Position and size the window on first frame

The optimal initial size was computed from the expected dimensions, sent
immediately by the server before encoding any video frame.

However, the actual frame size may be different, for example when the
device encoder does not support the requested size.

To always handle this case properly, position and size the window only
once the first frame size is known.

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

app/src/screen.c

@@ -369,6 +369,12 @@ sc_screen_init(struct sc_screen *screen,
     screen->mouse_captured = false;
     screen->mouse_capture_key_pressed = 0;
 
+    screen->req.x = params->window_x;
+    screen->req.y = params->window_y;
+    screen->req.width = params->window_width;
+    screen->req.height = params->window_height;
+    screen->req.fullscreen = params->fullscreen;
+
     static const struct sc_video_buffer_callbacks cbs = {
         .on_new_frame = sc_video_buffer_on_new_frame,
     };
@@ -397,9 +403,6 @@ sc_screen_init(struct sc_screen *screen,
         get_rotated_size(screen->frame_size, screen->rotation);
     screen->content_size = content_size;
 
-    struct sc_size window_size =
-        get_initial_optimal_size(content_size,params->window_width,
-                                 params->window_height);
     uint32_t window_flags = SDL_WINDOW_HIDDEN
                           | SDL_WINDOW_RESIZABLE
                           | SDL_WINDOW_ALLOW_HIGHDPI;
@@ -410,13 +413,9 @@ sc_screen_init(struct sc_screen *screen,
         window_flags |= SDL_WINDOW_BORDERLESS;
     }
 
-    int x = params->window_x != SC_WINDOW_POSITION_UNDEFINED
-          ? params->window_x : (int) SDL_WINDOWPOS_UNDEFINED;
-    int y = params->window_y != SC_WINDOW_POSITION_UNDEFINED
-          ? params->window_y : (int) SDL_WINDOWPOS_UNDEFINED;
-    screen->window = SDL_CreateWindow(params->window_title, x, y,
-                                      window_size.width, window_size.height,
-                                      window_flags);
+    // The window will be positioned and sized on first video frame
+    screen->window =
+        SDL_CreateWindow(params->window_title, 0, 0, 0, 0, window_flags);
     if (!screen->window) {
         LOGC("Could not create window: %s", SDL_GetError());
         goto error_destroy_fps_counter;
@@ -498,17 +497,6 @@ sc_screen_init(struct sc_screen *screen,
 
     sc_input_manager_init(&screen->im, &im_params);
 
-    // Reset the window size to trigger a SIZE_CHANGED event, to workaround
-    // HiDPI issues with some SDL renderers when several displays having
-    // different HiDPI scaling are connected
-    SDL_SetWindowSize(screen->window, window_size.width, window_size.height);
-
-    sc_screen_update_content_rect(screen);
-
-    if (params->fullscreen) {
-        sc_screen_switch_fullscreen(screen);
-    }
-
 #ifdef CONTINUOUS_RESIZING_WORKAROUND
     SDL_AddEventWatch(event_watcher, screen);
 #endif
@@ -545,7 +533,23 @@ error_destroy_video_buffer:
 }
 
 static void
-sc_screen_show_window(struct sc_screen *screen) {
+sc_screen_show_initial_window(struct sc_screen *screen) {
+    int x = screen->req.x != SC_WINDOW_POSITION_UNDEFINED
+          ? screen->req.x : (int) SDL_WINDOWPOS_CENTERED;
+    int y = screen->req.y != SC_WINDOW_POSITION_UNDEFINED
+          ? screen->req.y : (int) SDL_WINDOWPOS_CENTERED;
+
+    struct sc_size window_size =
+        get_initial_optimal_size(screen->content_size, screen->req.width,
+                                                       screen->req.height);
+
+    set_window_size(screen, window_size);
+    SDL_SetWindowPosition(screen->window, x, y);
+
+    if (screen->req.fullscreen) {
+        sc_screen_switch_fullscreen(screen);
+    }
+
     SDL_ShowWindow(screen->window);
 }
 
@@ -696,7 +700,7 @@ sc_screen_update_frame(struct sc_screen *screen) {
     if (!screen->has_frame) {
         screen->has_frame = true;
         // this is the very first frame, show the window
-        sc_screen_show_window(screen);
+        sc_screen_show_initial_window(screen);
     }
 
     sc_screen_render(screen, false);

app/src/screen.h

@@ -28,6 +28,15 @@ struct sc_screen {
     struct sc_video_buffer vb;
     struct fps_counter fps_counter;
 
+    // The initial requested window properties
+    struct {
+        int16_t x;
+        int16_t y;
+        uint16_t width;
+        uint16_t height;
+        bool fullscreen;
+    } req;
+
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *texture;