F12 — Cursors

System-themed cursors, custom cursors, and who composites them. Wayland made the client responsible for its cursor (with a newer protocol to hand the job back); everywhere else it's one call.

Requirements

1. Hover zones that switch the cursor among: default arrow, text I-beam, hand/link, and all eight resize-edge cursors; log every cursor_set name=….
   • Wayland: implement both mechanisms and select at runtime: cursor-shape-v1 (wp_cursor_shape_device_v1.set_shape) when the compositor offers it, else classic wl_pointer.set_cursor with a wl_surface rendered from the cursor theme via libwayland-cursor (theme lookup, size × scale, animated frames). Log which path ran.
   • X11: XCreateFontCursor/libXcursor themed lookup (XcursorLibraryLoadCursor).
   • Win32: LoadCursor/SetCursor on WM_SETCURSOR (log the WM_SETCURSOR storm).
   • macOS: NSCursor standard cursors + cursorUpdate:/tracking areas.
2. One custom pixmap cursor (e.g. 24×24 bullseye) with a non-trivial hotspot, from raw ARGB: wl_shm surface / XcursorImageLoadCursor / CreateIcon+SetCursor / NSCursor initWithImage:hotSpot:.
3. Set the cursor correctly under HiDPI (scale-aware size selection) — log chosen size.
4. Cursor visibility during F10's lock mode must not leak (no flicker on re-entry).

Instrumentation

cursor_set name=… path=shape|theme|font|… size=…, wm_setcursor events (Win32), cursor_update (macOS).

Findings to record

• Who composites the cursor (server vs client) and what that costs the client on Wayland (theme loading, animation timers).
• The standard-shape vocabulary per platform and the gaps between them.
• HiDPI cursor-size selection rules.
• Whether cursor-shape-v1 was offered by each tested compositor (headless weston, then mutter/kwin/sway via the manual queue).

Verification

Wayland/X11: Tier A (cursor requests are observable in the protocol trace; actual pixels need eyes — note the split). Win32 A[wine], macOS A[ssh]; a quick visual confirmation pass rides along with other Tier C items.