A bunch of cleanups spun out from the tiling animation work
Mostly simplifying the code to make it easier to read.
* render: Move damage checking to a separate function
* render: Stay clear of wlr_ namespace
We use `box` instead of `wlr_box` in function and method names elsewhere.
This makes sure a function doesn't look like if it is coming from
wlroots.
* output: Move phoc_output_scale_box to utils
The output argument is unused. This makes it clearer that we don't care
about any output rotation or scale in this function.
* output-shield: Use proper prefix
* utils: Document phoc_utils_compute_scale
* treewide: Use explicit cast for wlr_output->data
This gives us some additional type checks.
* desktop: Make it simple to get the output at given layout coordinates
* cursor: Use phoc_desktop_layout_get_output
This simplifies the back and forth between these. view's methods
will soon switch to using PhocOutput rather than wlr_output as
arguments which will further simplify this.
* desktop: Simplify phoc_desktop_surface_at
wlr_output->data, phoc_output and output all refer to the same output.
Just use output everywhere.
* view: Use phoc_desktop_layout_get_output