Implement measurement template support (resolves #13)

CHANGELOG.md

@@ -2,6 +2,7 @@
 **BREAKING** This update is incompatible with previous Terrain Ruler versions. If you're using Terrain Ruler, make sure you update Terrain Ruler to at least version 1.3.0.
 
 ### New features
+- A ruler will now be shown when dragging measurement templates over the map ([#13](https://github.com/manuelVo/foundryvtt-drag-ruler/issues/13))
 - Drag Ruler can now measure difficult terrain on gridless maps (if the Terrain Ruler module is installed and enabled)
 - Improved the positioning of the labels around the ruler. The labels should now never overlap with the waypoint.
 

src/compatibility.js

@@ -15,11 +15,12 @@ export function highlightMeasurementTerrainRuler(ray, startDistance, tokenShape=
 	}
 }
 
-export function measureDistances(segments, token, shape, options={}) {
+export function measureDistances(segments, entity, shape, options={}) {
+	const isToken = entity instanceof Token;
 	const opts = duplicate(options)
 	if (!opts.gridSpaces)
 		opts.gridSpaces = true;
-	const terrainRulerAvailable = game.modules.get("terrain-ruler")?.active && (!game.modules.get("TerrainLayer")?.active || canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS);
+	const terrainRulerAvailable = isToken && game.modules.get("terrain-ruler")?.active && (!game.modules.get("TerrainLayer")?.active || canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS);
 
 	if (terrainRulerAvailable) {
 		const firstNewSegmentIndex = segments.findIndex(segment => !segment.ray.dragRulerVisitedSpaces);
@@ -27,7 +28,7 @@ export function measureDistances(segments, token, shape, options={}) {
 		const newSegments = segments.slice(firstNewSegmentIndex);
 		const distances = previousSegments.map(segment => segment.ray.dragRulerVisitedSpaces[segment.ray.dragRulerVisitedSpaces.length - 1].distance);
 		previousSegments.forEach(segment => segment.ray.terrainRulerVisitedSpaces = duplicate(segment.ray.dragRulerVisitedSpaces));
-		opts.costFunction = (x, y) => getCostFromSpeedProvider(token, getAreaFromPositionAndShape({x, y}, shape), {x, y});
+		opts.costFunction = (x, y) => getCostFromSpeedProvider(entity, getAreaFromPositionAndShape({x, y}, shape), {x, y});
 		if (previousSegments.length > 0)
 			opts.terrainRulerInitialState = previousSegments[previousSegments.length - 1].ray.dragRulerFinalState;
 		return distances.concat(terrainRuler.measureDistances(newSegments, opts));

src/foundry_imports.js

@@ -4,10 +4,10 @@ import {Line} from "./geometry.js";
 import {getColorForDistance} from "./main.js"
 import {trackRays} from "./movement_tracking.js"
 import {recalculate} from "./socket.js";
-import {applyTokenSizeOffset, getSnapPointForToken, getTokenShape, highlightTokenShape, zip} from "./util.js";
+import {applyTokenSizeOffset, getSnapPointForMeasuredTemplate, getSnapPointForToken, getTokenShape, highlightTokenShape, zip} from "./util.js";
 
