Let yasl_app_desc describe its initial window

A new optional yasl_app_desc.window spec makes yasl_run() create that
toplevel and request its first frame before init(), which is now
optional too. If creation fails, yasl_run() closes the display and
returns an error without calling init().

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

1 files changed, 15 insertions, 2 deletions

diff --git a/src/common/app.c b/src/common/app.c
index 9ec1f6a..9d52e4a 100644
--- a/src/common/app.c
+++ b/src/common/app.c
@@ -332,7 +332,7 @@ static void app_runner_lost(void *ud)
 
 int yasl_run(const struct yasl_app_desc *desc)
 {
-    if (!desc || !desc->init)
+    if (!desc)
         return -1;
 
     struct app_runner runner = {.desc = desc, .running = true};
@@ -358,7 +358,20 @@ int yasl_run(const struct yasl_app_desc *desc)
     }
     d->app_runner = &runner;
 
-    if (desc->init(desc->userdata, d) == YASL_APP_QUIT) {
+    if (desc->window) {
+        struct yasl_surface *s = yasl_surface_create_toplevel(d, desc->window);
+        if (!s) {
+            int create_error = errno;
+            d->app_runner = NULL;
+            yasl_mutex_destroy(&runner.user_event_mutex);
+            yasl_display_close(d);
+            errno = create_error;
+            return -1;
+        }
+        yasl_surface_request_frame(s);
+    }
+
+    if (desc->init && desc->init(desc->userdata, d) == YASL_APP_QUIT) {
         runner.running = false;
     }