70% | graph Design/Column/Marker, Create Object Mosaic, Crop Image polish (an on-canvas crop box), Image Trace View modes (Outlines, Source Image) (Vector Halftone is done) | 6–10 |
+| Image Trace, graphs, image tools | 3 | 70% | graph Design/Column/Marker, Create Object Mosaic, Crop Image polish (an on-canvas crop box), Image Trace View modes (Outlines, Source Image), per-feature stroke/fill choice and varying widths in Create Strokes (Vector Halftone is done) | 6–10 |
 | Layers, artboards, document setup | 5 | 82% | Layers panel: a confirmation before deleting layers that hold art, Collect for Export, row context menus, the Layer Options dialog for several rows with mixed values, Paste Remembers Layers for sublayers, drag-scrolling a long panel while dragging rows; artboard presets/rearrange polish (Document Setup, New Document and the rest of the Layers panel are done) | 4–7 |
 | View & navigation | 3 | 70% | New View/Edit Views, multiple windows/arrange, Snap to Pixel/Glyph (print tiling is done) | 9–14 |
 | Guides, grids, smart guides, snapping, rulers | 3 | 84% | global/video rulers, Spacing Guides, Smart Guides' angle and distance readouts while drawing, Alt swapping a ruler guide's orientation, ruler guides selected together with art (marquee, Shift-click), ruler guides as Layers rows with their own lock and hide (#451: Lock Guides locks them all; Make Guides paths are Layers rows already) (dragging existing guides is done, #414; new guides snapping to side midpoints and artboards, and artboard guides, #451; the drawing tools snapping, with Construction Guides, #506) | 2–4 |

contributors/people.toml

@@ -31,3 +31,7 @@ sync_github_name = true
 
 [people.omd0]
 sync_github_name = true
+
+[people.dotCooCoo]
+real_name = "Robert Lee"
+sync_github_name = true

crates/color/src/palette_io.rs

@@ -1,6 +1,9 @@
 //! Swatch library files: the native `.vcswatches` JSON (colour models, global, spot, gradients
 //! and colour groups exactly), `.gpl` palettes (8-bit RGB; colour groups as `# Group:` comment
-//! headers) and CSS custom properties (written only).
+//! headers) and CSS custom properties (written only). Swatch exchange files (`.ase`) are read
+//! only ([`read_bytes`]).
+
+use std::collections::{HashMap, HashSet};
 
 use serde::{Deserialize, Serialize};
 
@@ -58,6 +61,15 @@ struct NativeFile {
 const NATIVE_FORMAT: &str = "vcswatches";
 const GPL_HEADER: &str = "GIMP Palette";
 const GPL_GROUP: &str = "# Group:";
+const ASE_SIGNATURE: &[u8] = b"ASEF";
+const ASE_GROUP_START: u16 = 0xC001;
+const ASE_GROUP_END: u16 = 0xC002;
+const ASE_COLOR: u16 = 0x0001;
+/// The most colors and groups read from one `.ase` file.
+const ASE_MAX_ENTRIES: usize = 100_000;
+/// The most UTF-16 code units of a name that are kept.
+const ASE_MAX_NAME: usize = 1024;
+const ASE_CUT_SHORT: &str = "the swatch exchange file is cut short";
 
 /// Write `lib` in `format`. Pattern swatches (their tiles live in a document) and None are left
 /// out; `.gpl` keeps solid colours only, as 8-bit RGB.
@@ -199,16 +211,34 @@ pub fn sniff(text: &str) -> bool {
     t.starts_with(GPL_HEADER) || (t.starts_with('{') && t.contains(NATIVE_FORMAT))
 }
 
+/// Read the bytes of a library file: a swatch exchange `.ase` file, else a `.vcswatches` or
+/// `.gpl` library ([`read`]). `name` names it when the file doesn't.
+pub fn read_bytes(bytes: &[u8], name: &str) -> Result<SwatchLibrary, String> {
+    if bytes.starts_with(ASE_SIGNATURE) {
+        return read_ase(bytes, name);
+    }
+    read(&String::from_utf8_lossy(bytes), name)
+}
+
+/// Are `bytes` a library [`read_bytes`] understands? Text that isn't valid UTF-8 is checked as
+/// [`read_bytes`] reads it, with the invalid bytes replaced (its first KiB is enough).
+pub fn sniff_bytes(bytes: &[u8]) -> bool {
+    bytes.starts_with(ASE_SIGNATURE)
+        || std::str::from_utf8(bytes).is_ok_and(sniff)
+        || sniff(&String::from_utf8_lossy(bytes.get(..1024).unwrap_or(bytes)))
+}
+
 /// `.gpl`: `Name:` names the library, `# Group: name` starts a colour group, other `#` lines and
-/// headers (`Columns:`) are skipped, as are lines that aren't `r g b [name]`. Unnamed colours are
-/// named by their values; repeated names get a number.
+/// headers (`Columns:`) are skipped, as are lines that aren't `r g b [name]`. Unnamed colors are
+/// named by their values and unnamed groups "Color Group"; a name a color or group already has gets
+/// a number ([`UniqueNames`]).
 fn read_gpl(text: &str, fallback: &str) -> SwatchLibrary {
     let mut lib = SwatchLibrary { name: fallback.into(), ..Default::default() };
-    let mut names: Vec<String> = vec![];
+    let mut names = UniqueNames::default();
     for line in text.lines().skip(1) {
         let line = line.trim();
         if let Some(g) = line.strip_prefix(GPL_GROUP) {
-            lib.groups.push(SwatchGroup { name: g.trim().to_string(), swatches: vec![] });
+            lib.groups.push(SwatchGroup { name: names.unique(group_name(g)), swatches: vec![] });
             continue;
         }
         if let Some(n) = line.strip_prefix("Name:") {
@@ -221,9 +251,7 @@ fn read_gpl(text: &str, fallback: &str) -> SwatchLibrary {
         let [r, g, b] = rgb[..] else { continue };
         let rest = words[3..].join(" ");
         let base = if rest.is_empty() { format!("R={r} G={g} B={b}") } else { rest };
-        let name = (1..).map(|i| if i == 1 { base.clone() } else { format!("{base} {i}") }).find(|n| !names.contains(n)).unwrap_or(base);
-        names.push(name.clone());
-        let w = Swatch { name, paint: Paint::solid(Color::rgb8(r, g, b)), global: false, spot: false };
+        let w = Swatch { name: names.unique(base), paint: Paint::solid(Color::rgb8(r, g, b)), global: false, spot: false };
         match lib.groups.last_mut() {
             Some(grp) => grp.swatches.push(w),
             None => lib.swatches.push(w),
@@ -232,6 +260,184 @@ fn read_gpl(text: &str, fallback: &str) -> SwatchLibrary {
     lib
 }
 
+/// `.ase`, from public descriptions of the format: the layout from
+/// <https://www.selapa.net/swatches/colors/fileformats.php>, the component ranges from
+/// <https://github.com/nsfmc/swatch>. After the signature come, big-endian, a `u16` major (1) and
+/// minor version, a `u32` block count and the blocks, each a `u16` type, a `u32` body length and
+/// the body. A group start's body is a name. A color's body is a name, a four-character model
+/// (`RGB `, `CMYK`, `LAB `, `Gray`), its components as `f32` (3, 4, 3 and 1 of them) and a `u16`
+/// color type (0 global, 1 spot, 2 process). RGB, CMYK and gray components run from 0 to 1 (a
+/// gray level of 1 is white), Lab lightness from 0 to 1 and a and b from −128 to 127. A lightness
+/// above 1 is read as L* itself. A name is a `u16` count of UTF-16 code units, the terminating zero
+/// included, then the units.
+///
+/// Color groups become groups: a group start inside an open group ends that group, and a group
+/// left open ends with the file. Blocks of other types and colors in other models are skipped.
+/// Unnamed colors are named by their values and unnamed groups "Color Group"; a name a color or
+/// group already has gets a number ([`UniqueNames`]). A truncated file, a major version other than
+/// 1 or more than [`ASE_MAX_ENTRIES`] colors and groups is an error.
+fn read_ase(bytes: &[u8], fallback: &str) -> Result<SwatchLibrary, String> {
+    let mut data = AseData(bytes);
+    data.bytes(ASE_SIGNATURE.len())?;
+    let (major, minor) = (data.u16()?, data.u16()?);
+    if major != 1 {
+        return Err(format!("swatch exchange version {major}.{minor} isn't supported (only 1.x)"));
+    }
+    let blocks = data.u32()?;
+    let mut lib = SwatchLibrary { name: fallback.into(), ..Default::default() };
+    let mut names = UniqueNames::default();
+    let (mut in_group, mut entries) = (false, 0usize);
+    for _ in 0..blocks {
+        let kind = data.u16()?;
+        let len = usize::try_from(data.u32()?).unwrap_or(usize::MAX);
+        let mut body = AseData(data.bytes(len)?);
+        if matches!(kind, ASE_GROUP_START | ASE_COLOR) {
+            entries += 1;
+            if entries > ASE_MAX_ENTRIES {
+                return Err(format!("the swatch exchange file holds more than {ASE_MAX_ENTRIES} colors and groups"));
+            }
+        }
+        match kind {
+            ASE_GROUP_START => {
+                lib.groups.push(SwatchGroup { name: names.unique(group_name(&body.name()?)), swatches: vec![] });
+                in_group = true;
+            }
+            ASE_GROUP_END => in_group = false,
+            ASE_COLOR => {
+                let Some(mut w) = ase_swatch(&mut body)? else { continue };
+                w.name = names.unique(std::mem::take(&mut w.name));
+                match lib.groups.last_mut().filter(|_| in_group) {
+                    Some(g) => g.swatches.push(w),
+                    None => lib.swatches.push(w),
+                }
+            }
+            // Other blocks are skipped.
+            _ => {}
+        }
+    }
+    Ok(lib)
+}
+
+/// The swatch of an `.ase` color block, `None` for a model other than RGB, CMYK, Lab and Gray.
+/// Components are clamped to their ranges.
+fn ase_swatch(body: &mut AseData) -> Result<Option<Swatch>, String> {
+    let name = body.name()?;
+    let unit = |v: f32| v.clamp(0.0, 1.0);
+    let color = match &body.array::<4>()? {
+        b"RGB " => {
+            let [r, g, b] = [body.f32()?, body.f32()?, body.f32()?];
+            Color::rgb(unit(r), unit(g), unit(b))
+        }
+        b"CMYK" => {
+            let [c, m, y, k] = [body.f32()?, body.f32()?, body.f32()?, body.f32()?];
+            Color::cmyk(unit(c), unit(m), unit(y), unit(k))
+        }
+        // Lightness is stored as a fraction of 100. Some writers store L* itself, which shows as a
+        // value above 1.
+        b"LAB " => {
+            let [l, a, b] = [body.f32()?, body.f32()?, body.f32()?];
+            let l = if l > 1.0 { l.min(100.0) } else { unit(l) * 100.0 };
+            Color::lab(l, a.clamp(-128.0, 127.0), b.clamp(-128.0, 127.0))
+        }
+        // A gray level (1 is white); a gray color holds its ink.
+        b"Gray" => Color::gray(1.0 - unit(body.f32()?)),
+        _ => return Ok(None),
+    };
+    // Some writers leave the color type out, which makes a process color.
+    let kind = if body.0.len() >= 2 { body.u16()? } else { 2 };
+    // Spot colors are global.
+    let (global, spot) = match kind {
+        0 => (true, false),
+        1 => (true, true),
+        _ => (false, false),
+    };
+    let name = if name.is_empty() { value_name(color) } else { name };
+    Ok(Some(Swatch { name, paint: Paint::solid(color), global, spot }))
+}
+
+/// A color's values in its own model, as new swatches are named ("C=10 M=20 Y=30 K=0",
+/// "R=255 G=128 B=0", "Gray K=40", "L=52 a=70 b=-30").
+fn value_name(c: Color) -> String {
+    let pct = |v: f32| (v * 100.0).round();
+    let byte = |v: f32| (v * 255.0).round();
+    match c {
+        Color::Cmyk { c, m, y, k } => format!("C={} M={} Y={} K={}", pct(c), pct(m), pct(y), pct(k)),
+        Color::Rgb { r, g, b } => format!("R={} G={} B={}", byte(r), byte(g), byte(b)),
+        Color::Gray { k } => format!("Gray K={}", pct(k)),
+        // `+ 0.0` turns a rounded -0 into 0.
+        Color::Lab { l, a, b } => format!("L={} a={} b={}", l.round() + 0.0, a.round() + 0.0, b.round() + 0.0),
+    }
+}
+
+/// `.ase` data, read field by field; reading past its end is an error.
+struct AseData<'a>(&'a [u8]);
+
+impl<'a> AseData<'a> {
+    fn bytes(&mut self, n: usize) -> Result<&'a [u8], String> {
+        let (head, rest) = self.0.split_at_checked(n).ok_or(ASE_CUT_SHORT)?;
+        self.0 = rest;
+        Ok(head)
+    }
+    fn array<const N: usize>(&mut self) -> Result<[u8; N], String> {
+        let (head, rest) = self.0.split_first_chunk::<N>().ok_or(ASE_CUT_SHORT)?;
+        self.0 = rest;
+        Ok(*head)
+    }
+    fn u16(&mut self) -> Result<u16, String> {
+        self.array().map(u16::from_be_bytes)
+    }
+    fn u32(&mut self) -> Result<u32, String> {
+        self.array().map(u32::from_be_bytes)
+    }
+    /// A component; one that isn't a finite number reads as 0.
+    fn f32(&mut self) -> Result<f32, String> {
+        let v = f32::from_be_bytes(self.array()?);
+        Ok(if v.is_finite() { v } else { 0.0 })
+    }
+    /// A name up to its terminating zero, trimmed. A block that ends before it has no name.
+    fn name(&mut self) -> Result<String, String> {
+        if self.0.is_empty() {
+            return Ok(String::new());
+        }
+        let n = usize::from(self.u16()?);
+        let (units, _) = self.bytes(n * 2)?.as_chunks::<2>();
+        let units: Vec<u16> = units.iter().take(ASE_MAX_NAME).map(|u| u16::from_be_bytes(*u)).take_while(|&u| u != 0).collect();
+        Ok(String::from_utf16_lossy(&units).trim().to_string())
+    }
+}
+
+/// A group's name as a file gives it, trimmed; "Color Group" when it has none.
+fn group_name(name: &str) -> String {
+    let name = name.trim();
+    if name.is_empty() { "Color Group".into() } else { name.to_string() }
+}
+
+/// The swatch and group names a reader has handed out. Swatches and color groups share one set of
+/// names, as in a document, and a name already taken gets the first free number ("Black 2").
+#[derive(Default)]
+struct UniqueNames {
+    taken: HashSet<String>,
+    /// The last number tried for each repeated name.
+    last: HashMap<String, usize>,
+}
+
+impl UniqueNames {
+    fn unique(&mut self, base: String) -> String {
+        if self.taken.insert(base.clone()) {
+            return base;
+        }
+        // Each pass tries the next number, and only finitely many names are taken.
+        let n = self.last.entry(base.clone()).or_insert(1);
+        loop {
+            *n += 1;
+            let name = format!("{base} {n}");
+            if self.taken.insert(name.clone()) {
+                return name;
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -294,6 +500,11 @@ mod tests {
         assert_eq!(names, ["Sky Blue", "R=10 G=20 B=30", "Black", "Black 2"]);
         assert_eq!(lib.swatches[0].paint.color(), Some(Color::rgb8(0, 128, 255)));
         assert_eq!(read("GIMP Palette\n1 2 3 x\n", "Fallback").unwrap().name, "Fallback");
+        // Colors and groups share names; an unnamed group is "Color Group".
+        let lib = read("GIMP Palette\n0 0 0 Black\n# Group: Black\n1 1 1 Black\n# Group:\n", "x").unwrap();
+        let groups: Vec<(&str, Vec<&str>)> =
+            lib.groups.iter().map(|g| (g.name.as_str(), g.swatches.iter().map(|w| w.name.as_str()).collect())).collect();
+        assert_eq!(groups, [("Black 2", vec!["Black 3"]), ("Color Group", vec![])]);
     }
 