 // This is a modified version of Ruler.moveToken from foundry 0.7.9
-export async function moveTokens(draggedEntity, selectedTokens) {
+export async function moveEntities(draggedEntity, selectedEntities) {
 	let wasPaused = game.paused;
 	if (wasPaused && !game.user.isGM) {
 		ui.notifications.warn(game.i18n.localize("GAME.PausedWarning"));
@@ -19,8 +19,8 @@ export async function moveTokens(draggedEntity, selectedTokens) {
 	// Get the movement rays and check collision along each Ray
 	// These rays are center-to-center for the purposes of collision checking
 	const rays = this.constructor.dragRulerGetRaysFromWaypoints(this.waypoints, this.destination);
-	if (!game.user.isGM) {
-		const hasCollision = selectedTokens.some(token => {
+	if (!game.user.isGM && draggedEntity instanceof Token) {
+		const hasCollision = selectedEntities.some(token => {
 			const offset = calculateTokenOffset(token, draggedEntity);
 			const offsetRays = rays.filter(ray => !ray.isPrevious).map(ray => applyOffsetToRay(ray, offset))
 			return offsetRays.some(r => canvas.walls.checkCollision(r));
@@ -35,7 +35,7 @@ export async function moveTokens(draggedEntity, selectedTokens) {
 	// Execute the movement path.
 	// Transform each center-to-center ray into a top-left to top-left ray using the prior token offsets.
 	this._state = Ruler.STATES.MOVING;
-	await animateTokens.call(this, selectedTokens, draggedEntity, rays, wasPaused);
+	await animateEntities.call(this, selectedEntities, draggedEntity, rays, wasPaused);
 
 	// Once all animations are complete we can clear the ruler
 	if (this.draggedEntity?.id === draggedEntity.id)
@@ -43,51 +43,53 @@ export async function moveTokens(draggedEntity, selectedTokens) {
 }
 
 // This is a modified version code extracted from Ruler.moveToken from foundry 0.7.9
-async function animateTokens(tokens, draggedEntity, draggedRays, wasPaused) {
+async function animateEntities(entities, draggedEntity, draggedRays, wasPaused) {
 	const newRays = draggedRays.filter(r => !r.isPrevious);
-	const tokenAnimationData = tokens.map(token => {
-		const tokenOffset = calculateTokenOffset(token, draggedEntity);
-		const offsetRays = newRays.map(ray => applyOffsetToRay(ray, tokenOffset));
+	const entityAnimationData = entities.map(entity => {
+		const entityOffset = calculateEntityOffset(entity, draggedEntity);
+		const offsetRays = newRays.map(ray => applyOffsetToRay(ray, entityOffset));
 
 		// Determine offset relative to the Token top-left.
 		// This is important so we can position the token relative to the ruler origin for non-1x1 tokens.
 		const firstWaypoint = this.waypoints.find(w => !w.isPrevious);
-		const origin = [firstWaypoint.x + tokenOffset.x, firstWaypoint.y + tokenOffset.y];
+		const origin = [firstWaypoint.x + entityOffset.x, firstWaypoint.y + entityOffset.y];
 		let dx, dy;
 		if (canvas.grid.type === CONST.GRID_TYPES.GRIDLESS) {
-			dx = token.data.x - origin[0];
-			dy = token.data.y - origin[1];
+			dx = entity.data.x - origin[0];
+			dy = entity.data.y - origin[1];
 		}
 		else {
-			dx = token.data.x - origin[0];
-			dy = token.data.y - origin[1];
+			dx = entity.data.x - origin[0];
+			dy = entity.data.y - origin[1];
 		}
 
-		return {token, rays: offsetRays, dx, dy};
+		return {entity, rays: offsetRays, dx, dy};
 	});
 
