html 饼图统计

 window.onload = function init() {
//绘制饼图  var data_arr = [0.5, 0.5];
        var color_arr = ["#26b899", "#b370cf"];
        var text_arr = ["补票", "卡"];
        drawCircle("canvas_circle", data_arr, color_arr, text_arr);


        //绘制饼图
        function drawCircle(canvasId, data_arr, color_arr, text_arr)
        {
            var c = document.getElementById(canvasId);
            var ctx = c.getContext("2d");

            var radius = c.height / 2 - 20; //半径
            var ox = radius + 20, oy = radius + 20; //圆心

            var width = 25, height = 15; //图例宽和高
            var posX = ox * 2 + 20, posY = 70;   //
            var textX = posX + width + 10, textY = posY + 15;

            var startAngle = 0; //起始弧度
            var endAngle = 0;   //结束弧度
            for (var i = 0; i < data_arr.length; i++)
            {
                //绘制饼图
                endAngle = endAngle + data_arr[i] * Math.PI * 2; //结束弧度
                ctx.fillStyle = color_arr[i];
                ctx.beginPath();
                ctx.moveTo(ox, oy); //移动到到圆心
                ctx.arc(ox, oy, radius, startAngle, endAngle, false);
                ctx.closePath();
                ctx.fill();
                startAngle = endAngle; //设置起始弧度

                //绘制比例图及文字
                ctx.fillStyle = color_arr[i];
                ctx.fillRect(posX, posY + 40 * i, width, height);
                ctx.moveTo(posX, posY + 40 * i);
                ctx.font = '18px 微软雅黑';    //斜体 30像素 微软雅黑字体
                ctx.fillStyle = color_arr[i]; //"#000000";

                var percent = text_arr[i] + "：" + (100.*data_arr[i]).toFixed(2) + "%";
                ctx.fillText(percent, textX, textY + 40 * i);
            }
        }
}

html：

  <canvas id="canvas_circle" width="600" height="300">
        浏览器不支持canvas
    </canvas>