vectorcraft/docs/mcp.md

337 lines
24 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# VectorCraft MCP server
`vectorcraft-cli mcp` runs a [Model Context Protocol](https://modelcontextprotocol.io) server on stdio
(newline-delimited JSON-RPC 2.0, protocol `2025-06-18`; `2025-03-26` and `2024-11-05` also accepted). Agents use it to
draw, inspect and look at VectorCraft documents.
It has two backends:
| Mode | How | What works |
|---|---|---|
| **Remote** | `vectorcraft-cli mcp --connect 127.0.0.1:7979` (the app must run with `vectorcraft --control 7979`) | Everything. Tool calls are forwarded over the [control protocol](control-protocol.md), so you watch the app change live. |
| **Headless** | `vectorcraft-cli mcp --headless` | An in-process engine session with a CPU renderer. Everything except the UI-only tools (`inspect_ui`, `type_text`, `open_panel`, `screenshot {window:true}`). |
With no flag, the server tries `127.0.0.1:7979` and falls back to headless. Logs go to stderr; stdout carries
only protocol messages.
## Build and register
```sh
cargo build --release -p vectorcraft-cli
claude mcp add vectorcraft -- "$PWD/target/release/vectorcraft-cli" mcp
# or pin a mode:
claude mcp add vectorcraft-headless -- "$PWD/target/release/vectorcraft-cli" mcp --headless
claude mcp add vectorcraft-app -- "$PWD/target/release/vectorcraft-cli" mcp --connect 127.0.0.1:7979
```
Other clients use the same command in their JSON config:
```json
{"mcpServers": {"vectorcraft": {"command": "/abs/path/target/release/vectorcraft-cli", "args": ["mcp"]}}}
```
For a live session, start the app first: `cargo run --release -p vectorcraft -- --control 7979`.
## Tools
Coordinates are points in document space: y points down, the origin is the first artboard's top-left, and a new
document is 612 × 792 (US Letter). New objects become the selection. Most commands act on the selection or on
explicit `ids`.
Paint values (`fill`, `stroke`) accept `"#rrggbb"`, `"none"`, `[r,g,b]` (0..1), `{"c","m","y","k"}`, `{"gray"}`,
or a full `paint.setFill` params object (`{"gradient": …}`, `{"swatch": "name"}`).
The Fill/Stroke proxy commands run through `run_command`: `paint.invert` and `paint.complement` recolour the active
proxy keeping each colour's model, `paint.lastColor` / `paint.lastGradient` re-apply the last solid colour or gradient,
and `paint.recent` returns the recent colours that every paint command (and the eyedropper) feeds.
`paint.proxies` returns what the proxies show: the fill and stroke, which one is active, and whether the selected
objects' fills or strokes differ (`fillMixed` / `strokeMixed`, drawn as a "?" proxy).
| Tool | Arguments | Notes |
|---|---|---|
| `list_commands` | `{filter?, enabledOnly?}` | The command catalogue: id, label, menu, shortcut, params doc, enablement. |
| `run_command` | `{command, params?}` | Runs any command. Use it for everything without a dedicated tool. |
| `inspect_document` | `{}` | Artboards, layer tree (ids, kinds, bounds, paint), selection, history, tool. |
| `inspect_ui` | `{}` | UI state. Remote mode only. |
| `select_tool` | `{tool}` | `selection`, `directSelection`, `pen`, `rectangle`, `ellipse`, `polygon`, `star`, `lineSegment`, … |
| `pointer_gesture` | `{events:[{kind,x,y,mods?}], tool?, mods?}` | `kind` is one of `down`, `drag`, `up`, `move`, `doubleclick`. Events go through the same path as the mouse. |
| `draw_path` | `{points \| d, closed?, fill?, stroke?, strokeWidth?}` | `points` is `[[x,y],…]` or `[{x,y,in?,out?,smooth?},…]`. `d` is SVG path data. |
| `draw_shape` | `{shape, …geometry, fill?, stroke?, strokeWidth?}` | `rectangle`/`ellipse`: `x,y,width,height` (plus `radius` for corners). `polygon`: `cx,cy,radius,sides`. `star`: `cx,cy,radius1,radius2,points`. `line`: `x1,y1,x2,y2`. |
