下面说一下我的实现思路:
1、首先是每个站点圆角矩形的绘制,一开始想着用canvas把圆角矩形绘制出来,但发现小程序暂时还没有绘制圆角的arcTo方法,所以用canvas绘制就相对比较麻烦,最后为了方便决定用图片代替;
2、将整个路线图分为四个小图片,(1)站点圆角矩形(2)站点之间的直连线(3)站点之间右侧弯曲连线(4)站点之间左侧弯曲连线;
3、通过观察分析,将绘制过程分为两步,(1)奇数行圆角矩形、连线的绘制点x坐标是从左至右递增,y坐标值是行数乘以某个固定值(2)偶数行圆角矩形、连线的绘制点x坐标是从左至右递减,y坐标值是行数乘以某个固定值
4、奇数行,偶数行的圆角矩形的下标index+1是3的倍数的话,奇数行当前下标右侧绘制右弯曲连线图片,偶数行当前下标左侧绘制左弯曲连线图片;
5、整个canvas绘制区域在不同手机上的适配
6、具体的一些细节请参照代码注释
7、开发工具上使用drawImage重复绘制同一张图片只显示第一次绘制的位置,暂时不知道什么原因,所以请在真机上测试;
8、有什么不足之处,望大家多多指点!感激!
wxml代码:
- <!--pages/Gline/index.wxml-->
- <view class="g-title">(G23)选择出发站点 <text class="chooseStation">{{chooseStation}}</text> </view>
- <canvas bindtouchstart="touchS" canvas-id="map" style='width:{{canvWidth}}rpx;height:{{canvHeight}}px;background-color: #eee' />
- /* pages/Gline/index.wxss */
- page{ background-color: #eeeeee }
- .g-title{font-size: 36rpx;font-weight: 600;color: #768da4;padding: 36rpx 0;padding-left: 20rpx; background-color: #fff}
- .chooseStation{color: #32b16c}
- // pages/Gline/index.js
- Page({
- data:{
- canvWidth:750,
- canvHeight:750,
- stations:['北京南','天津南','济南西','泰安','滕州东','徐州东','南京南','镇江南','苏州北','上海虹桥','北京南','天津南','济南西','泰安','滕州东','徐州东','南京南','镇江南','苏州北','上海虹桥','北京南','天津南','济南西','泰安','滕州东','徐州东','南京南','镇江南','苏州北','上海虹桥'],
- chooseStation:'',//页面显示选中的车站名字
- prevChooseIdx:null,//上一次选中车站的下标
- // stations:['北京南','天津南','济南西','泰安'],
- },
- onLoad:function(options){
- // 页面初始化 options为页面跳转所带来的参数
- // this.setData({canvHeight:502});
- const ctx = wx.createCanvasContext('map');//路线图绘制的画布上下文对象
- this.ctx = ctx;//将ctx对象绑定到当前页面中
- this.column = 3;//每行显示车站数量
- this.offsetTop = 30;//绘制起始坐标的top值,也就是距离canvas顶部的距离
- this.rect={//圆角矩形对象
- img_b:'/images/rect-b.png',//初始时图片
- img_g:'/images/rect-g.png',//选中时图片
- height:32,
- width:68
- }
- this.line = {//站与站之间的连线对象
- img:'/images/line.png',
- height:6,
- width:30
- },
- this.bendLine = {//站与站之间弯曲的连线
- img_l:'/images/line_l.png',//左侧连线
- img_r:'/images/line_r.png',//右侧连线
- height:70,
- width:20
- },
- this.rectArr=[];//记录所有车站的绘制起始点的坐标的数组
- this.oddRowIndexArr=[];//记录奇数行的车站的下标数组,如[0,1,2,6,.....]
- this.evenRowIndexArr=[];//记录偶数行的车站的下标数组,如[3,4,5,9,.....]
