Stop patching _highlightMeasurement and import it instead to increase compatibility with other modules

src/foundry_imports.js

@@ -166,7 +166,7 @@ export function measure(destination, {gridSpaces=true, snap=false} = {}) {
 		}
 
 		// Highlight grid positions
-		this._highlightMeasurement(ray, s.startDistance);
+		highlightMeasurementNative.call(this, ray, s.startDistance);
 	}
 
 	// Draw endpoints
@@ -177,3 +177,43 @@ export function measure(destination, {gridSpaces=true, snap=false} = {}) {
 	// Return the measured segments
 	return segments;
 }
+
+export function highlightMeasurementNative(ray, startDistance) {
+	const spacer = canvas.scene.data.gridType === CONST.GRID_TYPES.SQUARE ? 1.41 : 1;
+	const nMax = Math.max(Math.floor(ray.distance / (spacer * Math.min(canvas.grid.w, canvas.grid.h))), 1);
+	const tMax = Array.fromRange(nMax+1).map(t => t / nMax);
+
+	// Track prior position
+	let prior = null;
+
+	// Iterate over ray portions
+	for ( let [i, t] of tMax.entries() ) {
+		let {x, y} = ray.project(t);
+
+		// Get grid position
+		let [x0, y0] = (i === 0) ? [null, null] : prior;
+		let [x1, y1] = canvas.grid.grid.getGridPositionFromPixels(x, y);
+		if ( x0 === x1 && y0 === y1 ) continue;
+
+		// Highlight the grid position
+		let [xg, yg] = canvas.grid.grid.getPixelsFromGridPosition(x1, y1);
+		let subDistance = canvas.grid.measureDistances([{ray: new Ray(ray.A, {x: xg, y: yg})}], {gridSpaces: true})[0]
+		let color = dragRuler.getColorForDistance.call(this, startDistance, subDistance)
+		canvas.grid.highlightPosition(this.name, {x: xg, y: yg, color: color});
+
+		// Skip the first one
+		prior = [x1, y1];
+		if ( i === 0 ) continue;
+
+		// If the positions are not neighbors, also highlight their halfway point
+		if ( !canvas.grid.isNeighbor(x0, y0, x1, y1) ) {
+			let th = tMax[i - 1] + (0.5 / nMax);
+			let {x, y} = ray.project(th);
+			let [x1h, y1h] = canvas.grid.grid.getGridPositionFromPixels(x, y);
+			let [xgh, ygh] = canvas.grid.grid.getPixelsFromGridPosition(x1h, y1h);
+			subDistance = canvas.grid.measureDistances([{ray: new Ray(ray.A, {x: xg, y: yg})}], {gridSpaces: true})[0]
+			color = dragRuler.getColorForDistance.call(this, startDistance, subDistance)
+			canvas.grid.highlightPosition(this.name, {x: xgh, y: ygh, color: color});
+		}
+	}
+}

src/main.js

@@ -13,7 +13,6 @@ Hooks.once("init", () => {
 	hookTokenDragHandlers()
 	hookRulerFunctions()
 	hookKeyboardManagerFunctions()
-	patchRulerHighlightMeasurement()
 
 	window.dragRuler = {
 		getColorForDistance,
@@ -238,11 +237,6 @@ function deleteWaypoint() {
 	}
 }
 
-function strInsertAfter(haystack, needle, strToInsert) {
-	const pos = haystack.indexOf(needle) + needle.length
-	return haystack.slice(0, pos) + strToInsert + haystack.slice(pos)
-}
-
 export function getColorForDistance(startDistance, subDistance=0) {
 	if (!this.isDragRuler)
 		return this.color
@@ -263,22 +257,3 @@ export function getColorForDistance(startDistance, subDistance=0) {
 	}, {range: Infinity, color: getUnreachableColorFromSpeedProvider()})
 	return currentRange.color
 }
-
-// These patches were written with foundry-0.7.9.js as reference
-function patchRulerHighlightMeasurement() {
-	let code = Ruler.prototype._highlightMeasurement.toString()
-	// Replace CRLF with LF in case foundry.js has CRLF for some reason
-	code = code.replace(/\r\n/g, "\n")
-	// Remove function signature and closing curly bracket (those are on the first and last line)
-	code = code.slice(code.indexOf("\n"), code.lastIndexOf("\n"))
-
-	const calcColorCode = `
-		let subDistance = canvas.grid.measureDistances([{ray: new Ray(ray.A, {x: xg, y: yg})}], {gridSpaces: true})[0]
-		let color = dragRuler.getColorForDistance.call(this, startDistance, subDistance)
-	`
-
-	code = strInsertAfter(code, "Position(x1, y1);\n", calcColorCode)
-	code = strInsertAfter(code, "Position(x1h, y1h);\n", calcColorCode.replace("x: xg, y: yg", "x: xgh, y: ygh"))
-	code = code.replace(/color: this\.color\}/g, "color}")
-	Ruler.prototype._highlightMeasurement = new Function("ray", "startDistance=undefined", code)
-}