canvas绘制树形结构可视图形的实现

<canvas id="canvas" width="750" height="800"></canvas>

const canvas_options={
    canvasWidth: 750,
    canvasHeight: 800,
    chartZone: [70,70,750,570], //坐标绘制区域
    yAxisLabel: ['0%','10%','20%','30%','40%','50%','60%','70%','80%','90%','100%'],//y轴坐标text
    yAxisLabelWidth: 70,//y轴最大宽度
    yAxisLabelMax: 100,//y轴最大值
    middleLine: 410, //中间线
    pillarWidth: 10,//柱子宽度
    distanceBetween: 50,//柱状图绘制区域距离两边间隙
    pillar: [120,70,700,750],//柱状图绘制区域
    mainTrunkHeight: 90,//底部开始主干高度
    dialogWidth: 300,//弹窗宽度
    dialogLineHeight: 30,//弹窗高度
    dialogDrawLineMax: 4,
}
const nodeClick = [];
var chooseNode = null;
const datalist={
    showDataInfo: {
        city:[
            { 
                name: '项目1', 
                status: 1, //状态：0已完成 1进行中
                node: [
                    { value: 10, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 20, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                ] 
            },
            { 
                name: '项目2', 
                status: 0, //状态：0已完成 1进行中
                node: [
                    { value: 10, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 50, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 100, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                ] 
            },
            { 
                name: '项目3', 
                status: 1, //状态：0已完成 1进行中
                node: [
                    { value: 20, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 30, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 40, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                ] 
            },
            { 
                name: '项目4', 
                status: 1, //状态：0已完成 1进行中
                node: [
                    { value: 20, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                    { value: 30, date: '2020-03-12 15:50:02', content: '用于组织信息和操作，通常也作为详细信息的入口。' },
                ] 
            },
        ]
    }
}

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext('2d');
ctx.save();

drawYLabel(canvas_options,ctx); //绘制y轴坐标
drawStartButton(ctx,canvas_options);
drawData(ctx,datalist.showDataInfo,canvas_options);

canvas.addEventListener("click",event=>{
    //清除之前的弹窗
    if(chooseNode!=null){
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.save();
         drawYLabel(canvas_options,ctx); //绘制y轴坐标
         drawStartButton(ctx,canvas_options);
         drawData(ctx,datalist.showDataInfo,canvas_options);
        chooseNode = null
    }
    //判断点击节点
    let rect = canvas.getBoundingClientRect();
    let zoom = rect.width/canvas_options.canvasWidth;
    let x = (event.clientX/zoom - rect.left/zoom).toFixed(2);
    let y = (event.clientY/zoom - rect.top/zoom).toFixed(2);

    for(var t=0;t<nodeClick.length;t++){
        ctx.beginPath();
        ctx.arc(nodeClick[t].x,nodeClick[t].y,15,0,Math.PI*2,true);
        if(ctx.isPointInPath(x, y)){
            textPrewrap(ctx,`备注描述：${nodeClick[t].date}`,nodeClick[t].x+20,nodeClick[t].y+20,canvas_options.dialogWidth-40);
            ctx.restore();
            chooseNode=t
            break;
        }else{
            chooseNode=null
        }
    }
});

//content：需要绘制的文本内容; drawX：绘制文本的x坐标; drawY：绘制文本的y坐标;
//lineMaxWidth：每行文本的最大宽度
function textPrewrap(ctx,content,drawX, drawY, lineMaxWidth){
    var drawTxt=''; //当前绘制的内容
    var drawLine  = 1;//第几行开始绘制
    var drawIndex=0;//当前绘制内容的索引
    //判断内容是够可以一行绘制完毕
    if(ctx.measureText(content).width<=lineMaxWidth){
        drawDialog(ctx,canvas_options.dialogWidth,canvas_options.dialogLineHeight,drawX,drawY);
        ctx.fillText(content.substring(drawIndex,i),drawX.drawY);
    }else{
        for(var i=0;i<content.length;i++){
            drawTxt += content[i];
            if(ctx.measureText(drawTxt).width>=lineMaxWidth){
                drawDialog(ctx,canvas_options.dialogWidth,canvas_options.dialogLineHeight,drawX,drawY);
                ctx.fillText(content.substring(drawIndex,i+1),drawX,drawY);
                drawIndex = i+1;
                drawLine+=1;
                //drawY+=lineHeight;
                drawTxt='';
            }else{
                //内容绘制完毕，但是剩下的内容宽度不到lineMaxWidth
                if(i===content.length-1){
                    drawDialog(ctx,canvas_options.dialogWidth,canvas_options.dialogLineHeight,drawX,drawY);
                    ctx.fillText(content.substring(drawIndex,i+1),drawX,drawY)
                }
            }
        }
    }
}

function drawDialog(ctx,width,height,x,y){
    ctx.beginPath();
    ctx.fillStyle="rgba(0,0,0,0.8)";
    ctx.fillRect(x,y,width,height);
    ctx.font="22px ''";
    ctx.fillStyle="#fff";
    ctx.textAlign = 'left';
    ctx.textBaseline="top";
}

//绘制y轴坐标
function drawYLabel(options,ctx){
    let labels = options.yAxisLabel;
    let yLength = (options.chartZone[3]-options.chartZone[1])*0.98;
    let gap = yLength/(labels.length-1);

    labels.forEach((item,index)=>{
        //绘制圆角背景
        //this.radiusButton(ctx,0,options.chartZone[3]-index*gap-13,50,24,8,"#313947");

