I'm trying to figure out how to create a pixelation effect (like you would get with stylize>mosaic) that can be effected by a gradient. For example, if I have a left to right gradient/ramp from black to white, I'd want to the mosaic effect to use that gradient as a map to increase the size of the "block". The image would be clean on the left and have large pixel blocks on the right, and in between would be increasing sizes of pixel blocks.
How about a few adjustment layers with their corresponding luma mattes?
Stacking them in the right order, so that one mosaic effect adjustment layer with 25*25 rows has one luma matte, and above that a 50*50 with a separate luma matte.
I suppose one would have to do some maths so there won't be any weird overlaps..