tdf#138122 Add window scaling for retina displays on macOS

(1) Remove hack to make application look as if being linked against SDK 10.13

(2) Use quad storage size on virtual devices for displaying on retina displays thereafter

(3) Apply workaround to downsample bitmaps from scaled layers (to be implemented)

(4) Disable dark mode (to be implemented)

(5) Provide new environment variables:

VCL_MACOS_FORCE_WINDOW_SCALING:
window scaling on non retina displays

VCL_MACOS_FORCE_DARK_MODE:
enable dark mode (macOS 10.14, iOS 13 and newer)

VCL_MACOS_USE_SYSTEM_APPEARANCE:
use light mode or dark mode (macOS 10.14, iOS 13 and newer) as configured by system preferences

Change-Id: I99877cd62a98cb91bcbf27af62b043c31c5f5fc9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109072
Tested-by: Jenkins
Reviewed-by: Tor Lillqvist <tml@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109495
Reviewed-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>

8 files changed, 260 insertions, 288 deletions

diff --git a/desktop/Executable_soffice_bin.mk b/desktop/Executable_soffice_bin.mk
index 5c895ed0e7cb..9c08a28361df 100644
--- a/desktop/Executable_soffice_bin.mk
+++ b/desktop/Executable_soffice_bin.mk
@@ -23,18 +23,6 @@ $(eval $(call gb_Executable_add_cobjects,soffice_bin,\
     desktop/source/app/main \
 ))
 
-ifeq ($(OS),MACOSX)
-# At least when building against SDK 10.15, changing the LC_VERSION_MIN_MACOSX load command's sdk
-# value from 10.15 to "n/a" (i.e., 0.0.0) is necessary to avoid blurry text in the LO UI (see
-# <https://github.com/llvm/llvm-project/commit/25ce33a6e4f3b13732c0f851e68390dc2acb9123>
-# "[driver][darwin] Pass -platform_version flag to the linker instead of the
-# -<platform>_version_min flag", clang/test/Driver/darwin-ld-platform-version-macos.c in particular,
-# for the -platform_version that Clang passes by default to new-enough ld):
-$(eval $(call gb_Executable_add_ldflags,soffice_bin, \
-    -Xlinker -platform_version -Xlinker macos -Xlinker $(MACOSX_DEPLOYMENT_TARGET) -Xlinker 0.0.0 \
-))
-endif
-
 ifeq ($(OS),WNT)
 
 $(eval $(call gb_Executable_set_targettype_gui,soffice_bin,NO))
diff --git a/vcl/inc/quartz/salgdi.h b/vcl/inc/quartz/salgdi.h
index d718cf788dcc..64eb003e16cd 100644
--- a/vcl/inc/quartz/salgdi.h
+++ b/vcl/inc/quartz/salgdi.h
@@ -175,6 +175,7 @@ class AquaSalGraphics : public SalGraphics
 #ifdef MACOSX
     /// is this a window graphics
     bool                                    mbWindow;
+    bool                                    mbWindowScaling;
 
 #else // IOS
 
@@ -190,10 +191,10 @@ public:
     bool                    IsPenVisible() const    { return maLineColor.IsVisible(); }
     bool                    IsBrushVisible() const  { return maFillColor.IsVisible(); }
 
+    float                   GetWindowScaling();
     void                    SetWindowGraphics( AquaSalFrame* pFrame );
-    void                    SetPrinterGraphics(
-        CGContextRef, sal_Int32 nRealDPIX, sal_Int32 nRealDPIY );
-    void                    SetVirDevGraphics(CGLayerHolder const & rLayer, CGContextRef, int nBitDepth = 0);
+    void                    SetPrinterGraphics(CGContextRef, sal_Int32 nRealDPIX, sal_Int32 nRealDPIY);
+    void                    SetVirDevGraphics(CGLayerHolder const &rLayer, CGContextRef, int nBitDepth = 0);
 #ifdef MACOSX
     void                    initResolution( NSWindow* );
     void                    copyResolution( AquaSalGraphics& );
@@ -300,9 +301,14 @@ public:
     virtual bool            drawAlphaRect( tools::Long nX, tools::Long nY, tools::Long nWidth,
                                            tools::Long nHeight, sal_uInt8 nTransparency ) override;
 
+protected:
+    virtual void            copyScaledArea( tools::Long nDestX, tools::Long nDestY, tools::Long nSrcX, tools::Long nSrcY,
+                                                tools::Long nSrcWidth, tools::Long nSrcHeight, SalGraphics* pSrcGraphics );
+
     // native widget rendering methods that require mirroring
+
 #ifdef MACOSX
-protected:
+
     virtual bool            isNativeControlSupported( ControlType nType, ControlPart nPart ) override;
 
     virtual bool            hitTestNativeControl( ControlType nType, ControlPart nPart, const tools::Rectangle& rControlRegion,
@@ -314,9 +320,9 @@ protected:
                                                     const ImplControlValue& aValue, const OUString& aCaption,
                                                     tools::Rectangle &rNativeBoundingRegion, tools::Rectangle &rNativeContentRegion ) override;
 
