This is fine.
Changing cropping regions is moderately expensive, so should be avoided when possible. Scale fit and stretch never exceed the draw region, and tiled shouldn't depending on implementation (which will change to some like the cached text system in the future). Scale fill also could be implemented without cropping. All of this is low level renderer logic though, so should be handled there.drawTextureInternal is only cropping for one specific case of ScaleMode. It seems to me that it should crop for all of them. This was also the only place we conditionally cropped based on equality to the state crop state, so I'd say we should drop the condition as noted above.
drawTextInternal crops differently based on the font mesh. This is the only reason why we need to pass the cropRegion to the renderer as a method argument. I would suggest that you cache the crop parameters in renderer.crop() and retrieve it for cropping fonts, but I don't want to push my luck.In any case it shouldn't hurt to do the textureMat crop change before and after calling drawText and provides consistency. Perhaps textureMat croppingBoundaries should only be set on a call to renderer.drawTexture() from cached crop values like I suggested for fonts, but now we're moving into my area of opengl ignorance.
I'm fine with the renderer managing crop region.
The main handling is in the fragment shader. Effectively it tints the texture - commonly it is used with greyscale textures to allow them to have any color. An example is the current text rendering, although this will be changing.
