Drop edge scrolling adjustment for mobile (#2346)

This PR makes all edge scrolling distances 32px.

### Change Type

- [x] `patch` — Bug fix

packages/editor/src/lib/constants.ts

@@ -95,3 +95,6 @@ export const HIT_TEST_MARGIN = 8
 
 /** @internal */
 export const EDGE_SCROLL_SPEED = 20
+
+/** @internal */
+export const EDGE_SCROLL_DISTANCE = 32

packages/editor/src/lib/utils/edgeScrolling.ts

@@ -1,24 +1,21 @@
-import { EDGE_SCROLL_SPEED } from '../constants'
+import { EDGE_SCROLL_DISTANCE, EDGE_SCROLL_SPEED } from '../constants'
 import { Editor } from '../editor/Editor'
 
 /**
- * Helper function to get the scroll offset for a given position.
- * The closer the mouse is to the edge of the screen the faster we scroll.
- * We also adjust the speed and the start offset based on the screen size and zoom level.
- *
- * @param editor - The mouse position on the screen in pixels
- * @returns How much we should scroll in pixels
+ * Helper function to get the scroll proximity factor for a given position.
+ * @param position - The mouse position on the axis.
+ * @param dimension - The component dimension on the axis.
  * @internal
  */
-export function getEdgeProximityFactor(position: number, scrollOffset: number, extreme: number) {
+export function getEdgeProximityFactor(position: number, dimension: number) {
 	if (position < 0) {
 		return 1
-	} else if (position > extreme) {
+	} else if (position > dimension) {
 		return -1
-	} else if (position < scrollOffset) {
-		return (scrollOffset - position) / scrollOffset
-	} else if (position > extreme - scrollOffset) {
-		return -(scrollOffset - extreme + position) / scrollOffset
+	} else if (position < EDGE_SCROLL_DISTANCE) {
+		return (EDGE_SCROLL_DISTANCE - position) / EDGE_SCROLL_DISTANCE
+	} else if (position > dimension - EDGE_SCROLL_DISTANCE) {
+		return -(EDGE_SCROLL_DISTANCE - dimension + position) / EDGE_SCROLL_DISTANCE
 	}
 	return 0
 }
@@ -38,22 +35,17 @@ export function moveCameraWhenCloseToEdge(editor: Editor) {
 	const zoomLevel = editor.getZoomLevel()
 	const screenBounds = editor.getViewportScreenBounds()
 
-	// Determines how far from the edges we start the scroll behaviour
-	const insetX = screenBounds.w < 1000 ? 40 : 32
-	const insetY = screenBounds.h < 1000 ? 40 : 32
-
 	// Determines how much the speed is affected by the screen size
 	const screenSizeFactorX = screenBounds.w < 1000 ? 0.612 : 1
 	const screenSizeFactorY = screenBounds.h < 1000 ? 0.612 : 1
 
-	// Determines the base speed of the scroll
-	const pxSpeed = editor.user.getEdgeScrollSpeed() * EDGE_SCROLL_SPEED
-
-	const proximityFactorX = getEdgeProximityFactor(x, insetX, screenBounds.w)
-	const proximityFactorY = getEdgeProximityFactor(y, insetY, screenBounds.h)
+	const proximityFactorX = getEdgeProximityFactor(x, screenBounds.w)
+	const proximityFactorY = getEdgeProximityFactor(y, screenBounds.h)
 
 	if (proximityFactorX === 0 && proximityFactorY === 0) return
 
+	// Determines the base speed of the scroll
+	const pxSpeed = editor.user.getEdgeScrollSpeed() * EDGE_SCROLL_SPEED
 	const scrollDeltaX = (pxSpeed * proximityFactorX * screenSizeFactorX) / zoomLevel
 	const scrollDeltaY = (pxSpeed * proximityFactorY * screenSizeFactorY) / zoomLevel
 

packages/tldraw/src/test/resizing.test.ts

@@ -5,6 +5,7 @@ import {
 	PI2,
 	PointsSnapLine,
 	RotateCorner,
+	TLGeoShape,
 	TLSelectionHandle,
 	TLShapeId,
 	TLShapePartial,
@@ -3903,6 +3904,7 @@ describe('Resizing text from the right edge', () => {
 describe('When resizing near the edges of the screen', () => {
 	it('resizes past the edge of the screen', () => {
 		editor.user.updateUserPreferences({ edgeScrollSpeed: 1 })
+		const before = editor.getShape<TLGeoShape>(ids.boxA)!
 		editor
 			.select(ids.boxA)
 			.pointerDown(10, 10, {
@@ -3910,14 +3912,12 @@ describe('When resizing near the edges of the screen', () => {
 				target: 'selection',
 				handle: 'top_left',
 			})
-			.expectShapeToMatch({ id: ids.boxA, x: 10, y: 10, props: { w: 100, h: 100 } })
 			.pointerMove(10, 25)
 		jest.advanceTimersByTime(1000)
-		editor.expectShapeToMatch({
-			id: ids.boxA,
-			x: -842.5,
-			y: -259.58,
-			props: { w: 952.5, h: 369.58 },
-		})
+		const after = editor.getShape<TLGeoShape>(ids.boxA)!
+		expect(after.x).toBeLessThan(before.x)
+		expect(after.y).toBeLessThan(before.y)
+		expect(after.props.w).toBeGreaterThan(before.props.w)
+		expect(after.props.h).toBeGreaterThan(before.props.h)
 	})
 })

packages/tldraw/src/test/translating.test.ts

@@ -3,6 +3,7 @@ import {
 	PointsSnapLine,
 	SnapLine,
 	TLArrowShape,
+	TLGeoShape,
 	TLShapeId,
 	TLShapePartial,
 	Vec2d,
@@ -131,6 +132,8 @@ describe('When translating...', () => {
 		editor.user.updateUserPreferences({ edgeScrollSpeed: 1 })
 		editor.pointerDown(50, 50, ids.box1).pointerMove(0, 50) // [-50, 0]
 
+		const before = editor.getShape<TLGeoShape>(ids.box1)!
+
 		jest.advanceTimersByTime(100)
 		editor
 			// The change is bigger than expected because the camera moves
@@ -139,10 +142,14 @@ describe('When translating...', () => {
 			// The speed in the y position is smaller since we are further away from the edge.
 			.pointerMove(0, 25)
 		jest.advanceTimersByTime(100)
-		editor
-			.expectShapeToMatch({ id: ids.box1, x: -280, y: -42.54 })
-			.pointerUp()
-			.expectShapeToMatch({ id: ids.box1, x: -280, y: -42.54 })
+		editor.pointerUp()
+
+		const after = editor.getShape<TLGeoShape>(ids.box1)!
+
+		expect(after.x).toBeLessThan(before.x)
+		expect(after.y).toBeLessThan(before.y)
+		expect(after.props.w).toEqual(before.props.w)
+		expect(after.props.h).toEqual(before.props.h)
 	})
 
 	it('translates a single shape near the bottom right edge', () => {