-public:
 #endif
 
+public:
     // get device resolution
     virtual void            GetResolution( sal_Int32& rDPIX, sal_Int32& rDPIY ) override;
     // get the depth of the device
diff --git a/vcl/osx/salinst.cxx b/vcl/osx/salinst.cxx
index 91b22e9b77ec..87d81d2ac5d8 100644
--- a/vcl/osx/salinst.cxx
+++ b/vcl/osx/salinst.cxx
@@ -315,6 +315,21 @@ VCLPLUG_OSX_PUBLIC SalInstance* create_SalInstance()
     // put cocoa into multithreaded mode
     [NSThread detachNewThreadSelector:@selector(enableCocoaThreads:) toTarget:[[CocoaThreadEnabler alloc] init] withObject:nil];
 
+    // Dark mode is disabled as long as it is not implemented completely. For development purposes, it may be controlled by
+    // environment variables: VCL_MACOS_FORCE_DARK_MODE enable dark mode independent of system settings,
+    // VCL_MACOS_USE_SYSTEM_APPEARANCE to use system settings (light mode oder dark mode as configured within system preferences).
+
+    // TODO: After implementation of dark mode, this code has to be removed.
+
+    if (getenv("VCL_MACOS_FORCE_DARK_MODE"))
+    {
+        if (@available(macOS 10.14, iOS 13, *))
+            [NSApp setAppearance: [NSAppearance appearanceNamed: NSAppearanceNameDarkAqua]];
+    }
+    else
+        if (!getenv("VCL_MACOS_USE_SYSTEM_APPEARANCE"))
+           [NSApp setAppearance: [NSAppearance appearanceNamed: NSAppearanceNameAqua]];
+
     // activate our delegate methods
     [NSApp setDelegate: NSApp];
 
diff --git a/vcl/quartz/salbmp.cxx b/vcl/quartz/salbmp.cxx
index aa932de1fc69..7bf5ebe9c550 100644
--- a/vcl/quartz/salbmp.cxx
+++ b/vcl/quartz/salbmp.cxx
@@ -71,6 +71,10 @@ QuartzSalBitmap::~QuartzSalBitmap()
 
 bool QuartzSalBitmap::Create(CGLayerHolder const & rLayerHolder, int nBitmapBits, int nX, int nY, int nWidth, int nHeight, bool bFlipped)
 {
+
+    // TODO: Bitmaps from scaled layers are reverted to single precision. This is a workaround only unless bitmaps with precision of
+    // source layer are implemented.
+
     SAL_WARN_IF(!rLayerHolder.isSet(), "vcl", "QuartzSalBitmap::Create() from non-layered context");
 
     // sanitize input parameters
@@ -84,7 +88,10 @@ bool QuartzSalBitmap::Create(CGLayerHolder const & rLayerHolder, int nBitmapBits
         nY = 0;
     }
 
-    const CGSize aLayerSize = CGLayerGetSize(rLayerHolder.get());
+    CGSize aLayerSize = CGLayerGetSize(rLayerHolder.get());
+    const float fScale = rLayerHolder.getScale();
+    aLayerSize.width /= fScale;
+    aLayerSize.height /= fScale;
 
     if( nWidth >= static_cast<int>(aLayerSize.width) - nX )
         nWidth = static_cast<int>(aLayerSize.width) - nX;
@@ -104,17 +111,18 @@ bool QuartzSalBitmap::Create(CGLayerHolder const & rLayerHolder, int nBitmapBits
     CreateContext();
 
     // copy layer content into the bitmap buffer
-    const CGPoint aSrcPoint = { static_cast<CGFloat>(-nX), static_cast<CGFloat>(-nY) };
-    if (maGraphicContext.isSet()) // remove warning
+    const CGPoint aSrcPoint = { static_cast<CGFloat>(-nX * fScale), static_cast<CGFloat>(-nY * fScale) };
+    if (maGraphicContext.isSet())
     {
         if( bFlipped )
         {
-            CGContextTranslateCTM( maGraphicContext.get(), 0, +mnHeight );
-
-            CGContextScaleCTM( maGraphicContext.get(), +1, -1 );
+            CGContextTranslateCTM(maGraphicContext.get(), 0, +mnHeight);
+            CGContextScaleCTM(maGraphicContext.get(), +1, -1);
         }
-
+        maGraphicContext.saveState();
+        CGContextScaleCTM(maGraphicContext.get(), 1 / fScale, 1 / fScale);
         CGContextDrawLayerAtPoint(maGraphicContext.get(), aSrcPoint, rLayerHolder.get());
+        maGraphicContext.restoreState();
     }
     return true;
 }
diff --git a/vcl/quartz/salgdi.cxx b/vcl/quartz/salgdi.cxx
index 704bba1fae9c..12281e85517d 100644
--- a/vcl/quartz/salgdi.cxx
+++ b/vcl/quartz/salgdi.cxx
@@ -205,6 +205,14 @@ AquaSalGraphics::AquaSalGraphics()
     , mbVirDev( false )
 #ifdef MACOSX
     , mbWindow( false )
+
+    // Window scaling independent from main display may be forced by setting VCL_MACOS_FORCE_WINDOW_SCALING environment variable. If
+    // unset window scaling from main display will be used. After implementation of full support of scaled displays window scaling
+    // will be set to 2.0f for macOS as default.
+
+    // TODO: After implementation of full support of scaled displays VCL_FORCE_WINDOW_SCALING control has to be removed.
+
+    , mbWindowScaling( getenv("VCL_MACOS_FORCE_WINDOW_SCALING") )
 #else
     , mbForeignContext( false )
 #endif
diff --git a/vcl/quartz/salgdicommon.cxx b/vcl/quartz/salgdicommon.cxx
index d33b690fdaff..0597fe3d021d 100644
--- a/vcl/quartz/salgdicommon.cxx
+++ b/vcl/quartz/salgdicommon.cxx
@@ -199,109 +199,6 @@ static void alignLinePoint( const Point* i_pIn, float& o_fX, float& o_fY )
     o_fY = static_cast<float>(i_pIn->getY() ) + 0.5;
 }
 
