现在需要画一幅图表,主题部分是一条s型贝塞尔曲线,根据数据的比例给贝塞尔曲线填色,怎么获取部分贝塞尔曲线的控制点,结束点,是用bezierCurveTo函数
<canvas id="canvasId" width="500" height="400"></canvas>
<script type="text/javascript">
var canvas = document.getElementById("canvasId");
var cxt = canvas.getContext("2d");
var cp = [{x:43,y:131},{x:394,y:309},{x:144,y:19},{x:379,y:172}];
cxt.moveTo(cp[0].x,cp[0].y);
cxt.bezierCurveTo(cp[1].x,cp[1].y,cp[2].x,cp[2].y,cp[3].x,cp[3].y);
cxt.stroke();
</script>