Improved support for DPI on Mac and Vista/7

This significantly improves the support for
higher DPI-values on these platforms by
ensuring that common pixelmetrics are
scaled accordingly. In addition we mark all
Qt apps as DPI-aware on Windows 7 by calling
SetProcessDPIAware. We also changed the
way we draw pixmaps on the mac paintengine
when using dpi scaling > 1 to ensure smooth
pixmap scaling.

Reviewed-by: nrc
Task-id: 242417

1 files changed, 26 insertions, 1 deletions

diff --git a/src/gui/styles/qstylehelper.cpp b/src/gui/styles/qstylehelper.cpp
index 997bd682b8..f9010e8279 100644
--- a/src/gui/styles/qstylehelper.cpp
+++ b/src/gui/styles/qstylehelper.cpp
@@ -48,6 +48,12 @@
 #include <private/qstyle_p.h>
 #include <qmath.h>
 
+#if defined(Q_WS_WIN)
+#include "qt_windows.h"
+#elif defined(Q_WS_MAC)
+#include <private/qt_cocoa_helpers_mac_p.h>
+#endif
+
 QT_BEGIN_NAMESPACE
 
 namespace QStyleHelper {
@@ -72,6 +78,26 @@ QString uniqueName(const QString &key, const QStyleOption *option, const QSize &
     return tmp;
 }
 
+qreal dpiScaled(qreal value)
+{
+    static qreal scale = -1;
+    if (scale < 0) {
+        scale = 1.0;
+#if defined(Q_WS_WIN)
+        {
+            HDC hdcScreen = GetDC(0);
+            int dpi = GetDeviceCaps(hdcScreen, LOGPIXELSX);
+            ReleaseDC(0, hdcScreen);
+            scale = dpi/96.0;
+        }
+#elif defined(Q_WS_MAC)
+    scale = qt_mac_get_scalefactor();
+#endif
+    }
+    return value * scale;
+}
+
+
 #ifndef QT_NO_DIAL
 
 int calcBigLineSize(int radius)
@@ -178,7 +204,6 @@ QPolygonF calcLines(const QStyleOptionSlider *dial)
     return poly;
 }
 
-
 // This will draw a nice and shiny QDial for us. We don't want
 // all the shinyness in QWindowsStyle, hence we place it here