-void AquaSalGraphics::copyBits( const SalTwoRect& rPosAry, SalGraphics *pSrcGraphics )
-{
-
-    if( !pSrcGraphics )
-    {
-        pSrcGraphics = this;
-    }
-    //from unix salgdi2.cxx
-    //[FIXME] find a better way to prevent calc from crashing when width and height are negative
-    if( rPosAry.mnSrcWidth <= 0 ||
-        rPosAry.mnSrcHeight <= 0 ||
-        rPosAry.mnDestWidth <= 0 ||
-        rPosAry.mnDestHeight <= 0 )
-    {
-        return;
-    }
-
-#ifdef IOS
-    // If called from idle layout, maContextHolder.get() is NULL, no idea what to do
-    if (!maContextHolder.isSet())
-        return;
-#endif
-
-    // accelerate trivial operations
-    /*const*/ AquaSalGraphics* pSrc = static_cast<AquaSalGraphics*>(pSrcGraphics);
-    const bool bSameGraphics = (this == pSrc)
-#ifdef MACOSX
-        || (mbWindow && mpFrame && pSrc->mbWindow && (mpFrame == pSrc->mpFrame))
-#endif
-        ;
-
-    if( bSameGraphics &&
-        (rPosAry.mnSrcWidth == rPosAry.mnDestWidth) &&
-        (rPosAry.mnSrcHeight == rPosAry.mnDestHeight))
-    {
-        // short circuit if there is nothing to do
-        if( (rPosAry.mnSrcX == rPosAry.mnDestX) &&
-            (rPosAry.mnSrcY == rPosAry.mnDestY))
-        {
-            return;
-        }
-        // use copyArea() if source and destination context are identical
-        copyArea( rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnSrcX, rPosAry.mnSrcY,
-                  rPosAry.mnSrcWidth, rPosAry.mnSrcHeight, false/*bWindowInvalidate*/ );
-        return;
-    }
-
-    ApplyXorContext();
-    pSrc->ApplyXorContext();
-
-    SAL_WARN_IF (!pSrc->maLayer.isSet(), "vcl.quartz",
-                 "AquaSalGraphics::copyBits() from non-layered graphics this=" << this);
-
-    const CGPoint aDstPoint = CGPointMake(+rPosAry.mnDestX - rPosAry.mnSrcX, rPosAry.mnDestY - rPosAry.mnSrcY);
-    if ((rPosAry.mnSrcWidth == rPosAry.mnDestWidth &&
-         rPosAry.mnSrcHeight == rPosAry.mnDestHeight) &&
-        (!mnBitmapDepth || (aDstPoint.x + pSrc->mnWidth) <= mnWidth)
-        && pSrc->maLayer.isSet()) // workaround for a Quartz crash
-    {
-        // in XOR mode the drawing context is redirected to the XOR mask
-        // if source and target are identical then copyBits() paints onto the target context though
-        CGContextHolder aCopyContext = maContextHolder;
-        if( mpXorEmulation && mpXorEmulation->IsEnabled() )
-        {
-            if( pSrcGraphics == this )
-            {
-                aCopyContext.set(mpXorEmulation->GetTargetContext());
-            }
-        }
-        aCopyContext.saveState();
-
-        const CGRect aDstRect = CGRectMake(rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnDestWidth, rPosAry.mnDestHeight);
-        CGContextClipToRect(aCopyContext.get(), aDstRect);
-
-        // draw at new destination
-        // NOTE: flipped drawing gets disabled for this, else the subimage would be drawn upside down
-        if( pSrc->IsFlipped() )
-        {
-            CGContextTranslateCTM( aCopyContext.get(), 0, +mnHeight );
-            CGContextScaleCTM( aCopyContext.get(), +1, -1 );
-        }
-
-        // TODO: pSrc->size() != this->size()
-        CGContextDrawLayerAtPoint(aCopyContext.get(), aDstPoint, pSrc->maLayer.get());
-
-        aCopyContext.restoreState();
-        // mark the destination rectangle as updated
-        RefreshRect( aDstRect );
-    }
-    else
-    {
-        std::shared_ptr<SalBitmap> pBitmap = pSrc->getBitmap( rPosAry.mnSrcX, rPosAry.mnSrcY,
-                                              rPosAry.mnSrcWidth, rPosAry.mnSrcHeight );
-        if( pBitmap )
-        {
-            SalTwoRect aPosAry( rPosAry );
-            aPosAry.mnSrcX = 0;
-            aPosAry.mnSrcY = 0;
-            drawBitmap( aPosAry, *pBitmap );
-        }
-    }
-}
-
 static void DrawPattern50( void*, CGContextRef rContext )
 {
     static const CGRect aRects[2] = { { {0,0}, { 2, 2 } }, { { 2, 2 }, { 2, 2 } } };
@@ -370,83 +267,115 @@ void AquaSalGraphics::ApplyXorContext()
     }
 }
 
