display: Update grabbed mouse when resizing.

If the window's size is reduced such that the grabbed mouse is no longer inside the window, then a mouse click will go to another app. Therefore, check the mouse position and update if necessary every time the window changes size.

Author: joevt

core/hostevents_sdl.cpp

@@ -29,7 +29,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 EventManager* EventManager::event_manager;
 
 static int get_sdl_event_key_code(const SDL_KeyboardEvent& event, uint32_t kbd_locale);
-static void toggle_mouse_grab(const SDL_KeyboardEvent &event);
 
 constexpr int KMOD_ALL = KMOD_LSHIFT | KMOD_RSHIFT | KMOD_LCTRL | KMOD_RCTRL | KMOD_LALT | KMOD_RALT | KMOD_LGUI | KMOD_RGUI;
 
@@ -59,7 +58,6 @@ void EventManager::poll_events(uint32_t kbd_locale) {
                 // Control-G: mouse grab
                 if (event.key.keysym.sym == SDLK_g && (SDL_GetModState() & KMOD_ALL) == KMOD_LCTRL) {
                     if (event.type == SDL_KEYUP) {
-                        toggle_mouse_grab(event.key);
                         WindowEvent we;
                         we.sub_type  = DPPC_WINDOWEVENT_MOUSE_GRAB_CHANGED;
                         we.window_id = event.window.windowID;
@@ -427,23 +425,3 @@ static int get_sdl_event_key_code(const SDL_KeyboardEvent &event, uint32_t kbd_l
     }
     return -1;
 }
-
-static void toggle_mouse_grab(const SDL_KeyboardEvent &event) {
-    SDL_Window *window = SDL_GetWindowFromID(event.windowID);
-    if (SDL_GetRelativeMouseMode()) {
-        SDL_SetRelativeMouseMode(SDL_FALSE);
-    } else {
-        // If the mouse is initially outside the window, move it to the middle,
-        // so that clicks are handled by the window (instead making it lose
-        // focus, at least with macOS hosts).
-        int mouse_x, mouse_y, window_x, window_y, window_width, window_height;
-        SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
-        SDL_GetWindowPosition(window, &window_x, &window_y);
-        SDL_GetWindowSize(window, &window_width, &window_height);
-        if (mouse_x < window_x || mouse_x >= window_x + window_width ||
-                mouse_y < window_y || mouse_y >= window_y + window_height) {
-            SDL_WarpMouseInWindow(window, window_width / 2, window_height / 2);
-        }
-        SDL_SetRelativeMouseMode(SDL_TRUE);
-    }
-}

devices/video/display.h

@@ -77,6 +77,8 @@ class Display {
     void setup_hw_cursor(std::function<void(uint8_t *dst_buf, int dst_pitch)> draw_hw_cursor,
                          int cursor_width, int cursor_height);
     void update_window_title();
+    void toggle_mouse_grab();
+    void update_mouse_grab();
 private:
     class Impl; // Holds private fields
     std::unique_ptr<Impl> impl;

devices/video/display_sdl.cpp

@@ -117,6 +117,7 @@ void Display::update_window_size() {
     SDL_SetWindowSize(impl->display_wnd,
         impl->drawable_w / impl->default_scale_x,
         impl->drawable_h / impl->default_scale_y);
+    this->update_mouse_grab(); // make sure the mouse is still inside the window
 }
 
 void Display::configure_dest() {
@@ -289,12 +290,40 @@ void Display::handle_events(const WindowEvent& wnd_event) {
         break;
 
     case DPPC_WINDOWEVENT_MOUSE_GRAB_CHANGED:
+        this->toggle_mouse_grab();
         this->update_window_title();
         break;
 
     }
 }
 
+void Display::toggle_mouse_grab()
+{
+    if (SDL_GetRelativeMouseMode()) {
+        SDL_SetRelativeMouseMode(SDL_FALSE);
+    } else {
+        this->update_mouse_grab();
+        SDL_SetRelativeMouseMode(SDL_TRUE);
+    }
+}
+
+void Display::update_mouse_grab()
+{
+    if (SDL_GetRelativeMouseMode()) {
+        // If the mouse is initially outside the window, move it to the middle,
+        // so that clicks are handled by the window (instead making it lose
+        // focus, at least with macOS hosts).
+        int mouse_x, mouse_y, window_x, window_y, window_width, window_height;
+        SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
+        SDL_GetWindowPosition(impl->display_wnd, &window_x, &window_y);
+        SDL_GetWindowSize(impl->display_wnd, &window_width, &window_height);
+        if (mouse_x < window_x || mouse_x >= window_x + window_width ||
+                mouse_y < window_y || mouse_y >= window_y + window_height) {
+            SDL_WarpMouseInWindow(impl->display_wnd, window_width / 2, window_height / 2);
+        }
+    }
+}
+
 void Display::update_window_title()
 {
     std::string old_window_title = SDL_GetWindowTitle(impl->display_wnd);