snapshot of https://github.com/tldraw/tldraw.git (main, 2026-09-23; blobs > 131072B omitted)

apps/examples/e2e-device/tests/draw-pressure-encoding.e2e.ts

@@ -0,0 +1,78 @@
+import { expect } from '@wdio/globals'
+import type { Editor } from 'tldraw'
+import { openEditor } from '../helpers/app'
+import { drawTouchStroke } from '../helpers/stroke'
+
+declare const editor: Editor
+
+/**
+ * Guards the device-side contract behind 2D draw-shape encoding (#8963/#8879):
+ * tldraw drops the constant pressure channel (z) from mouse/trackpad/finger
+ * strokes, keyed off `isPenOrStylus` — which is inferred from the pressure the
+ * BROWSER reports for the input device (Drawing.ts). The unit tests pick the
+ * pressure values they feed in, so they verify the decision logic but not what
+ * real engines actually report for a finger.
+ *
+ * That engine contract is the fragile part: 3D Touch iPhones really did report
+ * varying force for plain finger touches. If an engine (re)introduces that,
+ * finger strokes silently flip back to 3D — losing the storage win and making
+ * stroke width track finger pressure — with no unit or Playwright test failing,
+ * because those layers synthesize their own pressure values. Drawing through
+ * the real OS touch pipeline and asserting the 2D encoding is the only
+ * automated check that can catch it.
+ *
+ * Skips (rather than fails) on builds whose schema predates the segment `dim`
+ * field, so the suite stays green until #8963 merges.
+ */
+describe('draw shape pressure encoding (#8963)', () => {
+	beforeEach(async () => {
+		await openEditor()
+	})
+
+	it('a finger-drawn stroke uses the 2D (no-pressure) encoding', async function () {
+		// Feature-detect the `dim` field: on builds that predate #8963 the segment
+		// validator rejects it, so probe with a throwaway shape and skip if absent.
+		const dimSupported = await browser.execute(() => {
+			try {
+				editor.createShapes([
+					{
+						id: 'shape:dimprobe',
+						type: 'draw',
+						props: { segments: [{ type: 'free', path: '', dim: 2 }] },
+					},
+				] as any)
+				editor.deleteShapes(['shape:dimprobe'] as any)
+				return true
+			} catch {
+				return false
+			}
+		})
+		if (!dimSupported) this.skip()
+
+		// Block body: a concise arrow would implicitly return the (circular)
+		// Editor instance, which can't be serialized over the WebDriver wire.
+		await browser.execute(() => {
+			editor.setCurrentTool('draw')
+		})
+		await drawTouchStroke({ from: { x: -80, y: -40 }, to: { x: 80, y: 40 } })
+
+		const segments = await browser.execute(() => {
+			const shape = editor.getCurrentPageShapes().find((s) => s.type === 'draw')
+			if (!shape) return null
+			return (shape as any).props.segments.map((s: any) => ({
+				dim: s.dim,
+				pathLength: s.path.length,
+			}))
+		})
+
+		// The stroke produced a real draw shape with encoded points...
+		expect(segments).not.toBeNull()
+		expect(segments!.length).toBeGreaterThan(0)
+		expect(segments!.every((s) => s.pathLength > 0)).toBe(true)
+		// ...and the engine reported finger input as non-pressure, so every
+		// segment took the 2D encoding. If this fails with dim undefined, the
+		// browser has started reporting varying pressure for plain touches and
+		// the classification in Drawing.ts needs revisiting.
+		expect(segments!.every((s) => s.dim === 2)).toBe(true)
+	})
+})