-void AquaSalGraphics::copyArea(
-    tools::Long nDstX, tools::Long nDstY,tools::Long nSrcX, tools::Long nSrcY,
-    tools::Long nSrcWidth, tools::Long nSrcHeight, bool /*bWindowInvalidate*/ )
+void AquaSalGraphics::copyBits(const SalTwoRect &rPosAry, SalGraphics *pSrcGraphics)
 {
-    SAL_WARN_IF (!maLayer.isSet(), "vcl.quartz",
-                 "AquaSalGraphics::copyArea() for non-layered graphics this=" << this);
+    if (!pSrcGraphics)
+        pSrcGraphics = this;
+    AquaSalGraphics *pSrc = static_cast<AquaSalGraphics*>(pSrcGraphics);
+    if (rPosAry.mnSrcWidth <= 0 || rPosAry.mnSrcHeight <= 0 || rPosAry.mnDestWidth <= 0 || rPosAry.mnDestHeight <= 0)
+        return;
+    if (!maContextHolder.isSet())
+        return;
 
-#ifdef IOS
-    if (!maLayer.isSet())
+    SAL_WARN_IF (!pSrc->maLayer.isSet(), "vcl.quartz", "AquaSalGraphics::copyBits() from non-layered graphics this=" << this);
+
+    // Layered graphics are copied by AquaSalGraphics::copyScaledArea() which is able to consider the layer's scaling.
+
+    if (pSrc->maLayer.isSet())
+        copyScaledArea(rPosAry.mnDestX, rPosAry.mnDestY, rPosAry.mnSrcX, rPosAry.mnSrcY,
+                       rPosAry.mnSrcWidth, rPosAry.mnSrcHeight, pSrcGraphics);
+    else
+    {
+        ApplyXorContext();
+        pSrc->ApplyXorContext();
+        std::shared_ptr<SalBitmap> pBitmap = pSrc->getBitmap(rPosAry.mnSrcX, rPosAry.mnSrcY,
+                                                             rPosAry.mnSrcWidth, rPosAry.mnSrcHeight);
+        if (pBitmap)
+        {
+            SalTwoRect aPosAry(rPosAry);
+            aPosAry.mnSrcX = 0;
+            aPosAry.mnSrcY = 0;
+            drawBitmap(aPosAry, *pBitmap);
+        }
+    }
+}
+
+void AquaSalGraphics::copyArea(tools::Long nDstX, tools::Long nDstY,tools::Long nSrcX, tools::Long nSrcY,
+                               tools::Long nSrcWidth, tools::Long nSrcHeight, bool)
+{
+    if (!maContextHolder.isSet())
         return;
-#endif
-    float fScale = maLayer.getScale();
 
-    tools::Long nScaledSourceX = nSrcX * fScale;
-    tools::Long nScaledSourceY = nSrcY * fScale;
+    // Functionality is implemented in protected member function AquaSalGraphics::copyScaledArea() which requires an additional
+    // parameter of type SalGraphics to be used in AquaSalGraphics::copyBits() too.
 
-    tools::Long nScaledTargetX = nDstX * fScale;
-    tools::Long nScaledTargetY = nDstY * fScale;
+    copyScaledArea(nDstX, nDstY, nSrcX, nSrcY, nSrcWidth, nSrcHeight, this);
+}
 
-    tools::Long nScaledSourceWidth = nSrcWidth * fScale;
-    tools::Long nScaledSourceHeight = nSrcHeight * fScale;
+void AquaSalGraphics::copyScaledArea(tools::Long nDstX, tools::Long nDstY,tools::Long nSrcX, tools::Long nSrcY,
+                                     tools::Long nSrcWidth, tools::Long nSrcHeight, SalGraphics *pSrcGraphics)
+{
+    if (!pSrcGraphics)
+        pSrcGraphics = this;
+    AquaSalGraphics *pSrc = static_cast<AquaSalGraphics*>(pSrcGraphics);
 
-    ApplyXorContext();
+    SAL_WARN_IF(!maLayer.isSet(), "vcl.quartz",
+                "AquaSalGraphics::copyScaledArea() without graphics context or for non-layered graphics this=" << this);
 
