Our codebase for ssd scenes has grown with a lot of technical debts:
- We needed to call `ssd_get_part()` everywhere to get the scene node of a
ssd part. We then needed to cast it to `wlr_scene_rect` and
`wlr_scene_buffer`. This bloated our codebase and even blocked
duplicated button types in `<titlebar><layout>`.
- `ssd_get_part_type()` was a dirty hack. It compared parent, grandparent
and grandgrandparent of a node with each subtree in the ssd to get the
part type of the node.
To resolve this issues, this commit changes how ssd scenes are managed:
- Access scene rects and scene buffers just as a member of `struct ssd`.
- `ssd_part` is now a attachment to a scene node that can be accessed via
node_descriptor->data, with a new node-descriptor type
`LAB_NODE_DESC_SSD_PART`. `LAB_NODE_DESC_SSD_BUTTON` is unified into it.
Now the scene graph under ssd->tree looks like below. The parentheses
indicate the type of ssd_part attached to the node:
ssd->tree (LAB_SSD_NONE)
+--titlebar (LAB_SSD_PART_TITLEBAR)
| +--inactive
| | +--background bar
| | +--left corner
| | +--right corner
| | +--title (LAB_SSD_PART_TITLE)
| | +--iconify button (LAB_SSD_BUTTON_ICONIFY)
| | | +--normal close icon image
| | | +--hovered close icon image
| | | +--...
| | +--window icon (LAB_SSD_BUTTON_WINDOW_ICON)
| | | +--window icon image
| | +--...
| +--active
| +--...
+--border
| +--inactive
| | +--top
| | +--...
| +--active
| +--top
| +--...
+--shadow
| +--inactive
| | +--top
| | +--...
| +--active
| +--top
| +--...
+--extents
+--top
+--...
When hovering on SSD, `get_cursor_context()` traverses this scene node
from the leaf. If it finds a `ssd_part` attached to the node, it returns
`ssd_part_type` that represents the resizing direction, button types or
`Title`/`Titlebar`.
This is a common practice in C projects, which simply enforces that
each header must compile cleanly without implicit dependencies on
other headers (see also the previous commit).
This matches the behavior of the surrounding borders and will usually
cause resizing instead of triggering the button itself. This effect
is only really visible when using a border width settings of > 1.
Fixes#379
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