     #[test]
@@ -321,4 +532,117 @@ mod tests {
         assert!(text.contains("--red: #000000;") && text.contains("--red-2: #000000;"));
         assert!(read(&text, "x").is_err(), "CSS is written only");
     }
+
+    /// A swatch exchange file of `blocks` (type, body).
+    fn ase(blocks: &[(u16, Vec<u8>)]) -> Vec<u8> {
+        let mut out = b"ASEF\0\x01\0\0".to_vec();
+        out.extend((blocks.len() as u32).to_be_bytes());
+        for (kind, body) in blocks {
+            out.extend(kind.to_be_bytes());
+            out.extend((body.len() as u32).to_be_bytes());
+            out.extend(body);
+        }
+        out
+    }
+
+    /// A name as `.ase` stores it.
+    fn ase_name(name: &str) -> Vec<u8> {
+        let units: Vec<u16> = name.encode_utf16().chain([0]).collect();
+        let mut out = (units.len() as u16).to_be_bytes().to_vec();
+        out.extend(units.iter().flat_map(|u| u.to_be_bytes()));
+        out
+    }
+
+    /// A color block: name, model, components and color type.
+    fn ase_color(name: &str, model: &[u8; 4], values: &[f32], kind: u16) -> (u16, Vec<u8>) {
+        let mut body = ase_name(name);
+        body.extend(model);
+        body.extend(values.iter().flat_map(|v| v.to_be_bytes()));
+        body.extend(kind.to_be_bytes());
+        (ASE_COLOR, body)
+    }
+
+    #[test]
+    fn ase_reads_color_models_kinds_and_groups() {
+        let bytes = ase(&[
+            ase_color("Sky", b"RGB ", &[0.0, 0.5, 1.0], 0),
+            ase_color("Ink", b"CMYK", &[1.0, 0.5, 0.0, 0.2], 1),
+            (ASE_GROUP_START, ase_name("Neutrals")),
+            ase_color("Mist", b"Gray", &[0.75], 2),
+            ase_color("Clay", b"LAB ", &[0.5, 20.0, -30.0], 2),
+            (ASE_GROUP_END, vec![]),
+            ase_color("Paper", b"RGB ", &[1.0, 1.0, 1.0], 2),
+        ]);
+        assert!(sniff_bytes(&bytes));
+        let sw = |name: &str, color, global, spot| Swatch { name: name.into(), paint: Paint::solid(color), global, spot };
+        let expected = SwatchLibrary {
+            name: "Brand".into(),
+            swatches: vec![
+                sw("Sky", Color::rgb(0.0, 0.5, 1.0), true, false),
+                sw("Ink", Color::cmyk(1.0, 0.5, 0.0, 0.2), true, true),
+                sw("Paper", Color::WHITE, false, false),
+            ],
+            groups: vec![SwatchGroup {
+                name: "Neutrals".into(),
+                swatches: vec![sw("Mist", Color::gray(0.25), false, false), sw("Clay", Color::lab(50.0, 20.0, -30.0), false, false)],
+            }],
+        };
+        assert_eq!(read_bytes(&bytes, "Brand").unwrap(), expected, "named after the file; 0 global, 1 spot, 2 process");
+        // A lightness above 1 is L* itself.
+        let deep = read_bytes(&ase(&[ase_color("Deep", b"LAB ", &[53.0, 20.0, -30.0], 2)]), "x").unwrap();
+        assert_eq!(deep.swatches[0].paint.color(), Some(Color::lab(53.0, 20.0, -30.0)));
+        // Text libraries read through the same call, also when they aren't valid UTF-8.
+        assert!(sniff_bytes(b"GIMP Palette\n1 2 3 x\n") && !sniff_bytes(b"ASE") && !sniff_bytes(&[0xff, 0xfe, 0]));
+        assert_eq!(read_bytes(b"GIMP Palette\n1 2 3 x\n", "F").unwrap().swatches.len(), 1);
+        let latin1 = b"GIMP Palette\n1 2 3 Caf\xe9\n";
+        assert!(sniff_bytes(latin1));
+        assert_eq!(read_bytes(latin1, "F").unwrap().swatches.len(), 1);
+    }
+
+    #[test]
+    fn ase_names_unnamed_and_repeated_entries_and_skips_other_blocks() {
+        let mut untyped = ase_color("Plain", b"RGB ", &[0.2, 0.4, 0.6], 2);
+        untyped.1.truncate(untyped.1.len() - 2);
+        let bytes = ase(&[
+            ase_color("Café 🎨", b"RGB ", &[1.0, 0.0, 0.0], 2),
+            ase_color("", b"CMYK", &[0.1, 0.2, 0.3, 0.0], 2),
+            ase_color(" Red ", b"RGB ", &[2.0, -1.0, f32::NAN], 0),
+            ase_color("Red", b"Gray", &[0.0], 2),
+            untyped,
+            ase_color("Hue", b"HSB ", &[0.1, 0.2, 0.3], 2),
+            (0x0042, vec![1, 2, 3]),
+            (ASE_GROUP_END, vec![]),
+            (ASE_GROUP_START, ase_name("")),
+            (ASE_GROUP_START, ase_name("Red")),
+            ase_color("Red", b"Gray", &[1.0], 2),
+        ]);
+        let lib = read_bytes(&bytes, "x").unwrap();
+        let names: Vec<&str> = lib.swatches.iter().map(|w| w.name.as_str()).collect();
+        assert_eq!(names, ["Café 🎨", "C=10 M=20 Y=30 K=0", "Red", "Red 2", "Plain"], "an HSB color and an unknown block are skipped");
+        assert_eq!(lib.swatches[2].paint.color(), Some(Color::rgb(1.0, 0.0, 0.0)), "clamped, NaN read as 0");
+        assert!(lib.swatches[2].global && !lib.swatches[4].global, "without a color type: process");
+        // A group start ends the open group, and groups and colors share names.
+        let groups: Vec<(&str, Vec<&str>)> =
+            lib.groups.iter().map(|g| (g.name.as_str(), g.swatches.iter().map(|w| w.name.as_str()).collect())).collect();
+        assert_eq!(groups, [("Color Group", vec![]), ("Red 3", vec!["Red 4"])]);
+        assert_eq!(lib.groups[1].swatches[0].paint.color(), Some(Color::gray(0.0)), "gray level 1 is white");
+    }
+
+    #[test]
+    fn damaged_ase_files_are_errors() {
+        let good = ase(&[(ASE_GROUP_START, ase_name("G")), ase_color("Sky", b"RGB ", &[0.0, 0.5, 1.0], 0)]);
+        assert_eq!(read_bytes(&good, "x").unwrap().len(), 1);
+        for n in ASE_SIGNATURE.len()..good.len() {
+            assert!(read_bytes(&good[..n], "x").is_err(), "cut at {n}");
+        }
+        let mut v2 = good.clone();
+        v2[5] = 2;
+        assert!(read_bytes(&v2, "x").unwrap_err().contains("2.0"), "version 2.0");
+        // Too many colors, or too many groups (empty group starts take 6 bytes each).
+        let colors: Vec<(u16, Vec<u8>)> = (0..=ASE_MAX_ENTRIES).map(|_| ase_color("Gray", b"Gray", &[0.5], 2)).collect();
+        assert!(read_bytes(&ase(&colors), "x").unwrap_err().contains("more than"));
+        let groups: Vec<(u16, Vec<u8>)> = (0..=ASE_MAX_ENTRIES).map(|_| (ASE_GROUP_START, vec![])).collect();
+        assert!(read_bytes(&ase(&groups), "x").unwrap_err().contains("more than"));
+        assert_eq!(read_bytes(&ase(&groups[1..]), "x").unwrap().groups.len(), ASE_MAX_ENTRIES, "up to the limit");
+    }
 }

crates/engine/src/cmd/buildcmds.rs

@@ -14,7 +14,7 @@ use std::sync::Arc;
 
 use serde_json::{Value, json};
 use vectorcraft_color::{Color, Paint};
-use vectorcraft_doc::appearance::{AppearanceItem, FillLayer, StrokeLayer};
+use vectorcraft_doc::appearance::{AppearanceItem, FillLayer, LineCap, LineJoin, StrokeLayer};
 use vectorcraft_doc::{Appearance, Document, Node, NodeId, NodeKind, Selection};
 use vectorcraft_geom::{FillRule, PathData, Point, Rect, SubPath};
 use vectorcraft_pathops as po;
@@ -120,7 +120,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Make",
             ["Object", "Image Trace"],
             None,
-            "{id?: image or Image Trace group (default: selection), preset?: name (imageTrace.presets), params?: {mode: \"blackAndWhite\"|\"grayscale\"|\"color\", threshold: 0-255, colors: 2-256, paths: 0-100, corners: 0-100, noise: px, method: \"abutting\"|\"overlapping\", ignoreWhite, snapCurvesToLines}} → {id, paths, anchors, colors}",
+            "{id?: image or Image Trace group (default: selection), preset?: name (imageTrace.presets), params?: {mode: \"blackAndWhite\"|\"grayscale\"|\"color\", threshold: 0-255, colors: 2-256, paths: 0-100, corners: 0-100, noise: px, method: \"abutting\"|\"overlapping\", ignoreWhite, snapCurvesToLines, fills: true, strokes: false (Create: lines up to strokeWidth wide become stroked centre lines; without fills, wider areas become stroked outlines), strokeWidth: px (10)}} → {id, paths, anchors, colors}",
             has_selection_or_ids,
             |s, p| trace_make(s, p, false)
         ),
@@ -648,7 +648,14 @@ fn trace_params(p: &Value) -> Result<tr::TraceParams> {
     for (k, val) in src {
         o.insert(k.clone(), val.clone());
     }
-    serde_json::from_value(v).map_err(|e| bad("imageTrace.make", e.to_string()))
+    let params: tr::TraceParams = serde_json::from_value(v).map_err(|e| bad("imageTrace.make", e.to_string()))?;
+    if !params.fills && !params.strokes {
+        return Err(bad("imageTrace.make", "Create needs fills, strokes or both"));
+    }
+    if !(params.stroke_width.is_finite() && params.stroke_width > 0.0) {
+        return Err(bad("imageTrace.make", "strokeWidth must be a positive number of pixels"));
+    }
+    Ok(params)
 }
 
 /// The most anchor points an Image Trace may make: a photo traced at high fidelity can make
@@ -692,6 +699,8 @@ fn trace_make(s: &mut Session, p: &Value, expand: bool) -> Result<Value> {
     let sx = img.width.max(1) as f64 / raster.width.max(1) as f64;
     let sy = img.height.max(1) as f64 / raster.height.max(1) as f64;
     let xf = img.xf * vectorcraft_geom::Affine::scale_non_uniform(sx, sy);
+    // Document units per raster pixel (stroke widths).
+    let unit = xf.determinant().abs().sqrt();
     let (npaths, anchors, colors) = (res.paths.len(), res.anchor_count(), res.palette.len());
     let label = if expand { "Image Trace (Make and Expand)" } else { "Image Trace" };
     let id = s.edit(label, |d, sel| {
@@ -714,7 +723,19 @@ fn trace_make(s: &mut Session, p: &Value, expand: bool) -> Result<Value> {
         for tp in res.paths {
             let path = tp.path.transformed(xf);
             let mut n = shape_node(d, path, None);
-            n.appearance = fill_only(Paint::solid(Color::rgb8(tp.color[0], tp.color[1], tp.color[2])));
+            let paint = Paint::solid(Color::rgb8(tp.color[0], tp.color[1], tp.color[2]));
+            n.appearance = match tp.stroke {
+                // Traced lines: round ends and corners, as drawn lines have.
+                Some(width) => Appearance {
+                    items: vec![AppearanceItem::Stroke(StrokeLayer {
+                        cap: LineCap::Round,
+                        join: LineJoin::Round,
+                        ..StrokeLayer::new(paint, width * unit)
+                    })],
+                    ..Default::default()
+                },
+                None => fill_only(paint),
+            };
             children.push(Arc::new(n));
         }
         let gid = d.alloc_id();

crates/engine/src/cmd/stylelib.rs

@@ -70,8 +70,8 @@ pub fn specs() -> Vec<CommandSpec> {
 
 impl LibraryFile for StyleLibrary {
     const EXTS: &'static [&'static str] = &[STYLES_EXT];
-    fn read(text: &str, stem: &str) -> std::result::Result<Self, String> {
-        style_libs::read(text, stem)
+    fn read(bytes: &[u8], stem: &str) -> std::result::Result<Self, String> {
+        style_libs::read(&String::from_utf8_lossy(bytes), stem)
     }
     fn name(&self) -> &str {
         &self.name

crates/engine/src/cmd/swatchlib.rs

@@ -69,7 +69,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Other Library…",
             ["Window", "Swatch Libraries"],
             None,
-            "{path? | data?: file text | dataBase64?, name?: file name (default: the path's)} load a .vcswatches or .gpl library, or the swatches of any document VectorCraft opens (see document.formats), for the library panel (Window → Swatch Libraries lists it until the app quits) → {library: id, name, count}",
+            "{path? | data?: file text | dataBase64?, name?: file name (default: the path's)} load a .vcswatches, .gpl or .ase (swatch exchange) library, or the swatches of any document VectorCraft opens (see document.formats), for the library panel (Window → Swatch Libraries lists it until the app quits) → {library: id, name, count}",
             always,
             load
         ),
@@ -98,23 +98,24 @@ struct Extra<L> {
 pub trait LibraryFile: Sized {
     /// The extensions of its files (lower case).
     const EXTS: &'static [&'static str];
-    /// Read a library file whose name without the extension is `stem` (an unnamed library's name).
-    fn read(text: &str, stem: &str) -> std::result::Result<Self, String>;
+    /// Read the bytes of a library file whose name without the extension is `stem` (an unnamed
+    /// library's name).
+    fn read(bytes: &[u8], stem: &str) -> std::result::Result<Self, String>;
     fn name(&self) -> &str;
 }
 
 impl LibraryFile for SwatchLibrary {
     const EXTS: &'static [&'static str] = LIBRARY_EXTS;
-    fn read(text: &str, stem: &str) -> std::result::Result<Self, String> {
-        palette_io::read(text, stem)
+    fn read(bytes: &[u8], stem: &str) -> std::result::Result<Self, String> {
+        palette_io::read_bytes(bytes, stem)
     }
     fn name(&self) -> &str {
         &self.name
     }
 }
 