| `set_paint` | `{fill?, stroke?, strokeWidth?, ids?}` | Applies to the selection (or `ids`) and becomes the default for new art. |
| `press_key` | `{key, mods?}` | Remote: a real key event. Headless: runs the command or tool bound to that shortcut, or sends the key to the busy tool. |
| `type_text` | `{text}` | Remote only. |
| `invoke_menu` | `{command, params?}` | Invokes a menu item by command id. Includes UI commands such as `view.*` and `window.*` in remote mode. |
| `open_panel` | `{panel}` | Remote only. |
| `screenshot` | `{path?, scale?, artboard?, window?}` | Returns MCP image content (`image/png`, base64) plus a text block. Renders the artboard; `window:true` captures the app window (remote only). |
| `open_file` | `{path}` | Opens any readable file as a new active document: `.vectorcraft`/`.drawcraft`, `.svg`/`.svgz`, `.pdf`/`.ai`, `.ait`, PNG, JPEG, GIF, WebP, TIFF, BMP (an image opens as a document of its pixel size). Templates open as a new untitled document. `run_command document.formats` lists the formats. |
| `save_file` | `{path?}` | Saves in the native `.vectorcraft` format. |
| `export` | `{path?, format?, scale?, artboard?, range?, selection?, outlineText?, options?}` | `svg`, `pdf`, `png`, `jpg`, `webp` or `vectorcraft` (the list comes from `document.formats`). When `format` is omitted, it comes from the path's extension. PDF writes one page per artboard: all of them, or `artboard` (0-based) / `range` (`"1-3, 5"`, 1-based); the other formats write one artboard. `options` carries more format options (e.g. `{"quality": 80}` for JPEG). `selection: true` exports the selected objects cropped to their bounds; `outlineText: true` writes SVG text as paths. Template layers are left out, live effects are kept, and exporting `vectorcraft` never changes the document's path. Without `path` the bytes come back as `dataBase64`. Both backends run the same `document.export` call. |
| `add_text` | `{text, x?, y?, width?, height?, path?, mode?, pathEffect?, size?, font?, color?}` | Point type at (x, y); area type with `width`/`height`; or `path` + `mode` (`area`/`onPath`) to flow text in or along a path, with `pathEffect` (`rainbow`, `skew`, `3dRibbon`, `stairStep`, `gravity`). |
| `apply_effect` | `{effect?, params?, ids?}` | Appends a live effect. Without `effect`, returns the effect catalogue with parameters and defaults. |
| `pathfinder` | `{operation, ids?}` | `unite`, `minusFront`, `intersect`, `exclude`, `divide`, `trim`, `merge`, `crop`, `outline`, `minusBack`. For a live version, apply the `pathfinder.*` effect to a group. |
| `transform` | `{ids?, dx?, dy?, rotate?, scale?, scaleX?, scaleY?, reflect?, shear?, origin?, copy?}` | Runs move, rotate, scale, reflect, shear in that order. With `copy`, the first step duplicates. |
| `create_graph` | `{type?, x, y, width, height, csv? \| series?, categories?, rows?}` | The nine Illustrator graph types: column, stacked column, bar, stacked bar, line, area, scatter, pie and radar. Edit later with `graph.setData` / `graph.setType` via `run_command`. |
| `text_wrap` | `{ids?, offset?, invert?, release?}` | Area type below the objects (same layer) flows around them. |
| `undo` / `redo` | `{}` | |
Appearance stacks: an object can carry several fills and strokes (`appearance.addFill`, `appearance.addStroke`), indexed
in paint order (0 is painted first, the bottom row of the Appearance panel). `paint.setFill`, `paint.setStroke`,
`stroke.set`, `stroke.setAdvanced`, `paint.editGradient`, `paint.setGradientGeom` and `transparency.set` take
`item` to edit one of them; `run_command appearance.setActiveItem {"index": n}` makes that row the target of later
calls that omit `item` (as clicking the row in the Appearance panel does) until the selection changes; the proxy of
its kind (`paint.proxies`) and the Gradient tool's annotator then show that row.
