Fix dialogs didn't position on the correct screen which qBittorrent window is on. Closes #1690, #2474, #3538.

src/base/utils/misc.cpp

@@ -219,21 +219,15 @@ void Utils::Misc::shutdownComputer(const ShutdownDialogAction &action)
 }
 
 #ifndef DISABLE_GUI
-// Get screen center
-QPoint Utils::Misc::screenCenter(QWidget *win)
+QPoint Utils::Misc::screenCenter(const QWidget *w)
 {
-    int scrn = 0;
-    const QWidget *w = win->window();
+    // Returns the QPoint which the widget will be placed center on screen (where parent resides)
 
-    if (w)
-        scrn = QApplication::desktop()->screenNumber(w);
-    else if (QApplication::desktop()->isVirtualDesktop())
-        scrn = QApplication::desktop()->screenNumber(QCursor::pos());
-    else
-        scrn = QApplication::desktop()->screenNumber(win);
-
-    QRect desk(QApplication::desktop()->availableGeometry(scrn));
-    return QPoint((desk.width() - win->frameGeometry().width()) / 2, (desk.height() - win->frameGeometry().height()) / 2);
+    QWidget *parent = w->parentWidget();
+    QDesktopWidget *desktop = QApplication::desktop();
+    int scrn = desktop->screenNumber(parent);  // fallback to `primaryScreen` when parent is invalid
+    QRect r = desktop->availableGeometry(scrn);
+    return QPoint(r.x() + (r.width() - w->frameSize().width()) / 2, r.y() + (r.height() - w->frameSize().height()) / 2);
 }
 
 #endif

src/base/utils/misc.h

@@ -102,7 +102,7 @@ namespace Utils
         void openPath(const QString& absolutePath);
         void openFolderSelect(const QString& absolutePath);
 
-        QPoint screenCenter(QWidget *win);
+        QPoint screenCenter(const QWidget *w);
         QSize smallIconSize();
         QSize largeIconSize();
 #endif