- this.initMap();
- },
- onReady:function(){
- },
- onShow:function(){
- // 页面显示
- },
- onHide:function(){
- // 页面隐藏
- },
- onUnload:function(){
- // 页面关闭
- },
- //对不同设备下图片大小的适配
- adaptiveScreenSize:function(o){
- let ww = this.data.winWidth;
- let zoom = ww/375;//375这里是按iPhone6的宽度做等比缩放
- this.setData({zoom:zoom});
- let rectW = o.width*zoom;
- let rectH = o.height*zoom;
- o.width = rectW;
- o.height = rectH;
- },
- //初始化路线图的方法
- initMap:function(){
- const that = this;
- wx.getSystemInfo({
- success: function(res){
- const ww = res.windowWidth;
- const pr = res.pixelRatio;
- that.setData({ winWidth:ww,pixelRatio:pr});//将设备的信息存入data中,供后面使用
- that.drawMap();
- }
- })
- },
- drawTxtAtPos:function(idx){
- const rectArr = this.rectArr;
- const w = this.rect.width;
- const h = this.rect.height;
- let txt = this.data.stations[idx];
- let len = txt.length;
- //当站点文本文字超过3个字,将缩小字号
- let fontSize = len>3?12:14;
- let x = rectArr[idx].x;
- let y = rectArr[idx].y;
- //计算文本在圆角矩形中的绘制点,使文字居中显示
- let txt_x = Math.floor((w - len*fontSize)/2)+x;
- let txt_y = Math.floor(h/2+fontSize/2)+y-2;//这里额外-2,文本才能更接近垂直居中
- this.ctx.setFontSize(fontSize);
- this.ctx.setFillStyle('#ffffff')
- this.ctx.fillText(txt, txt_x, txt_y);
- },
- //在下标为idx处绘制圆角矩形
- initRect:function(idx){
- const rectArr = this.rectArr;
- let x = rectArr[idx].x;
- let y = rectArr[idx].y;
- this.ctx.drawImage(this.rect.img_b,x, y, this.rect.width, this.rect.height);
- },
- //动态计算不同屏幕大小canvas的高度
- initCanvHeight:function(){
- let len = this.data.stations.length;
- let pr = this.data.pixelRatio;
- let z = this.data.zoom;
- let row = Math.ceil(len/this.column);
- let h = 0;
- if(row <= 1){
- console.log(this.rect.height);
- h = (this.offsetTop*2 + this.rect.height)*2;
- }else{
- h = this.offsetTop*2+(row-1)*(this.bendLine.height-this.line.height)+this.rect.height;
- }
- this.setData({canvHeight:h});
- },
- //绘制线路这逻辑比较乱,我是把路线分为奇数段和偶数段进行绘制
- drawLine:function(){
- const rectArr = this.rectArr;
- let x=0,y=0;
- if(rectArr.length==2){//首先当车站数量为2个的时候,只需绘制一条线段
- x = rectArr[0].x+this.rect.width;//计算绘制线段起始点的x坐标
- y = rectArr[0].y+Math.floor((this.rect.height-this.line.height)/2);//计算绘制线段起始点的y坐标
- this.ctx.drawImage(this.line.img, x, y, this.line.width, this.line.height);
- }else{
- const odd = this.oddRowIndexArr;
- const even = this.evenRowIndexArr;
- if(odd.length>0){
- for(let i=0;i<odd.length;i++){
- if((odd+1)!=rectArr.length){//判断当前下标绘制点后面是否还有绘制点
- x = rectArr[odd].x+this.rect.width;
- y = rectArr[odd].y+Math.floor((this.rect.height-this.line.height)/2);
- if((odd+1)%this.column!=0){//判断奇数行绘制点的下标如果不是3的整数倍将绘制一条直线,反之绘制右曲线
- this.ctx.drawImage(this.line.img, x, y, this.line.width, this.line.height);
- }else{
- this.ctx.drawImage(this.bendLine.img_r, x, y, this.bendLine.width, this.bendLine.height);
- }
- }
- }
- }
- //下面逻辑同奇数行的逻辑,不同的是绘制直线和弯曲线时x的坐标会有变化
- if(even.length>0){
- for(let i=0;i<even.length;i++){
- if((even+1)!=rectArr.length){
- y = rectArr[even].y+Math.floor((this.rect.height-this.line.height)/2);
- if((even+1)%this.column!=0){
- x = rectArr[even].x-this.line.width;//绘制直线时的计算公式
- this.ctx.drawImage(this.line.img, x, y, this.line.width, this.line.height);
- }else{
- x = rectArr[even].x-this.bendLine.width;//绘制弯曲线时的计算公式
- this.ctx.drawImage(this.bendLine.img_l, x, y, this.bendLine.width, this.bendLine.height);
- }
- }
