fix(video): fix scaling issues under HiDPI displays with desktop video

This commit fixes missing scaling factors with desktop video to allow
desktop video under HiDPI scaling to work as intended. Also removes a
few obsolete lines of scaling that that was required for older Qt
versions.

src/video/cameradevice.cpp

@@ -438,7 +438,13 @@ QVector<VideoMode> CameraDevice::getScreenModes()
         QRect rect = s->geometry();
         QPoint p = rect.topLeft();
 
-        VideoMode mode(rect.width(), rect.height(), p.x(), p.y());
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
+        qreal pixRatio = s->devicePixelRatio();
+#else
+        qreal pixRatio = 1.0;
+#endif
+
+        VideoMode mode(rect.width() * pixRatio, rect.height() * pixRatio, p.x() * pixRatio, p.y() * pixRatio);
         result.push_back(mode);
     });
 

src/widget/tool/screenshotgrabber.cpp

@@ -53,9 +53,6 @@ ScreenshotGrabber::ScreenshotGrabber()
     pixRatio = QApplication::primaryScreen()->devicePixelRatio();
 #endif
 
-    // Scale window down by devicePixelRatio to show full screen region
-    window->scale(1 / pixRatio, 1 / pixRatio);
-
     setupScene();
 }
 
@@ -131,6 +128,9 @@ void ScreenshotGrabber::acceptRegion()
     if (rect.width() < 1 || rect.height() < 1)
         return;
 
+    // Scale the accepted region from DIPs to actual pixels
+    rect.setRect(rect.x() * pixRatio, rect.y() * pixRatio, rect.width() * pixRatio, rect.height() * pixRatio);
+
     emit regionChosen(rect);
     qDebug() << "Screenshot accepted, chosen region" << rect;
     QPixmap pixmap = this->screenGrab.copy(rect);
@@ -152,10 +152,6 @@ void ScreenshotGrabber::setupScene()
     this->screenGrabDisplay = scene->addPixmap(this->screenGrab);
     this->helperTooltip = scene->addText(QString());
 
-    // Scale UI elements up by devicePixelRatio to compensate for window downscaling
-    this->helperToolbox->setScale(pixRatio);
-    this->helperTooltip->setScale(pixRatio);
-
     scene->addItem(this->overlay);
     this->chooserRect = new ScreenGrabberChooserRectItem(scene);
     scene->addItem(this->helperToolbox);
@@ -203,9 +199,8 @@ void ScreenshotGrabber::adjustTooltipPosition()
     int x = qAbs(recGL.x()) + rec.x() + ((rec.width() - ttRect.width()) / 2);
     int y = qAbs(recGL.y()) + rec.y();
 
-    // Multiply by devicePixelRatio to get centered positions under scaling
-    helperToolbox->setX(x * pixRatio);
-    helperToolbox->setY(y * pixRatio);
+    helperToolbox->setX(x);
+    helperToolbox->setY(y);
 }
 
 void ScreenshotGrabber::reject()