Improve pressure-detection logic in drawing (#3639)

This PR improves handling of pressure in the draw tool. While we
differentiate between pen and not-pen in the pointer type, there are
not-pen type inputs like styluses that present as "mouse" inputs. This
PR makes the freehand options for these inputs more pen-like so that
they benefit from the dialing-in of options for pressure-using devices.

### Change Type

- [x] `sdk` — Changes the tldraw SDK
- [x] `improvement` — Improving existing features

### Test Plan

1. Use pen inputs
2. Use mouse inputs
3. Use stylus inputs

- [x] Unit Tests

### Release Notes

- Improves handling of mouse-type devices that support pressure, e.g.
wacom tablets. They now use the same freehand options as true pen-type
inputs.

apps/docs/content/getting-started/releases-versioning.mdx

@@ -17,6 +17,27 @@ order: 3
 
 {/* START AUTO-GENERATED CHANGELOG */}
 
+### [v2.1.4](/releases/v2.1.4)
+
+### Release Notes
+
+#### textfields: fix up flakiness in text selection and for unfilled geo shapes fix edit->edit (#3577) ([#3643](https://github.com/tldraw/tldraw/pull/3643))
+
+- Text labels: fix up regression to selection when clicking into a text shape. (was causing flaky selections)
+- Text labels: fix edit→edit not working as expected when unfilled geo shapes are on 'top' of other shapes.
+
+---
+
+#### 🐛 Bug Fix
+
+- `@tldraw/editor`, `tldraw`
+  - textfields: fix up flakiness in text selection (#3578)
+  - textfields: for unfilled geo shapes fix edit->edit (#3577) [#3643](https://github.com/tldraw/tldraw/pull/3643) ([@mimecuvalo](https://github.com/mimecuvalo))
+
+#### Authors: 1
+
+- Mime Čuvalo ([@mimecuvalo](https://github.com/mimecuvalo))
+
 ### [v2.1.3](/releases/v2.1.3)
 
 #### Expose migrations, validators, and versions from tlschema ([#3613](https://github.com/tldraw/tldraw/pull/3613))

packages/tldraw/src/lib/shapes/draw/toolStates/Drawing.ts

@@ -34,6 +34,7 @@ export class Drawing extends StateNode {
 	util = this.editor.getShapeUtil(this.shapeType)
 
 	isPen = false
+	isPenOrStylus = false
 
 	segmentMode = 'free' as 'free' | 'straight' | 'starting_straight' | 'starting_free'
 
@@ -64,7 +65,7 @@ export class Drawing extends StateNode {
 	override onPointerMove: TLEventHandlers['onPointerMove'] = () => {
 		const { inputs } = this.editor
 
-		if (this.isPen !== inputs.isPen) {
+		if (this.isPen && !inputs.isPen) {
 			// The user made a palm gesture before starting a pen gesture;
 			// ideally we'd start the new shape here but we could also just bail
 			// as the next interaction will work correctly
@@ -82,7 +83,7 @@ export class Drawing extends StateNode {
 		}
 
 		if (this.canDraw) {
-			if (inputs.isPen) {
+			if (this.isPenOrStylus) {
 				// Don't update the shape if we haven't moved far enough from the last time we recorded a point
 				if (
 					Vec.Dist(inputs.currentPagePoint, this.lastRecordedPoint) >=
@@ -172,9 +173,16 @@ export class Drawing extends StateNode {
 		this.markId = 'draw start ' + uniqueId()
 		this.editor.mark(this.markId)
 
+		// If the pressure is weird, then it's probably a stylus reporting as a mouse
+		// We treat pen/stylus inputs differently in the drawing tool, so we need to
+		// have our own value for this. The inputs.isPen is only if the input is a regular
+		// pen, like an iPad pen, which needs to trigger "pen mode" in order to avoid
+		// accidental palm touches. We don't have to worry about that with styluses though.
+		const z = this.info.point.z === undefined ? 0.5 : this.info.point.z
 		this.isPen = isPen
+		this.isPenOrStylus = isPen || (z > 0 && z < 0.5) || (z > 0.5 && z < 1)
 
-		const pressure = this.isPen ? this.info.point.z! * 1.25 : 0.5
+		const pressure = this.isPenOrStylus ? z * 1.25 : 0.5
 
 		this.segmentMode = this.editor.inputs.shiftKey ? 'straight' : 'free'
 
@@ -197,8 +205,6 @@ export class Drawing extends StateNode {
 
 				const { x, y } = this.editor.getPointInShapeSpace(shape, originPagePoint).toFixed()
 
-				const pressure = this.isPen ? this.info.point.z! * 1.25 : 0.5
-
 				const newSegment: TLDrawShapeSegment = {
 					type: this.segmentMode,
 					points: [
@@ -261,7 +267,7 @@ export class Drawing extends StateNode {
 				x: originPagePoint.x,
 				y: originPagePoint.y,
 				props: {
-					isPen: this.isPen,
+					isPen: this.isPenOrStylus,
 					segments: [
 						{
 							type: this.segmentMode,
@@ -300,7 +306,7 @@ export class Drawing extends StateNode {
 
 		const { x, y, z } = this.editor.getPointInShapeSpace(shape, inputs.currentPagePoint).toFixed()
 
-		const newPoint = { x, y, z: this.isPen ? +(z! * 1.25).toFixed(2) : 0.5 }
+		const newPoint = { x, y, z: this.isPenOrStylus ? +(z! * 1.25).toFixed(2) : 0.5 }
 
 		switch (this.segmentMode) {
 			case 'starting_straight': {
@@ -634,11 +640,11 @@ export class Drawing extends StateNode {
 							x: toFixed(inputs.currentPagePoint.x),
 							y: toFixed(inputs.currentPagePoint.y),
 							props: {
-								isPen: this.isPen,
+								isPen: this.isPenOrStylus,
 								segments: [
 									{
 										type: 'free',
-										points: [{ x: 0, y: 0, z: this.isPen ? +(z! * 1.25).toFixed() : 0.5 }],
+										points: [{ x: 0, y: 0, z: this.isPenOrStylus ? +(z! * 1.25).toFixed() : 0.5 }],
 									},
 								],
 							},

packages/tldraw/src/lib/shapes/shared/polygon-helpers.ts

@@ -1,31 +1,4 @@
-import { Vec, VecLike, toDomPrecision } from '@tldraw/editor'
-
-function precise(A: VecLike) {
-	return `${toDomPrecision(A.x)},${toDomPrecision(A.y)} `
-}
-
-function rng(seed = '') {
-	let x = 0
-	let y = 0
-	let z = 0
-	let w = 0
-
-	function next() {
-		const t = x ^ (x << 11)
-		x = y
-		y = z
-		z = w
-		w ^= ((w >>> 19) ^ t ^ (t >>> 8)) >>> 0
-		return (w / 0x100000000) * 2
-	}
-
-	for (let k = 0; k < seed.length + 64; k++) {
-		x ^= seed.charCodeAt(k) | 0
-		next()
-	}
-
-	return next
-}
+import { Vec, VecLike, precise, rng } from '@tldraw/editor'
 
 /** @public */
 export function getRoundedInkyPolygonPath(points: VecLike[]) {