-/// The extensions of library files [`palette_io::read`] reads.
-pub const LIBRARY_EXTS: &[&str] = &["vcswatches", "gpl"];
+/// The extensions of library files [`palette_io::read_bytes`] reads.
+pub const LIBRARY_EXTS: &[&str] = &["vcswatches", "gpl", "ase"];
 
 impl<L: LibraryFile> Libraries<L> {
     pub fn user_dir(&self) -> Option<&str> {
@@ -133,7 +134,7 @@ impl<L: LibraryFile> Libraries<L> {
         let Some(dir) = self.user_dir.clone() else { return };
         for path in library_files(&dir, L::EXTS) {
             let file = file_name(&path);
-            let Some(lib) = read_file(&path).ok().and_then(|b| L::read(&String::from_utf8_lossy(&b), stem(&file)).ok()) else { continue };
+            let Some(lib) = read_file(&path).ok().and_then(|b| L::read(&b, stem(&file)).ok()) else { continue };
             let info = LibraryInfo { id: format!("user/{file}"), name: lib.name().to_string(), category: "user" };
             self.extra.push(Extra { info, path: Some(path), lib: Arc::new(lib) });
         }
@@ -351,12 +352,11 @@ fn load(s: &mut Session, p: &Value) -> Result<Value> {
     const C: &str = "swatch.library.load";
     let (info, lib) = s.swatch_libraries.load(p, C, |bytes, file| {
         // A library file, or a document whose swatches become the library.
-        match std::str::from_utf8(bytes).ok().filter(|t| palette_io::sniff(t)) {
-            Some(t) => palette_io::read(t, stem(file)).map_err(|e| bad(C, e)),
-            None => {
-                let doc = super::fileio::load(file, bytes).map_err(|e| bad(C, e.to_string()))?.doc;
-                document_library(&doc, &[], stem(file).to_string(), C)
-            }
+        if palette_io::sniff_bytes(bytes) {
+            palette_io::read_bytes(bytes, stem(file)).map_err(|e| bad(C, e))
+        } else {
+            let doc = super::fileio::load(file, bytes).map_err(|e| bad(C, e.to_string()))?.doc;
+            document_library(&doc, &[], stem(file).to_string(), C)
         }
     })?;
     Ok(json!({"library": info.id, "name": info.name, "count": lib.len()}))
@@ -417,12 +417,17 @@ fn add(s: &mut Session, p: &Value) -> Result<Value> {
     } else {
         s.edit("Add to Swatches", |d, _| {
             let mut out = vec![];
+            // Each library group goes into one document group: the group of that name the document
+            // already had, or one made here.
+            let before = d.swatch_groups.len();
+            let mut placed: Vec<(&str, usize)> = vec![];
             for (group, w) in fresh {
                 let name = d.free_swatch_name(&w.name);
                 let sw = Swatch { name: name.clone(), ..(*w).clone() };
                 match group {
                     Some(g) => {
-                        let i = match d.swatch_groups.iter().position(|x| x.name == *g) {
+                        let found = placed.iter().find(|(n, _)| *n == g).map(|&(_, i)| i);
+                        let i = match found.or_else(|| d.swatch_groups.iter().take(before).position(|x| x.name == *g)) {
                             Some(i) => i,
                             None => {
                                 let name = d.free_swatch_name(g);
@@ -430,6 +435,9 @@ fn add(s: &mut Session, p: &Value) -> Result<Value> {
                                 d.swatch_groups.len() - 1
                             }
                         };
+                        if found.is_none() {
+                            placed.push((g, i));
+                        }
                         d.swatch_groups[i].swatches.push(sw);
                     }
                     None => d.swatches.push(sw),

crates/engine/src/tests_build.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 
 use serde_json::{Value, json};
 use vectorcraft_color::{Color, Paint};
-use vectorcraft_doc::{ImageBlob, ImageObject, Node, NodeKind};
+use vectorcraft_doc::{AppearanceItem, ImageBlob, ImageObject, LineCap, LineJoin, Node, NodeKind};
 use vectorcraft_geom::{Affine, FillRule, PathData, Rect};
 use vectorcraft_tools::{Mods, PointerEvent, PointerKind};
 
@@ -669,6 +669,39 @@ fn image_trace_make_and_expand_and_color_presets() {
     assert!(s.execute("imageTrace.make", &json!({"params": {"mode": "rainbow"}})).is_err());
 }
 
+#[test]
+fn image_trace_create_strokes_makes_stroked_centre_lines() {
+    let mut s = session();
+    // A 3 px wide horizontal line from x = 10 to 90 at y = 50, placed at 2× from (100, 100).
+    let r =
+        vectorcraft_trace::Raster::from_fn(100, 100, |x, y| if (10..90).contains(&x) && (49..52).contains(&y) { [0, 0, 0, 255] } else { [255; 4] });
+    add_image(&mut s, &r, Affine::translate((100.0, 100.0)) * Affine::scale(2.0));
+    let res = s.execute("imageTrace.make", &json!({"params": {"ignoreWhite": true, "strokes": true, "strokeWidth": 5}})).unwrap();
+    assert_eq!(res["paths"], 1);
+    let g = NodeId(res["id"].as_u64().unwrap());
+    let paths = traced_paths(&node(&s, g));
+    let line = &paths[0];
+    assert!(line.appearance.fill_paint().color().is_none(), "not filled");
+    let st = line.appearance.items.iter().find_map(|i| if let AppearanceItem::Stroke(st) = i { Some(st) } else { None }).expect("stroked");
+    assert!((st.width - 6.0).abs() < 1.0, "3 px at 2× is about 6 pt: {}", st.width);
+    assert_eq!((st.cap, st.join), (LineCap::Round, LineJoin::Round));
+    assert_eq!(st.paint, Paint::solid(Color::rgb8(0, 0, 0)));
+    let sp = &line.path_data().unwrap().subpaths[0];
+    assert!(!sp.closed);
+    let (a, b) = (sp.anchors[0].p, sp.anchors[sp.anchors.len() - 1].p);
+    assert!((a.y - 201.0).abs() < 1.5 && (b.y - 201.0).abs() < 1.5 && (a.x - b.x).abs() > 140.0, "{a:?} … {b:?}");
+    let t = node(&s, g).trace.unwrap();
+    assert_eq!((t["params"]["strokes"].as_bool(), t["params"]["strokeWidth"].as_f64()), (Some(true), Some(5.0)));
+    // Expand keeps the stroked line.
+    s.execute("imageTrace.expand", &json!({})).unwrap();
+    assert!(node(&s, g).children().unwrap()[0].appearance.items.iter().any(|i| matches!(i, AppearanceItem::Stroke(_))));
+    // Create needs Fills or Strokes, and a stroke width.
+    s.execute("edit.undo", &json!({})).unwrap();
+    for p in [json!({"fills": false, "strokes": false}), json!({"strokes": true, "strokeWidth": 0}), json!({"strokeWidth": -3})] {
+        assert!(s.execute("imageTrace.make", &json!({"id": g.0, "params": p})).is_err(), "{p}");
+    }
+}
+
 #[test]
 fn image_trace_presets_query_and_errors() {
     let mut s = session();

crates/engine/src/tests_swatchlib.rs

@@ -197,6 +197,74 @@ fn another_documents_swatches_load_as_a_library() {
     assert!(s.execute("swatch.library.load", &json!({"data": "hello", "name": "x.txt"})).is_err());
 }
 
+#[test]
+fn swatch_exchange_files_load_add_and_list_as_user_libraries() {
+    let bytes = vectorcraft_testkit::ase::sample();
+    let mut s = session();
+    let r = run(&mut s, "swatch.library.load", json!({"dataBase64": vectorcraft_format::base64_encode(&bytes), "name": "Brand.ase"}));
+    assert_eq!((r["library"].as_str(), r["name"].as_str(), r["count"].as_u64()), (Some("loaded/Brand.ase"), Some("Brand"), Some(4)));
+    let g = run(&mut s, "swatch.library.get", json!({"library": r["library"]}));
+    let swatches = g["swatches"].as_array().unwrap();
+    let kinds: Vec<(&str, bool, bool)> =
+        swatches.iter().map(|w| (w["name"].as_str().unwrap(), w["global"].as_bool().unwrap(), w["spot"].as_bool().unwrap())).collect();
+    assert_eq!(kinds, [("Sky", true, false), ("Ink", true, true), ("Mist", false, false), ("Clay", false, false)]);
+    assert_eq!(swatches[3]["color"], json!({"model": "lab", "l": 50.0, "a": 20.0, "b": -30.0}));
+    // Added to the document, the spot color stays a spot color and the group stays a color group.
+    run(&mut s, "swatch.library.add", json!({"library": r["library"]}));
+    let d = doc(&s);
+    assert!(d.swatch("Ink").is_some_and(|w| w.spot && w.global));
+    assert_eq!(d.swatch_groups.iter().find(|g| g.name == "Neutrals").map(|g| g.swatches.len()), Some(2));
+    // A damaged file is an error from the swatch exchange reader, not from the document loader.
+    let cut = vectorcraft_format::base64_encode(&bytes[..bytes.len() - 1]);
+    let e = s.execute("swatch.library.load", &json!({"dataBase64": cut, "name": "Cut.ase"})).unwrap_err().to_string();
+    assert!(e.contains("cut short"), "{e}");
+    // `.ase` files in the user library folder are User Defined libraries.
+    let dir = temp_dir("ase");
+    std::fs::create_dir_all(&dir).unwrap();
+    std::fs::write(dir.join("Brand.ase"), &bytes).unwrap();
+    s.swatch_libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
+    let list = run(&mut s, "swatch.library.list", json!({}));
+    let user: Vec<(&str, u64)> = list["libraries"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .filter(|l| l["category"] == "user")
+        .map(|l| (l["id"].as_str().unwrap(), l["count"].as_u64().unwrap()))
+        .collect();
+    assert_eq!(user, [("user/Brand.ase", 4)]);
+    let _ = std::fs::remove_dir_all(dir);
+}
+
+#[test]
+fn a_library_group_stays_one_group_when_a_swatch_has_its_name() {
+    use vectorcraft_testkit::ase::{Block, ase};
+    let mut s = session();
+    assert!(doc(&s).swatch("Blue").is_some(), "a new document has a swatch named Blue");
+    let bytes = ase(&[
+        Block::GroupStart("Blue"),
+        Block::Color("Deep", b"RGB ", &[0.0, 0.0, 0.4], 2),
+        Block::Color("Pale", b"RGB ", &[0.6, 0.7, 1.0], 2),
+        Block::GroupEnd,
+        Block::GroupStart("Blue 2"),
+        Block::Color("Frost", b"RGB ", &[0.9, 0.95, 1.0], 2),
+        Block::GroupEnd,
+    ]);
+    let r = run(&mut s, "swatch.library.load", json!({"dataBase64": vectorcraft_format::base64_encode(&bytes), "name": "Blues.ase"}));
+    run(&mut s, "swatch.library.add", json!({"library": r["library"]}));
+    let groups: Vec<(&str, Vec<&str>)> =
+        doc(&s).swatch_groups.iter().map(|g| (g.name.as_str(), g.swatches.iter().map(|w| w.name.as_str()).collect())).collect();
+    assert!(groups.contains(&("Blue 2", vec!["Deep", "Pale"])), "{groups:?}");
+    assert!(groups.contains(&("Blue 2 2", vec!["Frost"])), "the library's own Blue 2 stays apart: {groups:?}");
+}
+
+#[test]
+fn text_libraries_sent_as_bytes_load_when_they_are_not_valid_utf8() {
+    let mut s = session();
+    let latin1 = vectorcraft_format::base64_encode(b"GIMP Palette\n237 28 36 Rouge fonc\xe9\n");
+    let r = run(&mut s, "swatch.library.load", json!({"dataBase64": latin1, "name": "Rouge.gpl"}));
+    assert_eq!(r["count"], 1);
+}
+
 #[test]
 fn gradient_libraries_are_listed_and_gradient_swatches_rename_and_take_new_gradients() {
     let mut s = session();

crates/engine/src/tests_xform.rs

@@ -247,10 +247,13 @@ fn artboard_tool_moves_with_art_creates_and_deletes() {
     assert_eq!(s.doc().unwrap().doc.artboards.len(), 2);
     assert_eq!(s.tool_options()["active"], 1);
     assert_eq!(s.doc().unwrap().doc.artboards[1].rect, Rect::new(1000.0, 0.0, 1200.0, 100.0));
-    // Delete it.
+    // Delete it: the tool takes the key ahead of the Clear shortcut (the UI only hands Delete to a
+    // tool that claims it).
+    assert!(s.tool_claims_key(ToolKey::Delete, ViewInfo::default()));
     s.tool_key(ToolKey::Delete, Mods::default(), ViewInfo::default()).unwrap();
     assert_eq!(s.doc().unwrap().doc.artboards.len(), 1);
-    // The last artboard can't be deleted.
+    // The last artboard can't be deleted, so Delete stays the shortcut's.
+    assert!(!s.tool_claims_key(ToolKey::Delete, ViewInfo::default()));
     s.tool_key(ToolKey::Delete, Mods::default(), ViewInfo::default()).unwrap();
     assert_eq!(s.doc().unwrap().doc.artboards.len(), 1);
 }

crates/engine/tests/import_fuzz.rs

@@ -1,5 +1,5 @@
 //! Untrusted files never crash the app: garbage, truncated, mutated and hostile SVG, PDF and DXF input,
-//! mutated raster images placed with File → Place, and swatch (`.vcswatches`, `.gpl`), graphic style (`.vcstyles`) and flattener preset
+//! mutated raster images placed with File → Place, and swatch (`.vcswatches`, `.gpl`, `.ase`), graphic style (`.vcstyles`) and flattener preset
 //! (`.vcflattener`) libraries, and native files (compressed, damaged, saved for older versions),
 //! must load as an error or as a document that then renders and exports, without a panic; nor may
 //! bitmaps, PDF and text pasted from other apps, nor EMF and WMF pictures (damaged files, records
@@ -529,12 +529,21 @@ fn saved(cmd: &str, params: Value) -> String {
     rich_session().execute(cmd, &params).unwrap()["data"].as_str().unwrap().to_string()
 }
 
