This is good feedback that I need to be clear and avoid terminological confusion when I write that blog post. Of course the compositor is using the GPU. The di

This is good feedback that I need to be clear and avoid terminological confusion when I write that blog post. Of course the compositor is using the GPU. The difference is entirely in how the capabilities of the GPU are exposed (or not) to the application. My thesis is that doing 2D rendering in a compute kernel is ideal for 2D workloads, because it lets the application express its scene graph in the most natural way, then computes it efficiently (in particular, avoiding global GPU memory traffic for intermediate textures) using the GPU's compute resources. Of course you could in theory have a compositor API that lets you do region-tracking for flat color areas, and this would save some power, but no system I know works that way.