Always request fullscreen and maximized state

The window state may be changed by the window manager without scrcpy
being aware of it (for example the fullscreen mode on macOS).

To avoid problems, request the window state to SDL when needed.

app/src/screen.c

@@ -15,6 +15,18 @@
 
 #define DISPLAY_MARGINS 96
 
+static bool
+is_maximized(const struct screen *screen) {
+    uint32_t flags = SDL_GetWindowFlags(screen->window);
+    return !!(flags & SDL_WINDOW_MAXIMIZED);
+}
+
+static bool
+is_fullscreen(const struct screen *screen) {
+    uint32_t flags = SDL_GetWindowFlags(screen->window);
+    return !!(flags & (SDL_WINDOW_FULLSCREEN | SDL_WINDOW_FULLSCREEN_DESKTOP));
+}
+
 static inline struct size
 get_rotated_size(struct size size, int rotation) {
     struct size rotated_size;
@@ -44,7 +56,7 @@ get_window_size(SDL_Window *window) {
 // get the windowed window size
 static struct size
 get_windowed_window_size(const struct screen *screen) {
-    if (screen->fullscreen || screen->maximized) {
+    if (is_fullscreen(screen) || is_maximized(screen)) {
         return screen->windowed_window_size;
     }
     return get_window_size(screen->window);
@@ -53,7 +65,7 @@ get_windowed_window_size(const struct screen *screen) {
 // apply the windowed window size if fullscreen and maximized are disabled
 static void
 apply_windowed_size(struct screen *screen) {
-    if (!screen->fullscreen && !screen->maximized) {
+    if (!is_fullscreen(screen) && !is_maximized(screen)) {
         SDL_SetWindowSize(screen->window, screen->windowed_window_size.width,
                                           screen->windowed_window_size.height);
     }
@@ -471,28 +483,27 @@ screen_render(struct screen *screen) {
 
 void
 screen_switch_fullscreen(struct screen *screen) {
-    uint32_t new_mode = screen->fullscreen ? 0 : SDL_WINDOW_FULLSCREEN_DESKTOP;
+    bool was_fullscreen = is_fullscreen(screen);
+    uint32_t new_mode = was_fullscreen ? 0 : SDL_WINDOW_FULLSCREEN_DESKTOP;
     if (SDL_SetWindowFullscreen(screen->window, new_mode)) {
         LOGW("Could not switch fullscreen mode: %s", SDL_GetError());
         return;
     }
 
-    screen->fullscreen = !screen->fullscreen;
     apply_windowed_size(screen);
 
-    LOGD("Switched to %s mode", screen->fullscreen ? "fullscreen" : "windowed");
+    LOGD("Switched to %s mode", was_fullscreen ? "windowed" : "fullscreen");
     screen_render(screen);
 }
 
 void
 screen_resize_to_fit(struct screen *screen) {
-    if (screen->fullscreen) {
+    if (is_fullscreen(screen)) {
         return;
     }
 
-    if (screen->maximized) {
+    if (is_maximized(screen)) {
         SDL_RestoreWindow(screen->window);
-        screen->maximized = false;
     }
 
     struct size optimal_size =
@@ -504,13 +515,12 @@ screen_resize_to_fit(struct screen *screen) {
 
 void
 screen_resize_to_pixel_perfect(struct screen *screen) {
-    if (screen->fullscreen) {
+    if (is_fullscreen(screen)) {
         return;
     }
 
-    if (screen->maximized) {
+    if (is_maximized(screen)) {
         SDL_RestoreWindow(screen->window);
-        screen->maximized = false;
     }
 
     struct size content_size = screen->content_size;
@@ -527,7 +537,7 @@ screen_handle_window_event(struct screen *screen,
             screen_render(screen);
             break;
         case SDL_WINDOWEVENT_SIZE_CHANGED:
-            if (!screen->fullscreen && !screen->maximized) {
+            if (!is_fullscreen(screen) && !is_maximized(screen)) {
                 // Backup the previous size: if we receive the MAXIMIZED event,
                 // then the new size must be ignored (it's the maximized size).
                 // We could not rely on the window flags due to race conditions
@@ -552,10 +562,8 @@ screen_handle_window_event(struct screen *screen,
             screen->windowed_window_size_backup.width = 0;
             screen->windowed_window_size_backup.height = 0;
 #endif
-            screen->maximized = true;
             break;
         case SDL_WINDOWEVENT_RESTORED:
-            screen->maximized = false;
             apply_windowed_size(screen);
             break;
     }

app/src/screen.h

@@ -29,8 +29,6 @@ struct screen {
     // client rotation: 0, 1, 2 or 3 (x90 degrees counterclockwise)
     unsigned rotation;
     bool has_frame;
-    bool fullscreen;
-    bool maximized;
     bool no_window;
     bool mipmaps;
 };
@@ -59,8 +57,6 @@ struct screen {
     }, \
     .rotation = 0, \
     .has_frame = false, \
-    .fullscreen = false, \
-    .maximized = false, \
     .no_window = false, \
     .mipmaps = false, \
 }