Merge pull request #7335 from dotCooCoo/fix/live-paint-noop-undo

Live Paint: an edit that changes nothing records no undo step

docs/mcp.md

@@ -3529,6 +3529,12 @@ already walks Image Trace. Short agent entry points:
   `livePaint.fill` does not fill a face that is hidden on its own. With `group`, a point on a hidden face is an
   error. With `ids`, at a point on a hidden face it fills the face there of another Live Paint group among the
   objects; otherwise it returns an error and does not merge the objects.
+  A Live Paint command that changes nothing records no undo step, keeps the redo steps, leaves a saved document saved
+  and replies as usual: `livePaint.fill` (a click, or a Bucket drag) when every face it reaches already has the paint,
+  `livePaint.strokeEdge` when the edge already has the paint and the width, `livePaint.gapOptions` (and the Gap Options
+  dialog's OK) when every group already has the options and `closeGaps` finds no gap, and `livePaint.make` or
+  `livePaint.merge` given one Live Paint group alone, which they select. Such a fill or stroke also leaves the recent
+  colors and the last color as they are. `livePaint.gapOptions` makes a group's faces again, with new ids, only when it adds a path or when Gap Detection is turned on or off or given a new size while it is on.
 
 `brush.selectionArt {ids?|id?}` (a query) replies `{art}`: the object that `brush.new` given the same `ids` or `id`,
 or the same selection, takes as a new scatter or art brush's art and as a new pattern brush's side tile. Several

docs/target-app-parity.md

@@ -1440,6 +1440,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   View › Show Live Paint Gaps (`view.livePaintGaps`) draws the gaps of the selected Live Paint groups up to their Paint Stops At size, each in its group's Gap Preview Color, until Hide Live Paint Gaps or Hide Edges hides them ([Live Paint gaps](https://web.archive.org/web/20260105111201/https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/find-and-close-gaps-in-live-paint-groups.html)).
   Double-clicking the Live Paint Selection tool opens its Tool Options ([Live Paint Selection tool options](https://web.archive.org/web/20250904012025/https://helpx.adobe.com/illustrator/using/selecting-objects.html)): with Select Fills off, a click selects an edge instead of a face; with Select Strokes off, Alt-click selects a face instead of an edge; Color and Width set the color and width of the highlight on the face or edge under the pointer (red and 4 px by default). The options last across tool switches and are saved with the preferences (`tool.setOption {tool: "livePaintSelection"}`).
   As VectorCraft's own rule, OK in Live Paint Selection Tool Options, Live Paint Bucket Options, Gap Options and Tile Edge Color gives an error for a color with an alpha part (`#rrggbbaa` or `#rgba`) and changes nothing.
+  As VectorCraft's own rule, a Live Paint edit that changes nothing records no undo step, keeps the redo steps and leaves a saved document saved: a Live Paint Bucket click or drag over faces that already have the fill, a stroke on an edge that already has the paint and weight, Gap Options OK with the options the groups have and no gap to close, and Make or Merge with one Live Paint group alone. Such a fill or stroke also leaves the recent colors as they are. Regression tests: `live_paint_fill_same_paint_is_no_op`, `live_paint_bucket_click_with_the_face_paint_is_no_op`, `live_paint_stroke_edge_same_paint_and_width_is_no_op`, `live_paint_gap_options_same_values_are_no_op`, `live_paint_gap_options_close_without_gaps_is_no_op`, `live_paint_make_existing_group_is_no_op` and `live_paint_merge_single_group_is_no_op` in `crates/engine/src/tests/build.rs`, and `ok_on_unchanged_options_records_no_undo_step` in `crates/ui-egui/src/dialogs/live_paint_gaps.rs`.
   As VectorCraft's own rule, `tool.setOption` for the Live Paint Bucket and the Live Paint Selection tool, chosen or not, checks every value before it sets any: a switch that is not `true` or `false`, a `color` that is not an RGB color or a layer color's name, or that has an alpha part, a `width` that is not a number and an option the tool does not have give an error naming the option, and nothing is set or saved. A `width` outside 1 to 20 px is still set to the nearest end of that range. Saved settings that hold an invalid value still load, and the tool keeps its default for that option. Evidence: `tests::build::{live_paint_tool_options_refuse_invalid_values_and_change_nothing, live_paint_tool_options_take_rgb_colors_and_clamp_the_width, live_paint_tools_load_saved_settings_with_invalid_values}`.
   As VectorCraft's own rule, `tool.setOption` for the Shape Builder, chosen or not, checks every value the same way: a switch that is not `true` or `false`, a `pickColorFrom` or `selection` that is not one of its names, a `gapLength` that is not a number, a `highlightColor` that is not an RGB color or a layer color's name, or that has an alpha part, and an option the tool does not have give an error naming the option, and nothing is set or saved. A `gapLength` outside 0 to 72 pt is still set to the nearest end of that range. Evidence: `tests::build::{shape_builder_tool_options_refuse_invalid_values_and_change_nothing, shape_builder_tool_options_take_valid_values_and_clamp_the_gap}`.
   A drag of 3 screen pixels or more with the Live Paint Selection tool draws a marquee and selects the faces and edges it touches, partly enclosed ones included, and a Shift-drag adds them to the selection or removes them from it ([Modify Live Paint groups](https://web.archive.org/web/20261006115247/https://helpx.adobe.com/illustrator/desktop/paint-and-fill/learn-painting-basics/modify-live-paint-groups.html)). A click and a marquee change the selection on release, and Escape before the release leaves the selection as it was. Locked Live Paint groups, those on a locked layer or artboard, and in isolation mode those outside the isolated art are not highlighted or selected.