Qt: Improved HiDPI support

CHANGES

@@ -3,6 +3,8 @@ Bugfixes:
  - ARM7: Fix MLA/*MULL/*MLAL timing
  - GBA: Fix multiboot ROM loading
  - Libretro: Fix saving in GB games (fixes mgba.io/i/486)
+Misc:
+ - Qt: Improved HiDPI support
 
 0.5.2: (2016-12-31)
 Bugfixes:

src/platform/qt/DisplayGL.cpp

@@ -75,7 +75,11 @@ void DisplayGL::startDrawing(mCoreThread* thread) {
 
 	lockAspectRatio(isAspectRatioLocked());
 	filter(isFiltered());
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+	messagePainter()->resize(size(), isAspectRatioLocked(), devicePixelRatioF());
+#else
 	messagePainter()->resize(size(), isAspectRatioLocked(), devicePixelRatio());
+#endif
 	resizePainter();
 }
 
@@ -362,7 +366,11 @@ void PainterGL::unpause() {
 
 void PainterGL::performDraw() {
 	m_painter.beginNativePainting();
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+	float r = m_gl->devicePixelRatioF();
+#else
 	float r = m_gl->devicePixelRatio();
+#endif
 	m_backend->resized(m_backend, m_size.width() * r, m_size.height() * r);
 	m_backend->drawFrame(m_backend);
 	m_painter.endNativePainting();

src/platform/qt/Window.cpp

@@ -205,6 +205,9 @@ void Window::argumentsPassed(mArguments* args) {
 
 void Window::resizeFrame(const QSize& size) {
 	QSize newSize(size);
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+	newSize /= m_screenWidget->devicePixelRatioF();
+#endif
 	m_screenWidget->setSizeHint(newSize);
 	newSize -= m_screenWidget->size();
 	newSize += this->size();