Simplify the public event and CPU API

Applications now need far less ceremony: hello.c is a 20-line loop that
handles REFRESH, CLOSE and QUIT and draws into the surface's own pixels.

- Fold GEOMETRY, STATE and FOCUS into one WINDOW event carrying size,
  scale and state; unchanged values send nothing.
- Guarantee REFRESH once a window has a size and after every resize,
  never at size zero.
- Merge DROP_HOVER into DROP with over/leave/data actions and give drag
  and drop actions enums.
- Keep event strings valid until the next wait and drop
  yasl_event_release; empty or failed waits report NONE.
- Replace copy-in presentation with a lent pixel buffer:
  yasl_cpu_pixels and yasl_cpu_present.
- Remove yasl_poll_event, yasl_cpu_read_pixels, unused event fields and
  comments that restated names.
- Wayland: resize floating windows in request_size instead of reporting
  it unsupported, and stop marking new GPU surfaces as Vulkan so
  yasl_vulkan_create_surface no longer fails with NATIVE_WINDOW_IN_USE.

Also includes the in-progress public API refactor that was uncommitted
in the tree (removal of the app/loop layer, new surface, GL and Vulkan
entry points).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/yasl/metal.h b/include/yasl/metal.h
new file mode 100644
index 0000000..695f80c
--- /dev/null
+++ b/include/yasl/metal.h
@@ -0,0 +1,20 @@
+/** @file Direct Metal layer; application configures its device/format and presents. */
+#ifndef YASL_METAL_H
+#define YASL_METAL_H
+#include "yasl/yasl.h"
+#ifdef __OBJC__
+@class CAMetalLayer;
+#else
+typedef struct objc_object CAMetalLayer;
+#endif
+#ifdef __cplusplus
+extern "C" {
+#endif
+/** Borrowed until surface destruction. YASL owns view/layer and drawableSize.
+ * No device, drawable acquisition, command submission, or implicit present.
+ * Returns NULL on unsupported backend, CPU/GL surface, or incompatible presenter. */
+YASL_API CAMetalLayer *yasl_metal_layer(yasl_surface *surface);
+#ifdef __cplusplus
+}
+#endif
+#endif