在Android的画布综合业务 [英] Composite operations in Android Canvas

问题描述

我刚开始与Android的发展，我从JavaScript / HTML世界未来，所以我目前正在调查Android SDK的准备。

I'm just starting with Android development and I'm coming from JavaScript/HTML world so I'm currently investigating the possibilities of the Android SDK.

在HTML 5画布支持复合操作（见这里）。

The HTML 5 canvas supports composite operations (See here).

这是可能在Android印刷品吗？我扫视了Canvas类的API，但找不到任何有用。我至少需要复合操作源式或（如果这是不可能的），源之上。

Is this possible in an Android Canvas? I scanned the API of the Canvas class but couldn't find anything useful. I need at least the composite operation "source-in" or (if this isn't possible) "source-atop".

推荐答案

成分是通过在画布与油漆一个使用 PorterDuffXfermode 。

Composition is handled by drawing on a Canvas with a Paint that uses a PorterDuffXfermode.

Paint p=new Paint();
p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DARKEN));
canvas.drawBitmap(bitmap, 0, 0, p);

请参阅<一href="http://stackoverflow.com/questions/2763572/override-ondraw-to-change-how-the-drawing-occurs-android">here获取更多信息。我也设法覆盖的OnPaint 这样我们就可以该组合物适用于画themeselves元素。

See here for more info. I also managed to override onPaint so that we can apply this composition to elements that draw themeselves.

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