+/// `r`, after failing the case if the command panicked. The engine's guard reports a panic as
+/// `EngineError::Internal`.
+fn no_panic(r: Result<Value, vectorcraft_engine::EngineError>) -> Result<Value, vectorcraft_engine::EngineError> {
+    if let Err(vectorcraft_engine::EngineError::Internal { cmd, msg }) = &r {
+        panic!("{cmd} panicked: {msg}");
+    }
+    r
+}
+
 /// Library file `data` loaded with `load`; what it holds is then used on the rich document
 /// (`then`, given the load's result), which renders and exports.
 fn survive_library(what: &str, load: &str, data: &str, then: impl FnOnce(&mut vectorcraft_engine::Session, &Value)) -> Result<(), TestCaseError> {
     survive(what, || {
         let mut s = rich_session();
-        let r = s.execute(load, &json!({"data": data, "name": "fuzz"})).ok()?;
+        let r = no_panic(s.execute(load, &json!({"data": data, "name": "fuzz"}))).ok()?;
         then(&mut s, &r);
         Some((*s.doc().ok()?.doc).clone())
     })
@@ -542,27 +551,55 @@ fn survive_library(what: &str, load: &str, data: &str, then: impl FnOnce(&mut ve
 
 fn swatches(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "swatch.library.load", data, |s, r| {
-        let _ = s.execute("swatch.library.add", &json!({"library": r["library"], "apply": "fill"}));
+        let _ = no_panic(s.execute("swatch.library.add", &json!({"library": r["library"], "apply": "fill"})));
     })
 }
 
 fn styles(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "graphicStyle.loadLibrary", data, |s, r| {
-        let _ = s.execute("select.all", &json!({}));
-        let _ = s.execute("graphicStyle.addFromLibrary", &json!({"library": r["library"], "apply": true}));
+        let _ = no_panic(s.execute("select.all", &json!({})));
+        let _ = no_panic(s.execute("graphicStyle.addFromLibrary", &json!({"library": r["library"], "apply": true})));
     })
 }
 
 fn flattener_presets(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "flattener.presets.import", data, |s, r| {
-        let _ = s.execute("select.all", &json!({}));
+        let _ = no_panic(s.execute("select.all", &json!({})));
         if let Some(name) = r["imported"].get(0) {
-            let _ = s.execute("flattener.preview", &json!({"preset": name, "highlight": "allAffected"}));
-            let _ = s.execute("object.flattenTransparency", &json!({"preset": name, "lineArtPpi": 36, "gradientPpi": 36}));
+            let _ = no_panic(s.execute("flattener.preview", &json!({"preset": name, "highlight": "allAffected"})));
+            let _ = no_panic(s.execute("object.flattenTransparency", &json!({"preset": name, "lineArtPpi": 36, "gradientPpi": 36})));
         }
     })
 }
 
+/// Swatch exchange (`.ase`) bytes loaded as a swatch library, then added to the rich document.
+fn swatch_exchange(what: &str, bytes: &[u8]) -> Result<(), TestCaseError> {
+    survive(what, || {
+        let mut s = rich_session();
+        let load = json!({"dataBase64": vectorcraft_format::base64_encode(bytes), "name": "fuzz.ase"});
+        let r = no_panic(s.execute("swatch.library.load", &load)).ok()?;
+        let _ = no_panic(s.execute("swatch.library.add", &json!({"library": r["library"], "apply": "fill"})));
+        Some((*s.doc().ok()?.doc).clone())
+    })
+}
+
+/// A random swatch exchange block (type, body). The body holds a name, a color model when the block
+/// is a color, and random bytes for the rest.
+fn arb_ase_block() -> impl Strategy<Value = (u16, Vec<u8>)> {
+    let kind = prop::sample::select(vec![0xC001u16, 0xC002, 0x0001, 0x0042]);
+    let model = prop::sample::select(vec![*b"RGB ", *b"CMYK", *b"LAB ", *b"Gray", *b"HSB "]);
+    (kind, "[ -~]{0,8}", model, prop::collection::vec(any::<u8>(), 0..24)).prop_map(|(kind, name, model, rest)| {
+        let units: Vec<u16> = name.encode_utf16().chain([0]).collect();
+        let mut body = (units.len() as u16).to_be_bytes().to_vec();
+        body.extend(units.iter().flat_map(|u| u.to_be_bytes()));
+        if kind == 0x0001 {
+            body.extend(model);
+        }
+        body.extend(rest);
+        (kind, body)
+    })
+}
+
 /// Characters that break JSON and GPL palettes.
 fn arb_edit() -> impl Strategy<Value = (usize, char)> {
     (0usize..20_000, prop::sample::select(vec!['{', '}', '[', ']', '"', ':', ',', '-', '9', 'e', '.', ' ', '\n', '#', 'n', 'x', '\t']))
@@ -596,6 +633,32 @@ proptest! {
         let text = saved("flattener.presets.export", json!({"names": ["high", "medium", "low"]}));
         flattener_presets("mutated flattener presets", &mutate_text(&text, cut, &edits))?;
     }
+
+    #[test]
+    fn swatch_exchange_garbage_never_panics(blocks in prop::collection::vec(arb_ase_block(), 0..12), tail in prop::collection::vec(any::<u8>(), 0..16)) {
+        let mut bytes = b"ASEF\0\x01\0\0".to_vec();
+        bytes.extend((blocks.len() as u32).to_be_bytes());
+        for (kind, body) in &blocks {
+            bytes.extend(kind.to_be_bytes());
+            bytes.extend((body.len() as u32).to_be_bytes());
+            bytes.extend(body);
+        }
+        bytes.extend(tail);
+        swatch_exchange("swatch exchange garbage", &bytes)?;
+    }
+
+    #[test]
+    fn mutated_swatch_exchange_files_never_panic(cut in prop::option::of(0usize..200), edits in prop::collection::vec((0usize..200, any::<u8>()), 0..12)) {
+        let mut bytes = vectorcraft_testkit::ase::sample();
+        for (at, b) in edits {
+            let n = bytes.len();
+            bytes[at % n] = b;
+        }
+        if let Some(cut) = cut {
+            bytes.truncate(cut);
+        }
+        swatch_exchange("mutated swatch exchange file", &bytes)?;
+    }
 }
 
 /// A small image of each raster format Place reads, with resolution metadata where it has some.
@@ -704,8 +767,8 @@ proptest! {
 fn pdf_presets(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "pdf.preset.import", data, |s, r| {
         for name in r["imported"].as_array().into_iter().flatten() {
-            let _ = s.execute("document.exportPdf", &json!({"preset": name}));
-            let _ = s.execute("document.save", &json!({"format": "ai", "preset": name}));
+            let _ = no_panic(s.execute("document.exportPdf", &json!({"preset": name})));
+            let _ = no_panic(s.execute("document.save", &json!({"format": "ai", "preset": name})));
         }
     })
 }
@@ -1219,14 +1282,14 @@ proptest! {
 /// each one imported.
 fn print_presets(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "print.presets.import", data, |s, r| {
-        let list = s.execute("print.presets.list", &json!({})).unwrap_or_default();
+        let list = no_panic(s.execute("print.presets.list", &json!({}))).unwrap_or_default();
         for name in r["imported"].as_array().into_iter().flatten() {
             let Some(p) = list["presets"].as_array().into_iter().flatten().find(|p| &p["name"] == name) else { continue };
             let settings = json!({ "settings": p["settings"] });
-            let pages = s.execute("print.preview", &settings).ok().and_then(|v| v["pages"].as_u64());
-            let _ = s.execute("print.setup", &settings);
+            let pages = no_panic(s.execute("print.preview", &settings)).ok().and_then(|v| v["pages"].as_u64());
+            let _ = no_panic(s.execute("print.setup", &settings));
             if pages.is_some_and(|n| n <= 8) {
-                let _ = s.execute("file.print", &settings);
+                let _ = no_panic(s.execute("file.print", &settings));
             }
         }
     })
@@ -1256,9 +1319,11 @@ proptest! {
 fn perspective_presets(what: &str, data: &str) -> Result<(), TestCaseError> {
     survive_library(what, "perspective.presets.import", data, |s, r| {
         for name in r["imported"].as_array().into_iter().flatten() {
-            let _ = s.execute("perspective.grid.preset", &json!({"name": name}));
-            let _ = s.execute("perspective.grid.define", &json!({"name": name, "gridline": 3}));
-            let _ = s.execute("perspective.draw", &json!({"command": "shape.rectangle", "params": {"x": 300, "y": 400, "width": 40, "height": 30}}));
+            let _ = no_panic(s.execute("perspective.grid.preset", &json!({"name": name})));
+            let _ = no_panic(s.execute("perspective.grid.define", &json!({"name": name, "gridline": 3})));
+            let _ = no_panic(
+                s.execute("perspective.draw", &json!({"command": "shape.rectangle", "params": {"x": 300, "y": 400, "width": 40, "height": 30}})),
+            );
         }
     })
 }

crates/mcp/src/prompts.rs

@@ -296,7 +296,8 @@ Method:
 1. open_file the image: it becomes a document of its own pixel size.
 2. imageTrace.make with the preset name, adjusting `params` — mode blackAndWhite, grayscale or
    color, then threshold, colors, paths, corners, noise, method abutting or overlapping,
-   ignoreWhite, snapCurvesToLines. Run imageTrace.presets to see every preset with its numbers.
+   ignoreWhite, snapCurvesToLines; for line art, strokes: true (with strokeWidth, the widest
+   line in pixels) traces lines as stroked centre lines instead of filled outlines. Run imageTrace.presets to see every preset with its numbers.
    Lower paths and higher corners give the clean, logo-like result; high fidelity needs paths
    near 90.
 3. apply_effect {effect} on the traced shapes. Call apply_effect with no `effect` for the

crates/svg/src/import.rs

@@ -33,6 +33,7 @@ pub(crate) fn import(svg: &str, opts: &ImportOptions) -> Result<(Document, Vec<S
     let xml = roxmltree::Document::parse_with_options(svg, roxmltree::ParsingOptions { allow_dtd: true, ..Default::default() })
         .map_err(|e| SvgError::Parse(e.to_string()))?;
     let units = RootUnits::of(xml.root_element());
+    let root_name = root_layer_name(xml.root_element());
     let mut warnings = found.warnings;
     let (src, slots) = text::prepare(svg, &xml, units.dpi, &mut warnings);
     let files = found.files;
@@ -141,11 +142,17 @@ pub(crate) fn import(svg: &str, opts: &ImportOptions) -> Result<(Document, Vec<S
             im.doc.layers.push(Arc::new(l));
         }
     } else {
+        // An export of a one-layer document names the layer on the root element, its art (groups
+        // among it) loose inside: the one layer takes that name.
         let children = im.children(top, base);
-        if let Some(l) = im.doc.layers.first_mut()
-            && let Some(ch) = Arc::make_mut(l).children_mut()
-        {
-            *ch = children;
+        if let Some(l) = im.doc.layers.first_mut() {
+            let l = Arc::make_mut(l);
+            if let Some(ch) = l.children_mut() {
+                *ch = children;
+            }
+            if root_name.is_some() {
+                l.name = root_name;
+            }
         }
     }
     if !im.sublayer_groups.is_empty() {
@@ -163,6 +170,13 @@ pub(crate) const SUBLAYER: &str = "data-vc-layer";
 /// The Inkscape namespace (its layers and their labels).
 const INKSCAPE: &str = "http://www.inkscape.org/namespaces/inkscape";
 
+/// The layer name on root element `root` (`<svg id="Main">`, or its `data-name`), as exports of
+/// one-layer documents write it. An Inkscape root's id (`svg8`) is one Inkscape made up, not a name.
+fn root_layer_name(root: XNode) -> Option<String> {
+    let id = root.attribute("id").filter(|_| root.attribute((INKSCAPE, "version")).is_none());
+    root.attribute("data-name").or(id).map(str::trim).filter(|n| !n.is_empty()).map(str::to_string)
+}
+
 /// Is element `g` a `<g>` marked as a layer ([`SUBLAYER`])? Only one with an id counts: the id (or
 /// the label beside it) is its name.
 fn marked_layer(g: XNode) -> bool {

crates/svg/tests/symbols_layers.rs

@@ -1,7 +1,8 @@
 //! Symbols export as one `<symbol>` def and a `<use>` per instance (instances the def can't stand
 //! for get their own art), hidden layers and objects are kept hidden when asked and come back
 //! hidden with their `data-*` attributes, clipped layers come in as clipping layers, layers and
-//! sublayers keep their names and nesting, and the editing data notices edits made elsewhere.
+//! sublayers keep their names and nesting (a one-layer file's from its root element), and the
+//! editing data notices edits made elsewhere.
 // Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
 #![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
@@ -482,6 +483,25 @@ fn sublayers_round_trip() {
     );
 }
 
