strokeRect (0, 0, canvasWidth, canvasHeight);
绘制一个完整的矩形,但线宽减半,这是一个示例:
<canvas></canvas>
<script>
var canvas = document.getElementsByTagName ("canvas");
var lineWidth = 10;
var canvasHeight = canvas[0].height;
var canvasWidth = canvas[0].width;
var ctx = canvas[0].getContext ("2d");
ctx.lineWidth = lineWidth;
ctx.strokeRect (0, 0, canvasWidth, canvasHeight);
</script>
我可以解决这个问题,但并不优雅:
<canvas></canvas>
<script>
var canvas = document.getElementsByTagName ("canvas");
var lineWidth = 10;
var canvasHeight = canvas[0].height - lineWidth;
var canvasWidth = canvas[0].width - lineWidth;
var ctx = canvas[0].getContext ("2d");
ctx.lineWidth = lineWidth;
lineWidth /= 2;
ctx.strokeRect (lineWidth, lineWidth, canvasWidth, canvasHeight);
</script>
有没有本地方法可以做到这一点?类似于“box-sizing”css3 属性的东西:
canvas {
box-sizing: border-box;
}
谢谢。