spicec: Don't show a white screen if guest resolution does not fit fullscreen

Currently when going / starting fullscreen if the guest resolution for one of
the monitors is higher then that monitor on the client can handle, we show a
white screen. Leaving the user stuck (unless they know the fullscreen key
switch combi) with a white screen when starting the client fullscreen from
the XPI.

This patch changes the client to fall back to windowed mode in this case
instead.

client/application.cpp

@@ -348,6 +348,7 @@ Application::Application()
     , _active (false)
     , _full_screen (false)
     , _changing_screens (false)
+    , _out_of_sync (false)
     , _exit_code (0)
     , _active_screen (NULL)
     , _num_keys_pressed (0)
@@ -674,6 +675,12 @@ RedScreen* Application::get_screen(int id)
                 prepare_monitors();
                 position_screens();
                 screen->show_full_screen();
+                if (screen->is_out_of_sync()) {
+                    _out_of_sync = true;
+                    /* If the client monitor cannot handle the guest resolution
+                       drop back to windowed mode */
+                    exit_full_screen();
+                }
 
                 if (capture) {
                     _main_screen->activate();
@@ -1492,6 +1499,9 @@ void Application::show_full_screen()
     for (int i = 0; i < (int)_screens.size(); i++) {
         if (_screens[i]) {
             _screens[i]->show_full_screen();
+            if (_screens[i]->is_out_of_sync()) {
+                _out_of_sync = true;
+            }
         }
     }
 }
@@ -1512,6 +1522,11 @@ void Application::enter_full_screen()
     }
     _changing_screens = false;
     _full_screen = true;
+    /* If the client monitor cannot handle the guest resolution drop back
+       to windowed mode */
+    if (_out_of_sync) {
+        exit_full_screen();
+    }
 }
 
 void Application::restore_screens_size()
@@ -1529,6 +1544,9 @@ void Application::exit_full_screen()
     if (!_full_screen) {
         return;
     }
+    if (_out_of_sync) {
+        LOG_WARN("Falling back to windowed mode (guest resolution too large for client?)");
+    }
     LOG_INFO("");
     _changing_screens = true;
     release_capture();
@@ -1544,6 +1562,7 @@ void Application::exit_full_screen()
         }
     }
     _full_screen = false;
+    _out_of_sync = false;
     restore_screens_size();
     show();
     _main_screen->activate();
@@ -1560,6 +1579,17 @@ bool Application::toggle_full_screen()
     return _full_screen;
 }
 
+void Application::resize_screen(RedScreen *screen, int width, int height)
+{
+    screen->resize(width, height);
+    if (screen->is_out_of_sync()) {
+        _out_of_sync = true;
+        /* If the client monitor cannot handle the guest resolution
+           drop back to windowed mode */
+        exit_full_screen();
+    }
+}
+
 void Application::minimize()
 {
     for (int i = 0; i < (int)_screens.size(); i++) {

client/application.h

@@ -217,6 +217,7 @@ public:
     void enter_full_screen();
     void exit_full_screen();
     bool toggle_full_screen();
+    void resize_screen(RedScreen *screen, int width, int height);
     void minimize();
     void set_title(const std::string& title);
     void hide();
@@ -352,6 +353,7 @@ private:
     bool _active;
     bool _full_screen;
     bool _changing_screens;
+    bool _out_of_sync;
     int _exit_code;
     RedScreen* _active_screen;
     bool _keyboard_state[REDKEY_NUM_KEYS];

client/display_channel.cpp

@@ -57,7 +57,7 @@ public:
     {
         Application* app = (Application*)events_loop.get_owner();
         _channel.screen()->lock_size();
-        _channel.screen()->resize(_width, _height);
+        app->resize_screen(_channel.screen(), _width, _height);
         _channel.create_canvas(0, app->get_canvas_types(), _width, _height, _format);
     }
 

client/screen.h

@@ -78,6 +78,7 @@ public:
     void set_monitor(Monitor *monitor) { _monitor = monitor;}
     Monitor* get_monitor() { return _monitor;}
     RedWindow* get_window() { return &_window;}
+    bool is_out_of_sync() { return _out_of_sync;}
     void set_cursor(LocalCursor* cursor);
     void hide_cursor();
     void exit_full_screen();
@@ -118,7 +119,6 @@ private:
     void notify_new_size();
     void adjust_window_rect(int x, int y);
     void save_position();
-    bool is_out_of_sync() { return _out_of_sync;}
     void __show_full_screen();
 
     bool _invalidate(const SpiceRect& rect, bool urgent, uint64_t& update_mark);