一个简单的应用场景，流程图连线

源码：

    addExample("A星路径查找", function () {return {template: `<div><div ref="main"></div></div>`,data() { return {}; },computed: {},methods: {},mounted() {var container = this.$refs.main;var render = new CanvasShapeRender(container, {width: 700,height: 700,background: '#efefef'})var group = render.addShape({ type: 'group', x: 50, y: 50 })const start = Vector.create(2, 2)const end = Vector.create(8, 6)let dragObjconst tileMap = group.addShape({type: 'tileMap',visibleGrid: true,onCreateTileData(col, row) {if (row === start.y && col === start.x) {return {type: 'rect',color: '#ff0000',value: 1,canMove: true}}else if (row === end.y && col === end.x) {return {type: 'rect',color: '#00ff00',value: 2,canMove: true}} else {return {type: 'rect',color: '#ddd',value: 0}}},onAfterDrawMapCell(ctx, col, row, x, y, data) {if (!gui.visibleDist || data.value !== 4) {return}ctx.beginPath()ctx.fillStyle = '#000'ctx.font = '12px sans-serif'ctx.textAlign = 'start'ctx.textBaseline = 'base'const getDist = distOps[gui.dist]const startDist = Number(data.startDist.toFixed(2)) // Number(getDist({ col: start.x, row: start.y }, { col, row }).toFixed(2))const endDist = Number(data.endDist.toFixed(2))// Number(getDist({ col, row }, { col: end.x, row: end.y }).toFixed(2))const dist = Number(data.dist.toFixed(2))//Number((endDist + startDist).toFixed(2))ctx.fillText('' + startDist, x, y + 10)ctx.fillText('' + endDist, x, y + this.cellSize[1] - 5)ctx.beginPath()ctx.font = '14px sans-serif'ctx.textAlign = 'center'ctx.textBaseline = 'middle'//  CanvasRenderingContext2D.prototype.textBaselinectx.fillText('' + dist, x + this.cellSize[0] / 2, y + this.cellSize[1] / 2)},cellSize: [50, 50],mapSize: [10, 10],mousedown(e) {const downPoint = e.downPointconst [x, y] = group.transformLocalCoord(downPoint.x, downPoint.y)const [col, row] = this.getMapCoordinate(x, y)const data = this.getCellData(col, row)if (data && data.canMove) {dragObj = {col,row,data}} else if (data && (data.value == 0 || data.value == 3)) {dragObj = {col,row,data: {value: data.value}}}},drag(e) {if (dragObj) {const point = e.pointconst [x, y] = group.transformLocalCoord(point.x, point.y)let [col, row] = this.getMapCoordinate(x, y)const data = this.getCellData(col, row)if (dragObj.data.value === 0 && !data.canMove) {// 变成障碍data.value = 3data.color = '#666'this.setCellData(col, row, data)render.requestDraw()} else if (dragObj.data.value === 3 && !data.canMove) {// 移除障碍data.value = 0data.color = '#ddd'this.setCellData(col, row, data)render.requestDraw()}else if (dragObj.data.canMove && data && data !== dragObj.data) {this.setCellData(dragObj.col, dragObj.row, data)this.setCellData(col, row, dragObj.data)if (dragObj.data.value === 1) {start.x = colstart.y = row}if (dragObj.data.value === 2) {end.x = colend.y = row}dragObj.col = coldragObj.row = rowrender.requestDraw()}}},mouseup() {dragObj = null}})render.requestDraw()const map = tileMap.map // 0 空 1 起点 2终点 3障碍const clear = () => {tileMap.visitMap(tileMap.map, (r, c, data) => {if (data.value === 4) {data.value = 0data.color = '#ddd'}})render.requestDraw()}const renderPaths = (paths, color, renderPath, duration = 1000) => {if (paths.length <= 0) {return}let start = performance.now()let len = paths.length - 1const animate = (time) => {const d = performance.now() - startconst p = Math.min(d / duration, 1)const index = Math.floor(p * len);const data = paths[index]if (renderPath || !data.isPath) {tileMap.setCellData(data.col, data.row, {...data,type: 'rect',value: 4,color: color})}render.requestDraw()if (p < 1) {requestAnimationFrame(animate)}}requestAnimationFrame(animate)}// 计算两个点的距离//Manhattan Distanceconst getManhattanDist = (a, b) => {// 曼哈顿距离　return Math.abs(a.col - b.col) + Math.abs(a.row - b.row)}// 欧几里得距离( Euclidean distance)也称欧氏距离const getEuclideanDist = (a, b) => {const x = a.col - b.colconst y = a.row - b.rowreturn Math.sqrt(x * x + y * y)}//，切比雪夫距离（Chebyshev distance）const getChebyshevDist = (a, b) => {const x = a.col - b.colconst y = a.row - b.rowreturn Math.max(Math.abs(x), Math.abs(y))}const distOps = {getManhattanDist,getEuclideanDist,getChebyshevDist}// 返回最短路径const findPath = function* (start, end, _map) {// 创建图顶点信息const map = _map.map((rd, row) => {return rd.map((cd, col) => {return {...cd,row,col,value: cd.value,isPath: false,visited: false,// 是否访问过// 无有可走的路closed: false, // 已经查找过parent: null,startDist: 0, // 起点距离当前格子endDist: 0, // 当前距离终点dist: 0, // 总距离weight: 0, // 权重order: 0,}})})const rows = map.length, cols = map[0].lengthconst getNode = (col, row) => {if (col < 0 || col >= cols || row < 0 || row >= rows) {return null}return map[row][col]}// 找相邻的const getAdjacent = (node) => {const c = node.colconst r = node.rowconst left = getNode(c - 1, r) // leftconst top = getNode(c, r - 1) // topconst right = getNode(c + 1, r) // rightconst bottom = getNode(c, r + 1) // bottomreturn [left, top, right, bottom].filter(Boolean)}const getCost=()=>{return 0.1}const findNearestDistance = (node) => {const adjacent = getAdjacent(node)let min = Infinity, minNode// let resultNode;adj:for (let i = 0; i < adjacent.length; i++) {const adj = adjacent[i]// 如果已关闭或是障碍，不处理if (adj.closed || adj.value === 3) {continue;}let startDist=node.startDist+getCost(adj,node) //getDist(adj,node)// 如果还未访问if (!adj.visited) {// g(n)表示从初始结点到任意结点n的代价，// h(n)表示从结点n到目标点的启发式评估代价（heuristic estimated cost）。// f=g(n)+h(n)// getDist(startNode, adj)adj.startDist = startDistadj.endDist = getDist(adj, endNode)adj.dist = adj.startDist + adj.endDist //getDist(adj, startNode)adj.parent = nodeadj.visited = trueopenList.push(adj)// 如果是空闲if (adj.value === 0) {visitedPaths.push(adj)}}else{if(startDist<node.startDist){adj.parent = nodeadj.startDist = startDistadj.dist = adj.startDist + adj.endDist //getDist(adj, startNode)}}if (adj.value === 2) {return adj}}openList.sort((a, b) => a.dist - b.dist)// openList.sort((a, b) => a.dist === b.dist ? a.dist - b.dist : a.order - b.order)}const getDist = distOps[gui.dist]// 查找邻居四个方位，上下左右let current = nulllet startNode = getNode(start[0], start[1])let endNode = getNode(end[0], end[1])let paths = []let visitedPaths = []let openList = []openList.push(startNode)let resultNode;path:while (openList.length) {yield { visitedPaths, paths };current = openList.shift()current.closed = true;if (current === endNode) {resultNode = currentbreak}resultNode = findNearestDistance(current)if (resultNode) {break}}current = resultNode ? resultNode.parent : nullwhile (current && current !== startNode) {current.isPath = true;paths.unshift(current)current = current.parent}return {paths: paths,visitedPaths}}const resultGenerator = (result) => {let current;do {current = result.next();} while (!current.done)return current.value}const stepGenerator = (generatorFn, callback) => {let result;let isStart = falseconst next = () => {if (!isStart) {isStart = true;result = generatorFn()}let current = result.next();callback(current.value)if (current.done) {isStart = false}}return {next,}}const distList = Object.keys(distOps)const step = stepGenerator(function* () {return yield* findPath([start.x, start.y], [end.x, end.y], map)}, ({ visitedPaths, paths }) => {renderPaths(visitedPaths, '#aaa', false)renderPaths(paths, '#ffff00', true)})const gui = addGuiScheme(this.$gui, {source: {dist: 'getEuclideanDist',visibleDist: false,start: () => {const { paths, visitedPaths } = resultGenerator(findPath([start.x, start.y], [end.x, end.y], map))renderPaths(visitedPaths, '#aaa', false)renderPaths(paths, '#ffff00', true)},step: () => {step.next()},clear() {clear()}},schemes: {dist: { type: 'list', params: distList }},onChange() {render.requestDraw()}})}}})