PerScreenDpi | QLabels incorrectly handle scale for icons (#4070)

* Fixes to icon generation. Generating a pixmap out of a size won't take the screen scaling factor into account, resulting in blurry results.
Note that this is not a catchall solution, every case needs to be addressed manually.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* HighDpi fixes for startup splashscreen and About dialog

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Add helper function to generate appropriate pixmaps for a screen based on its dpi settings.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

Code/Framework/AzQtComponents/AzQtComponents/Utilities/PixmapScaleUtilities.cpp

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#include <AzCore/Casting/numeric_cast.h>
+#include <AzQtComponents/Utilities/PixmapScaleUtilities.h>
+
+#include <QtGui/private/qhighdpiscaling_p.h>
+
+namespace AzQtComponents
+{
+    QPixmap ScalePixmapForScreenDpi(
+        QPixmap pixmap, QScreen* screen, QSize size, Qt::AspectRatioMode aspectRatioMode, Qt::TransformationMode transformationMode)
+    {
+        qreal screenDpiFactor = QHighDpiScaling::factor(screen);
+        pixmap.setDevicePixelRatio(screenDpiFactor);
+
+        QPixmap scaledPixmap;
+
+        size.setWidth(aznumeric_cast<int>(aznumeric_cast<qreal>(size.width()) * screenDpiFactor));
+        size.setHeight(aznumeric_cast<int>(aznumeric_cast<qreal>(size.height()) * screenDpiFactor));
+
+        scaledPixmap = pixmap.scaled(size, aspectRatioMode, transformationMode);
+
+        return scaledPixmap;
+    }
+}

Code/Framework/AzQtComponents/AzQtComponents/Utilities/PixmapScaleUtilities.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzQtComponents/AzQtComponentsAPI.h>
+
+#include <QPixmap>
+#include <QScreen>
+
+namespace AzQtComponents
+{
+    AZ_QT_COMPONENTS_API QPixmap ScalePixmapForScreenDpi(QPixmap pixmap, QScreen* screen, QSize size, Qt::AspectRatioMode aspectRatioMode, Qt::TransformationMode transformationMode);
+}; // namespace AzQtComponents

Code/Framework/AzQtComponents/AzQtComponents/azqtcomponents_files.cmake

@@ -276,6 +276,8 @@ set(FILES
     Utilities/HandleDpiAwareness.cpp
     Utilities/HandleDpiAwareness.h
     Utilities/MouseHider.h
+    Utilities/PixmapScaleUtilities.cpp
+    Utilities/PixmapScaleUtilities.h
     Utilities/QtPluginPaths.cpp
     Utilities/QtPluginPaths.h
     Utilities/QtWindowUtilities.cpp