-	const animate = !game.keyboard.isDown("Alt");
-	const startWaypoint = animate ? 0 : tokenAnimationData[0].rays.length - 1;
-	for (let i = startWaypoint;i < tokenAnimationData[0].rays.length; i++) {
+	const isToken = draggedEntity instanceof Token;
+	const animate = isToken && !game.keyboard.isDown("Alt");
+	const startWaypoint = animate ? 0 : entityAnimationData[0].rays.length - 1;
+	for (let i = startWaypoint;i < entityAnimationData[0].rays.length; i++) {
 		if (!wasPaused && game.paused) break;
-		const tokenPaths = tokenAnimationData.map(({token, rays, dx, dy}) => {
+		const entityPaths = entityAnimationData.map(({entity, rays, dx, dy}) => {
 			const ray = rays[i];
 			const dest = [ray.B.x, ray.B.y];
-			const path = new Ray({x: token.x, y: token.y}, {x: dest[0] + dx, y: dest[1] + dy});
-			return {token, path};
+			const path = new Ray({x: entity.x, y: entity.y}, {x: dest[0] + dx, y: dest[1] + dy});
+			return {entity, path};
 		});
-		const updates = tokenPaths.map(({token, path}) => {
-			return {x: path.B.x, y: path.B.y, _id: token.id};
+		const updates = entityPaths.map(({entity, path}) => {
+			return {x: path.B.x, y: path.B.y, _id: entity.id};
 		});
 		await draggedEntity.scene.updateEmbeddedEntity(draggedEntity.constructor.embeddedName, updates, {animate});
 		if (animate)
-			await Promise.all(tokenPaths.map(({token, path}) => token.animateMovement(path)));
+			await Promise.all(entityPaths.map(({entity, path}) => entity.animateMovement(path)));
 	}
-	trackRays(tokens, tokenAnimationData.map(({rays}) => rays)).then(() => recalculate(tokens));
+	if (isToken)
+		trackRays(entities, entityAnimationData.map(({rays}) => rays)).then(() => recalculate(entities));
 }
 
-function calculateTokenOffset(tokenA, tokenB) {
-	return {x: tokenA.data.x - tokenB.data.x, y: tokenA.data.y - tokenB.data.y}
+function calculateEntityOffset(entityA, entityB) {
+	return {x: entityA.data.x - entityB.data.x, y: entityA.data.y - entityB.data.y};
 }
 
 function applyOffsetToRay(ray, offset) {
@@ -119,17 +121,22 @@ export function onMouseMove(event) {
 
 // This is a modified version of Ruler.measure form foundry 0.7.9
 export function measure(destination, {gridSpaces=true, snap=false} = {}) {
-	if (this.isDragRuler && !this.draggedEntity.isVisible)
+	const isToken = this.draggedEntity instanceof Token;
+	if (isToken && !this.draggedEntity.isVisible)
 		return []
 
-	if (snap)
-		destination = getSnapPointForToken(destination.x, destination.y, this.draggedEntity);
+	if (snap) {
+		if (isToken)
+			destination = getSnapPointForToken(destination.x, destination.y, this.draggedEntity);
+		else
+			destination = getSnapPointForMeasuredTemplate(destination.x, destination.y);
+	}
 
-	const terrainRulerAvailable = game.modules.get("terrain-ruler")?.active && (!game.modules.get("TerrainLayer")?.active || canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS);
+	const terrainRulerAvailable = isToken && game.modules.get("terrain-ruler")?.active && (!game.modules.get("TerrainLayer")?.active || canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS);
 
 	const waypoints = this.waypoints.concat([destination]);
 	// Move the waypoints to the center of the grid if a size is used that measures from edge to edge
-	const centeredWaypoints = applyTokenSizeOffset(waypoints, this.draggedEntity);
+	const centeredWaypoints = isToken ? applyTokenSizeOffset(waypoints, this.draggedEntity) : duplicate(waypoints);
 	// Foundries native ruler requires the waypoints to sit in the dead center of the square to work properly
 	if (!terrainRulerAvailable)
 		centeredWaypoints.forEach(w => [w.x, w.y] = canvas.grid.getCenter(w.x, w.y));
@@ -162,7 +169,7 @@ export function measure(destination, {gridSpaces=true, snap=false} = {}) {
 	}
 
 
-	const shape = getTokenShape(this.draggedEntity)
+	const shape = isToken ? getTokenShape(this.draggedEntity) : null;
 
 	// Compute measured distance
 	const distances = measureDistances(centeredSegments, this.draggedEntity, shape, {gridSpaces});
@@ -220,7 +227,7 @@ export function measure(destination, {gridSpaces=true, snap=false} = {}) {
 		}
 
