canvas+js绘制折线图

效果：
源码：
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>坐标系绘制</title>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
    (function () {
        //canvas布局
      var canvas = document.getElementById("canvas");
      canvas.width  = 600;
      canvas.height = 600;
      canvas.style.border = "1px solid red";
      //获取上下文
      var ctx = canvas.getContext("2d");

      //绘制坐标轴
        var x0 = 100,y0 = 500;// xy轴原点
        var maxX = 500,maxY = 100;
        var lineWidth = 10;//箭头宽度
        //x轴
        ctx.beginPath();
        ctx.moveTo(x0,y0);
        ctx.lineTo(maxX,y0);
        ctx.lineTo(maxX-lineWidth,y0+lineWidth);
        ctx.moveTo(maxX,y0);
        ctx.lineTo(maxX-lineWidth,y0-lineWidth);
        ctx.stroke();
        //y轴
        ctx.beginPath();
        ctx.moveTo(x0,y0);
        ctx.lineTo(x0,maxY);
        ctx.lineTo(x0-lineWidth,maxY+lineWidth);
        ctx.lineTo(x0,maxY);
        ctx.lineTo(x0+lineWidth,maxY+lineWidth);
        ctx.stroke();

        //折线
        var data = [.5,.4,.6,.8,.7,.9,.3];
        var xWidht = 400/(data.length+1);//x轴间距
        ctx.beginPath();
        for(var i = 0;i<data.length;i++){
            ctx.lineTo(100+xWidht*(i+1),500-400*data[i]);
        }
        ctx.strokeStyle = 'blue';
        ctx.stroke();


    }())
</script>
</body>
</html>
posted on 2018-11-29 20:19 xxcxxc 阅读(1808) 评论(0) 编辑收藏举报