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);
        })
    })
}