Document the four vector point types (#195)

Vector Art explains straight, corner, smooth and symmetric points,
the Point menu in the tab header and the pen that pulls out both
handles. Keyboard keeps Alt-click as the straight/symmetric toggle.
Architecture names the mode rules in polygonEdit, Development the
check sum.

Tests: check sum 1195 is computed (1188 + 7), CI measures it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Architecture.md

@@ -126,7 +126,8 @@ src/editor/            App → Editor (layout + ticker), PlaySession (the run),
                        polygonEdit (points of an outline: what is under the pointer, whether a point is inside,
                        put / move / take away — scene view and Texture tab; and the same for a ring of a vector art
                        shape, where a point may carry Bezier handles: `ringGripAt`, splitting a curved segment
-                       without changing the curve, making a corner round, #129),
+                       without changing the curve, the four point types and how a dragged handle moves the other,
+                       #129, #195),
                        fileImport (drop/paste) → assetImport (one upload pipeline, an ImportKind per sort) ← textureImport / fontImport / soundImport,
                        FilePicker (the shared "+ → Texture / Font / Sound" dialog; ImagePicker/FontPicker/SoundPicker only describe their row),
                        framing (fit/marquee/snap maths), FormDialog (the small modal forms: label column, Cancel + confirm, one open at a time; `dialogButtons` is the closing row every dialog shares, the pickers' included), AssetTabEditor (the shared shell of the asset tabs), TabHeader (the bar across the top of a tab — asset tabs, Plugins tab, NodeBoard; drawn by `drawHeaderBar` like the toolbar and the breadcrumb),
@@ -163,7 +164,7 @@ src/editor/graph/      GraphEditor (header, breadcrumb), GraphCanvas, graphView
 src/editor/container/  ContainerEditor (header), ContainerCanvas (a SceneViewport on a template)
 src/editor/texture/    TextureEditor (header), TextureCanvas (picture + frames), SliceDialog (a FormDialog), sheetView (the grid maths),
                        ImagePicker + imageGrid (the "+ → Texture" dialog), checker (the transparency board)
-src/editor/vectorart/  VectorArtEditor (header: the two tools and the magnet), VectorArtCanvas (the drawing
+src/editor/vectorart/  VectorArtEditor (header: the two tools, the picked point's type and the magnet), VectorArtCanvas (the drawing
                        painted from core/model/vectorPath onto its own Graphics, with points and handles over it;
                        the pen puts points down, the arrow drags points, handles and whole shapes, #129),
                        ShapeList (the shapes as rows with a preview each, in the inspector; a row may be dragged to

Development.md

@@ -13,7 +13,7 @@ npm run check        # typecheck + lint + format:check + tests, the gate CI runs
 npm run build        # writes dist/ and regenerates index.html
 ./build.sh           # the same under `set -o pipefail`, for callers that pipe the output
 php tools/make-user.php <name> <password>                     # an account; every tool signs in (see Accounts)
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1188 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1195 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result

Keyboard.md

@@ -14,4 +14,4 @@ and every tab), the value itself is kept at that precision — fields that are i
 milliseconds, the index and count ports of list and text nodes) set `NumberField`'s
 `decimals: 0` and round to whole numbers · viewport: wheel zooms,
 middle-drag or `Shift`+drag pans, drag on empty space rubber-bands, `Ctrl`/`Shift`-click toggles an
-object in the selection (hierarchy rows too) · tilemap panel: holding `Alt` switches to Pick – a click takes that cell's tile from the active layer – and releasing it brings back the tool before ([Tilemaps](Tilemaps)) · Vector art tab: `Alt`-click a point to make it round and square again, double-click takes it away, `Esc` ends the line the Pen is drawing, `Delete` removes the selected shape ([Vector art](Vector-Art)).
+object in the selection (hierarchy rows too) · tilemap panel: holding `Alt` switches to Pick – a click takes that cell's tile from the active layer – and releasing it brings back the tool before ([Tilemaps](Tilemaps)) · Vector art tab: `Alt`-click a point to make it symmetric and straight again, double-click takes it away, `Esc` ends the line the Pen is drawing, `Delete` removes the selected shape ([Vector art](Vector-Art)).

Vector-Art.md

@@ -37,20 +37,28 @@ A second ring **inside** another cuts a **hole** into it, which is how a ring-sh
 letter-like form is made. Holes work by containment: a ring inside a ring is a hole, a ring beside
 it is a second area of the same shape.
 
-A point is a **corner** or **round**. A round point carries two handles, `in` and `out`, and the
-segment between two points is a curve as soon as one of its two ends has a handle — so a corner may
-stand right beside a curved side. The two handles are kept apart, not mirrored: pulling one does not
-swing the other, which is what lets a curve break at a point.
+A point may carry two handles, `in` and `out`, and the segment between two points is a curve as soon
+as one of its two ends has a handle — so a sharp point may stand right beside a curved side. What a
+point is decides what dragging one of its handles does to the other:
+
+| Type | Handles | Dragging one handle |
+|---|---|---|
+| **Straight** | none | — both sides of the point are straight |
+| **Corner** | free | leaves the other where it is, so the curve breaks at the point |
+| **Smooth** | in line | turns the other to the opposite side and keeps its length |
+| **Symmetric** | in line, same length | mirrors the other exactly |
+
+The type only steers the next drag; it changes nothing that is drawn.
 
 ## The tab
 
-The toolbar holds **Select**, **Pen**, the magnet and **Fit**; the view pans and zooms like the
-Texture tab, and the checkerboard behind the canvas is what is transparent.
+The toolbar holds **Select**, **Pen**, **Point**, the magnet and **Fit**; the view pans and zooms
+like the Texture tab, and the checkerboard behind the canvas is what is transparent.
 
 **Pen** draws a new shape:
 
-- A click puts a point down; **dragging** while putting it down pulls the two handles out, so a
-  curve is drawn in one gesture.
+- A click puts a straight point down; **dragging** while putting it down pulls both handles out,
+  mirrored, so a curve is drawn in one gesture and the point is symmetric.
 - A click on the **first point** closes the ring and ends the shape.
 - **Esc** ends the line where it is, leaving an open ring.
 
@@ -60,9 +68,22 @@ Texture tab, and the checkerboard behind the canvas is what is transparent.
 - A click **on a segment** puts a new point there. On a curved segment the curve is *split*, not
   cut: both halves together draw exactly what was drawn before.
 - A **double click** on a point takes it away.
-- **Alt** on a point makes it round, and a round one square again.
+- **Alt** on a straight point makes it symmetric, and a point with handles straight again.
 - **Delete** removes the selected shape.
 
+The point pressed last — or put down last with the Pen — is **picked** and drawn filled. The
+**Point** menu in the toolbar shows its type and turns it into another one, as one undo step:
+
+- **Straight** takes both handles away.
+- A straight point that becomes **Corner**, **Smooth** or **Symmetric** first grows handles along
+  the line between its two neighbours, a third of the way to each.
+- **Smooth** and **Symmetric** line the handles up on the direction between them, so the curve keeps
+  its general course; Smooth keeps each length, Symmetric gives both their mean.
+- **Corner** leaves the handles where they are and sets them free.
+
+A point put on a curved segment is smooth, since the split leaves its handles in line; a symmetric
+point at either end of that segment becomes smooth, because the split shortens one of its handles.
+
 The **magnet** snaps to 8 units while it is lit; it is off by default. It is the same switch the
 graph tabs carry. **Fit** brings the whole canvas back
 into view.