-    maContextHolder.saveState();
+    if (!maContextHolder.isSet() || !maLayer.isSet())
+        return;
 
-    // in XOR mode the drawing context is redirected to the XOR mask
-    // copyArea() always works on the target context though
-    CGContextRef xCopyContext = maContextHolder.get();
+    // Determine scaled geometry of source and target area assuming source and target area have the same scale
 
-    if( mpXorEmulation && mpXorEmulation->IsEnabled() )
-    {
-        xCopyContext = mpXorEmulation->GetTargetContext();
-    }
+    float fScale = maLayer.getScale();
+    CGFloat nScaledSourceX = nSrcX * fScale;
+    CGFloat nScaledSourceY = nSrcY * fScale;
+    CGFloat nScaledTargetX = nDstX * fScale;
+    CGFloat nScaledTargetY = nDstY * fScale;
+    CGFloat nScaledSourceWidth = nSrcWidth * fScale;
+    CGFloat nScaledSourceHeight = nSrcHeight * fScale;
 
-    // If we have a scaled layer, we need to revert the scaling or else
-    // it will interfere with the coordinate calculation
-    CGContextScaleCTM(xCopyContext, 1.0 / fScale, 1.0 / fScale);
+    // Apply XOR context and get copy context from current graphics context or XOR context
 
-    // drawing a layer onto its own context causes trouble on OSX => copy it first
-    // TODO: is it possible to get rid of this unneeded copy more often?
-    //       e.g. on OSX>=10.5 only this situation causes problems:
-    //          mnBitmapDepth && (aDstPoint.x + pSrc->mnWidth) > mnWidth
+    ApplyXorContext();
+    maContextHolder.saveState();
+    CGContextRef xCopyContext = maContextHolder.get();
+    if (mpXorEmulation && mpXorEmulation->IsEnabled())
+        xCopyContext = mpXorEmulation->GetTargetContext();
 
-    CGLayerHolder sSourceLayerHolder(maLayer);
-    {
-        const CGSize aSrcSize = CGSizeMake(nScaledSourceWidth, nScaledSourceHeight);
-        sSourceLayerHolder.set(CGLayerCreateWithContext(xCopyContext, aSrcSize, nullptr));
+    // Set scale matrix of copy context to consider layer scaling
 
-        const CGContextRef xSrcContext = CGLayerGetContext(sSourceLayerHolder.get());
+    CGContextScaleCTM(xCopyContext, 1 / fScale, 1 / fScale);
 
-        CGPoint aSrcPoint = CGPointMake(-nScaledSourceX, -nScaledSourceY);
-        if( IsFlipped() )
-        {
-            CGContextTranslateCTM( xSrcContext, 0, +nScaledSourceHeight );
-            CGContextScaleCTM( xSrcContext, +1, -1 );
-            aSrcPoint.y = (nScaledSourceY + nScaledSourceHeight) - (mnHeight * fScale);
-        }
-        CGContextSetBlendMode(xSrcContext, kCGBlendModeCopy);
+    // Creating an additional layer is required for drawing with the required scale and extent at the drawing destination
+    // thereafter.
 
-        CGContextDrawLayerAtPoint(xSrcContext, aSrcPoint, maLayer.get());
+    CGLayerHolder aSourceLayerHolder(pSrc->maLayer);
+    const CGSize aSourceSize = CGSizeMake(nScaledSourceWidth, nScaledSourceHeight);
+    aSourceLayerHolder.set(CGLayerCreateWithContext(xCopyContext, aSourceSize, nullptr));
+    const CGContextRef xSourceContext = CGLayerGetContext(aSourceLayerHolder.get());
+    CGPoint aSrcPoint = CGPointMake(-nScaledSourceX, -nScaledSourceY);
+    if (pSrc->IsFlipped())
+    {
+        CGContextTranslateCTM(xSourceContext, 0, nScaledSourceHeight);
+        CGContextScaleCTM(xSourceContext, 1, -1);
+        aSrcPoint.y = nScaledSourceY + nScaledSourceHeight - mnHeight * fScale;
     }
+    CGContextSetBlendMode(xSourceContext, kCGBlendModeCopy);
+    CGContextDrawLayerAtPoint(xSourceContext, aSrcPoint, pSrc->maLayer.get());
+
+    // Copy source area from additional layer to traget area
 
-    // draw at new destination
     const CGRect aTargetRect = CGRectMake(nScaledTargetX, nScaledTargetY, nScaledSourceWidth, nScaledSourceHeight);
     CGContextSetBlendMode(xCopyContext, kCGBlendModeCopy);
-    CGContextDrawLayerInRect(xCopyContext, aTargetRect, sSourceLayerHolder.get());
+    CGContextDrawLayerInRect(xCopyContext, aTargetRect, aSourceLayerHolder.get());
 