`inspect_document` reports it as `paint.appearanceItem`. Live effects take the same `item` to apply to one fill or
stroke instead of the whole object: `run_command effect.apply {"effect": "path.offsetPath", "item": 0}`, and
`effect.remove`, `effect.setParams` (`visible` toggles one) and `effect.duplicate` address that item's effects;
`apply_effect` uses the active item. `effect.list` reports each object's item effects under `applied[].items`.
Errors (unknown tool, bad arguments, a disabled or failing command) come back as a normal result with
`isError: true` and a message. The model can read the message and retry.
Swatches go through `run_command`: `swatch.list` lists every swatch with its colour group, kind and colour;
`swatch.edit {name, newName?, color?, mode?, global?, spot?}` edits one (fills, strokes and text linked to a
global or spot swatch follow its colour and name, as one undo step); `swatch.delete {names, unlink?}` deletes
swatches and colour groups in one undo step (art using a deleted global swatch keeps its colour, unlinked).
`swatch.new {color?, mode?, spot?, global?, group?}` saves a colour (into a colour group with `group`), gradient
or pattern; `swatch.newGroup {fromArtwork: true, toGlobal?, includeTints?}` makes a colour group of the selected
art's colours (by default as global swatches the art links to).
`swatch.move {names, to?, group?}` reorders swatches or moves them into or out of a colour group (as dragging
them in the Swatches panel does); give colour group names instead to reorder the groups. Dropping a swatch on art
in the app runs `paint.setFill` (or `paint.setStroke`, the active proxy) with `ids: [the object under the pointer]`.
The Swatches panel menu's commands: `swatch.addUsedColors {selection?, global?}`, `swatch.unused` (a query: the
names Select All Unused selects), `swatch.merge {names}` (the first is kept), `swatch.ungroup {name}` and
`swatch.sortByKind`.
Document colour mode: `file.new {colorMode: "cmyk"}` starts a CMYK document with CMYK default swatches, and RGB
colours applied to it (`paint.setFill`/`setStroke` colours and gradient stops, `swatch.new`) are stored as CMYK;
Gray stays Gray, and `keepModel: true` keeps a colour as given. RGB documents keep colours as given. Harmonies, Edit
Colors blends, inversions and Recolor Artwork keep each colour's model (a blend between models takes the document's).
`swatch.new {colors: [...]}` saves several colours as swatches in one undo step. `color.harmony {color, rule, steps?, variation?, amount?}` answers what the Color
Guide panel shows: the harmony rule's colours, base first, and per colour its row of `2·steps+1` variations
(shades, cool or muted on the left, tints, warm or vivid on the right).
## Resources
| URI | Content |
|---|---|
| `vectorcraft://document` | `document.inspect` summary (JSON) |
| `vectorcraft://document/json` | The complete document model (JSON) |
## Examples
Draw, look, export:
```json
{"name":"draw_shape","arguments":{"shape":"rectangle","x":72,"y":72,"width":200,"height":120,"radius":12,"fill":"#1e88e5","stroke":"none"}}
{"name":"draw_shape","arguments":{"shape":"star","cx":400,"cy":300,"radius1":90,"radius2":40,"points":5,"fill":"#ffc107","stroke":"#000000","strokeWidth":2}}
{"name":"draw_path","arguments":{"d":"M72 400 C 150 300 250 500 330 400","stroke":"#e53935","strokeWidth":4,"fill":"none"}}
{"name":"screenshot","arguments":{"scale":0.5}}
{"name":"export","arguments":{"path":"/tmp/art.svg"}}
```
Long-tail commands:
```json
{"name":"list_commands","arguments":{"filter":"align"}}
{"name":"run_command","arguments":{"command":"select.all"}}
{"name":"run_command","arguments":{"command":"object.align","params":{"align":"left"}}}
{"name":"run_command","arguments":{"command":"object.group"}}
```
Drive a tool like a mouse:
```json
{"name":"pointer_gesture","arguments":{"tool":"ellipse","events":[
{"kind":"down","x":100,"y":100},{"kind":"drag","x":150,"y":140},{"kind":"up","x":200,"y":180}]}}
```
Edit a gradient with the Gradient tool's annotator (the bar runs along the vector; stop chips sit 10 px under