+#[test]
+fn a_root_element_names_the_one_layer() {
+    // A one-layer document exported with its art loose under the root, which carries the name.
+    let svg = r##"<svg version="1.1" id="Main" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 300">
+  <rect x="20" y="50" width="120" height="60" style="fill:none;stroke:#000;stroke-width:4"/>
+  <g id="HiddenSub" style="display:none;"><circle cx="45" cy="175" r="25"/></g>
+</svg>"##;
+    assert_eq!(outline(&import(svg).unwrap()), ["Layer Main", "  Path", "  Group HiddenSub (hidden)", "    Path"]);
+    // `data-name` when the id can't hold the name.
+    let named = svg.replace("id=\"Main\"", "id=\"Main_Art\" data-name=\"Main Art\"");
+    assert_eq!(import(&named).unwrap().layers[0].name.as_deref(), Some("Main Art"));
+    let names = |svg: &str| import(svg).unwrap().layers.iter().map(|l| l.name.clone().unwrap()).collect::<Vec<_>>();
+    // Not when the groups at the top are the layers.
+    assert_eq!(names(&svg.replace("<rect", "<g id=\"Art\"><rect").replace("stroke-width:4\"/>", "stroke-width:4\"/></g>")), ["Art", "HiddenSub"]);
+    // Nor from the id Inkscape gives its root.
+    let inkscape = svg.replace("id=\"Main\"", "id=\"svg8\" xmlns:inkscape=\"http://www.inkscape.org/namespaces/inkscape\" inkscape:version=\"1.3\"");
+    assert_eq!(names(&inkscape), ["Layer 1"]);
+}
+
 #[test]
 fn marked_groups_are_sublayers_only_in_layers() {
     // Inkscape marks its layers and sublayers; one marked group in a plain group stays a group.

crates/testkit/src/ase.rs

@@ -0,0 +1,61 @@
+//! Hand-written swatch exchange (`.ase`) files for swatch library tests: version 1.0, big-endian,
+//! with colors in each model and color type, and color groups.
+
+/// One block of a swatch exchange file.
+#[derive(Clone, Debug)]
+pub enum Block<'a> {
+    /// A color group starts (its name).
+    GroupStart(&'a str),
+    /// The open color group ends.
+    GroupEnd,
+    /// A color: its name, model (`b"RGB "`, `b"CMYK"`, `b"LAB "` or `b"Gray"`), components and
+    /// color type (0 global, 1 spot, 2 process).
+    Color(&'a str, &'a [u8; 4], &'a [f32], u16),
+}
+
+/// A name: a `u16` count of UTF-16 code units, the terminating zero included, then the units.
+fn name(out: &mut Vec<u8>, name: &str) {
+    let units: Vec<u16> = name.encode_utf16().chain([0]).collect();
+    out.extend(u16::try_from(units.len()).unwrap().to_be_bytes());
+    out.extend(units.iter().flat_map(|u| u.to_be_bytes()));
+}
+
+/// A swatch exchange file of `blocks`.
+pub fn ase(blocks: &[Block]) -> Vec<u8> {
+    let mut out = b"ASEF\0\x01\0\0".to_vec();
+    out.extend(u32::try_from(blocks.len()).unwrap().to_be_bytes());
+    for b in blocks {
+        let mut body = vec![];
+        let kind: u16 = match b {
+            Block::GroupStart(n) => {
+                name(&mut body, n);
+                0xC001
+            }
+            Block::GroupEnd => 0xC002,
+            Block::Color(n, model, values, kind) => {
+                name(&mut body, n);
+                body.extend(*model);
+                body.extend(values.iter().flat_map(|v| v.to_be_bytes()));
+                body.extend(kind.to_be_bytes());
+                0x0001
+            }
+        };
+        out.extend(kind.to_be_bytes());
+        out.extend(u32::try_from(body.len()).unwrap().to_be_bytes());
+        out.extend(body);
+    }
+    out
+}
+
+/// A library of four colors: "Sky" (global RGB) and "Ink" (spot CMYK), then the group "Neutrals"
+/// of the process colors "Mist" (Gray, 25% ink) and "Clay" (Lab 50, 20, −30).
+pub fn sample() -> Vec<u8> {
+    ase(&[
+        Block::Color("Sky", b"RGB ", &[0.0, 0.5, 1.0], 0),
+        Block::Color("Ink", b"CMYK", &[1.0, 0.5, 0.0, 0.2], 1),
+        Block::GroupStart("Neutrals"),
+        Block::Color("Mist", b"Gray", &[0.75], 2),
+        Block::Color("Clay", b"LAB ", &[0.5, 20.0, -30.0], 2),
+        Block::GroupEnd,
+    ])
+}

crates/testkit/src/lib.rs

@@ -10,6 +10,7 @@
 //! - [`raster`]: rendering helpers and image comparison with a perceptual tolerance.
 //! - [`geom`]: geometry assertions (approximate equality, curve sampling, Hausdorff distance).
 //! - [`pdf`]: hand-written PDF files (page boxes, colour spaces, encryption) for import tests.
+//! - [`ase`]: hand-written swatch exchange (`.ase`) files for swatch library tests.
 //!
 //! This crate may only be used as a dev-dependency (enforced by `cargo xtask layers`).
 // Test support only (a dev-dependency of every crate that uses it): a failed setup or assertion
@@ -18,6 +19,7 @@
 #![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 #![forbid(unsafe_code)]
 
+pub mod ase;
 pub mod fixtures;
 pub mod geom;
 pub mod invariants;

crates/tools/src/xform/artboard.rs

@@ -259,10 +259,19 @@ impl Tool for ArtboardTool {
         }
     }
 
+    /// Delete/Backspace remove the active artboard ahead of the Clear shortcut, which would only
+    /// delete selected art; with one artboard left (it can't be deleted) they stay the shortcut's.
+    fn claims_key(&self, cx: &ToolContext, key: ToolKey) -> bool {
+        matches!(key, ToolKey::Delete | ToolKey::Backspace)
+            && self.drag.is_none()
+            && cx.doc.artboards.len() > 1
+            && self.active < cx.doc.artboards.len()
+    }
+
     fn key(&mut self, cx: &ToolContext, key: ToolKey, _mods: Mods) -> Vec<Action> {
         match key {
-            ToolKey::Delete | ToolKey::Backspace if self.drag.is_none() => {
-                if cx.doc.artboards.len() <= 1 || self.active >= cx.doc.artboards.len() {
+            ToolKey::Delete | ToolKey::Backspace => {
+                if !self.claims_key(cx, key) {
                     return vec![];
                 }
                 let i = self.active;
@@ -522,7 +531,8 @@ mod tests {
         let a = t.pointer(&cx, &ev(PointerKind::Up, 1100.0, 1050.0));
         assert_eq!(a[0], Action::Exec("artboard.new".into(), json!({"x": 1000.0, "y": 1000.0, "width": 100.0, "height": 50.0})));
         assert_eq!(a[1], Action::Notify("created".into()));
-        // Delete removes the active artboard.
+        // Delete removes the active artboard, ahead of the Clear shortcut.
+        assert!(t.claims_key(&cx, ToolKey::Delete) && t.claims_key(&cx, ToolKey::Backspace));
         assert_eq!(t.key(&cx, ToolKey::Delete, Mods::default()), vec![Action::Exec("artboard.delete".into(), json!({"index": 1}))]);
         assert_eq!(t.key(&cx, ToolKey::Escape, Mods::default()), vec![Action::SwitchTool("selection".into())]);
     }

