Fix an issue with minimap. (#3621)

Fixes an issue where minimap would sometimes completely bug out. The
problem was when you resized the window height. We only had resize
observer for the minimap's canvas element, but we were missing the
observer for the window / container. This caused an issue with
[calculating the minimap page
point](https://github.com/tldraw/tldraw/blob/mitja%2Ffix-minimap-when-resizing-window/packages/tldraw/src/lib/ui/components/Minimap/MinimapManager.ts#L153)
via `getMinimapPagePoint`. They y coordinate would get incorrectly
calculated.

Before


https://github.com/tldraw/tldraw/assets/2523721/ecf4c860-0aa2-46ac-8b90-964bff7f04b3

After


https://github.com/tldraw/tldraw/assets/2523721/38047877-7657-45cf-89b1-31ac0c47228c



Resolves https://github.com/tldraw/tldraw/issues/3589

### Change Type

<!-- ❗ Please select a 'Scope' label ❗️ -->

- [x] `sdk` — Changes the tldraw SDK
- [ ] `dotcom` — Changes the tldraw.com web app
- [ ] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [ ] `internal` — Does not affect user-facing stuff

<!-- ❗ Please select a 'Type' label ❗️ -->

- [x] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [ ] `improvement` — Improving existing features
- [ ] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [ ] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know


### Test Plan

1. Insert some shapes.
2. Now open dev panel below or change the height of the window.
3. Use the minimap. It should no longer bug out.

- [ ] Unit Tests
- [ ] End to end tests

### Release Notes

- Fixes an issue with the minimap bugging out after you change the
window's height.

packages/tldraw/src/lib/ui/components/Minimap/DefaultMinimap.tsx

@@ -6,6 +6,7 @@ import {
 	normalizeWheel,
 	releasePointerCapture,
 	setPointerCapture,
+	useContainer,
 	useEditor,
 	useIsDarkMode,
 } from '@tldraw/editor'
@@ -15,6 +16,7 @@ import { MinimapManager } from './MinimapManager'
 /** @public */
 export function DefaultMinimap() {
 	const editor = useEditor()
+	const container = useContainer()
 
 	const rCanvas = React.useRef<HTMLCanvasElement>(null!)
 	const rPointing = React.useRef(false)
@@ -22,10 +24,10 @@ export function DefaultMinimap() {
 	const minimapRef = React.useRef<MinimapManager>()
 
 	React.useEffect(() => {
-		const minimap = new MinimapManager(editor, rCanvas.current)
+		const minimap = new MinimapManager(editor, rCanvas.current, container)
 		minimapRef.current = minimap
 		return minimapRef.current.close
-	}, [editor])
+	}, [editor, container])
 
 	const onDoubleClick = React.useCallback(
 		(e: React.MouseEvent<HTMLCanvasElement>) => {

packages/tldraw/src/lib/ui/components/Minimap/MinimapManager.ts

@@ -21,7 +21,8 @@ export class MinimapManager {
 	shapeGeometryCache: ComputedCache<Float32Array | null, TLShape>
 	constructor(
 		public editor: Editor,
-		public readonly elem: HTMLCanvasElement
+		public readonly elem: HTMLCanvasElement,
+		public readonly container: HTMLElement
 	) {
 		this.gl = setupWebGl(elem)
 		this.shapeGeometryCache = editor.store.createComputedCache('webgl-geometry', (r: TLShape) => {
@@ -94,6 +95,7 @@ export class MinimapManager {
 			this.canvasBoundingClientRect.set(rect)
 		})
 		observer.observe(this.elem)
+		observer.observe(this.container)
 		return () => observer.disconnect()
 	}