Additive blending with Core Graphics

Question

How can I blend two images in additive blending mode with Core Graphics?

The enum does not have something like a kCGBlendModeAdd: http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGContext/Reference/reference.html#//apple_ref/doc/c_ref/CGBlendMode

Any solution?

Answer 1

What is wrong with kCGBlendModePlusLighter?

From the linked document:

R = MIN(1, S + D)

So that is an additive blending capped at 1.0.