crates/trace/src/centerline.rs

@@ -0,0 +1,379 @@
+//! Create Strokes: the parts of a colour layer no wider than the Stroke width, traced as stroked
+//! centre lines instead of filled outlines.
+//!
+//! 1. **Distance**: a chamfer (3-4) distance transform gives each pixel its distance to the nearest
+//!    pixel outside the layer.
+//! 2. **Lines**: an 8-connected component whose widest point (twice its largest distance, less
+//!    one) is within the stroke width is a line; wider ones stay filled areas.
+//! 3. **Skeleton**: the line is thinned to one pixel (Zhang–Suen, applied pixel by pixel so it
+//!    keeps its topology and two-pixel-wide lines don't vanish), then staircase corners that
+//!    don't connect anything are dropped.
+//! 4. **Graph**: runs of skeleton pixels between ends and junctions (touching junction pixels
+//!    merged into one point) become polylines through the pixel centres; rings without ends
+//!    become closed ones. Short spurs that thinning leaves at junctions are pruned and the runs
+//!    on either side of a junction left with two of them are joined.
+//! 5. **Curves**: each polyline is fitted like an outline ([`fit::fit_polyline`]); the stroke
+//!    width is the line's mean width (its pixel count over its length).
+
+use std::collections::HashSet;
+
+use vectorcraft_geom::{PathData, Point};
+
+use crate::fit::{self, FitOptions};
+
+/// One line of a colour layer: its centre lines and the width to stroke them with.
+pub(crate) struct Line {
+    pub path: PathData,
+    /// Stroke width in pixels.
+    pub width: f64,
+    pub pixels: usize,
+}
+
+/// The lines of colour `label` in `labels` (`w` × `h`, row-major) no wider than `max_width`
+/// pixels, and which pixels they cover (to leave out of the filled areas).
+pub(crate) fn lines(labels: &[u16], label: u16, w: usize, h: usize, max_width: f64, o: &FitOptions) -> (Vec<bool>, Vec<Line>) {
+    let mut thin = vec![false; labels.len()];
+    let mut out = vec![];
+    if w == 0 || h == 0 || labels.len() != w * h {
+        return (thin, out);
+    }
+    let mask = |i: usize| labels.get(i) == Some(&label);
+    let dt = distance(&mask, w, h);
+    let mut seen = vec![false; w * h];
+    let mut stack = vec![];
+    for start in 0..w * h {
+        if !mask(start) || seen[start] {
+            continue;
+        }
+        let mut comp = vec![];
+        seen[start] = true;
+        stack.push(start);
+        while let Some(i) = stack.pop() {
+            comp.push(i);
+            for j in neighbours(i, w, h) {
+                if mask(j) && !seen[j] {
+                    seen[j] = true;
+                    stack.push(j);
+                }
+            }
+        }
+        let widest = 2.0 * f64::from(comp.iter().map(|&i| dt[i]).max().unwrap_or(0)) / 3.0 - 1.0;
+        if widest > max_width {
+            continue;
+        }
+        let Some(line) = trace_line(&comp, w, max_width, o) else { continue };
+        for &i in &comp {
+            thin[i] = true;
+        }
+        out.push(line);
+    }
+    (thin, out)
+}
+
+/// The 8 neighbours of pixel `i` inside the `w` × `h` image.
+fn neighbours(i: usize, w: usize, h: usize) -> impl Iterator<Item = usize> {
+    let (x, y) = ((i % w) as i64, (i / w) as i64);
+    const AROUND: [(i64, i64); 8] = [(-1, -1), (0, -1), (1, -1), (-1, 0), (1, 0), (-1, 1), (0, 1), (1, 1)];
+    AROUND.into_iter().filter_map(move |(dx, dy)| {
+        let (nx, ny) = (x + dx, y + dy);
+        (nx >= 0 && ny >= 0 && nx < w as i64 && ny < h as i64).then(|| ny as usize * w + nx as usize)
+    })
+}
+
+/// Chamfer 3-4 distance (3 per pixel step, saturating) of each pixel in `mask` to the nearest
+/// pixel outside it; outside the image counts as outside.
+fn distance(mask: &impl Fn(usize) -> bool, w: usize, h: usize) -> Vec<u16> {
+    let mut d = vec![0u16; w * h];
+    let at = |d: &[u16], x: i64, y: i64| {
+        if x < 0 || y < 0 || x >= w as i64 || y >= h as i64 { 0 } else { d.get(y as usize * w + x as usize).copied().unwrap_or(0) }
+    };
+    for y in 0..h {
+        for x in 0..w {
+            let i = y * w + x;
+            if mask(i) {
+                let (x, y) = (x as i64, y as i64);
+                let steps = [(x - 1, y, 3), (x - 1, y - 1, 4), (x, y - 1, 3), (x + 1, y - 1, 4)];
+                d[i] = steps.iter().map(|&(nx, ny, c)| at(&d, nx, ny).saturating_add(c)).min().unwrap_or(0);
+            }
+        }
+    }
+    for y in (0..h).rev() {
+        for x in (0..w).rev() {
+            let i = y * w + x;
+            if mask(i) {
+                let (xi, yi) = (x as i64, y as i64);
+                let steps = [(xi + 1, yi, 3), (xi + 1, yi + 1, 4), (xi, yi + 1, 3), (xi - 1, yi + 1, 4)];
+                let v = steps.iter().map(|&(nx, ny, c)| at(&d, nx, ny).saturating_add(c)).min().unwrap_or(0);
+                d[i] = d[i].min(v);
+            }
+        }
+    }
+    d
+}
+
+/// A grid around one line: its pixels with a one-pixel empty border.
+struct Grid {
+    on: Vec<bool>,
+    w: usize,
+    h: usize,
+    /// Image position of grid pixel (0, 0).
+    x0: i64,
+    y0: i64,
+}
+
+impl Grid {
+    /// The 8 neighbours (N, NE, E, SE, S, SW, W, NW) of interior pixel `i`.
+    fn ring(&self, i: usize) -> [bool; 8] {
+        let w = self.w;
+        let g = |j: usize| self.on.get(j).copied().unwrap_or(false);
+        [g(i - w), g(i - w + 1), g(i + 1), g(i + w + 1), g(i + w), g(i + w - 1), g(i - 1), g(i - w - 1)]
+    }
+    fn interior(&self) -> impl Iterator<Item = usize> + use<> {
+        let (w, h) = (self.w, self.h);
+        (1..h.saturating_sub(1)).flat_map(move |y| (1..w.saturating_sub(1)).map(move |x| y * w + x))
+    }
+    fn neighbours(&self, i: usize) -> impl Iterator<Item = usize> + '_ {
+        let w = self.w;
+        [i - w, i - w + 1, i + 1, i + w + 1, i + w, i + w - 1, i - 1, i - w - 1].into_iter().filter(|&j| self.on.get(j).copied().unwrap_or(false))
+    }
+    fn degree(&self, i: usize) -> usize {
+        self.neighbours(i).count()
+    }
+    /// The centre of pixel `i` in image coordinates.
+    fn centre(&self, i: usize) -> Point {
+        Point::new((self.x0 + (i % self.w) as i64) as f64 + 0.5, (self.y0 + (i / self.w) as i64) as f64 + 0.5)
+    }
+}
+
+/// Zhang–Suen thinning. Each sub-iteration picks the pixels to remove from the same state, so the
+/// skeleton stays centred; they are then removed one by one, each only if it still doesn't
+/// disconnect anything, so a two-pixel-wide line thins to one pixel instead of vanishing.
+fn thin(g: &mut Grid) {
+    let removable = |p: &[bool; 8]| {
+        let b = p.iter().filter(|v| **v).count();
+        let a = (0..8).filter(|&k| !p[k] && p[(k + 1) % 8]).count();
+        (2..=6).contains(&b) && a == 1
+    };
+    let mut picked = vec![];
+    loop {
+        let mut changed = false;
+        for step in 0..2 {
+            picked.clear();
+            for i in g.interior() {
+                if !g.on[i] {
+                    continue;
+                }
+                let p = g.ring(i);
+                let (n, e, s, w) = (p[0], p[2], p[4], p[6]);
+                let side = if step == 0 { !(e && s && (n || w)) } else { !(n && w && (e || s)) };
+                if side && removable(&p) {
+                    picked.push(i);
+                }
+            }
+            for &i in &picked {
+                if removable(&g.ring(i)) {
+                    g.on[i] = false;
+                    changed = true;
+                }
+            }
+        }
+        if !changed {
+            break;
+        }
+    }
+    // Staircase corners: a pixel whose neighbours stay connected without it (Yokoi's
+    // 8-connectivity number 1) and that doesn't end the line.
+    loop {
+        let mut changed = false;
+        for i in g.interior() {
+            if !g.on[i] || g.degree(i) < 2 {
+                continue;
+            }
+            let p = g.ring(i);
+            // x1 = E, x2 = NE, x3 = N, x4 = NW, x5 = W, x6 = SW, x7 = S, x8 = SE.
+            let x = [p[2], p[1], p[0], p[7], p[6], p[5], p[4], p[3]];
+            let off = |k: usize| !x[k % 8];
+            let c8: usize = [0, 2, 4, 6].iter().map(|&k| usize::from(off(k)) - usize::from(off(k) && off(k + 1) && off(k + 2))).sum();
+            if c8 == 1 {
+                g.on[i] = false;
+                changed = true;
+            }
+        }
+        if !changed {
+            break;
+        }
+    }
+}
+
+/// A run of skeleton pixels between two nodes (`None`: none, a ring).
+#[derive(Clone)]
+struct Run {
+    pts: Vec<Point>,
+    ends: [Option<usize>; 2],
+    closed: bool,
+}
+
+impl Run {
+    fn length(&self) -> f64 {
+        self.pts.windows(2).map(|p| p[0].distance(p[1])).sum::<f64>()
+            + if self.closed { self.pts.first().zip(self.pts.last()).map_or(0.0, |(a, b)| a.distance(*b)) } else { 0.0 }
+    }
+}
+
+/// The centre lines of one line component (pixel indices of the `w`-wide image).
+fn trace_line(comp: &[usize], w: usize, max_width: f64, o: &FitOptions) -> Option<Line> {
+    let xs = comp.iter().map(|&i| i % w);
+    let ys = comp.iter().map(|&i| i / w);
+    let (x0, x1, y0, y1) = (xs.clone().min()?, xs.max()?, ys.clone().min()?, ys.max()?);
+    let (gw, gh) = (x1 - x0 + 3, y1 - y0 + 3);
+    let mut g = Grid { on: vec![false; gw * gh], w: gw, h: gh, x0: x0 as i64 - 1, y0: y0 as i64 - 1 };
+    for &i in comp {
+        g.on[(i / w - y0 + 1) * gw + (i % w - x0 + 1)] = true;
+    }
+    thin(&mut g);
+    let skeleton: Vec<usize> = g.interior().filter(|&i| g.on[i]).collect();
+    if skeleton.len() < 2 {
+        return None;
+    }
+    // Nodes: line ends, and junctions with the junction pixels touching them.
+    let mut node = vec![usize::MAX; g.on.len()];
+    let mut centres: Vec<Point> = vec![];
+    for &i in &skeleton {
+        let d = g.degree(i);
+        if d == 2 || node[i] != usize::MAX {
+            continue;
+        }
+        let id = centres.len();
+        let mut members = vec![i];
+        node[i] = id;
+        if d > 2 {
+            let mut k = 0;
+            while let Some(&p) = members.get(k) {
+                k += 1;
+                for q in g.neighbours(p).collect::<Vec<_>>() {
+                    if node[q] == usize::MAX && g.degree(q) > 2 {
+                        node[q] = id;
+                        members.push(q);
+                    }
+                }
+            }
+        }
+        let sum = members.iter().fold(Point::ZERO, |s, &m| s + g.centre(m).to_vec2());
+        centres.push(Point::new(sum.x / members.len() as f64, sum.y / members.len() as f64));
+    }
+    // Runs from each node, then the rings left.
+    let mut used: HashSet<(usize, usize)> = HashSet::new();
+    let edge = |a: usize, b: usize| (a.min(b), a.max(b));
+    let mut runs: Vec<Run> = vec![];
+    for &p in skeleton.iter().filter(|&&i| node[i] != usize::MAX) {
+        for q in g.neighbours(p).collect::<Vec<_>>() {
+            if node[q] == node[p] || !used.insert(edge(p, q)) {
+                continue;
+            }
+            let mut pts = vec![centres[node[p]], g.centre(q)];
+            let (mut prev, mut cur) = (p, q);
+            while node[cur] == usize::MAX {
+                let Some(next) = g.neighbours(cur).find(|&n| n != prev && !used.contains(&edge(cur, n))) else { break };
+                used.insert(edge(cur, next));
+                pts.push(g.centre(next));
+                (prev, cur) = (cur, next);
+            }
+            let end = (node[cur] != usize::MAX).then_some(node[cur]);
+            if let (Some(e), Some(last)) = (end, pts.last_mut()) {
+                *last = centres[e];
+            }
+            runs.push(Run { pts, ends: [Some(node[p]), end], closed: false });
+        }
+    }
+    for &s in &skeleton {
+        if node[s] != usize::MAX || g.neighbours(s).any(|n| used.contains(&edge(s, n))) {
+            continue;
+        }
+        let mut pts = vec![g.centre(s)];
+        let (mut prev, mut cur) = (usize::MAX, s);
+        let mut closed = false;
+        while let Some(next) = g.neighbours(cur).find(|&n| n != prev && !used.contains(&edge(cur, n))) {
+            used.insert(edge(cur, next));
+            if next == s {
+                closed = true;
+                break;
+            }
+            pts.push(g.centre(next));
+            (prev, cur) = (cur, next);
+        }
+        runs.push(Run { pts, ends: [None, None], closed });
+    }
+    // The line's mean width: its pixels over its length (the skeleton stops about half a width
+    // short of each end).
+    let width = |runs: &[Run]| {
+        let length: f64 = runs.iter().map(Run::length).sum();
+        let px = comp.len() as f64;
+        ((-length + (length * length + 4.0 * px).sqrt()) / 2.0).clamp(1.0, max_width.max(1.0))
+    };
+    let spur = width(&runs);
+    let runs = join(prune(runs, centres.len(), spur), centres.len());
+    let width = width(&runs);
+    let subs: Vec<_> = runs.iter().filter_map(|r| fit::fit_polyline(&r.pts, r.closed, o)).collect();
+    if subs.is_empty() {
+        return None;
+    }
+    Some(Line { path: PathData::new(subs), width, pixels: comp.len() })
+}
+
+/// The runs without the spurs thinning leaves: runs shorter than the line's `width` from a line end
+/// to a junction that keeps at least two other runs.
+fn prune(runs: Vec<Run>, nodes: usize, width: f64) -> Vec<Run> {
+    let mut degree = vec![0usize; nodes];
+    for e in runs.iter().flat_map(|r| r.ends.iter().flatten()) {
+        degree[*e] += 1;
+    }
+    let mut order: Vec<usize> = (0..runs.len()).collect();
+    order.sort_by(|a, b| runs[*a].length().total_cmp(&runs[*b].length()));
+    let mut keep = vec![true; runs.len()];
+    for i in order {
+        let r = &runs[i];
+        let [Some(a), Some(b)] = r.ends else { continue };
+        let (tip, fork) = if degree[a] == 1 { (a, b) } else { (b, a) };
+        if degree[tip] == 1 && degree[fork] >= 3 && r.length() < width.max(2.0) {
+            keep[i] = false;
+            degree[tip] -= 1;
+            degree[fork] -= 1;
+        }
+    }
+    runs.into_iter().zip(keep).filter_map(|(r, k)| k.then_some(r)).collect()
+}
+
+/// The runs joined through every node exactly two of them meet at (a run meeting itself closes).
+fn join(runs: Vec<Run>, nodes: usize) -> Vec<Run> {
+    let mut runs: Vec<Option<Run>> = runs.into_iter().map(Some).collect();
+    for n in 0..nodes {
+        let at: Vec<(usize, usize)> = runs
+            .iter()
+            .enumerate()
+            .flat_map(|(i, r)| r.iter().flat_map(move |r| (0..2).filter(move |&k| r.ends[k] == Some(n)).map(move |k| (i, k))))
+            .collect();
+        let [(i, ki), (j, kj)] = at[..] else { continue };
+        if i == j {
+            if let Some(r) = runs[i].as_mut() {
+                r.pts.pop();
+                r.ends = [None, None];
+                r.closed = r.pts.len() >= 3;
+            }
+            continue;
+        }
+        let (Some(mut a), Some(mut b)) = (runs[i].take(), runs[j].take()) else { continue };
+        // a ends at n, b starts at n.
+        if ki == 0 {
+            a.pts.reverse();
+            a.ends.reverse();
+        }
+        if kj == 1 {
+            b.pts.reverse();
+            b.ends.reverse();
+        }
+        a.pts.extend(b.pts.into_iter().skip(1));
+        a.ends[1] = b.ends[1];
+        runs[i] = Some(a);
+    }
+    runs.into_iter().flatten().collect()
+}

crates/trace/src/fit.rs

@@ -133,6 +133,49 @@ pub(crate) fn fit_loop(l: &Loop, o: &FitOptions) -> Option<SubPath> {
     Some(sp)
 }
 
+/// Fit a centre line through `pts` (pixel-centre points in order) into a Bézier subpath: the
+/// points within `polygon_tol` of it are dropped (Douglas–Peucker), then curves are fitted. A
+/// `closed` line runs back to its first point.
+pub(crate) fn fit_polyline(pts: &[Point], closed: bool, o: &FitOptions) -> Option<SubPath> {
+    let n = pts.len();
+    let first = *pts.first()?;
+    if n < 2 {
+        return None;
+    }
+    let mut ext = pts.to_vec();
+    let mut keep = vec![false; n + 1];
+    keep[0] = true;
+    if closed {
+        // Split the ring at its first point and the point farthest from it.
+        ext.push(first);
+        let far = (1..n).max_by(|&i, &j| pts[i].distance_squared(first).total_cmp(&pts[j].distance_squared(first))).unwrap_or(n / 2);
+        keep[far] = true;
+        rdp(&ext, 0, far, o.polygon_tol, &mut keep);
+        rdp(&ext, far, n, o.polygon_tol, &mut keep);
+    } else {
+        keep[n - 1] = true;
+        rdp(&ext, 0, n - 1, o.polygon_tol, &mut keep);
+    }
+    let mut poly: Vec<Point> = (0..n).filter(|&i| keep[i]).map(|i| pts[i]).collect();
+    if closed && poly.len() < 3 {
+        poly = pts.to_vec();
+    }
+    if poly.len() < if closed { 3 } else { 2 } {
+        return None;
+    }
+    let sp = SubPath::polyline(&poly, closed);
+    let fitted =
+        simplify_with(&PathData::single(sp), &SimplifyOptions { tolerance: o.fit_tol, corner_angle_deg: o.corner_angle, straight_lines: false });
+    let mut sp = fitted.subpaths.into_iter().next()?;
+    if sp.anchors.len() < 2 {
+        return None;
+    }
+    if o.snap_lines {
+        snap_to_lines(&mut sp, (o.fit_tol * 2.0).max(1.5));
+    }
+    Some(sp)
+}
+
 /// Retract the handles of curves that stay within `tol` of their chord.
 fn snap_to_lines(sp: &mut SubPath, tol: f64) {
     let n = sp.anchors.len();

crates/trace/src/lib.rs

@@ -18,10 +18,15 @@
 //! 5. **Curves**: the polygon is fitted with cubic Béziers (`vectorcraft_pathops::simplify_with`,
 //!    least squares with corner detection); optionally nearly-straight curves snap to lines.
 //!
+//! With **Create: Strokes**, the parts of a colour layer no wider than the stroke width are traced
+//! as stroked centre lines instead (see `centerline`); without Fills, wider parts become stroked
+//! outlines.
+//!
 //! Colour layers are traced either *abutting* (each colour's own area; shapes share edges) or
 //! *overlapping* (stacked: each layer also covers every layer above it, so no hairline gaps).
 #![forbid(unsafe_code)]
 
+mod centerline;
 mod contour;
 mod fit;
 mod mosaic;
@@ -152,6 +157,12 @@ pub struct TraceParams {
     pub ignore_white: bool,
     /// Replace nearly-straight curves with straight lines.
     pub snap_curves_to_lines: bool,
+    /// Create: trace areas as filled shapes.
+    pub fills: bool,
+    /// Create: trace lines no wider than `stroke_width` as stroked centre lines.
+    pub strokes: bool,
+    /// Stroke: the widest feature (px) traced as a stroke.
+    pub stroke_width: f64,
 }
 
 impl Default for TraceParams {
@@ -167,6 +178,9 @@ impl Default for TraceParams {
             method: Method::Abutting,
             ignore_white: false,
             snap_curves_to_lines: false,
+            fills: true,
+            strokes: false,
+            stroke_width: 10.0,
         }
     }
 }
@@ -250,7 +264,8 @@ pub fn presets() -> Vec<(&'static str, TraceParams)> {
     PRESET_NAMES.iter().filter_map(|n| Some((*n, preset(n)?))).collect()
 }
 
-/// One traced shape: an outer contour plus its holes, filled with `color`.
+/// One traced shape: an outer contour plus its holes, filled with `color`, or (with `stroke`)
+/// lines stroked with it.
 #[derive(Clone, Debug, PartialEq)]
 pub struct TracedPath {
     /// In pixel coordinates (x right, y down; the image spans `0..width × 0..height`).
@@ -258,6 +273,9 @@ pub struct TracedPath {
     pub color: [u8; 3],
     /// Filled pixel count of the component the path came from.
     pub pixels: usize,
+    /// Create Strokes: the path is stroked this wide (px), not filled (centre lines, or the
+    /// outlines of wider areas without Fills).
+    pub stroke: Option<f64>,
 }
 
