Eraser: Angle and Roundness in Eraser Tool Options shape the tip

Squashed from #4180 onto main.

docs/control-protocol.md

@@ -786,7 +786,8 @@ keeps: `fidelity` (pt; Pencil, Paintbrush, Smooth), `fill` (Pencil, Paintbrush),
 Blob Brush; on by default for the Pencil and Paintbrush and off for the Blob Brush, and while it is off the path a
 stroke draws, continues or merges into is not selected afterwards), `mergeOnlySelection` (Blob Brush; off by default,
 and while it is on a stroke merges only with selected blobs), `closeWithin` and `editWithin` (screen pixels, 0 turns
-it off; Pencil, Paintbrush) and `size` (pt; Blob Brush, Eraser). `ui.dialog.confirm` runs
+it off; Pencil, Paintbrush), `size` (pt; Blob Brush, Eraser), and `angle` (°, −180 to 180; 0) and `roundness`
+(%, 1 to 100; 100) of the Eraser's tip (Eraser). `ui.dialog.confirm` runs
 `tool.setOption {tool, values}`.
 
 `ui.pointer` events also take `holdMs` (0..60000): the pointer then holds still that long, button down, before the

docs/mcp.md

@@ -2389,7 +2389,8 @@ These commands refuse a string or another value that is not a number with `` `dy
 naming the key; the document does not change and no undo step is recorded: `t`, `dx` and `dy` in
 `path.reshapeSegment` and `object.blend.spine.reshapeSegment`; `x`, `y` and `t` in `path.curvatureEdit`; `x` and `y`
 in `path.convertAnchor`; `t` in `path.insertAnchor`; `fidelity` and the `within` of `redraw` in `path.freehand` (and in
-`brush.freehand`, which runs it); `size` in `path.eraseRegion` and `path.blob`; `width` in `path.eraseSegments`;
+`brush.freehand`, which runs it); `size`, `angle` and `roundness` in `path.eraseRegion`; `size` in `path.blob`;
+`width` in `path.eraseSegments`;
 `radius` and `fidelity` in `path.smoothRegion`; `tolerance` in `path.joinScrub`; `dx` and `dy` in `path.moveAnchors`;
 and `dx`, `dy`, `tol` and `radius` in `path.reshape`. A null is read as a key left out. `path.convertAnchor` refuses
 an `x` without a `y`, or a `y` without an `x`, with "x and y must be given together". `path.freehand`,

