Add-ons: Color Effects — live exposure, desaturate and invert, apply as filter, panel

A built-in add-on in Effect › Color Effects and Object › Plug-ins › Color Effects:
- Exposure (stops of linear light, offset and gamma), Desaturate and
  Invert Colors as live colour adjustments, evaluated in stack order with
  those of Effect › Color Adjustments.
- addon.color.filter applies any colour adjustment to the colours
  themselves, through the Edit Colors pass, as one undo step.
- A panel picks an adjustment and its values, then adds it as a live
  effect or applies it as a filter.

The add-on lives in its own modules (effects, engine and ui-egui addons
folders) and leaves the existing effects, commands and menus as they
were.

docs/mcp.md

@@ -5708,3 +5708,31 @@ topmost piece.
 {"name":"run_command","arguments":{"command":"addon.cleanup.fix","params":{"kinds":["strayPoints","needlessGroups"]}}}
 {"name":"run_command","arguments":{"command":"addon.cleanup.simplify","params":{"tolerance":40,"protectCorners":true}}}
 ```
+
+## Color Effects add-on
+
+Color Effects is a built-in add-on: its effects are colour adjustments in Effect › Color Effects, its command is
+`addon.color.filter`, and in the desktop app it also lives in Object › Plug-ins › Color Effects and in its panel
+(`window.panel {panel: "colorEffects"}`).
+
+Its live effects go on through `effect.apply` like any other and recolour what the object paints, in stack order with
+the other colour adjustments (Effect › Color Adjustments); each colour keeps its colour model:
+
+| Effect | Parameters | Does |
+|---|---|---|
+| `addon.color.exposure` (Exposure…) | `exposure` stops −20…20 (0), `offset` −0.5…0.5 (0), `gamma` 0.1…10 (1) | Scales the light in linear light (each stop doubles or halves it, mostly in the highlights), adds the offset (shadows and midtones) and applies the gamma |
+| `addon.color.desaturate` (Desaturate) | none | Turns every colour to the grey of its lightness |
+| `addon.color.invert` (Invert Colors) | none | Turns every colour to its RGB inverse |
+
+`addon.color.filter {effect, params?, fill?, stroke?, includeImages?, includePatterns?, ids?}` applies any colour
+adjustment, the add-on's or one of Effect › Color Adjustments', to the colours themselves instead of as a live effect:
+fills, strokes, type, gradient meshes, embedded images and pattern tiles, as `edit.colors.invert` reaches them, as one
+undo step. Missing `params` take the effect's dialog defaults; the objects' own effects stay as they are.
+
+```json
+{"name":"run_command","arguments":{"command":"effect.apply","params":{"effect":"addon.color.exposure","params":{"exposure":1.5}}}}
+{"name":"run_command","arguments":{"command":"addon.color.filter","params":{"effect":"adjust.hueSaturation","params":{"hue":120}}}}
+```
+
+The panel picks an adjustment (Brightness/Contrast, Hue/Saturation, Levels, Temperature/Tint, Exposure, Desaturate or
+Invert Colors), sets its values, and then Add as Effect (`effect.apply`) or Apply as Filter (`addon.color.filter`).

docs/target-app-parity.md

@@ -1,6 +1,6 @@
 # Parity with Adobe Illustrator
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Artwork Cleanup, a built-in add-on beyond Illustrator; scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x; public release notes through 30.7, August 2026)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Color Effects, a built-in add-on beyond Illustrator; scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x; public release notes through 30.7, August 2026)
 
 ## Feature submission evidence
 
@@ -1216,10 +1216,22 @@ Show, Fix Selected and Fix All (each one undo step), Deep Ungroup and Rejoin Pat
 alone; Fix All as one step; scopes; rejoin within the gap only) and `addons::cleanup::tests` in `vectorcraft-ui-egui`
 (the submenu opens the panel; Check lists what it finds). Commands: `docs/mcp.md` › Artwork Cleanup add-on.
 
+## Color Effects add-on (2026-10-30)
+
+A VectorCraft addition, not an Illustrator feature, so no area score moves. Effect › Color Effects adds live Exposure