 /// The traced result, bottom-most path first.
@@ -357,15 +375,37 @@ impl Layers<'_> {
         let (params, opts) = (self.params, &self.opts);
         let color = *self.q.palette.get(ci)?;
         let overlapping = params.method == Method::Overlapping;
+        let (w, h) = (self.w, self.h);
+        // Create Strokes: this colour's lines, left out of its areas.
+        let (thin, lines) = if params.strokes {
+            centerline::lines(&self.q.labels, u16::try_from(ci).unwrap_or(TRANSPARENT), w, h, params.stroke_width, opts)
+        } else {
+            (vec![], vec![])
+        };
         let mask: Vec<bool> = self
             .q
             .labels
             .iter()
-            .map(|&l| l != TRANSPARENT && if overlapping { self.rank.get(l as usize).is_some_and(|&lr| lr >= r) } else { l as usize == ci })
+            .enumerate()
+            .map(|(i, &l)| {
+                l != TRANSPARENT
+                    && !thin.get(i).copied().unwrap_or(false)
+                    && if overlapping { self.rank.get(l as usize).is_some_and(|&lr| lr >= r) } else { l as usize == ci }
+            })
             .collect();
+        // Without Fills, areas are outlined with a 1 px stroke.
+        let area_stroke = (params.strokes && !params.fills).then_some(1.0);
         let min_hole = params.noise.max(1) as i64;
         let mut paths = vec![];
-        for comp in trace_mask(&mask, self.w, self.h) {
+        let mut add = |path: PathData, pixels: usize, stroke: Option<f64>| {
+            let n = path.anchor_count();
+            if self.anchors.fetch_add(n, Ordering::Relaxed).saturating_add(n) > self.max_anchors {
+                return false;
+            }
+            paths.push(TracedPath { path, color, pixels, stroke });
+            true
+        };
+        for comp in trace_mask(&mask, w, h) {
             let Some(outer) = fit::fit_loop(&comp.outer, opts) else { continue };
             let mut subs = vec![outer];
             for hole in &comp.holes {
@@ -374,12 +414,14 @@ impl Layers<'_> {
                 }
                 subs.extend(fit::fit_loop(hole, opts));
             }
-            let path = PathData::new(subs);
-            let n = path.anchor_count();
-            if self.anchors.fetch_add(n, Ordering::Relaxed).saturating_add(n) > self.max_anchors {
+            if !add(PathData::new(subs), comp.pixels, area_stroke) {
+                return None;
+            }
+        }
+        for line in lines {
+            if !add(line.path, line.pixels, Some(line.width)) {
                 return None;
             }
-            paths.push(TracedPath { path, color, pixels: comp.pixels });
         }
         Some(paths)
     }

crates/trace/src/tests.rs

@@ -1,4 +1,5 @@
 use super::*;
+use vectorcraft_geom::Point;
 
 const BLACK: [u8; 4] = [0, 0, 0, 255];
 const WHITE: [u8; 4] = [255, 255, 255, 255];
@@ -348,3 +349,116 @@ fn an_image_too_large_to_trace_is_refused_before_decoding() {
     assert!(matches!(err, TraceError::TooLarge { width: 30_000, height: 30_000, .. }), "{err}");
     assert!(matches!(Raster::decode(&png_header(64, 64)), Err(TraceError::Decode(_))), "a small header goes on to decoding");
 }
+
+fn strokes(fills: bool) -> TraceParams {
+    TraceParams { strokes: true, fills, stroke_width: 6.0, noise: 4, ..bw() }
+}
+
+/// Endpoints (first and last anchor) of each open subpath of the stroked paths.
+fn stroked(res: &TraceResult) -> Vec<(&TracedPath, &vectorcraft_geom::SubPath)> {
+    res.paths.iter().filter(|p| p.stroke.is_some()).flat_map(|p| p.path.subpaths.iter().map(move |s| (p, s))).collect()
+}
+
+#[test]
+fn a_thin_line_traces_as_one_stroked_centre_line() {
+    // A 3 px wide diagonal line from (20, 20) to (180, 100).
+    let img = Raster::from_fn(200, 120, |x, y| {
+        let (px, py) = (x as f64 + 0.5, y as f64 + 0.5);
+        let t = (((px - 20.0) * 160.0 + (py - 20.0) * 80.0) / (160.0f64.powi(2) + 80.0f64.powi(2))).clamp(0.0, 1.0);
+        let (cx, cy) = (20.0 + 160.0 * t, 20.0 + 80.0 * t);
+        if (px - cx).hypot(py - cy) <= 1.5 { BLACK } else { WHITE }
+    });
+    let res = trace(&img, &strokes(true));
+    assert_eq!(res.paths.len(), 1, "{:?}", res.paths.iter().map(|p| p.stroke).collect::<Vec<_>>());
+    let p = &res.paths[0];
+    let width = p.stroke.expect("stroked");
+    assert!((2.0..=4.0).contains(&width), "width {width}");
+    assert_eq!(p.path.subpaths.len(), 1);
+    let sp = &p.path.subpaths[0];
+    assert!(!sp.closed);
+    let (a, b) = (sp.anchors[0].p, sp.anchors[sp.anchors.len() - 1].p);
+    let (a, b) = if a.x < b.x { (a, b) } else { (b, a) };
+    assert!(a.distance(Point::new(20.0, 20.0)) < 3.0 && b.distance(Point::new(180.0, 100.0)) < 3.0, "{a:?} … {b:?}");
+    // A straight line: a few anchors, all on it.
+    assert!(sp.anchors.len() <= 4, "{} anchors", sp.anchors.len());
+    // Without Create Strokes, the same line is a filled outline.
+    let filled = trace(&img, &bw());
+    assert!(filled.paths.iter().all(|p| p.stroke.is_none()) && filled.paths[0].path.subpaths[0].closed);
+}
+
+#[test]
+fn a_thin_ring_traces_as_a_closed_centre_line() {
+    let img = Raster::from_fn(120, 120, |x, y| {
+        let d = (x as f64 + 0.5 - 60.0).hypot(y as f64 + 0.5 - 60.0);
+        if (d - 40.0).abs() <= 1.5 { BLACK } else { WHITE }
+    });
+    let res = trace(&img, &strokes(true));
+    let lines = stroked(&res);
+    assert_eq!(lines.len(), 1, "one ring");
+    let sp = lines[0].1;
+    assert!(sp.closed);
+    let len = PathData::single(sp.clone()).length();
+    let want = std::f64::consts::TAU * 40.0;
+    assert!((len - want).abs() / want < 0.05, "length {len} vs {want}");
+}
+
+#[test]
+fn wide_areas_stay_filled_and_lines_cross_at_junctions() {
+    // A disc (r = 20) and, apart from it, a plus sign of 3 px wide bars.
+    let img = Raster::from_fn(200, 100, |x, y| {
+        let (px, py) = (x as f64 + 0.5, y as f64 + 0.5);
+        let disc = (px - 50.0).hypot(py - 50.0) <= 20.0;
+        let plus = ((px - 150.0).abs() <= 1.5 && (20.0..=80.0).contains(&py)) || ((py - 50.0).abs() <= 1.5 && (120.0..=180.0).contains(&px));
+        if disc || plus { BLACK } else { WHITE }
+    });
+    let res = trace(&img, &strokes(true));
+    let fills: Vec<_> = res.paths.iter().filter(|p| p.stroke.is_none()).collect();
+    assert_eq!(fills.len(), 1, "the disc");
+    let a = net_area(&fills[0].path);
+    assert!((a - std::f64::consts::PI * 400.0).abs() < 60.0, "disc area {a}");
+    let lines = stroked(&res);
+    assert!((2..=4).contains(&lines.len()), "{} centre lines", lines.len());
+    // The centre lines stop about half a width short of each end of the bars (their round caps
+    // cover it).
+    let total: f64 = lines.iter().map(|(_, s)| PathData::single((*s).clone()).length()).sum();
+    assert!((106.0..=120.0).contains(&total), "both bars' length: {total}");
+    let ends: Vec<Point> = lines.iter().flat_map(|(_, s)| [s.anchors[0].p, s.anchors[s.anchors.len() - 1].p]).collect();
+    for want in [Point::new(150.0, 20.0), Point::new(150.0, 80.0), Point::new(120.0, 50.0), Point::new(180.0, 50.0)] {
+        assert!(ends.iter().any(|e| e.distance(want) < 4.0), "a line ends near {want:?}: {ends:?}");
+    }
+    // Strokes only: the disc is outlined.
+    let res = trace(&img, &strokes(false));
+    assert!(res.paths.iter().all(|p| p.stroke.is_some()));
+    assert!(res.paths.iter().any(|p| p.stroke == Some(1.0) && p.path.subpaths[0].closed), "the disc's outline");
+}
+
+#[test]
+fn create_settings_parse_with_defaults() {
+    let p: TraceParams = serde_json::from_value(serde_json::json!({ "strokes": true, "strokeWidth": 4 })).unwrap();
+    assert!(p.fills && p.strokes && p.stroke_width == 4.0);
+    let d = TraceParams::default();
+    assert!(d.fills && !d.strokes && d.stroke_width == 10.0);
+}
+
+#[test]
+fn create_strokes_survives_noise_and_tiny_images() {
+    let mut seed = 0x9E37_79B9_7F4A_7C15u64;
+    let mut next = move || {
+        seed ^= seed << 13;
+        seed ^= seed >> 7;
+        seed ^= seed << 17;
+        seed
+    };
+    let noise: Vec<u8> = (0..120 * 120).flat_map(|_| if next() % 3 == 0 { BLACK } else { WHITE }).collect();
+    let noise = Raster::new(120, 120, noise);
+    for img in [noise, Raster::from_fn(1, 1, |_, _| BLACK), Raster::from_fn(3, 2, |x, _| if x == 1 { BLACK } else { WHITE })] {
+        for (fills, width) in [(true, 1.0), (false, 4.0), (true, 100.0)] {
+            for noise in [0, 1, 4] {
+                let p = TraceParams { strokes: true, fills, stroke_width: width, noise, ..TraceParams::default() };
+                for t in trace(&img, &p).paths {
+                    assert!(t.stroke.is_none_or(|w| w.is_finite() && w >= 1.0), "{:?}", t.stroke);
+                }
+            }
+        }
+    }
+}

crates/ui-egui/src/dock.rs

@@ -151,6 +151,7 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
     ui.ctx().data_mut(|d| {
         d.insert_temp(column_left_id(), column.left());
         d.insert_temp(floating::dock_rect_id(), dock);
+        d.insert_temp(floating::icons_rect_id(), column);
     });
 }
 

crates/ui-egui/src/floating.rs

@@ -70,6 +70,12 @@ pub(crate) fn dock_rect_id() -> Id {
 }
 
 /// The strip along the window's left edge where the Tools panel docks, as last laid out.
+/// The icon column's bounds (egui temp memory, one frame old), where panels without a tab in the
+/// tabbed group go back to when docked.
+pub(crate) fn icons_rect_id() -> Id {
+    Id::new("floating-icons-rect")
+}
+
 pub(crate) fn tools_zone_id() -> Id {
     Id::new("floating-tools-zone")
 }
@@ -216,7 +222,13 @@ fn drop_target(app: &VectorcraftApp, ctx: &egui::Context, what: Moving, at: Pos2
             return Some((Drop::Stack(first), head));
         }
     }
-    zone(dock_rect_id()).filter(|_| app.ui.dock && app.ui.screen_mode < 3).map(|r| (Drop::Dock, r))
+    let dock = zone(dock_rect_id()).filter(|_| app.ui.dock && app.ui.screen_mode < 3)?;
+    // Panels that aren't tabs of the tabbed group (or all of them, with it collapsed) go back to
+    // their icons: light up the icon column, where they land, rather than the tabs.
+    let tabbed = !app.ui.dock_collapsed
+        && own.and_then(|i| app.ui.floating_panels.get(i)).is_some_and(|g| ids_of(g).into_iter().any(|p| DockTab::from_id(p).is_some()));
+    let lit = if tabbed { dock } else { ctx.data(|d| d.get_temp::<Rect>(icons_rect_id())).unwrap_or(dock) };
+    Some((Drop::Dock, lit))
 }
 
 /// Light up a drop zone: over the docked panels, under the floating ones (the moved one too).
@@ -262,7 +274,13 @@ pub fn track(app: &mut VectorcraftApp, ctx: &egui::Context) {
     let ids = ids_of(g);
     let active = ids.get(g.active).copied().unwrap_or(id);
     match drop {
-        Drop::Dock => dock(&mut app.ui, &ids, active),
+        Drop::Dock => {
+            dock(&mut app.ui, &ids, active);
+            // One that went back to its icon pops out of it, so it doesn't seem to vanish.
+            if app.ui.dock_collapsed || DockTab::from_id(active).is_none() {
+                app.ui.open_panel = Some(active.to_string());
+            }
+        }
         Drop::Stack(onto) => stack(&mut app.ui, &ids, active, onto),
     }
 }
@@ -607,7 +625,7 @@ mod tests {
         h.hold(h.title("layers"), over);
         assert!(h.group("layers").contains(over), "the group follows the pointer");
         let target = drop_target(&h.app, &h.ctx, Moving::Panel("layers"), over);
-        assert_eq!(target.map(|t| t.0), Some(Drop::Dock), "the dock is the drop zone");
+        assert_eq!(target, Some((Drop::Dock, dock)), "the dock is the drop zone, lit whole: its tab comes back");
         h.release(over);
         assert!(h.groups().is_empty(), "docked: {:?}", h.groups());
         assert_eq!((h.dock_tabs().len(), h.app.ui.dock_tab), (3, DockTab::Layers), "back in the dock, shown");
@@ -666,6 +684,24 @@ mod tests {
         assert_eq!(h.icons().len(), count - 1, "Color is back in the column");
     }
 