        //绘制坐标文字
        ctx.beginPath();
        ctx.fillStyle="#878787";
        ctx.font="18px ''";
        ctx.textAlign="center";
        ctx.fillText(item,25,options.chartZone[3]-index*gap+5);
        //绘制辅助线
        ctx.beginPath();
        ctx.strokeStyle="#eaeaea";
        ctx.strokeWidth=2;
        ctx.moveTo(options.chartZone[0],options.chartZone[3]-index*gap);
        ctx.lineTo(options.chartZone[2],options.chartZone[3]-index*gap);
        ctx.stroke();
    })

}
//绘制开始按钮
function drawStartButton(ctx,options){
    //绘制按钮图形
    this.radiusButton(ctx,options.middleLine-(160/2),options.canvasHeight-50,160,50,8,'#F4C63D');
    ctx.fillStyle="#fff";
    ctx.font="24px ''";
    ctx.textAlign="center";
    ctx.fillText('开始',options.middleLine,options.canvasHeight-15);

    //绘制状态
    ctx.beginPath();
    ctx.fillStyle="#333";
    ctx.font="24px ''";
    ctx.textAlign = "left";
    ctx.fillText("已完成",0,options.canvasHeight-100);
    ctx.fillText("进行中",0,options.canvasHeight-50);
    //绘制红色按钮
    ctx.beginPath();
    ctx.fillStyle="#d35453";
    ctx.arc(options.chartZone[0]+30,options.canvasHeight-100-7,8,0,2 * Math.PI,true);
    ctx.fill();
    ctx.beginPath();
    ctx.strokeStyle="#d35453";
    ctx.arc(options.chartZone[0]+30,options.canvasHeight-100-7,14,0,2 * Math.PI,true);
    ctx.stroke();
    //绘制蓝色按钮
    ctx.beginPath();
    ctx.fillStyle="#24b99a";
    ctx.arc(options.chartZone[0]+30,options.canvasHeight-50-8,8,0,2 * Math.PI,true);
    ctx.fill();
    ctx.beginPath();
    ctx.strokeStyle="#24b99a";
    ctx.arc(options.chartZone[0]+30,options.canvasHeight-50-8,14,0,2 * Math.PI,true);
    ctx.stroke();

}
//封装绘制圆角矩形函数
function radiusButton(ctx,x,y,width,height,radius,color_back){
    ctx.beginPath();
    ctx.fillStyle= color_back
    ctx.moveTo(x,y+radius);
    ctx.lineTo(x,y+height-radius);
    ctx.quadraticCurveTo(x,y+height,x+radius,y+height);
    ctx.lineTo(x+width-radius,y+height);
    ctx.quadraticCurveTo(x+width,y+height,x+width,y+height-radius);
    ctx.lineTo(x+width,y+radius);
    ctx.quadraticCurveTo(x+width,y,x+width-radius,y);
    ctx.lineTo(x+radius,y);
    ctx.quadraticCurveTo(x,y,x,y+radius);
    ctx.fill()
}
//绘制数据
function drawData(ctx,data,options){

    //const paths=[];
    let number = data.city.length;
    //绘制矩形
    data.city.forEach((item,index)=>{
        let indexVal = number==1?1:index;
        let numberVal = number==1?2:number-1
        let x0 = options.chartZone[0]+options.distanceBetween+(options.chartZone[2]-options.chartZone[0]-options.distanceBetween*2)/numberVal*indexVal;
        let value = item.node[item.node.length-1].value;
        let height = (value/options.yAxisLabelMax*(options.chartZone[3]-options.chartZone[0])*0.98).toFixed(2);
        let y0=options.chartZone[3] - height;

        //柱状图底部
        ctx.beginPath();
        ctx.fillStyle= '#eee';
        ctx.fillRect(x0-5,80,options.pillarWidth,options.chartZone[3]-80);

        //贝塞尔曲线
        ctx.beginPath();

        ctx.strokeStyle = item.status==0?"#d35453":'#24b99a';
        ctx.lineWidth=options.pillarWidth;
        ctx.moveTo(options.middleLine,options.pillar[3]); //贝塞尔曲线起始点
        ctx.lineTo(options.middleLine,options.canvasHeight-50-options.mainTrunkHeight); //贝塞尔曲线中间竖线
        ctx.quadraticCurveTo(x0,options.canvasHeight-50-options.mainTrunkHeight,x0,options.chartZone[3]);
        //绘制柱状图进度
        ctx.lineTo(x0,y0);
        ctx.stroke();

        //绘制文字
        ctx.font="28px ''";
        ctx.textAlign='center';
        ctx.fillStyle="#333";
        ctx.fillText(item.name,x0,options.chartZone[1]-20);

        //绘制节点
        item.node.forEach((node_item,node_index)=>{
            let y1= options.chartZone[3] - (node_item.value/options.yAxisLabelMax*(options.chartZone[3]-options.chartZone[0])*0.98).toFixed(2);
            ctx.beginPath();
            ctx.arc(x0,y1,15,0,Math.PI*2,true);
            ctx.fillStyle="rgba(108,212,148,1)";
            ctx.fill();
            ctx.beginPath();
            ctx.arc(x0,y1,9,0,Math.PI*2,true);
            ctx.fillStyle="rgba(255,255,255,0.8)";
            ctx.fill();
            const pointInfo={
                x:x0,
                y:y1,
                date: node_item.data,
                content: node_item.content,
                value: node_item.value
            };
            nodeClick.push(pointInfo);
        })
    })
}