 		// Highlight grid positions
-		if (canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS) {
+		if (isToken && canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS) {
 			if (terrainRulerAvailable)
 				highlightMeasurementTerrainRuler.call(this, cs.ray, cs.startDistance, shape, opacityMultiplier)
 			else

src/main.js

@@ -2,7 +2,7 @@
 
 import {currentSpeedProvider, getMovedDistanceFromToken, getRangesFromSpeedProvider, getUnreachableColorFromSpeedProvider, initApi, registerModule, registerSystem} from "./api.js"
 import {checkDependencies, getHexSizeSupportTokenGridCenter} from "./compatibility.js";
-import {moveTokens, onMouseMove} from "./foundry_imports.js"
+import {moveEntities, onMouseMove} from "./foundry_imports.js"
 import {performMigrations} from "./migration.js"
 import {DragRulerRuler} from "./ruler.js";
 import {getMovementHistory, resetMovementHistory} from "./movement_tracking.js";
@@ -13,7 +13,8 @@ import {SpeedProvider} from "./speed_provider.js"
 Hooks.once("init", () => {
 	registerSettings()
 	initApi()
-	hookTokenDragHandlers()
+	hookDragHandlers(Token);
+	hookDragHandlers(MeasuredTemplate);
 	hookKeyboardManagerFunctions()
 
 	Ruler = DragRulerRuler;
@@ -54,29 +55,29 @@ Hooks.on("getCombatTrackerEntryContext", function (html, menu) {
 	menu.splice(1, 0, entry);
 });
 
-function hookTokenDragHandlers() {
-	const originalDragLeftStartHandler = Token.prototype._onDragLeftStart
-	Token.prototype._onDragLeftStart = function(event) {
+function hookDragHandlers(entityType) {
+	const originalDragLeftStartHandler = entityType.prototype._onDragLeftStart
+	entityType.prototype._onDragLeftStart = function(event) {
 		originalDragLeftStartHandler.call(this, event)
-		onTokenLeftDragStart.call(this, event)
+		onEntityLeftDragStart.call(this, event)
 	}
 
-	const originalDragLeftMoveHandler = Token.prototype._onDragLeftMove
-	Token.prototype._onDragLeftMove = function (event) {
+	const originalDragLeftMoveHandler = entityType.prototype._onDragLeftMove
+	entityType.prototype._onDragLeftMove = function (event) {
 		originalDragLeftMoveHandler.call(this, event)
-		onTokenLeftDragMove.call(this, event)
+		onEntityLeftDragMove.call(this, event)
 	}
 
-	const originalDragLeftDropHandler = Token.prototype._onDragLeftDrop
-	Token.prototype._onDragLeftDrop = function (event) {
-		const eventHandled = onTokenDragLeftDrop.call(this, event)
+	const originalDragLeftDropHandler = entityType.prototype._onDragLeftDrop
+	entityType.prototype._onDragLeftDrop = function (event) {
+		const eventHandled = onEntityDragLeftDrop.call(this, event)
 		if (!eventHandled)
 			originalDragLeftDropHandler.call(this, event)
 	}
 
-	const originalDragLeftCancelHandler = Token.prototype._onDragLeftCancel
-	Token.prototype._onDragLeftCancel = function (event) {
-		const eventHandled = onTokenDragLeftCancel.call(this, event)
+	const originalDragLeftCancelHandler = entityType.prototype._onDragLeftCancel
+	entityType.prototype._onDragLeftCancel = function (event) {
+		const eventHandled = onEntityDragLeftCancel.call(this, event)
 		if (!eventHandled)
 			originalDragLeftCancelHandler.call(this, event)
 	}
@@ -124,45 +125,48 @@ function onKeyShift(up) {
 	ruler.measure(measurePosition, {snap: up})
 }
 
