tdf#138122 Detect window scaling for multi display configurations on macOS

(1) Activate window scaling when at least one retina display is connected

(2) Remove environment variable VCL_MACOS_FORCE_WINDOW_SCALING

(3) Disable related unit tests unless bitmap scaling has been implemented

Backport of 0c36f364b14aacd0eeb53087ae2fce54402dc741 and
06d918dcc47ae3f1c511cbdccfeacc8adb123f28 for LibreOffice 7.1

Change-Id: I20b075bf4e2927d62a04cd935e4496721b4c695d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112106
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

7 files changed, 48 insertions, 39 deletions

diff --git a/vcl/inc/quartz/salgdi.h b/vcl/inc/quartz/salgdi.h
index f5ff134259a6..7282c50fef1c 100644
--- a/vcl/inc/quartz/salgdi.h
+++ b/vcl/inc/quartz/salgdi.h
@@ -175,7 +175,6 @@ class AquaSalGraphics : public SalGraphics
 #ifdef MACOSX
     /// is this a window graphics
     bool                                    mbWindow;
-    bool                                    mbWindowScaling;
 
 #else // IOS
 
@@ -197,7 +196,7 @@ public:
     void                    copyResolution( AquaSalGraphics& );
     void                    updateResolution();
 
-    float                   GetWindowScaling();
+    static float            GetWindowScaling();
     void                    SetWindowGraphics( AquaSalFrame* pFrame );
     bool                    IsWindowGraphics()      const   { return mbWindow; }
     void                    SetPrinterGraphics(CGContextRef, sal_Int32 nRealDPIX, sal_Int32 nRealDPIY);
diff --git a/vcl/osx/salgdiutils.cxx b/vcl/osx/salgdiutils.cxx
index 892baed13ac9..a1012e704796 100644
--- a/vcl/osx/salgdiutils.cxx
+++ b/vcl/osx/salgdiutils.cxx
@@ -35,37 +35,35 @@
 #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: Scale will be set to 2.0f as default after implementation of full scaled display support . This will allow moving of
+// windows between non retina and retina displays without blurry text and graphics. Static variables have to be removed thereafter.
 
-    // 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;
-    }
+// Currently scaled display support is not implemented for bitmaps. This will cause a slight performance degradation on displays
+// with single precision. To preserve performance for now, window scaling is only activated if at least one display with double
+// precision is present. Moving windows between displays is then possible without blurry text and graphics too. Adapting window
+// scaling when displays are added while application is running is not supported.
 
-#endif
+static bool  bWindowScaling = false;
+static float fWindowScale = 1.0f;
 
-    AquaSalFrame *pSalFrame = mpFrame;
-    if (!pSalFrame)
-        pSalFrame = static_cast<AquaSalFrame *>(GetSalData()->mpInstance->anyFrame());
-    if (pSalFrame)
+float AquaSalGraphics::GetWindowScaling()
+{
+    if (!bWindowScaling)
     {
-        NSWindow *pNSWindow = pSalFrame->getNSWindow();
-        if (pNSWindow)
-            fScale = [pNSWindow backingScaleFactor];
+        NSArray *aScreens = [NSScreen screens];
+        if (aScreens != nullptr)
+        {
+            int nScreens = [aScreens count];
+            for (int i = 0; i < nScreens; i++)
+            {
+                float fScale = [[aScreens objectAtIndex:i] backingScaleFactor];
+                if (fScale > fWindowScale)
+                  fWindowScale = fScale;
+            }
+            bWindowScaling = true;
+        }
     }
-    return fScale;
+    return fWindowScale;
 }
 
 void AquaSalGraphics::SetWindowGraphics( AquaSalFrame* pFrame )
diff --git a/vcl/osx/salmacos.cxx b/vcl/osx/salmacos.cxx
index 88f15e22d229..24a4b5b5a4d6 100644
--- a/vcl/osx/salmacos.cxx
+++ b/vcl/osx/salmacos.cxx
@@ -19,7 +19,7 @@
 
 // This file contains the macOS-specific versions of the functions which were touched in the commit
 // to fix tdf#138122. The iOS-specific versions of these functions are kept (for now, when this
-// comment is written) as they were before that commit in vcl/isx/salios.cxx.
+// comment is written) as they were before that commit in vcl/ios/salios.cxx.
 
 #include <sal/config.h>
 #include <sal/log.hxx>
@@ -345,7 +345,7 @@ bool AquaSalVirtualDevice::SetSize(tools::Long nDX, tools::Long nDY)
 
     mnWidth = nDX;
     mnHeight = nDY;
-    fScale = mpGraphics->GetWindowScaling();
+    fScale = AquaSalGraphics::GetWindowScaling();
     CGColorSpaceRef aColorSpace;
     uint32_t nFlags;
     if (mnBitmapDepth && (mnBitmapDepth < 16))
diff --git a/vcl/qa/cppunit/BackendTest.cxx b/vcl/qa/cppunit/BackendTest.cxx
index 94bf1e142960..29d7268445e1 100644
--- a/vcl/qa/cppunit/BackendTest.cxx
+++ b/vcl/qa/cppunit/BackendTest.cxx
@@ -674,6 +674,8 @@ public:
     // Test SalGraphics::blendBitmap() and blendAlphaBitmap() calls.
     void testDrawBlendExtended()
     {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
         // Create virtual device with alpha.
         ScopedVclPtr<VirtualDevice> device
             = VclPtr<VirtualDevice>::Create(DeviceFormat::DEFAULT, DeviceFormat::DEFAULT);
@@ -719,10 +721,13 @@ public:
         exportDevice("/tmp/blend_extended_04.png", device);
         CPPUNIT_ASSERT_EQUAL(COL_BLUE, device->GetPixel(Point(2, 2)));
         CPPUNIT_ASSERT_EQUAL(COL_WHITE, device->GetPixel(Point(6, 6)));
+#endif
     }
 