it, midpoint diamonds 7 px above): a click on the bar adds a stop, dragging a chip moves it (drag it off the bar to
delete it, hold Alt to copy it), dragging the end handle changes the vector. The selected stop
(`gradient.selectStop`) takes Delete and ←/→:
```json
{"name":"run_command","arguments":{"command":"paint.setFill","params":{"gradient":{"start":[100,150],"end":[200,150]}}}}
{"name":"pointer_gesture","arguments":{"tool":"gradient","events":[{"kind":"down","x":130,"y":150},{"kind":"up","x":130,"y":150}]}}
{"name":"pointer_gesture","arguments":{"events":[{"kind":"down","x":130,"y":160},{"kind":"drag","x":160,"y":160},{"kind":"up","x":160,"y":160}]}}
{"name":"press_key","arguments":{"key":"Delete"}}
```
Raw protocol (for debugging):
```sh
printf '%s\n' \
'{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"sh","version":"0"}}}' \
'{"jsonrpc":"2.0","method":"notifications/initialized"}' \
'{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"draw_shape","arguments":{"shape":"ellipse","x":10,"y":10,"width":100,"height":80,"fill":"#ff0000"}}}' \
'{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"inspect_document","arguments":{}}}' \
| target/release/vectorcraft-cli mcp --headless
```
## Headless batch CLI
```sh
vectorcraft-cli commands # command catalogue (JSON)
vectorcraft-cli run --in in.svg \
--cmd select.all --cmd paint.setFill --params '{"color":"#ff0000"}' \
--export out.svg --export out.png --scale 2
vectorcraft-cli run --cmd file.new --params '{"width":800,"height":600}' \
--cmd shape.star --params '{"cx":400,"cy":300,"radius1":200,"radius2":90}' \
--export star.vectorcraft
```
`run` prints one JSON line per step (`open`, `cmd`, `export`) and exits non-zero on the first failure. `--params`
applies to the `--cmd` just before it. `run` also accepts the host commands `file.open`, `file.save`, `file.export`,
`file.exportForScreens` and `tool.select`. `run --in`, `convert` and `info` read every format `document.open` reads
(`vectorcraft-cli --help` lists them).
## Transparency and opacity masks
Transparency and opacity-mask commands take `ids` (or `id`), so they need no selection. Opacity is a percentage
(0..100) in every command (`transparency.set`, `object.setProps`, `appearance.setItem`). `transparency.info` returns
the Transparency panel's values, with `null` where the objects differ. Making a mask from one object gives it an
empty mask and enters mask editing: art drawn then becomes the mask, and the mask commands act on the masked object
until `transparency.stopEditingOpacityMask`. Saves and exports never include the editing layer.
```json
{"name":"run_command","arguments":{"command":"transparency.set","params":{"ids":[12],"opacity":40,"blend":"Multiply"}}}
{"name":"run_command","arguments":{"command":"transparency.makeOpacityMask","params":{"ids":[12,15],"invert":true}}}
{"name":"run_command","arguments":{"command":"transparency.setOpacityMask","params":{"id":12,"clip":false}}}
{"name":"run_command","arguments":{"command":"transparency.info","params":{"ids":[12,20]}}}
```
Knockout Group has three states: `transparency.set {knockout: "on"|"off"|"neutral"}` (`true` = on, `false` =
neutral, the default). In a knockout group each child hides what it covers of the children below it; neutral groups
pass the enclosing group's setting to their children, off groups never knock out. `knockoutShape: true` makes the
object's opacity and opacity mask scale how much it knocks out. `transparency.togglePageKnockoutGroup` and
`transparency.togglePageIsolatedBlending` (`{value?}`) treat the whole page as a knockout or isolated group; they are
saved with the document and undoable, and `transparency.info` reports them. PDF and SVG write knockout groups as
soft-masked groups with the same look (the PDF export reports a warning).
Groups are not isolated unless Isolate Blending is on: a blend mode inside a group with opacity, a blend mode, an
opacity mask, knockout or a clip reaches the art below the group, on screen and in PDF (a knockout group's elements
then composite against the art below it). SVG has no non-isolated groups, so there such groups stay isolated.