-function onTokenLeftDragStart(event) {
-	if (!currentSpeedProvider.usesRuler(this))
+function onEntityLeftDragStart(event) {
+	const isToken = this instanceof Token;
+	if (isToken && !currentSpeedProvider.usesRuler(this))
 		return
 	const ruler = canvas.controls.ruler
 	ruler.draggedEntity = this;
-	let tokenCenter
-	if (canvas.grid.isHex && game.modules.get("hex-size-support")?.active && CONFIG.hexSizeSupport.getAltSnappingFlag(this))
-		tokenCenter = getHexSizeSupportTokenGridCenter(this)
+	let entityCenter;
+	if (isToken && canvas.grid.isHex && game.modules.get("hex-size-support")?.active && CONFIG.hexSizeSupport.getAltSnappingFlag(this))
+		entityCenter = getHexSizeSupportTokenGridCenter(this);
 	else
-		tokenCenter = this.center
+		entityCenter = this.center;
 	ruler.clear();
 	ruler._state = Ruler.STATES.STARTING;
-	ruler.rulerOffset = {x: tokenCenter.x - event.data.origin.x, y: tokenCenter.y - event.data.origin.y}
-	if (game.settings.get(settingsKey, "enableMovementHistory"))
+	ruler.rulerOffset = {x: entityCenter.x - event.data.origin.x, y: entityCenter.y - event.data.origin.y};
+	if (isToken && game.settings.get(settingsKey, "enableMovementHistory"))
 		ruler.dragRulerAddWaypointHistory(getMovementHistory(this));
-	ruler.dragRulerAddWaypoint(tokenCenter, false);
+	ruler.dragRulerAddWaypoint(entityCenter, false);
 }
 
-function onTokenLeftDragMove(event) {
+function onEntityLeftDragMove(event) {
 	const ruler = canvas.controls.ruler
 	if (ruler.isDragRuler)
 		onMouseMove.call(ruler, event)
 }
 
-function onTokenDragLeftDrop(event) {
+function onEntityDragLeftDrop(event) {
 	const ruler = canvas.controls.ruler
 	if (!ruler.isDragRuler)
 		return false
 	onMouseMove.call(ruler, event);
+	// When we're dragging a measured template no token will ever be selected,
+	// resulting in only the dragged template to be moved as would be expected
 	const selectedTokens = canvas.tokens.controlled
 	// This can happen if the user presses ESC during drag (maybe there are other ways too)
 	if (selectedTokens.length === 0)
 		selectedTokens.push(ruler.draggedEntity);
 	ruler._state = Ruler.STATES.MOVING
-	moveTokens.call(ruler, ruler.draggedEntity, selectedTokens);
+	moveEntities.call(ruler, ruler.draggedEntity, selectedTokens);
 	return true
 }
 
-function onTokenDragLeftCancel(event) {
+function onEntityDragLeftCancel(event) {
 	// This function is invoked by right clicking
 	const ruler = canvas.controls.ruler
 	if (!ruler.isDragRuler || ruler._state === Ruler.STATES.MOVING)

src/util.js

@@ -39,6 +39,29 @@ export function getSnapPointForToken(x, y, token) {
 	return new PIXI.Point(snappedX + canvas.grid.w / 2, snappedY + canvas.grid.h / 2)
 }
 
+export function getSnapPointForMeasuredTemplate(x, y) {
+	if (canvas.grid.type === CONST.GRID_TYPES.GRIDLESS) {
+		return new PIXI.Point(x, y);
+	}
+	let subgridWidth, subgridHeight;
+	if (canvas.grid.type === CONST.GRID_TYPES.SQUARE) {
+		subgridWidth = subgridHeight = canvas.dimensions.size / 2;
+	}
+	else {
+		if (canvas.grid.grid.columns) {
+			subgridWidth = canvas.grid.w / 4;
+			subgridHeight = canvas.grid.h / 2;
+		}
+		else {
+			subgridWidth = canvas.grid.w / 2;
+			subgridHeight = canvas.grid.h / 4;
+		}
+	}
+	const snappedX = Math.round(x / subgridWidth) * subgridWidth;
+	const snappedY = Math.round(y / subgridHeight) * subgridHeight;
+	return new PIXI.Point(snappedX, snappedY);
+}
+
 export function highlightTokenShape(position, shape, color, alpha) {
 	const layer = canvas.grid.highlightLayers[this.name];
     if ( !layer )