The Show Paint effect is useful when debugging repaint regions issued by
effects. The only headache with it is necessity to enable/disable it.
Consider the following workflow:
- Do some change to an effect;
- Compile KWin (or the effect);
- Go to System Settings and enable the Show Paint effect;
- Test effect, check repaint regions, etc;
- Disable the Show Paint effect;
- Go to the step 1.
This workflow is really exhausting. Also, when testing repaints in a
nested compositor, things become quite messy.
Because purpose of this effect is to debug repaints (and because this
effect is not meant for daily usage), I think that's fine to change
how it's activated.
This patch improves the workflow by changing the way how this effect
gets activated. Instead of enabling/disabling it, one can just use a shortcut
to activate or deactivate the effect.