     void testDrawAlphaBitmapMirrored()
     {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
         // Normal virtual device.
         ScopedVclPtr<VirtualDevice> device = VclPtr<VirtualDevice>::Create(DeviceFormat::DEFAULT);
         // Virtual device with alpha.
@@ -777,10 +782,13 @@ public:
         CPPUNIT_ASSERT_EQUAL(COL_RED, alphaDevice->GetPixel(Point(2, 2)));
         CPPUNIT_ASSERT_EQUAL(COL_BLUE, alphaDevice->GetPixel(Point(3, 2)));
         alphaDevice->Erase();
+#endif
     }
 
     void testTdf124848()
     {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
         ScopedVclPtr<VirtualDevice> device = VclPtr<VirtualDevice>::Create(DeviceFormat::DEFAULT);
         device->SetOutputSizePixel(Size(100, 100));
         device->SetBackground(Wallpaper(COL_WHITE));
@@ -809,6 +817,7 @@ public:
         CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(50, 20)));
         CPPUNIT_ASSERT_EQUAL(COL_WHITE, device->GetPixel(Point(49, 20)));
         CPPUNIT_ASSERT_EQUAL(COL_WHITE, device->GetPixel(Point(51, 20)));
+#endif
     }
 
     void testTdf136171()
diff --git a/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx b/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
index fb892395ecc1..8a60eebbc44c 100644
--- a/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
+++ b/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
@@ -45,6 +45,7 @@ public:
     CPPUNIT_TEST_SUITE(BitmapRenderTest);
     CPPUNIT_TEST(testTdf104141);
     CPPUNIT_TEST(testTdf113918);
+
     CPPUNIT_TEST(testDrawAlphaBitmapEx);
     CPPUNIT_TEST(testAlphaVirtualDevice);
     CPPUNIT_TEST(testTdf116888);
@@ -101,7 +102,7 @@ void BitmapRenderTest::testTdf113918()
     CPPUNIT_ASSERT(aColor.GetGreen() > 100);
 }
 
-#if defined(_WIN32) || defined(MACOSX) || defined(IOS)
+#if defined(_WIN32) || defined(IOS)
 
 namespace
 {
@@ -119,6 +120,8 @@ int deltaColor(BitmapColor aColor1, BitmapColor aColor2)
 
 void BitmapRenderTest::testDrawAlphaBitmapEx()
 {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
     ScopedVclPtrInstance<VirtualDevice> pVDev;
     pVDev->SetOutputSizePixel(Size(8, 8));
     pVDev->SetBackground(Wallpaper(COL_WHITE));
@@ -163,10 +166,13 @@ void BitmapRenderTest::testDrawAlphaBitmapEx()
 #else
     CPPUNIT_ASSERT_EQUAL(Color(0x00, 0x7F, 0xFF, 0x7F), pVDev->GetPixel(Point(2, 2)));
 #endif
+#endif
 }
 
 void BitmapRenderTest::testAlphaVirtualDevice()
 {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
     // Create an alpha virtual device
     ScopedVclPtr<VirtualDevice> pAlphaVirtualDevice(VclPtr<VirtualDevice>::Create(
         *Application::GetDefaultDevice(), DeviceFormat::DEFAULT, DeviceFormat::DEFAULT));
@@ -228,6 +234,7 @@ void BitmapRenderTest::testAlphaVirtualDevice()
 #else
     CPPUNIT_ASSERT_EQUAL(Color(0x4422FF55), aColor);
 #endif
+#endif
 }
 
 void BitmapRenderTest::testTdf116888()
diff --git a/vcl/qa/cppunit/outdev.cxx b/vcl/qa/cppunit/outdev.cxx
index 97ec62096ce9..5081082afc0b 100644
--- a/vcl/qa/cppunit/outdev.cxx
+++ b/vcl/qa/cppunit/outdev.cxx
@@ -41,6 +41,7 @@ public:
     void testRTLGuard();
 
     CPPUNIT_TEST_SUITE(VclOutdevTest);
+
     CPPUNIT_TEST(testVirtualDevice);
     CPPUNIT_TEST(testUseAfterDispose);
     CPPUNIT_TEST(testPrinterBackgroundColor);
@@ -83,6 +84,8 @@ void VclOutdevTest::testWindowBackgroundColor()
 
 void VclOutdevTest::testVirtualDevice()
 {
+// TODO: This unit test is not executed for macOS unless bitmap scaling is implemented
+#ifndef MACOSX
     ScopedVclPtrInstance<VirtualDevice> pVDev;
     pVDev->SetOutputSizePixel(Size(32, 32));
     pVDev->SetBackground(Wallpaper(COL_WHITE));
@@ -131,6 +134,7 @@ void VclOutdevTest::testVirtualDevice()
     CPPUNIT_ASSERT( pWin );
     OutputDevice *pOutDev = pWin.get();
 #endif
+#endif
 }
 
 void VclOutdevTest::testUseAfterDispose()
diff --git a/vcl/quartz/salgdi.cxx b/vcl/quartz/salgdi.cxx
index 12281e85517d..704bba1fae9c 100644
--- a/vcl/quartz/salgdi.cxx
+++ b/vcl/quartz/salgdi.cxx
@@ -205,14 +205,6 @@ 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