Introduce DPI scale factor for Hi-DPI displays.

This is supposed to stay 1 (no scale) for printers and default virtual
devices, but should be set accordingly (2 or 3) for windows and virtual
devices derived from windows.

Various VCL widgets or paint operations should incrementally become aware of
this, and changed so that they draw nicely on the Hi-DPI displays.  This patch
only introduces the behavior for waved lines.

The default is currently being set depending on the DPI setting only; could be
changed to a more clever way if necessary.

Change-Id: I71118f9ab6b64028d1eeee76e860e999d5cd9d19

4 files changed, 12 insertions, 3 deletions

diff --git a/vcl/source/gdi/outdev.cxx b/vcl/source/gdi/outdev.cxx
index b6f894583799..8009275f24da 100644
--- a/vcl/source/gdi/outdev.cxx
+++ b/vcl/source/gdi/outdev.cxx
@@ -344,6 +344,7 @@ OutputDevice::OutputDevice() :
     mnOutHeight         = 0;
     mnDPIX              = 0;
     mnDPIY              = 0;
+    mnDPIScaleFactor    = 1;
     mnTextOffX          = 0;
     mnTextOffY          = 0;
     mnOutOffOrigX       = 0;
diff --git a/vcl/source/gdi/outdev3.cxx b/vcl/source/gdi/outdev3.cxx
index 36c7203064ed..850f63a10925 100644
--- a/vcl/source/gdi/outdev3.cxx
+++ b/vcl/source/gdi/outdev3.cxx
@@ -5319,9 +5319,10 @@ void OutputDevice::DrawWaveLine( const Point& rStartPos, const Point& rEndPos,
      if( nWaveHeight > pFontEntry->maMetric.mnWUnderlineSize )
          nWaveHeight = pFontEntry->maMetric.mnWUnderlineSize;
 
-     ImplDrawWaveLine( nStartX, nStartY, 0, 0,
-                      nEndX-nStartX, nWaveHeight, 1,
-                      nOrientation, GetLineColor() );
+    ImplDrawWaveLine(nStartX, nStartY, 0, 0,
+            nEndX-nStartX, nWaveHeight * mnDPIScaleFactor,
+            mnDPIScaleFactor, nOrientation, GetLineColor());
+
     if( mpAlphaVDev )
         mpAlphaVDev->DrawWaveLine( rStartPos, rEndPos, nStyle );
 }
diff --git a/vcl/source/gdi/virdev.cxx b/vcl/source/gdi/virdev.cxx
index 54d40f300f5a..4ef472047e02 100644
--- a/vcl/source/gdi/virdev.cxx
+++ b/vcl/source/gdi/virdev.cxx
@@ -97,6 +97,7 @@ void VirtualDevice::ImplInitVirDev( const OutputDevice* pOutDev,
     mpFontCache     = pSVData->maGDIData.mpScreenFontCache;
     mnDPIX          = pOutDev->mnDPIX;
     mnDPIY          = pOutDev->mnDPIY;
+    mnDPIScaleFactor = pOutDev->mnDPIScaleFactor;
     maFont          = pOutDev->maFont;
 
     if( maTextColor != pOutDev->maTextColor )
@@ -406,6 +407,7 @@ void VirtualDevice::ImplSetReferenceDevice( RefDevMode i_eRefDevMode, sal_Int32
 {
     mnDPIX = i_nDPIX;
     mnDPIY = i_nDPIY;
+    mnDPIScaleFactor = 1;
 
     EnableOutput( sal_False );  // prevent output on reference device
     mbScreenComp = sal_False;
diff --git a/vcl/source/window/window.cxx b/vcl/source/window/window.cxx
index 78995af16b6b..e68966884965 100644
--- a/vcl/source/window/window.cxx
+++ b/vcl/source/window/window.cxx
@@ -1711,12 +1711,17 @@ void Window::ImplInitResolutionSettings()
         sal_uInt16 nScreenZoom = rStyleSettings.GetScreenZoom();
         mnDPIX = (mpWindowImpl->mpFrameData->mnDPIX*nScreenZoom)/100;
         mnDPIY = (mpWindowImpl->mpFrameData->mnDPIY*nScreenZoom)/100;
+
+        // setup the scale factor for Hi-DPI displays
+        mnDPIScaleFactor = std::max(1, (mpWindowImpl->mpFrameData->mnDPIY + 48) / 96);
+
         SetPointFont( rStyleSettings.GetAppFont() );
     }
     else if ( mpWindowImpl->mpParent )
     {
         mnDPIX  = mpWindowImpl->mpParent->mnDPIX;
         mnDPIY  = mpWindowImpl->mpParent->mnDPIY;
+        mnDPIScaleFactor = mpWindowImpl->mpParent->mnDPIScaleFactor;
     }
 
     // update the recalculated values for logical units