<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<canvas id="canvas" style="margin:0 auto;border:1px #ddd solid;">
The current browser does not support Canvas, can replace the browser a try!
</canvas>
<script>
window.onload = function(){
var canvas = document.getElementById('canvas');
canvas.width = 1024;
canvas.height = 768;
if(canvas.getContext('2d')){
var context = canvas.getContext('2d');
context.beginPath();
context.moveTo(150,150);
context.arcTo(650,150,650,650,300);
context.lineWidth = 6;
context.strokeStyle = "red";
context.stroke();
// baseline
context.beginPath();
context.moveTo(150,150);
context.lineTo(650,150);
context.lineTo(650,650);
context.lineWidth = 2;
context.strokeStyle = "gray"
context.stroke();
}else{
alert('当前游览器不支持Canvas，请更换游览器后再试！');
}
}
function arcToTest(cxt,x0,y0,x1,y1,x2,y2,R){
cxt.beginPath();
cxt.moveTo(x0,y0);
cxt.arcTo(x1,y1,x2,y2,R);
cxt.lineWidth = 6;
cxt.strokeStyle = "red";
cxt.stroke();
// baseline
cxt.beginPath();
cxt.moveTo(x0,y0);
cxt.lineTo(x1,y1);
cxt.lineTo(x2,y2);
cxt.lineWidth = 2;
cxt.strokeStyle = "gray"
cxt.stroke();
}
</script>
</body>
<script>
/*总结
context.arc(x1,y1,x2,y2,r)
*/
</script>
</html>