+(stops of linear light, offset and gamma), Desaturate and Invert Colors as colour adjustments evaluated with those of
+Effect › Color Adjustments (`vectorcraft_effects::addons::color`), and `addon.color.filter` applies any colour adjustment
+to the colours themselves through the Edit Colors pass. Object › Plug-ins › Color Effects and its panel reach them.
+Tests: `addons::color` in `vectorcraft-effects` (exposure in stops, desaturate keeps lightness, invert twice is
+identity), `cmd::addons::color::tests` in `vectorcraft-engine` (drawn live without changing the colours; a filter as one
+undo step, with any adjustment and its params; bad requests refused) and `addons::color::tests` in
+`vectorcraft-ui-egui` (the menus and the panel). Commands: `docs/mcp.md` › Color Effects add-on.
+
 ## Revision history
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-30 | minor | Color Effects, a built-in add-on beyond Illustrator; scores and estimates unchanged |
 | 2026-10-30 | minor | Artwork Cleanup add-on (a VectorCraft addition): evidence added; scores unchanged. |
 | 2026-10-30 | minor | Hardware: a second finger cancels the tool press the first finger began, and a finger landing while another is down presses nothing, so a pinch only navigates (#4198); evidence added; scores unchanged (estimated). |
 | 2026-10-30 | minor | File formats: SVG export writes axis-aligned rectangles as `<rect>`, circles and ellipses as `<circle>`/`<ellipse>`, straight lines as `<line>` and other straight-segment paths as `<polygon>`/`<polyline>`, keeping `<path>` where a shape element would draw differently (#4652); evidence added; scores and hours unchanged (estimated). |

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI and interaction parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Artwork Cleanup add-on: its panel and Object › Plug-ins submenu; scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Color Effects add-on: its effects, panel and Object › Plug-ins submenu; scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
 
 ## Feature submission evidence
 
@@ -322,6 +322,7 @@ next unit in the order a right-click on a ruler lists them, from Feet back to Po
 | Tabs panel: a stop drags from where the press landed, a stop just added included | done | #1458 |
 | Outline view keeps template layers in Preview, dimmed | done | #1486; a picture placed to be traced stays visible under the outlines |
 | Artwork Cleanup add-on (VectorCraft addition): Object › Plug-ins › Artwork Cleanup opens its panel, which checks the selection or the document for 16 kinds of issue, lists them with counts, and shows or fixes the picked rows or all of them, each fix one undo step; Simplify Anchors (Keep Shape), Rejoin Path Pieces and Deep Ungroup open their options first | done | `addon.cleanup.*`, `crates/ui-egui/src/addons/cleanup.rs` and its tests; not an Illustrator feature, so it is not scored |
+| Color Effects add-on (VectorCraft addition): live Exposure, Desaturate and Invert Colors in Effect › Color Effects and Object › Plug-ins › Color Effects; its panel picks a colour adjustment and its values and adds it as a live effect or applies it as a filter, into the colours, as one undo step | done | `addon.color.*`, `crates/ui-egui/src/addons/color.rs` and its tests; not an Illustrator feature, so it is not scored |
 
 ## Look and feel
 
@@ -362,6 +363,7 @@ separate. Scores and hours unchanged. [Behavior and command details](development
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-30 | minor | Color Effects add-on: its effects, panel and Object › Plug-ins submenu; scores and estimates unchanged |
 | 2026-10-30 | minor | Artwork Cleanup add-on (a VectorCraft addition): its panel and Object › Plug-ins › Artwork Cleanup; scores and estimates unchanged |
 | 2026-10-30 | minor | Spinners: a held arrow repeats after a pause (#4267); scores and estimates unchanged |
 | 2026-10-30 | minor | Control bar: a Replace menu swaps the selected symbol instances' symbol (#4121); scores and estimates unchanged |