docs/target-app-parity.md

@@ -638,6 +638,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     With Shift held at the press, the Pencil draws a straight line from the press point to the pointer at 45° steps from the Constrain Angle, as [Draw straight lines with the Pencil tool](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/draw-shapes/draw-straight-lines-with-the-pencil-tool.html) describes; pressed on an end of a selected open path, the line continues the path from that end (part of #3799). With Option/Alt held at the press and Alt key toggles to Smooth Tool off, the Pencil draws a straight line at any angle, whose ends snap to Smart Guides, and it stays open when Alt is still held at the release; Shift and Alt together keep the 45° steps (#3799). While Shift or Alt is held before the press, the Pencil shows a straight-line cursor (a crosshair with a short line), and over an end of a selected open path, where the line continues the path, a path-continuation cursor (the same line leaving a small square), as the page describes.
   - **Shapes:** all shape tools (including Flare) and the line, arc, spiral and grid tools. Space held while dragging out a shape, line, arc, spiral or grid moves it at its current size. While a grid is dragged out, Up/Down change its rows (concentric dividers) and Left/Right its columns (radial dividers). A click with a grid tool asks for the size, the divider counts and the grid options (#1377, in part): a skew for each set of dividers, Use Outside Rectangle As Frame or Create Compound Path From Ellipses, and Fill Grid; they are parameters of `shape.rectangularGrid` and `shape.polarGrid`, stay as the tool's options and apply to drags too. The curve a skew percentage follows and the direction of the radial skew are our own (the public documentation gives neither), and the dialogs have no reference point locator. An ellipse's Pie Start and End Angle and Invert Pie (Transform and Properties panels' Ellipse Properties, `object.setLiveShape {pieStart, pieEnd, invertPie}`) cut it as a pie (#812). With the bounding box showing, the Selection tool shows a selected ellipse's two pie widgets just outside it; dragging one sets its angle in one undo step and double-clicking one makes the ellipse whole again. A live polygon's Polygon Properties there: side count, angle, corner type and radius, radius, side length and Make Sides Equal once an uneven scale has made its sides differ (`object.setLiveShape {sides, polygonAngle, polygonRadius, sideLength, makeSidesEqual}`, part of #812); a star is a plain path, as in Illustrator. The Flare Tool Options last as the tool's options: the next flare dragged out uses them, a click's dialog shows them and double-clicking the tool opens them (part of #812).
   - **Cutting:** Eraser, Scissors, Knife, Mirror & Cut, Line Cut and Rectangle Cut (real geometry, compound paths keep their holes).
+    Eraser Tool Options has Angle and Roundness besides Size, as [Erase paths using the Eraser tool](https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/erase-paths-using-eraser-tool.html) describes: the Eraser's tip is an ellipse Size across, its long axis at Angle and its short axis Roundness percent of the long one, and a drag with a tip that is not round shows the outline of the area it erases (`path.eraseRegion` `angle` and `roundness`).
   - **Transform:** Rotate, Reflect, Scale, Shear (click or Alt-click snaps the reference point to anchors and centres; Alt-click opens the tool's dialog, and a drag with Alt down at the release, from the press or pressed mid-drag, transforms a copy), Reshape, Free Transform (free and perspective distort and shear, switched by the keys held during a handle drag).
     Align, Distribute, Distribute Spacing, Reflect and Shear return an error for any `horizontal`, `vertical`, `to`, `axis`, `bounds` or `spacing` value they don't take, listing the choices, and Align returns one when a call gives neither `horizontal` nor `vertical`; nothing moves and no undo step is recorded. Align and Distribute act on the anchor points selected with Direct Selection: the points of one path align to each other, not to the artboard, and Distribute spaces them (#1641, fixes #1636; aligning to a key anchor is still missing).
     Transform Again uses the Copy, Transform Patterns, Scale Strokes & Effects and Scale Corners choices of the transform it repeats; after a bounding-box handle drag on area type, it resizes the type area again and the type keeps its size (`object.transformAgain`). With anchors selected with Direct Selection, Move, Rotate, Scale, Reflect, Shear and Transform Again (the commands, their dialogs and the four tools' drags) transform only those anchors, their handles with them, about the centre of the box around them unless a point was clicked; a copy still copies the whole object (#1408; behaviour reference: [adjust path segments](https://helpx.adobe.com/illustrator/using/adjust-path-segments.html); the default reference point and the copy are our choices). The Move, Rotate, Scale, Reflect and Shear dialogs have a Preview checkbox, off when they open: while it is on the canvas follows the values, Cancel rolls it back and OK is still one undo step; Up/Down step the Rotate and Shear angles and the Scale percentages by 1, Shift by 10 (#1412). The five dialogs and Transform Each have Transform Objects beside Transform Patterns: off, the art stays and only its pattern tiles transform (`objects` on the transform commands), and Transform Again repeats the choice (#1448; behaviour reference: [scale objects](https://helpx.adobe.com/illustrator/desktop/manage-objects/reshape-transform-objects/scale-objects.html); the checkboxes are always enabled and the Scale page's pair is applied to all of them, our choices). Reflect's axis is Horizontal, Vertical or an angle (#1460; [reflect objects along an axis](https://helpx.adobe.com/illustrator/desktop/manage-objects/arrange-objects/reflect-objects-along-an-axis.html)). The link that keeps Transform Each's two scales equal is not built.