Android PorterDuff Mode Creating a PorterDuff XferMode


An Xfermode (think "transfer" mode) works as a transfer step in drawing pipeline. When an Xfermode is applied to a Paint, the pixels drawn with the paint are combined with underlying pixels (already drawn) as per the mode:

paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

Now we have a blue tint paint. Any shape drawn will tint the already existing, non-transparent pixels blue in the area of the shape.