+    #[test]
+    fn a_panel_dropped_on_the_dock_lights_up_and_pops_out_of_its_icon() {
+        let mut h = Harness::new();
+        let count = h.icons().len();
+        h.drag(h.icons()[0].center(), pos2(500.0, 400.0));
+        assert_eq!(h.groups(), [["color"]]);
+        // Over the tabbed group: Color has no tab there, so the icon column lights up, not the tabs.
+        let (dock, column) = (h.temp_rect(dock_rect_id()), h.temp_rect(icons_rect_id()));
+        let over = h.dock_tabs()[1].center();
+        h.hold(h.title("color"), over);
+        assert_eq!(drop_target(&h.app, &h.ctx, Moving::Panel("color"), over), Some((Drop::Dock, column)));
+        assert!(column.width() < dock.width(), "the column, not the whole dock: {column:?} {dock:?}");
+        // Dropped, it's back in the column and pops out of its icon rather than vanishing.
+        h.release(over);
+        assert!(h.groups().is_empty());
+        assert_eq!((h.icons().len(), h.app.ui.open_panel.as_deref()), (count, Some("color")));
+    }
+
     #[test]
     fn a_popped_out_panel_dragged_by_its_title_floats() {
         let mut h = Harness::new();

crates/ui-egui/src/i18n/es.tsv

@@ -1566,6 +1566,9 @@
 	No text selected	No hay texto seleccionado
 	No Thumbnails	Sin miniaturas
 	Noise	Ruido
+	Create:	Crear:
+	Fills	Rellenos
+	Strokes	Trazos
 	Nonbreaking Hyphen	Guion de no separación
 	Nonbreaking Space	Espacio de no separación
 	None	Ninguno

crates/ui-egui/src/i18n/fr.tsv

@@ -1563,6 +1563,9 @@
 	No text selected	Aucun texte sélectionné
 	No Thumbnails	Sans vignettes
 	Noise	Bruit
+	Create:	Créer :
+	Fills	Fonds
+	Strokes	Contours
 	Nonbreaking Hyphen	Trait d’union insécable
 	Nonbreaking Space	Espace insécable
 	None	Aucun

crates/ui-egui/src/i18n/it.tsv

@@ -1566,6 +1566,9 @@
 	No text selected	Nessun testo selezionato
 	No Thumbnails	Nessuna miniatura
 	Noise	Disturbo
+	Create:	Crea:
+	Fills	Riempimenti
+	Strokes	Tracce
 	Nonbreaking Hyphen	Trattino indivisibile
 	Nonbreaking Space	Spazio indivisibile
 	None	Nessuno

crates/ui-egui/src/i18n/ja.tsv

@@ -1696,6 +1696,9 @@
 	No symbols in this document	このドキュメントにシンボルはありません
 	No text selected	テキストが選択されていません
 	Noise	ノイズ
+	Create:	作成:
+	Fills	塗り
+	Strokes	線
 	None	なし
 	None.	なし。
 	Normal	通常

crates/ui-egui/src/i18n/ru.tsv

@@ -1562,6 +1562,9 @@
 	No text selected	Текст не выделен
 	No Thumbnails	Без миниатюр
 	Noise	Шум
+	Create:	Создать:
+	Fills	Заливки
+	Strokes	Обводки
 	Nonbreaking Hyphen	Неразрывный дефис
 	Nonbreaking Space	Неразрывный пробел
 	None	Нет

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -1541,6 +1541,9 @@
 	No text selected	未选择文字
 	No Thumbnails	无缩略图
 	Noise	杂色
+	Create:	创建：
+	Fills	填色
+	Strokes	描边
 	Nonbreaking Hyphen	不断行连字号
 	Nonbreaking Space	不断行空格
 	None	无

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -1583,6 +1583,9 @@
 	No text selected	未選取文字
 	No Thumbnails	無縮圖
 	Noise	雜訊
+	Create:	建立：
+	Fills	填色
+	Strokes	筆畫
 	Nonbreaking Hyphen	不斷行連字號
 	Nonbreaking Space	不斷行空格
 	None	無

crates/ui-egui/src/io.rs

@@ -43,6 +43,8 @@ pub fn open_bytes(app: &mut VectorcraftApp, name: &str, bytes: &[u8], path: Opti
     if swatches || ext == vectorcraft_doc::style_libs::STYLES_EXT {
         let p = match path {
             Some(path) => serde_json::json!({ "path": path }),
+            // `.ase` swatch libraries are binary.
+            None if swatches => serde_json::json!({"name": name, "dataBase64": vectorcraft_format::base64_encode(bytes)}),
             None => serde_json::json!({"name": name, "data": String::from_utf8_lossy(bytes)}),
         };
         let load = if swatches { crate::panels::swatches::load_library } else { crate::panels::graphic_styles::load_library };

crates/ui-egui/src/menus.rs

@@ -346,7 +346,7 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
         "window.swatchLibrary.other",
         "Other Library…",
         "",
-        "{path?} (default: pick a file) load a .vcswatches or .gpl library, or another document's swatches (engine: swatch.library.load), and open it in the library panel",
+        "{path?} (default: pick a file) load a .vcswatches, .gpl or .ase library, or another document's swatches (engine: swatch.library.load), and open it in the library panel",
     ),
     (
         "ui.saveSwatchLibrary",

crates/ui-egui/src/panels/image_trace.rs

@@ -1,4 +1,5 @@
-//! Image Trace panel: preset, mode, threshold or colour count, and the advanced fidelity options.
+//! Image Trace panel: preset, mode, threshold or colour count, and the advanced options (fidelity,
+//! method, Create: Fills / Strokes with the widest line stroked).
 //! With an Image Trace object selected, changing a setting re-traces it (one undo step per change;
 //! sliders apply when released). With an image selected, Trace makes a new Image Trace object.
 
@@ -207,6 +208,27 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
                 }
             }
         });
+        // Create: Fills and/or Strokes (one of them stays on), and the widest line stroked.
+        let create = |p: &Value, key: &str| p[key].as_bool().unwrap_or(key == "fills");
+        let strokes = create(&st.params, "strokes");
+        ui.horizontal(|ui| {
+            widgets::dim_label(ui, tl!("Create:"));
+            for (key, other, label) in [("fills", "strokes", tl!("Fills")), ("strokes", "fills", tl!("Strokes"))] {
+                let on = create(&st.params, key);
+                if widgets::check(ui, label, on, !on || create(&st.params, other)) {
+                    st.params[key] = json!(!on);
+                    st.preset = "Custom".into();
+                    retrace = true;
+                }
+            }
+        });
+        let mut v = st.params["strokeWidth"].as_f64().unwrap_or(10.0);
+        let (changed, release) = ui.add_enabled_ui(strokes, |ui| slider(ui, tl!("Stroke"), &mut v, 1.0..=100.0, " px")).inner;
+        if changed {
+            st.params["strokeWidth"] = json!(v.round());
+            st.preset = "Custom".into();
+        }
+        retrace |= release;
         for (key, label) in [("snapCurvesToLines", tl!("Snap Curves To Lines")), ("ignoreWhite", tl!("Ignore White"))] {
             let on = st.params[key].as_bool().unwrap_or(false);
             if widgets::check(ui, label, on, true) {
@@ -258,6 +280,57 @@ pub fn menu(app: &mut VectorcraftApp, ui: &mut Ui) {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use egui::{Event, PointerButton, Pos2, Rect, vec2};
+
+    /// One headless frame of the panel (and its menu) with `events`: the texts drawn, with where.
+    fn frame(app: &mut VectorcraftApp, ctx: &egui::Context, events: Vec<Event>) -> Vec<(String, Rect)> {
+        let screen = Rect::from_min_size(Pos2::ZERO, vec2(280.0, 700.0));
+        let mut out = ctx.run_ui(egui::RawInput { screen_rect: Some(screen), events, ..Default::default() }, |ui| show(app, ui));
+        out.textures_delta.clear();
+        crate::tests_removeanchors::shapes_text(&out.shapes.iter().map(|c| c.shape.clone()).collect::<Vec<_>>())
+    }
+
+    /// Click the panel's `label` (the first one drawn).
+    fn click(app: &mut VectorcraftApp, ctx: &egui::Context, label: &str) {
+        let texts = frame(app, ctx, vec![]);
+        let at = texts.iter().find(|(t, _)| t == label).map(|(_, r)| r.center()).unwrap_or_else(|| panic!("no `{label}` in {texts:?}"));
+        let press = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers: Default::default() };
+        frame(app, ctx, vec![Event::PointerMoved(at), press(true)]);
+        frame(app, ctx, vec![press(false)]);
+    }
+
+    fn traced_app() -> VectorcraftApp {
+        let mut app = VectorcraftApp::new(vectorcraft_engine::Session::new(), Default::default());
+        app.session.execute("file.new", &json!({"width": 100, "height": 100})).unwrap();
+        let img = image::RgbaImage::from_fn(20, 20, |x, _| image::Rgba(if x < 10 { [0, 0, 0, 255] } else { [255, 255, 255, 255] }));
+        let mut png = vec![];
+        img.write_to(&mut std::io::Cursor::new(&mut png), image::ImageFormat::Png).unwrap();
+        let data = vectorcraft_format::base64_encode(&png);
+        app.run("file.place", json!({"name": "half.png", "dataBase64": data, "link": false})).unwrap();
+        app.run("imageTrace.make", json!({"preset": "Default"})).unwrap();
+        app
+    }
+
+    #[test]
+    fn create_strokes_traces_again_and_keeps_one_kind_on() {
+        let mut app = traced_app();
+        let ctx = egui::Context::default();
+        crate::theme::install_fonts(&ctx);
+        let create = |app: &VectorcraftApp| target(app).2.map(|t| (t["params"]["fills"].clone(), t["params"]["strokes"].clone()));
+        let texts = frame(&mut app, &ctx, vec![]);
+        for s in ["Create:", "Fills", "Strokes", "Stroke", "10"] {
+            assert!(texts.iter().any(|(t, _)| t == s), "{s}: {texts:?}");
+        }
+        // Fills alone can't be turned off.
+        click(&mut app, &ctx, "Fills");
+        assert_eq!(create(&app), Some((json!(true), json!(false))));
+        click(&mut app, &ctx, "Strokes");
+        assert_eq!(create(&app), Some((json!(true), json!(true))), "traced again with strokes");
+        click(&mut app, &ctx, "Fills");
+        assert_eq!(create(&app), Some((json!(false), json!(true))));
+        click(&mut app, &ctx, "Strokes");
+        assert_eq!(create(&app), Some((json!(false), json!(true))), "Strokes alone stays on");
+    }
 
     #[test]
     fn panel_and_menu_draw_headless() {
@@ -266,6 +339,7 @@ mod tests {
         app.session.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 10, "height": 10})).unwrap();
         for _ in 0..2 {
             let ctx = egui::Context::default();
+            crate::theme::install_fonts(&ctx);
             let mut out = ctx.run_ui(egui::RawInput::default(), |ui| {
                 show(&mut app, ui);
                 menu(&mut app, ui);

crates/ui-egui/src/panels/library_panel.rs

@@ -616,4 +616,16 @@ mod tests {
         }
         assert!(!builtin_library(&open.id) && builtin_library(vectorcraft_engine::cmd::swatchlib::DOCUMENT_SWATCHES));
     }
+
+    #[test]
+    fn swatch_exchange_files_without_a_path_open_in_the_library_panel() {
+        // A file opened on the web has no path; open_bytes passes its bytes as dataBase64.
+        let mut app = app();
+        crate::io::open_bytes(&mut app, "Brand.ase", &vectorcraft_testkit::ase::sample(), None).unwrap();
+        let open = app.ui.library_panel.clone().unwrap();
+        assert_eq!(open.id, "loaded/Brand.ase");
+        let (_, lib) = SwatchLibraries::get(&app, &open.id).unwrap();
+        assert_eq!((lib.len(), lib.groups.len()), (4, 1));
+        assert_eq!(app.session.documents().len(), 1, "not opened as a document");
+    }
 }

crates/ui-egui/src/tests_removeanchors.rs

@@ -37,7 +37,7 @@ fn labels(items: &[Item]) -> Vec<&'static str> {
         .collect()
 }
 
-fn shapes_text(shapes: &[Shape]) -> Vec<(String, Rect)> {
+pub(crate) fn shapes_text(shapes: &[Shape]) -> Vec<(String, Rect)> {
     fn walk(s: &Shape, v: &mut Vec<(String, Rect)>) {
         match s {
             Shape::Text(t) => v.push((t.galley.text().to_string(), Rect::from_min_size(t.pos, t.galley.size()))),

docs/control-protocol.md

@@ -154,7 +154,7 @@ Clicking a swatch there runs `swatch.library.add {library, names: [name], apply}
 one with Alt), so one undo step adds and applies it; Shift/Cmd-clicks select swatches and colour groups for
 Add to Swatches.
 `window.swatchLibrary.other {path?}` loads a library file (or another document's swatches) and opens it there;
-opening a `.vcswatches` or `.gpl` file with `app.open` does the same. `ui.saveSwatchLibrary {names?}` opens the
+opening a `.vcswatches`, `.gpl` or `.ase` file with `app.open` does the same. `ui.saveSwatchLibrary {names?}` opens the
 `saveSwatchLibrary` dialog (fields `name`, `format`: `vcswatches`/`gpl`/`css`, `user`: save to the user library
 folder, `selectedOnly` with `names`); `ui.dialog.confirm` runs `swatch.library.save` (to a file it asks for a path).
 

docs/development.md

@@ -239,7 +239,7 @@ web build has no net at all.
 Untrusted input has property tests that must never panic:
 
 - `crates/engine/tests/import_fuzz.rs`: garbage, hostile and mutated SVG and PDF, and swatch
-  (`.vcswatches`, `.gpl`), graphic style (`.vcstyles`) and flattener preset (`.vcflattener`)
+  (`.vcswatches`, `.gpl`, `.ase`), graphic style (`.vcstyles`) and flattener preset (`.vcflattener`)
   libraries, loaded and used, then rendered and exported.
 - `crates/engine/tests/command_sweep.rs`: every command with junk parameters.
 - `crates/format/tests/prop_format.rs`: garbage and mutated `.vectorcraft` files.

docs/mcp.md

@@ -740,7 +740,9 @@ swatch in the library panel does). `swatch.resetDefaults {replace?}` brings back
 as a library (`.vcswatches` keeps colour models, global, spot, gradients and colour groups; `.gpl` is 8-bit RGB;
 CSS writes custom properties); without `path` it returns `{data}`, and `user: true` saves into the user library
 folder of the desktop app (listed as category `user`, User Defined). `swatch.library.load {path? | data? |
-dataBase64?, name?}` loads a `.vcswatches` or `.gpl` file, or another document's swatches, as a library to add from.
+dataBase64?, name?}` loads a `.vcswatches`, `.gpl` or swatch exchange (`.ase`) file, or another document's swatches,
+as a library to add from. From an `.ase` file it reads RGB, CMYK, Lab and Gray colors as global, spot or process
+swatches and keeps their color groups.
 
 ## Graphic style libraries