The Wayland protocol specifies output transform rotations to be
counterclockwise and applied to the surface. Previously, wlroots
copied Weston and incorrectly made rotations act clockwise on
surfaces. This commit fixes that.
This change will break compositors which expect transform rotations
to be clockwise, and the rare applications that make use of surface
transforms.
I do not think the conversion is specifically defined, but on my system and SirCmpwn's
the floats are rounded instead of floored, which is incorrect in this case, since
for a range from 0 to 256, any value greater or equal to 0 and less than 256 is valid.
I.e. [0;256[, or 0 <= x < 256, but if x is e.g. -0.1, then it will be rounded to 0, which
is invalid. The correct behavior would be to floor to -1.
It was broken because the damage extents were rotated about its
own center, not about the center of the surface.
This adds a new wlr_region_rotated_bounds that rotates regions.
This allows us to have only one code path (for both non-rotated
views and rotated views) and optimizes rendering for rotated
views.
