如何在HTML5画布中清除圆弧或圆？ [英] How can I clear an arc or circle in HTML5 canvas?

问题描述

我发现有一个 clearRect（）方法，但找不到任何清除弧（或一个完整的圆）。

I found that there's a clearRect() method, but can't find any to clear an arc (or a full circle).

有没有办法在画布上清除一个弧？

Is there any way to clear an arc in canvas?

推荐答案

在画布上绘制的东西没有要清除的对象，只是您绘制的像素。 clearRect 方法不会清除先前绘制的对象，它只是清除由参数定义的空间中的像素。如果你知道一个包含它的矩形，你可以使用 clearRect 方法来清除弧。这当然会清除区域中的任何其他像素，因此您必须重新绘制它们。

Nope, once you've drawn something on a canvas there is no object to clear, just the pixels you've drawn. The clearRect method doesn't clear a previously drawn object, it just clears the pixels in the space defined by the parameters. You can use the clearRect method to clear the arc if you know a rectangle which contains it. This will of course clear any other pixels in the area, so you'll have to redraw them.

编辑： MooGoo在下面给出了更好的答案

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