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, 21 insertions, 33 deletions

diff --git a/examples/hello.c b/examples/hello.c
index 31ab18b..9e324a6 100644
--- a/examples/hello.c
+++ b/examples/hello.c
@@ -1,38 +1,26 @@
-/* A complete CPU-rendered window. Build instructions: docs/getting-started.md. */
-#include <yasl/app.h>
-#include <stdio.h>
+/* A CPU-rendered window. Build instructions: docs/getting-started.md. */
+#include <yasl/yasl.h>
+#include <yasl/cpu.h>
 
-static bool failed;
-static void draw(void *ud, struct yasl_surface *surface, struct yasl_frame *frame)
+int main(void)
 {
-    (void)ud;
-    int w = frame->target.size.x, h = frame->target.size.y;
-    for (int y = 0; y < h; y++) {
-        uint32_t *row = frame->target.pixels + (size_t)y * (frame->target.stride_bytes / 4);
-        for (int x = 0; x < w; x++) {
-            /* Red grows rightward, green downward, blue fades; opaque premultiplied ARGB. */
-            uint32_t r = (uint32_t)(x * 255 / (w > 1 ? w - 1 : 1));
-            uint32_t g = (uint32_t)(y * 255 / (h > 1 ? h - 1 : 1));
-            row[x] = 0xff000000 | r << 16 | g << 8 | (255 - r);
+    yasl_surface *surface = yasl_surface_create("Hello YASL", 640, 480, YASL_SURFACE_CPU);
+    yasl_event event;
+    while (surface && yasl_wait_event(&event, -1) >= 0 &&
+           event.type != YASL_EVENT_CLOSE && event.type != YASL_EVENT_QUIT) {
+        if (event.type != YASL_EVENT_REFRESH) continue;
+        int w, h;
+        uint32_t *pixels = yasl_cpu_pixels(surface, &w, &h);
+        for (int y = 0; pixels && y < h; y++) {
+            for (int x = 0; x < w; x++) {
+                /* Red grows rightward, green downward, blue fades; opaque premultiplied ARGB. */
+                uint32_t r = (uint32_t)(x * 255 / (w > 1 ? w - 1 : 1));
+                uint32_t g = (uint32_t)(y * 255 / (h > 1 ? h - 1 : 1));
+                pixels[(size_t)y * w + x] = 0xff000000 | r << 16 | g << 8 | (255 - r);
+            }
         }
+        yasl_cpu_present(surface);
     }
-
-    if (!yasl_frame_present(frame, NULL, 0)) {
-        fprintf(stderr, "Could not present the draw target\n");
-        failed = true;
-    }
-    if (failed) yasl_app_exit(yasl_surface_display(surface), YASL_APP_ERROR);
-}
-
-int main(void)
-{
-    struct yasl_window_spec window = {.title = "Hello YASL", .size_logical = {640, 480}};
-    struct yasl_app_desc desc = {
-        .app_id = "org.example.hello",
-        .window = &window,
-        .frame = draw,
-    };
-    int result = yasl_run(&desc);
-    if (result) fprintf(stderr, "Could not run the application\n");
-    return result || failed ? 1 : 0;
+    yasl_shutdown();
+    return surface ? 0 : 1;
 }