Original author: f...@processing.org (November 12, 2012 22:39:15)

For 2.0, we're working to get rid of the blend() function in favor of a blendMode() method that changes the current blending mode so that you can get all that composited blendy goodness.

Using Java2D, it's possible to implement this behavior using an AlphaComposite. Romain Guy has written up a really nice tutorial on doing this with Java2D:
http://www.curious-creature.org/2006/09/20/new-blendings-modes-for-java2d/
It's possible an adaptation of this code could even be used, though we'd need to clear that with him according to the license that's on the code.

You can see our old blending code inside PImage.java, though it has some issues with accuracy (it trades speed for accuracy) and needs other updates.

These changes also concern issue #120, issue #133, issue #285, and issue #475. The last one, in particular, has some helpful fixes if we decide to stick with our own blending code.

Original issue: http://code.google.com/p/processing/issues/detail?id=1385