Composite operations in Android Canvas


Question

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.

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

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".

1
7
12/12/2013 6:03:05 AM

Accepted Answer

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);

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

9
5/23/2017 12:07:08 PM

Found it myself. The PorterDuffXfermode implements all these composite modes.


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