Arrows followup (#1972)

This PR includes a few followup small fixes for arrows.

### Change Type

- [x] `patch` — Bug fix

packages/editor/src/lib/editor/shapes/shared/arrow/curved-arrow.ts

@@ -235,9 +235,7 @@ export function getCurvedArrowInfo(
 		)
 	}
 
-	const dist = Vec2d.Dist(tA, tB)
-
-	if (dist < MIN_ARROW_LENGTH) {
+	if (Vec2d.Dist(tA, tB) < MIN_ARROW_LENGTH) {
 		if (offsetA !== 0 && offsetB !== 0) {
 			offsetA *= -1.5
 			offsetB *= -1.5
@@ -266,29 +264,31 @@ export function getCurvedArrowInfo(
 	)
 
 	// Did we miss intersections? This happens when we have overlapping shapes.
-	if (
-		startShapeInfo &&
-		endShapeInfo &&
-		startShapeInfo.shape !== endShapeInfo.shape &&
-		!startShapeInfo.isExact &&
-		!endShapeInfo.isExact
-	) {
+	if (startShapeInfo && endShapeInfo && !startShapeInfo.isExact && !endShapeInfo.isExact) {
 		const startAngle = Vec2d.Angle(handleArc.center, tempA)
 		const endAngle = Vec2d.Angle(handleArc.center, tempB)
 		const length = getArcLength(handleArc.center, handleArc.radius, tempA, tempB)
 
-		if (startShapeInfo && !startShapeInfo.didIntersect) {
-			tempA.setTo(a)
-		}
-
-		if (endShapeInfo && !endShapeInfo.didIntersect) {
-			const size = angleDelta(startAngle, endAngle)
-			let mid = lerpAngles(startAngle, endAngle, Math.abs(MIN_ARROW_LENGTH / length))
-			if (+(size > 0) !== handleArc.sweepFlag) {
-				mid = PI2 - mid
+		if (startShapeInfo.shape === endShapeInfo.shape) {
+			if (Math.abs(length) < 100) {
+				tempA.setTo(a)
+				tempB.setTo(b)
+				tempC.setTo(c)
+			}
+		} else {
+			if (startShapeInfo && !startShapeInfo.didIntersect) {
+				tempA.setTo(a)
 			}
 
-			tempB.setTo(getPointOnCircle(handleArc.center.x, handleArc.center.y, handleArc.radius, mid))
+			if (endShapeInfo && !endShapeInfo.didIntersect) {
+				const size = angleDelta(startAngle, endAngle)
+				let mid = lerpAngles(startAngle, endAngle, Math.abs(MIN_ARROW_LENGTH / length))
+				if (+(size > 0) !== handleArc.sweepFlag) {
+					mid = PI2 - mid
+				}
+
+				tempB.setTo(getPointOnCircle(handleArc.center.x, handleArc.center.y, handleArc.radius, mid))
+			}
 		}
 	}
 

packages/editor/src/lib/editor/shapes/shared/arrow/straight-arrow.ts

@@ -50,7 +50,8 @@ export function getStraightArrowInfo(editor: Editor, shape: TLArrowShape): TLArr
 		startShapeInfo
 	)
 
