绘制心形

首先绘制心型主要是运用3次贝塞尔曲线，是通过bezierCurveTo(x1,x2,x3,x4,x5,x6)这个方法，其中有六个参数，x1,x2是第一个控制点的坐标，x3,x4是第二个控制点的坐标，x5,x6是结束点的坐标
下面看代码：

<canvas id="canvas" width="300" height="300" style="border: 1px dashed #808080"></canvas>
<script>  
function $$ (id) {    
    return document.getElementById(id)  
}  
window.onload = function () {    
    var con = $$("canvas")    
    var cxt = con.getContext('2d')    
    cxt.moveTo(75, 40)    
    cxt.bezierCurveTo(75, 37, 70, 25, 50, 25)    
    cxt.bezierCurveTo(20, 25, 20, 62.5, 20, 62.5)    
    cxt.bezierCurveTo(20, 80, 40, 102, 75, 120)    
    cxt.bezierCurveTo(110, 102, 130, 80, 130, 62.5)    
    cxt.bezierCurveTo(130, 62.5, 130, 25, 100, 25)    
    cxt.bezierCurveTo(85, 25, 75, 37, 75, 40)    
    cxt.fillStyle = 'rgb(249, 18, 4)'    
    cxt.fill()  
}
</script>

效果图