## Clipping masks
`object.clippingMask.make` clips the selected objects by the topmost one, which may be a path, a compound path or a
text object (it loses its paint). Compound holes, even-odd fills, glyph outlines and the union of a group's members
clip alike on screen, in raster export and in SVG and PDF. `object.clippingMask.release` turns the clip group into a
plain group and keeps the clipping path, unpainted.
```json
{"name":"run_command","arguments":{"command":"select.set","params":{"ids":[12,15]}}}
{"name":"run_command","arguments":{"command":"object.clippingMask.make","params":{}}}
```
`layer.clippingMask.toggle {id?}` is the Layers panel's clipping mask button: the top object of the layer `id` (default:
the one selected group, else the current layer) becomes its clipping path (unpainted, moved to the bottom of the layer,
so art added later is clipped too); called again it releases the mask. It returns `{clip}`, and the Layers panel
underlines clipping-path names.
## Graphic styles
A graphic style holds an appearance (fills, strokes, effects) plus opacity, blend mode, isolate and knockout.
`graphicStyle.new {name?, id?}` captures an object (a group without its own fills or strokes lends its topmost
object's, type its characters'). `graphicStyle.apply {name, ids?}` gives the objects the style and links them;
`add: true` adds the style on top of the existing appearance instead. Linked objects stay linked while they keep the
style's look: editing their appearance or transparency breaks the link, and `graphicStyle.redefine {name?, id?}`
updates only the objects still linked. `graphicStyle.list` returns each style with the ids linked to it and the
style of the first selected object; `select.same.graphicStyle` selects an object's fellow users.
Styles keep placed gradients relative to the bounds of the object they were made from, and each object a
style is applied to gets them at the same place relative to its own bounds.
```json
{"name":"run_command","arguments":{"command":"graphicStyle.new","params":{"id":12,"name":"Glow"}}}
{"name":"run_command","arguments":{"command":"graphicStyle.apply","params":{"name":"Glow","ids":[15,20]}}}
{"name":"run_command","arguments":{"command":"graphicStyle.redefine","params":{"id":12}}}
{"name":"run_command","arguments":{"command":"graphicStyle.list","params":{}}}
```
## Editing appearance stacks
`effect.move {from, to, fromItem?, toItem?, copy?}` reorders an effect or moves it between the object's effects
(`null`) and a fill's or stroke's (an item index), as dragging its row in the Appearance panel does; `copy: true` copies
it (Alt-drag). `appearance.duplicateItem {index, to?}` / `{indices}` and `appearance.removeItem {index | indices}`
act on several fills/strokes at once, and `appearance.showAllHidden` makes every hidden fill, stroke and effect
visible again. In remote mode, `effect.dialog {effect, index, item}` opens an applied effect's dialog prefilled
(`ui.dialog.confirm` runs `effect.setParams`); see the control protocol for the "already applied" question.
## Overprint
Each fill and stroke (and each character's fill and stroke) can overprint: its inks print over the inks below instead
of knocking them out. `object.setOverprint {fill?, stroke?, item?, ids?}` sets it (groups set their contents, type its
characters too; `item` aims at one appearance item) and `attributes.info {ids?}` reads it back (`null` where the
objects differ). Overprint Preview (`view.overprintPreview`) and Separations Preview show it; rendering approximates
it by multiplying. Older files that listed Overprint Black objects in the document get the flags on load.
```json
{"name":"run_command","arguments":{"command":"object.setOverprint","params":{"ids":[12],"stroke":true}}}
{"name":"run_command","arguments":{"command":"attributes.info","params":{"ids":[12]}}}
{"name":"run_command","arguments":{"command":"view.overprintPreview","params":{"on":true}}}
```
## Edit Colors and Recolor Artwork
`edit.colors.invert`, `edit.colors.toCMYK`, `edit.colors.toGrayscale`, `edit.colors.toRGB`, `edit.colors.saturate`,
`edit.colors.adjustBalance` and `recolor.apply` recolour everything inside the selection (or `ids`) in one undo step:
fills, strokes, text, gradient stops, gradient-mesh points, embedded images (a recoloured copy of the image; linked
images are left alone) and the tiles of pattern fills and strokes (a recoloured copy saved as a new pattern swatch,
e.g. "Dots 2"; the original pattern is untouched). `includeImages: false` / `includePatterns: false` leave images or
patterns out. The Blend commands also grade gradient meshes, which keep their shading.