-    maContextHolder.restoreState();
+    // Housekeeping on exit
 
-    // cleanup
-    if (sSourceLayerHolder.get() != maLayer.get())
-    {
-        CGLayerRelease(sSourceLayerHolder.get());
-    }
-    // mark the destination rectangle as updated
-    RefreshRect( nDstX, nDstY, nSrcWidth, nSrcHeight );
+    maContextHolder.restoreState();
+    if (aSourceLayerHolder.get() != maLayer.get())
+        CGLayerRelease(aSourceLayerHolder.get());
+    RefreshRect(nDstX, nDstY, nSrcWidth, nSrcHeight);
 }
 
 #ifndef IOS
@@ -1897,62 +1826,74 @@ bool XorEmulation::UpdateTarget()
     return true;
 }
 
-void AquaSalGraphics::SetVirDevGraphics(CGLayerHolder const & rLayer, CGContextRef xContext,
-                                        int nBitmapDepth)
+void AquaSalGraphics::SetVirDevGraphics(CGLayerHolder const &rLayer, CGContextRef xContext, int nBitmapDepth)
 {
-    SAL_INFO( "vcl.quartz", "SetVirDevGraphics() this=" << this << " layer=" << rLayer.get() << " context=" << xContext );
+    SAL_INFO("vcl.quartz", "SetVirDevGraphics() this=" << this << " layer=" << rLayer.get() << " context=" << xContext);
 
-#ifndef IOS
+    // Set member variables
+
+    InvalidateContext();
     mbWindow = false;
-#endif
     mbPrinter = false;
     mbVirDev = true;
-
-    // set graphics properties
     maLayer = rLayer;
-    maContextHolder.set(xContext);
-
     mnBitmapDepth = nBitmapDepth;
 
 #ifdef IOS
+
     mbForeignContext = xContext != NULL;
+
 #endif
 
-    // return early if the virdev is being destroyed
-    if( !xContext )
-        return;
+    // Get size and scale from layer if set else from bitmap and AquaSalGraphics::GetWindowScaling(), which is used to determine
+    // scaling for direct graphics output too
 
-    // get new graphics properties
-    if (!maLayer.isSet())
+    CGSize aSize;
+    float fScale;
+    if (maLayer.isSet())
     {
-        mnWidth = CGBitmapContextGetWidth( maContextHolder.get() );
-        mnHeight = CGBitmapContextGetHeight( maContextHolder.get() );
+        maContextHolder.set(CGLayerGetContext(maLayer.get()));
+        aSize = CGLayerGetSize(maLayer.get());
+        fScale = maLayer.getScale();
     }
     else
     {
-        const CGSize aSize = CGLayerGetSize(maLayer.get());
-        mnWidth = static_cast<int>(aSize.width);
-        mnHeight = static_cast<int>(aSize.height);
+        maContextHolder.set(xContext);
+        if (!xContext)
+            return;
+        aSize.width = CGBitmapContextGetWidth(xContext);
+        aSize.height = CGBitmapContextGetHeight(xContext);
+        fScale = GetWindowScaling();
     }
+    mnWidth = aSize.width / fScale;
+    mnHeight = aSize.height / fScale;
+
+    // Set color space for fill and stroke
+
+    CGColorSpaceRef aColorSpace = GetSalData()->mxRGBSpace;
+    CGContextSetFillColorSpace(maContextHolder.get(), aColorSpace);
+    CGContextSetStrokeColorSpace(maContextHolder.get(), aColorSpace);
 
-    // prepare graphics for drawing
-    const CGColorSpaceRef aCGColorSpace = GetSalData()->mxRGBSpace;
-    CGContextSetFillColorSpace( maContextHolder.get(), aCGColorSpace );
-    CGContextSetStrokeColorSpace( maContextHolder.get(), aCGColorSpace );
+    // Apply scale matrix to virtual device graphics
 
-    // re-enable XorEmulation for the new context
-    if( mpXorEmulation )
+    CGContextScaleCTM(maContextHolder.get(), fScale, fScale);
+
+    // Apply XOR emulation if required
+
+    if (mpXorEmulation)
     {
         mpXorEmulation->SetTarget(mnWidth, mnHeight, mnBitmapDepth, maContextHolder.get(), maLayer.get());
-        if( mpXorEmulation->IsEnabled() )
-        {
+        if (mpXorEmulation->IsEnabled())
             maContextHolder.set(mpXorEmulation->GetMaskContext());
-        }
     }
 
-    // initialize stack of CGContext states
+    // Housekeeping on exit
+
     maContextHolder.saveState();
     SetState();
+
+    SAL_INFO("vcl.quartz", "SetVirDevGraphics() this=" << this <<
+             " (" << mnWidth << "x" << mnHeight << ") fScale=" << fScale << " mnBitmapDepth=" << mnBitmapDepth);
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/quartz/salgdiutils.cxx b/vcl/quartz/salgdiutils.cxx
index 985fe38a2d11..892baed13ac9 100644
--- a/vcl/quartz/salgdiutils.cxx
+++ b/vcl/quartz/salgdiutils.cxx
@@ -35,6 +35,39 @@
 #include <osx/salframe.h>
 #include <osx/saldata.hxx>
 