- }
- }
- }
- },
- drawMap:function(){
- this.adaptiveScreenSize(this.rect);
- this.adaptiveScreenSize(this.line);
- this.adaptiveScreenSize(this.bendLine);
- this.initCanvHeight();
- this.createRectTopPoints();
- // setTimeout(()=>{
- const rectArr = this.rectArr;
- for(let i=0;i<rectArr.length;i++){
- this.initRect(i);
- this.drawTxtAtPos(i);
- }
- this.ctx.draw(true);
- // },500);
- this.drawLine();
- this.ctx.draw(true);
- },
- //计算后,每行的所有绘制点的起始坐标x值是一个固定数组
- //如:奇数行[10,20,30],偶数行:[30,20,10]
- getDisXArr:function(){
- let arr = [];
- let ww = this.data.winWidth;
- let disX = Math.floor((ww-(this.column*this.rect.width+(this.column-1)*this.line.width))/2);
- for(let i=0;i<this.column;i++){
- let x = disX+i%this.column*(this.rect.width+this.line.width);
- arr = x;
- }
- return arr;
- },
- //根据给出的车站数量,将每个车站的绘制顶点计算出来存入数组rectArr中
- createRectTopPoints:function(){
- let rectArr = [];
- let disXArr = this.getDisXArr();
- let disXArrRev = this.getDisXArr().reverse();
- let disY = this.offsetTop;//绘制初始点距离canvas顶部的高度
- let len = this.data.stations.length;
- let row = Math.ceil(len/this.column);//根据车站数量计算需要绘制的行数
- let n=0,x=0,y=0;
- for(let j = 1;j<=row;j++){
- for(let i=0;i<this.column;i++){
- ++n;
- if(n<=len){
- if(j%2!=0){
- this.oddRowIndexArr.push(n-1);
- //console.log("奇数行:"+n);
- x = disXArr;
- }else{
- this.evenRowIndexArr.push(n-1);
- //console.log("偶数行:"+n);
- x = disXArrRev;
- }
- y = disY + (j-1)*(this.bendLine.height-this.line.height);
- this.rectArr[n-1] = {x:x,y:y};
- }
- }
- }
- },
- //判断手指触摸点是否在圆角矩形中
- pointInRectPolygon : function (point, vs) {
- let x = point[0], y = point[1],inside = false;
- for (let i = 0, j = vs.length - 1; i < vs.length; j = i++) {
- let xi = vs[0], yi = vs[1];
- let xj = vs[j][0], yj = vs[j][1];
- let intersect = ((yi > y) != (yj > y))
- && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
- if (intersect) inside = !inside;
- }
- return inside;
- },
- //根据某个圆角矩形的绘制点和宽高,计算出圆角矩形4个顶点的坐标值
- //顺序为左上,右上,右下,左下,也就是顺时针方向
- getRectPolygon:function(x,y,w,h){
- let vs = new Array() ;
- vs[0] = [x,y];
- vs[1] = [x+w,y];
- vs[2] = [x+w,y+h];
- vs[3] = [x,y+h];
- return vs;
- } ,
- //点击车站调取的事件,事件中需要处理:
- //1、需要获取到当前点击的车站文本
- //2、判断是否有过选取,如果之前有选取,需要将之前选取过的区块颜色改为默认色
- //3、改变当前区块的颜色
- //4、记录当前点击的下标
- chooseStation:function(currIdx){
- let txt = this.data.stations[currIdx];
- let prevIdx = this.data.prevChooseIdx;
- if(prevIdx!=null){
- let x = this.rectArr[prevIdx].x;
- let y = this.rectArr[prevIdx].y;
- this.ctx.drawImage(this.rect.img_b,x, y, this.rect.width, this.rect.height);
- this.drawTxtAtPos(prevIdx);
- }
- let x = this.rectArr[currIdx].x;
- let y = this.rectArr[currIdx].y;
- this.ctx.drawImage(this.rect.img_g,x, y, this.rect.width, this.rect.height);
- this.drawTxtAtPos(currIdx);
- this.ctx.draw(true);
- this.setData({chooseStation:txt,prevChooseIdx:currIdx});
- },
- //点击事件
- touchS:function(e){
- console.log(e);
- let touch = e.changedTouches;//这里一定要用changedTouches,如果用touches,安卓机会有问题
- if(touch.length==1){
- let tapPoint = [touch[0].x,touch[0].y];
- let rectArr = this.rectArr;
- for(let i=0;i<rectArr.length;i++){
- let vs = this.getRectPolygon(rectArr.x,rectArr.y,this.rect.width,this.rect.height);
- let inside = this.pointInRectPolygon(tapPoint,vs);
- if(inside){
- this.chooseStation(i);
- break;
- }
- }
- }
- }
- })
wxapp-Gline.zip |