hostevents: Fix mouse grab for multiple displays.

Create a mouse grab toggle event to toggle the mouse grab using the current window. After the toggle event is transmitted, transmit a mouse grab changed event so that all windows can update their title.

Author: joevt

core/hostevents.h

@@ -39,6 +39,7 @@ enum : uint16_t {
     // Standard SDL window event types are uint8_t's.
     // We add our own custom events after that.
     DPPC_WINDOWEVENT_WINDOW_SCALE_QUALITY_TOGGLE = 1 << 8,
+    DPPC_WINDOWEVENT_MOUSE_GRAB_TOGGLE,
     DPPC_WINDOWEVENT_MOUSE_GRAB_CHANGED,
     DPPC_WINDOWEVENT_WINDOW_FULL_SCREEN_TOGGLE,
     DPPC_WINDOWEVENT_WINDOW_BIGGER,

core/hostevents_sdl.cpp

@@ -59,6 +59,9 @@ void EventManager::poll_events(uint32_t kbd_locale) {
                 if (event.key.keysym.sym == SDLK_g && (SDL_GetModState() & KMOD_ALL) == KMOD_LCTRL) {
                     if (event.type == SDL_KEYUP) {
                         WindowEvent we;
+                        we.sub_type  = DPPC_WINDOWEVENT_MOUSE_GRAB_TOGGLE;
+                        we.window_id = event.window.windowID;
+                        this->_window_signal.emit(we);
                         we.sub_type  = DPPC_WINDOWEVENT_MOUSE_GRAB_CHANGED;
                         we.window_id = event.window.windowID;
                         this->_window_signal.emit(we);

devices/video/display_sdl.cpp

@@ -289,8 +289,12 @@ void Display::handle_events(const WindowEvent& wnd_event) {
         }
         break;
 
+    case DPPC_WINDOWEVENT_MOUSE_GRAB_TOGGLE:
+        if (wnd_event.window_id == impl->disp_wnd_id)
+            this->toggle_mouse_grab();
+        break;
+
     case DPPC_WINDOWEVENT_MOUSE_GRAB_CHANGED:
-        this->toggle_mouse_grab();
         this->update_window_title();
         break;