-	let minDist = MIN_ARROW_LENGTH
+	let offsetA = 0
+	let offsetB = 0
 
 	const isSelfIntersection =
 		startShapeInfo && endShapeInfo && startShapeInfo.shape === endShapeInfo.shape
@@ -66,14 +67,14 @@ export function getStraightArrowInfo(editor: Editor, shape: TLArrowShape): TLArr
 			// ...and if only the end shape intersected, then make it
 			// a short arrow ending at the end shape intersection.
 			if (startShapeInfo.isClosed) {
-				a.setTo(Vec2d.Nudge(b, a, minDist))
+				a.setTo(b.clone().add(uAB.clone().mul(MIN_ARROW_LENGTH)))
 			}
 		} else if (!endShapeInfo.didIntersect) {
 			// ...and if only the end shape intersected, or if neither
 			// shape intersected, then make it a short arrow starting
 			// at the start shape intersection.
 			if (endShapeInfo.isClosed) {
-				b.setTo(Vec2d.Nudge(a, b, minDist))
+				b.setTo(a.clone().sub(uAB.clone().mul(MIN_ARROW_LENGTH)))
 			}
 		}
 	}
@@ -85,48 +86,49 @@ export function getStraightArrowInfo(editor: Editor, shape: TLArrowShape): TLArr
 	// start point has an arrowhead offset the start point
 	if (!isSelfIntersection) {
 		if (startShapeInfo && arrowheadStart !== 'none' && !startShapeInfo.isExact) {
-			const offset =
+			offsetA =
 				BOUND_ARROW_OFFSET +
 				STROKE_SIZES[shape.props.size] / 2 +
 				('size' in startShapeInfo.shape.props
 					? STROKE_SIZES[startShapeInfo.shape.props.size] / 2
 					: 0)
-
-			minDist -= offset
-			a.nudge(b, offset * (didFlip ? -1 : 1))
 		}
 
 		// If the arrow is bound non-exact to an end shape and the
 		// end point has an arrowhead offset the end point
 		if (endShapeInfo && arrowheadEnd !== 'none' && !endShapeInfo.isExact) {
-			const offset =
+			offsetB =
 				BOUND_ARROW_OFFSET +
 				STROKE_SIZES[shape.props.size] / 2 +
 				('size' in endShapeInfo.shape.props ? STROKE_SIZES[endShapeInfo.shape.props.size] / 2 : 0)
-
-			minDist -= offset
-			b.nudge(a, offset * (didFlip ? -1 : 1))
 		}
 	}
 
-	if (startShapeInfo && endShapeInfo) {
-		// If we have two bound shapes...
-		if (didFlip) {
-			// If we flipped, then make the arrow a short arrow from
-			// the start point towards where the end point should be.
-			b.setTo(Vec2d.Add(a, u.mul(-minDist)))
-		} else if (Vec2d.Dist(a, b) < MIN_ARROW_LENGTH / 2) {
-			// Otherwise, if the arrow is too short, make it a short
-			// arrow from the start point towards where the end point
-			// should be.
-			b.setTo(Vec2d.Add(a, u.mul(MIN_ARROW_LENGTH / 2)))
+	const tA = a.clone().add(u.clone().mul(offsetA * (didFlip ? -1 : 1)))
+	const tB = b.clone().sub(u.clone().mul(offsetB * (didFlip ? -1 : 1)))
+	if (Vec2d.Dist(tA, tB) < MIN_ARROW_LENGTH) {
+		if (offsetA !== 0 && offsetB !== 0) {
+			offsetA *= -1.5
+			offsetB *= -1.5
+		} else if (offsetA !== 0) {
+			offsetA *= -2
+		} else if (offsetB !== 0) {
+			offsetB *= -2
 		}
 	}
 
+	a.add(u.clone().mul(offsetA * (didFlip ? -1 : 1)))
+	b.sub(u.clone().mul(offsetB * (didFlip ? -1 : 1)))
+
 	// If the handles flipped their order, then set the center handle
 	// to the midpoint of the terminals (rather than the midpoint of the
 	// arrow body); otherwise, it may not be "between" the other terminals.
 	if (didFlip) {
+		if (startShapeInfo && endShapeInfo) {
+			// If we have two bound shapes...then make the arrow a short arrow from
+			// the start point towards where the end point should be.
+			b.setTo(Vec2d.Add(a, u.clone().mul(-MIN_ARROW_LENGTH)))
+		}
 		c.setTo(Vec2d.Med(terminalsInArrowSpace.start, terminalsInArrowSpace.end))
 	} else {
 		c.setTo(Vec2d.Med(a, b))