Filled/outlined rectangles shown as snapping overlay are now enabled/disabled
independently with `snapping.overlay.[region|edge].bg.enabled` and
`snapping.overlay.[region|edge].border.enabled`.
To keep the default behavior, `*.bg.enabled` is yes and `*.border.enabled` is
no for hardware-based renderers, while `*.bg.enabled` is no and
`*.border.enabled` is yes for software-based (pixman) renderer.
Users can now use a filled rectangle as an overlay even with pixman renderer.
However, this may severely impact performance when used with translucent
`snapping.overlay.[region|edge].bg.color`.
This commit includes a refactor to use substruct `theme_snapping_overlay`
inside `theme` in order to pass it to `create_overlay_rect()` in a cleaner way.
Breaking changes is:
- `snapping.overlay.[region|edge].fill` is now removed.
Replace "preview" in rc.xml and themerc with "overlay" since "preview" sounds
like it shows the window content.
Breaking changes are:
- `snapping.preview.*` in themerc is now replaced with `snapping.overlay`.
- `<snapping><preview>` in rc.xml is now replaced with `<snapping><overlay>`.
wlr_scene_rects expect their color to be pre-multiplied
while cairo_set_source_rgba() expects them to not be
pre-multiplied. With this patch we now use premultiplied
colors internally by default and then reverse it when
setting cairo colors.
This ensures the titlebar uses a consistent color in case
it was defined with some transparency by the user.
Fixes: #1684
...and unify region overlay and snap-to-edge overlay into overlay.c.
Snap-to-edge overlay is delayed for 500ms to prevent flickering when
the view is dragged from an output to another (demo in discussion labwc#1613).
This also fixes a bug that region overlay is not shown when a modifier
key is re-pressed.
