<!DOCTYPE html>
<html>
<body>
<span>没有 clip():</span>
<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">
您的浏览器不支持 HTML5 canvas 标签。</canvas>
<script>
var c = document.getElementById("myCanvas");var ctx = c.getContext("2d");
ctx.rect(50, 20, 200, 120);
ctx.stroke();
ctx.fillStyle = "red";
ctx.fillRect(0, 0, 150, 100);
</script>
<span>有 clip():</span>
<canvas id="myCanvas2" width="300" height="150" style="border:1px solid #d3d3d3;">
您的浏览器不支持 HTML5 canvas 标签。</canvas>
<script>
var c = document.getElementById("myCanvas2");var ctx = c.getContext("2d");
ctx.rect(50, 20, 200, 120);
ctx.stroke();
ctx.clip();
ctx.fillStyle = "red";
ctx.fillRect(0, 0, 150, 100);
</script>
</body>
</html>