qt: Implement per-monitor resizing

src/qt/qt_main.cpp

@@ -122,14 +122,6 @@ main_thread_fn()
             /* Just so we dont overload the host OS. */
             std::this_thread::sleep_for(std::chrono::milliseconds(1));
         }
-
-        /* If needed, handle a screen resize. */
-        if (!atomic_flag_test_and_set(&doresize) && !video_fullscreen && !is_quit) {
-            if (vid_resize & 2)
-                plat_resize_monitor(fixed_size_x, fixed_size_y, 0);
-            else
-                plat_resize_monitor(scrnsz_x, scrnsz_y, 0);
-        }
     }
 
     is_quit = 1;
@@ -292,6 +284,22 @@ int main(int argc, char* argv[]) {
         main_thread = new std::thread(main_thread_fn);
     });
 
+    QTimer resizeTimer;
+    resizeTimer.setInterval(0);
+    resizeTimer.callOnTimeout([]()
+    {
+        /* If needed, handle a screen resize. */
+        for (int i = 0; i < MONITORS_NUM; i++) {
+            if (!atomic_flag_test_and_set(&doresize_monitors[i]) && !video_fullscreen && !is_quit) {
+                if (vid_resize & 2)
+                    plat_resize_monitor(fixed_size_x, fixed_size_y, i);
+                else
+                    plat_resize_monitor(monitors[i].mon_scrnsz_x, monitors[i].mon_scrnsz_y, i);
+            }
+        }
+    });
+    resizeTimer.start();
+
     auto ret = app.exec();
     cpu_thread_run = 0;
     main_thread->join();

src/qt/qt_mainwindow.cpp

@@ -224,7 +224,7 @@ MainWindow::MainWindow(QWidget *parent) :
     });
 
     connect(this, &MainWindow::resizeContents, this, [this](int w, int h) {
-        if (!QApplication::platformName().contains("eglfs") && vid_resize == 0) {
+        if (!QApplication::platformName().contains("eglfs") && vid_resize != 1) {
             w = (w / (!dpi_scale ? util::screenOfWidget(this)->devicePixelRatio() : 1.));
 
             int modifiedHeight = (h / (!dpi_scale ? util::screenOfWidget(this)->devicePixelRatio() : 1.))
@@ -237,6 +237,17 @@ MainWindow::MainWindow(QWidget *parent) :
         }
     });
 
+    connect(this, &MainWindow::resizeContentsMonitor, this, [this](int w, int h, int monitor_index)
+    {
+        if (!QApplication::platformName().contains("eglfs") && vid_resize != 1) {
+            w = (w / (!dpi_scale ? util::screenOfWidget(renderers[monitor_index].get())->devicePixelRatio() : 1.));
+
+            int modifiedHeight = (h / (!dpi_scale ? util::screenOfWidget(renderers[monitor_index].get())->devicePixelRatio() : 1.));
+
+            renderers[monitor_index]->setFixedSize(w, modifiedHeight);
+        }
+    });
+
     connect(ui->menubar, &QMenuBar::triggered, this, [this] {
         config_save();
         if (QApplication::activeWindow() == this)
@@ -1605,7 +1616,8 @@ static void update_scaled_checkboxes(Ui::MainWindow* ui, QAction* selected) {
     reset_screen_size();
     device_force_redraw();
     video_force_resize_set(1);
-    atomic_flag_clear(&doresize);
+    for (int i = 0; i < MONITORS_NUM; i++)
+        atomic_flag_clear(&doresize_monitors[i]);
     config_save();
 }
 

src/qt/qt_mainwindow.hpp

@@ -33,6 +33,7 @@ public:
 signals:
     void paint(const QImage& image);
     void resizeContents(int w, int h);
+    void resizeContentsMonitor(int w, int h, int monitor_index);
     void pollMouse();
     void statusBarMessage(const QString& msg);
     void updateStatusBarPanes();

src/qt/qt_ui.cpp

@@ -65,7 +65,8 @@ void mouse_poll() {
 }
 
 void plat_resize_monitor(int w, int h, int monitor_index) {
-    main_window->resizeContents(w, h);
+    if (monitor_index >= 1) main_window->resizeContentsMonitor(w, h, monitor_index);
+    else main_window->resizeContents(w, h);
 }
 
 void plat_setfullscreen(int on) {