Simplify the public API into one dense header

yasl.h now holds everything except Vulkan: 45 functions instead of 62,
and three installed headers instead of ten.

- One constructor: yasl_surface_create takes CPU, GL or NATIVE, with
  zero-initialized GL options meaning 3.2 core, RGBA8, D24S8.
- Events carry action, mods, x, y and text at the top level; pen
  positions are now logical like pointer positions.
- yasl_cpu_pixels/yasl_cpu_present draw into one persistent canvas,
  cutting three full-frame copies per frame.
- yasl_surface_get_info, yasl_surface_request, YASL_CURSOR_LOCKED,
  yasl_surface_set_text_input, yasl_surface_begin_move_resize and
  yasl_surface_get_native replace groups of narrower calls.
- Interactive calls drop the decorative trigger event argument.
- yasl_wait_event returns 0 only on timeout or yasl_wake, the refresh
  callback runs only in native modal loops, focus loss sends
  INPUT_RESET, and a lost event no longer fails every later wait.
- Unsupported operations and bad arguments report ENOTSUP and EINVAL
  instead of EIO; the keycodes header no longer needs C23.
- The shared library gets a versioned SONAME and version macros.

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

1 files changed, 11 insertions, 10 deletions

diff --git a/src/common/backend.h b/src/common/backend.h
index 246a9bc..e26f9d2 100644
--- a/src/common/backend.h
+++ b/src/common/backend.h
@@ -8,6 +8,7 @@
 #include "common/gl_options.h"
 #include "common/timing.h"
 
+#include <stdatomic.h>
 #include <string.h>
 
 struct yasl_private_backend_ops;
@@ -16,7 +17,12 @@ struct yasl_private_event_state;
 struct yasl_private_display {
     const struct yasl_private_backend_ops *ops;
     void *native_handle;
-    bool offline; /* Connection lost; native handles are unusable until it is restored. */
+    /* Connection lost; native handles are unusable until it is restored. Read by GL
+     * rendering threads, so it is atomic. */
+    atomic_bool offline;
+    /* Set by the backend while a native modal loop (macOS live resize) blocks the
+     * event loop; refresh callbacks run only then. */
+    bool modal;
     struct yasl_private_loop *loop;
     /* Backend's copy of yasl_private_display_spec.app_id, or NULL; for desktop services. */
     const char *app_id;
@@ -29,19 +35,14 @@ struct yasl_surface {
     unsigned creation_flags;
     enum yasl_private_presenter presenter;
     struct yasl_surface *parent;
-    uint32_t *cpu_pixels;
-    int cpu_width, cpu_height;
-    uint64_t cpu_token;
-    bool cpu_acquired;
-    uint32_t *committed_pixels;
-    int committed_width, committed_height;
+    /* CPU canvas returned by yasl_cpu_pixels and copied into each drawn frame. */
+    uint32_t *canvas;
+    int canvas_width, canvas_height;
     /* Window values last reported through public WINDOW events. */
     struct yasl_private_vector2i reported_size;
     uint32_t reported_scale_120, reported_state;
     bool refresh_owed;
-    bool refresh_active;
-    void (*refresh_callback)(struct yasl_surface *, void *);
-    void *refresh_userdata;
+    void (*refresh)(struct yasl_surface *);
     bool text_input_active;
     unsigned text_purpose;
     char *text_surrounding;