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.
There were some missing headers like <stddef.h> for `NULL`, <wayland-util.h>
for `wl_link` and <stdbool.h> for `true`/`false`.
Also this commit fixes that `labwc.h` and `ime.h` included each other.
...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.
Before this patch following would cause a use-after-free:
- calling the Debug action when there was at least one view around
- closing that view
- calling the Debug action again
Also add a label for the layer popup tree.
- Store a pointer to the `struct view` in `struct ssd`
- Pass `struct ssd *` instead of `struct view *` to ssd functions
- Add `ssd_get_margin()` convenience function
IMHO it encourages better design (by making dependencies more obvious)
to have source file/header file pairs like view.c/view.h, rather than a
monolithic header like labwc.h with everything in it.
I don't think we need to break up all of labwc.h at once, but maybe we
can start pulling it apart bit by bit as it's convenient.
Also:
- Move "struct border" to ssd.h so that view.h can use it without pulling
in all of labwc.h.
- Add a missing required #include within scaled_font_buffer.h (forward
declaration of "struct font" is not enough).
Support returning the following structs:
- view from LAB_NODE_DESC_VIEW or LAB_NODE_DESC_XDG_POPUP
- lab_layer_surface form LAB_NODE_DESC_LAYER_SURFACE
- lab_layer_popup from LAB_NODE_DESC_LAYER_POPUP