+float AquaSalGraphics::GetWindowScaling()
+{
+    float fScale = 1.0f;
+
+#ifdef MACOSX
+
+    // Window scaling independent from main display may be forced by setting VCL_MACOS_FORCE_WINDOW_SCALING environment variable
+    // whose setting is stored in mbWindowScaling. After implementation of full support of scaled displays window scaling will be
+    // set to 2.0f for macOS as default. This will allow moving of windows between non retina and retina displays without blurry
+    // text and graphics.
+
+    // TODO: After implementation of full support of scaled displays code has to be modified to set a scaling of 2.0f as default.
+
+    if (mbWindowScaling)
+    {
+        fScale = 2.0f;
+        return fScale;
+    }
+
+#endif
+
+    AquaSalFrame *pSalFrame = mpFrame;
+    if (!pSalFrame)
+        pSalFrame = static_cast<AquaSalFrame *>(GetSalData()->mpInstance->anyFrame());
+    if (pSalFrame)
+    {
+        NSWindow *pNSWindow = pSalFrame->getNSWindow();
+        if (pNSWindow)
+            fScale = [pNSWindow backingScaleFactor];
+    }
+    return fScale;
+}
+
 void AquaSalGraphics::SetWindowGraphics( AquaSalFrame* pFrame )
 {
     mpFrame = pFrame;
@@ -116,13 +149,7 @@ bool AquaSalGraphics::CheckContext()
     {
         const unsigned int nWidth = mpFrame->maGeometry.nWidth;
         const unsigned int nHeight = mpFrame->maGeometry.nHeight;
-
-        // Let's get the window scaling factor if possible, or use 1.0
-        // as the scaling factor.
-        float fScale = 1.0f;
-        if (mpFrame->getNSWindow())
-            fScale = [mpFrame->getNSWindow() backingScaleFactor];
-
+        const float fScale = GetWindowScaling();
         CGLayerRef rReleaseLayer = nullptr;
 
         // check if a new drawing context is needed (e.g. after a resize)
diff --git a/vcl/quartz/salvd.cxx b/vcl/quartz/salvd.cxx
index 57ba971a927a..c48e9e97bb34 100644
--- a/vcl/quartz/salvd.cxx
+++ b/vcl/quartz/salvd.cxx
@@ -104,6 +104,10 @@ AquaSalVirtualDevice::AquaSalVirtualDevice(
         }
 
         mpGraphics->SetVirDevGraphics(maLayer, pData->rCGContext);
+
+        SAL_INFO("vcl.virdev", "AquaSalVirtualDevice::AquaSalVirtualDevice() this=" << this <<
+                 " (" << nDX << "x" << nDY << ") mbForeignContext=" << (mbForeignContext ? "YES" : "NO"));
+
     }
     else
     {
@@ -180,8 +184,6 @@ void AquaSalVirtualDevice::Destroy()
 
     if (maBitmapContext.isSet())
     {
-        void* pRawData = CGBitmapContextGetData(maBitmapContext.get());
-        std::free(pRawData);
         CGContextRelease(maBitmapContext.get());
         maBitmapContext.set(nullptr);
     }
@@ -202,101 +204,78 @@ void AquaSalVirtualDevice::ReleaseGraphics( SalGraphics* )
     mbGraphicsUsed = false;
 }
 
-bool AquaSalVirtualDevice::SetSize( tools::Long nDX, tools::Long nDY )
+bool AquaSalVirtualDevice::SetSize(tools::Long nDX, tools::Long nDY)
 {
-    SAL_INFO( "vcl.virdev", "AquaSalVirtualDevice::SetSize() this=" << this <<
-              " (" << nDX << "x" << nDY << ") mbForeignContext=" << (mbForeignContext ? "YES" : "NO"));
+    SAL_INFO("vcl.virdev", "AquaSalVirtualDevice::SetSize() this=" << this <<
+             " (" << nDX << "x" << nDY << ") mbForeignContext=" << (mbForeignContext ? "YES" : "NO"));
 
-    if( mbForeignContext )
-    {
-        // Do not delete/resize mxContext that we have received from outside VCL
+    // Do not delete/resize graphics context if it has been received from outside VCL
+
+    if (mbForeignContext)
         return true;
-    }
 
+    // Do not delete/resize graphics context if no change of geometry has been requested
+
+    float fScale;
     if (maLayer.isSet())
     {
+        fScale = maLayer.getScale();
         const CGSize aSize = CGLayerGetSize(maLayer.get());
-        if( (nDX == aSize.width) && (nDY == aSize.height) )
-        {
-            // Yay, we do not have to do anything :)
+        if ((nDX == aSize.width / fScale) && (nDY  == aSize.height / fScale))
             return true;
-        }
     }
 
+    // Destroy graphics context if change of geometry has been requested
+
     Destroy();
 
