Move "show window" call on first frame

Show the window only after the actual frame size is known (and if no
error has occurred).

This will allow to properly position and size the window when the size
of the first frame is different from the size initially announced by the
server.

PR #2947 <https://github.com/Genymobile/scrcpy/pull/2947>

app/src/screen.c

@@ -693,6 +693,12 @@ sc_screen_update_frame(struct sc_screen *screen) {
     }
     update_texture(screen, frame);
 
+    if (!screen->has_frame) {
+        screen->has_frame = true;
+        // this is the very first frame, show the window
+        sc_screen_show_window(screen);
+    }
+
     sc_screen_render(screen, false);
     return true;
 }
@@ -763,17 +769,13 @@ sc_screen_is_mouse_capture_key(SDL_Keycode key) {
 bool
 sc_screen_handle_event(struct sc_screen *screen, SDL_Event *event) {
     switch (event->type) {
-        case EVENT_NEW_FRAME:
-            if (!screen->has_frame) {
-                screen->has_frame = true;
-                // this is the very first frame, show the window
-                sc_screen_show_window(screen);
-            }
+        case EVENT_NEW_FRAME: {
             bool ok = sc_screen_update_frame(screen);
             if (!ok) {
                 LOGW("Frame update failed\n");
             }
             return true;
+        }
         case SDL_WINDOWEVENT:
             if (!screen->has_frame) {
                 // Do nothing