Merge pull request #4379 from dotCooCoo/fix/shape-builder-merge-off-ui-thread

Shape Builder: a large selection merges on another thread

docs/control-protocol.md

@@ -96,7 +96,7 @@ the two can still win that race.
 | `ui.menu.list` / `ui.menu.invoke` | `{command, params}` | the full menu tree / invoke an item |
 | `ui.contextMenu.list` | | the canvas context menu for the current selection, flattened like `ui.menu.list` (`path` holds its submenus). `ui.click {x, y, button: "right"}` on the canvas opens it, after selecting the object there unless it is already selected. With the Artboard tool it lists the artboard entries (see `docs/mcp.md`), after selecting the artboard there unless it is already selected. While a menu opened over locked objects is open, it has an `Unlock` submenu with one item for each locked object under the pointer, topmost first and at most 20, labeled with the object's name, which runs `layer.setProps {ids: [id], locked: false}`. A locked group gets one item, and the locked objects inside it get none. Hidden objects, objects on hidden, locked or template layers, and in isolation mode objects outside the isolated group get no item |
 | `ui.tool.select` / `ui.tool.list` | `{tool}` | |
-| `ui.pointer` | `{events:[{kind: down|drag|up|move|doubleclick, x, y, space?: "doc"|"screen", mods?}]}` | drive the active tool exactly like the mouse: `mods.cmd` held at a press with any tool but a selection tool drags with the selection tool chosen last (Direct Selection with the Pen until one is), and the release gives the tool back as it was; the reply lists `selection`, `key` (the key object, null without one) and `tool`. With the Shape Builder or the Live Paint Bucket and a selection of more than 128 segments, the app finds the regions off the UI thread, so a `move` replies before the region under the pointer is highlighted, and the highlight shows in the first frame after the regions are found |
+| `ui.pointer` | `{events:[{kind: down|drag|up|move|doubleclick, x, y, space?: "doc"|"screen", mods?}]}` | drive the active tool exactly like the mouse: `mods.cmd` held at a press with any tool but a selection tool drags with the selection tool chosen last (Direct Selection with the Pen until one is), and the release gives the tool back as it was; the reply lists `selection`, `key` (the key object, null without one) and `tool`. With the Shape Builder or the Live Paint Bucket and a selection of more than 128 segments, the app finds the regions off the UI thread, so a `move` replies before the region under the pointer is highlighted, and the highlight shows in the first frame after the regions are found. With the Shape Builder and such a selection, the app also merges off the UI thread: the reply to the events that end a click or drag comes once the merge is applied. A click or drag made before the regions are found does not wait for them; the app records it and makes it once they are found. Until then the canvas keeps drawing, with the touched regions highlighted and the busy pointer. A click or drag sent meanwhile, with `mods.cmd` too, and the Shape Builder's arrow keys are made after the merge in the order sent, and the reply to such a request comes once its events are made and any merge they start is applied; a request of `move` events alone is answered at once. A command that can edit, select, save or redraw the documents (an edit, an undo, a selection, a save or an export, a tool option, another tool, another document, closing, a dialog's preview, a menu item, a command of the app's own such as `ui.recolorDialog`, the proof and separations views, a preference, added fonts) waits for the merge and the input sent before it, and runs after them; queries that only read, such as `document.inspect`, run at once on the document before the merge |
 | `ui.key` / `ui.text` | `{key, shift?, alt?, cmd?}` / `{text}` | synthetic keyboard input |
 | `ui.move` | `{x, y}` | screen-point pointer move |
 | `ui.click` / `ui.drag` | `{x, y, button?, count?, shift?, alt?, ctrl?, cmd?}` / `{x, y, toX, toY, steps?, count?, button?, shift?, alt?, ctrl?, cmd?}` | egui pointer input; see synthetic input budgets above |