+    // Prepare new graphics context for initialization, use scaling independent of prior graphics context calculated by
+    // AquaSalGraphics::GetWindowScaling(), which is used to determine scaling for direct graphics output too
+
     mnWidth = nDX;
     mnHeight = nDY;
-
-    // create a Quartz layer matching to the intended virdev usage
-    CGContextHolder xCGContextHolder;
-    if( mnBitmapDepth && (mnBitmapDepth < 16) )
+    fScale = mpGraphics->GetWindowScaling();
+    CGColorSpaceRef aColorSpace;
+    uint32_t nFlags;
+    if (mnBitmapDepth && (mnBitmapDepth < 16))
     {
-        mnBitmapDepth = 8;  // TODO: are 1bit vdevs worth it?
-        const int nBytesPerRow = (mnBitmapDepth * nDX + 7) / 8;
-
-        void* pRawData = std::malloc( nBytesPerRow * nDY );
-        maBitmapContext.set(CGBitmapContextCreate( pRawData, nDX, nDY,
-                                                 mnBitmapDepth, nBytesPerRow,
-                                                 GetSalData()->mxGraySpace, kCGImageAlphaNone));
-        xCGContextHolder = maBitmapContext;
+        mnBitmapDepth = 8;
+        aColorSpace = GetSalData()->mxGraySpace;
+        nFlags = kCGImageAlphaNone;
     }
     else
     {
+        mnBitmapDepth = 32;
+        aColorSpace = GetSalData()->mxRGBSpace;
+
 #ifdef MACOSX
-        // default to a NSView target context
-        AquaSalFrame* pSalFrame = mpGraphics->getGraphicsFrame();
-        if( !pSalFrame || !AquaSalFrame::isAlive( pSalFrame ))
-        {
-            pSalFrame = static_cast<AquaSalFrame*>( GetSalData()->mpInstance->anyFrame() );
-            if ( pSalFrame )
-                // update the frame reference
-                mpGraphics->setGraphicsFrame( pSalFrame );
-        }
-        if( pSalFrame )
-        {
-            // #i91990#
-            NSWindow* pNSWindow = pSalFrame->getNSWindow();
-            if ( pNSWindow )
-            {
-                NSGraphicsContext* pNSContext = [NSGraphicsContext graphicsContextWithWindow: pNSWindow];
-                if( pNSContext )
-                {
-                    xCGContextHolder.set([pNSContext CGContext]);
-                }
-            }
-        }
-#endif
 
-        if (!xCGContextHolder.isSet())
-        {
-            // assert(Application::IsBitmapRendering());
-            mnBitmapDepth = 32;
+        nFlags = kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Host;
 
-            const int nBytesPerRow = (mnBitmapDepth * nDX) / 8;
-            void* pRawData = std::malloc( nBytesPerRow * nDY );
-#ifdef MACOSX
-            const int nFlags = kCGImageAlphaNoneSkipFirst;
 #else
-            const int nFlags = kCGImageAlphaNoneSkipFirst | kCGImageByteOrder32Little;
+
+        nFlags = kCGImageAlphaNoneSkipFirst | kCGImageByteOrder32Little;
+
 #endif
-            maBitmapContext.set(CGBitmapContextCreate(pRawData, nDX, nDY, 8, nBytesPerRow,
-                                                      GetSalData()->mxRGBSpace, nFlags));
-            xCGContextHolder = maBitmapContext;
-        }
+
     }
 
-    SAL_WARN_IF(!xCGContextHolder.isSet(), "vcl.quartz", "No context");
+    // Allocate buffer for virtual device graphics as bitmap context to store graphics with highest required (scaled) resolution
 
-    const CGSize aNewSize = { static_cast<CGFloat>(nDX), static_cast<CGFloat>(nDY) };
-    maLayer.set(CGLayerCreateWithContext(xCGContextHolder.get(), aNewSize, nullptr));
+    size_t nScaledWidth = mnWidth * fScale;
+    size_t nScaledHeight = mnHeight * fScale;
+    size_t nBytesPerRow = mnBitmapDepth * nScaledWidth / 8;
+    maBitmapContext.set(CGBitmapContextCreate(nullptr, nScaledWidth, nScaledHeight, 8, nBytesPerRow, aColorSpace, nFlags));
 
-    if (maLayer.isSet() && mpGraphics)
-    {
-        // get the matching Quartz context
-        CGContextRef xDrawContext = CGLayerGetContext( maLayer.get() );
-        mpGraphics->SetVirDevGraphics(maLayer.get(), xDrawContext, mnBitmapDepth);
-    }
+    SAL_INFO("vcl.virdev", "AquaSalVirtualDevice::SetSize() this=" << this <<
+             " fScale=" << fScale << " mnBitmapDepth=" << mnBitmapDepth);
+
+    CGSize aLayerSize = { static_cast<CGFloat>(nScaledWidth), static_cast<CGFloat>(nScaledHeight) };
+    maLayer.set(CGLayerCreateWithContext(maBitmapContext.get(), aLayerSize, nullptr));
+    maLayer.setScale(fScale);
+    mpGraphics->SetVirDevGraphics(maLayer, CGLayerGetContext(maLayer.get()), mnBitmapDepth);
+
+    SAL_WARN_IF(!maBitmapContext.isSet(), "vcl.quartz", "No context");
 
     return maLayer.isSet();
 }