```json
{"name":"run_command","arguments":{"command":"recolor.colors","params":{}}}
{"name":"run_command","arguments":{"command":"recolor.apply","params":{"map":{"#ff0000":"#0055ff"},"includeImages":false}}}
{"name":"run_command","arguments":{"command":"edit.colors.adjustBalance","params":{"mode":"cmyk","m":-20,"k":10}}}
```
## Group, layer and type appearance
Groups and layers carry fills, strokes and effects of their own, as in the reference app: their fills and strokes
paint every member's geometry, and their effects apply to the members as one piece (one combined drop shadow; a
Transform or Warp moves or bends the whole group). Their Contents row (type: Characters) is a slot in the stack:
fills and strokes above it paint over the members (characters), those below under them; new items go above it.
`appearance.moveItem {"from": "contents", "to": n}` puts the row above the bottom `n` items, and an item move takes
`contents` to say where the row ends up in the same undo step; `document.node` shows the slot as
`appearance.contents_index`. The `appearance.*`, `effect.*` and `graphicStyle.apply` commands edit the selected
objects themselves (a group's own stack; layers through `ids`) or, with `target: "contents"`, the objects inside the
groups and layers. `appearance.targetContents` selects a group's members (double-clicking the Contents row).
SVG and PDF export bake a group's own fills, strokes and geometry effects into paths; its raster effects stay a
filter on the whole group.
```json
{"name":"run_command","arguments":{"command":"appearance.addFill","params":{"ids":[7]}}}
{"name":"run_command","arguments":{"command":"appearance.moveItem","params":{"ids":[7],"from":"contents","to":1}}}
{"name":"run_command","arguments":{"command":"effect.apply","params":{"ids":[2],"effect":"stylize.dropShadow"}}}
{"name":"run_command","arguments":{"command":"appearance.addStroke","params":{"ids":[7],"target":"contents"}}}
## Swatch libraries
Swatch libraries are read-only sets of swatches computed in code (Web Safe 216, Grays and Neutrals, Earth Tones,
Skin Tone Ramps, Pastels, Brights, Metallic Gradients, Perceptual Scales, Harmony Sets). `swatch.library.list` lists
them (`id`, `name`, `category`, `count`) and `swatch.library.get {library}` returns one's swatches and colour groups
in the `swatch.list` shape (`library` is an id or a name). `swatch.library.add {library, names?}` copies swatches
into the document as one undo step: a colour group's name brings the whole group, a swatch's name the swatch alone,
no names the whole library; swatches the document already has (same name and paint) are reported under `existing`
and not added again. `apply: "fill"|"stroke"` also applies the first one, in the same undo step (what clicking a
swatch in the library panel does). `swatch.resetDefaults {replace?}` brings back the missing default swatches.
```json
{"name":"run_command","arguments":{"command":"swatch.library.get","params":{"library":"earth-tones"}}}
{"name":"run_command","arguments":{"command":"swatch.library.add","params":{"library":"earth-tones","names":["Clay"]}}}
```
`swatch.library.save {path?, format?: "vcswatches"|"gpl"|"css", names?, name?, user?}` writes the document's swatches
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.
## Strokes on type
`stroke.set` without an `item` gives type its characters' stroke: weight, cap, join, miter limit and the dash
options go to every run (the object keeps no stroke of its own); an `item` still edits an object-level stroke added
with `appearance.addStroke`, which takes every stroke option (dashes, profile, opacity, blend) like a path's and paints under or over the
characters as its place relative to the Characters row says. To stroke
some characters, use `text.setRangeStyle {id, start, end, strokeOptions: {weight?, cap?, join?, miterLimit?, dash?,
dashOffset?, alignDashes?}}`. `inspect_document` reports each object's stroke as `strokeOptions` (type: its first
run's) in `stroke.set` terms. `stroke.set` on a group leaves the images and symbol instances in it alone.