如何在 html5 中制作透明画布? [英] How do I make a transparent canvas in html5?

问题描述

如何使画布透明?我需要这样做，因为我想将两个画布叠在一起.

How can I make a canvas transparent? I need to because I want to put two canvases on top of one another.

推荐答案

默认情况下画布是透明的.

Canvases are transparent by default.

尝试设置页面背景图像，然后在其上放置画布.如果画布上什么都没画，就可以完全看到页面背景.

Try setting a page background image, and then put a canvas over it. If nothing is drawn on the canvas, you can fully see the page background.

把画布想象成在玻璃板上作画.

要在画布上绘制后清除画布，只需使用 clearRect:

To clear a canvas after having drawn on it, just use clearRect:

const context = canvas.getContext('2d');
context.clearRect(0, 0, canvas.width, canvas.height);

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