Here is the first test on rendering filter effects. It applies constant gaussian blur to every rendered object of type NRArenaShape. This is mostly to test the speed of rendering filter effects in real time.
This test does not apply blurring to all types of objects - that would result in blurring the object, blurring the layer the (already blurred) object is on, etc.
The biggest problem at the moment seems to be transparent areas appearing, when an object is drawn in several smaller pieces rather than in one piece. Guess the object needs to be drawn on a larger buffer thet is larger than the result will be - thus allowing blurring to take in to account the pixels outside the actual area, we are rendering to.