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, 43 insertions, 7 deletions

diff --git a/src/common/native.c b/src/common/native.c
index 42b065c..88604c9 100644
--- a/src/common/native.c
+++ b/src/common/native.c
@@ -2,7 +2,7 @@
 
 #include <errno.h>
 
-void *yasl_display_get_native_handle(struct yasl_display *d)
+void *yasl_private_display_get_native_handle(struct yasl_private_display *d)
 {
     if (!d) return NULL;
     if (d->native_handle) return d->native_handle;
@@ -10,7 +10,7 @@ void *yasl_display_get_native_handle(struct yasl_display *d)
         d->ops->display_get_native_handle(d) : NULL;
 }
 
-void *yasl_surface_get_native_handle(struct yasl_surface *s)
+void *yasl_private_surface_get_native_handle(struct yasl_surface *s)
 {
     if (!s) return NULL;
     if (s->native_handle) return s->native_handle;
@@ -18,18 +18,18 @@ void *yasl_surface_get_native_handle(struct yasl_surface *s)
         s->display->ops->surface_get_native_handle(s) : NULL;
 }
 
-struct yasl_surface *yasl_surface_create_native(struct yasl_display *d,
-        const struct yasl_window_spec *spec, void *graphics_device)
+struct yasl_surface *yasl_private_surface_create_native(struct yasl_private_display *d,
+        const struct yasl_private_window_spec *spec, void *graphics_device)
 {
     if (!graphics_device) {
         errno = EINVAL;
         return NULL;
     }
-    return yasl_create_toplevel(d, spec, graphics_device);
+    return yasl_private_create_toplevel(d, spec, graphics_device);
 }
 
-bool yasl_surface_get_native_frame(struct yasl_surface *s,
-        const struct yasl_framebuffer *target, struct yasl_native_frame *out)
+bool yasl_private_surface_get_native_frame(struct yasl_surface *s,
+        const struct yasl_private_framebuffer *target, struct yasl_private_native_frame *out)
 {
     if (!s || !target || !out || !target->generation ||
         target->generation != s->frame_generation ||
@@ -37,3 +37,39 @@ bool yasl_surface_get_native_frame(struct yasl_surface *s,
         return false;
     return s->display->ops->surface_get_native_frame(s, target, out);
 }
+
+#include "public_internal.h"
+#include "yasl/metal.h"
+#if YASL_HAS_WAYLAND
+#include "yasl/native/wayland.h"
+struct wl_display *yasl_wayland_display(const yasl_surface *s)
+{ return s && s->display->ops->type==YASL_PRIVATE_BACKEND_WAYLAND ? yasl_private_display_get_native_handle(s->display):NULL; }
+struct wl_surface *yasl_wayland_surface(const yasl_surface *s)
+{ return s && s->display->ops->type==YASL_PRIVATE_BACKEND_WAYLAND ? yasl_private_surface_get_native_handle((yasl_surface*)s):NULL; }
+#endif
+#if YASL_HAS_X11
+#include "yasl/native/x11.h"
+Display *yasl_x11_display(const yasl_surface *s)
+{ return s && s->display->ops->type==YASL_PRIVATE_BACKEND_X11 ? yasl_private_display_get_native_handle(s->display):NULL; }
+uintptr_t yasl_x11_window(const yasl_surface *s)
+{ return s && s->display->ops->type==YASL_PRIVATE_BACKEND_X11 ? (uintptr_t)yasl_private_surface_get_native_handle((yasl_surface*)s):0; }
+#endif
+#if YASL_HAS_COCOA
+#include "yasl/native/cocoa.h"
+#include "common/private_native_cocoa.h"
+NSApplication *yasl_cocoa_application(void)
+{ struct yasl_private_display *d=yasl_public_display();return d ? yasl_private_cocoa_display_get_application(d):NULL; }
+NSWindow *yasl_cocoa_window(const yasl_surface *s)
+{ return yasl_private_cocoa_surface_get_window((yasl_surface*)s); }
+NSView *yasl_cocoa_view(const yasl_surface *s)
+{ return yasl_private_cocoa_surface_get_view((yasl_surface*)s); }
+#endif
+CAMetalLayer *yasl_metal_layer(yasl_surface *s)
+{
+    if(!yasl_public_surface(s,false))return NULL;
+    if(s->presenter!=YASL_PRIVATE_PRESENTER_NONE && s->presenter!=YASL_PRIVATE_PRESENTER_METAL) {yasl_public_fail(EBUSY);return NULL;}
+    if(!s->display->ops->surface_get_metal_layer){yasl_public_fail(ENOTSUP);return NULL;}
+    CAMetalLayer *layer=s->display->ops->surface_get_metal_layer(s);
+    if(!layer){yasl_public_fail(ENOTSUP);return NULL;}
+    s->presenter=YASL_PRIVATE_PRESENTER_METAL;return layer;
+}