make the Color constructors explicitly specify transparency

to reduce the churn, we leave the existing constructor in place,
and add a clang plugin to detect when the value passed to the
existing constructor may contain transparency/alpha data.

i.e. we leave expressions like Color(0xffffff) alone, but
warn about any non-constant expression, and any expression
like Color(0xff000000)

Change-Id: Id2ce58e08882d9b7bd0b9f88eca97359dcdbcc8c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/109362
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

24 files changed, 231 insertions, 174 deletions

diff --git a/vcl/headless/CustomWidgetDraw.cxx b/vcl/headless/CustomWidgetDraw.cxx
index 6ff10a34c7bb..b9341e648700 100644
--- a/vcl/headless/CustomWidgetDraw.cxx
+++ b/vcl/headless/CustomWidgetDraw.cxx
@@ -339,74 +339,87 @@ bool CustomWidgetDraw::updateSettings(AllSettings& rSettings)
     {
         StyleSettings aStyleSet = rSettings.GetStyleSettings();
 
-        aStyleSet.SetFaceColor(aStyle.maFaceColor);
-        aStyleSet.SetCheckedColor(aStyle.maCheckedColor);
-        aStyleSet.SetLightColor(aStyle.maLightColor);
-        aStyleSet.SetLightBorderColor(aStyle.maLightBorderColor);
-        aStyleSet.SetShadowColor(aStyle.maShadowColor);
-        aStyleSet.SetDarkShadowColor(aStyle.maDarkShadowColor);
-        aStyleSet.SetDefaultButtonTextColor(aStyle.maDefaultButtonTextColor);
-        aStyleSet.SetButtonTextColor(aStyle.maButtonTextColor);
-        aStyleSet.SetDefaultActionButtonTextColor(aStyle.maDefaultActionButtonTextColor);
-        aStyleSet.SetActionButtonTextColor(aStyle.maActionButtonTextColor);
-        aStyleSet.SetFlatButtonTextColor(aStyle.maFlatButtonTextColor);
-        aStyleSet.SetDefaultButtonRolloverTextColor(aStyle.maDefaultButtonRolloverTextColor);
-        aStyleSet.SetButtonRolloverTextColor(aStyle.maButtonRolloverTextColor);
+        aStyleSet.SetFaceColor(Color(ColorTransparency, aStyle.maFaceColor));
+        aStyleSet.SetCheckedColor(Color(ColorTransparency, aStyle.maCheckedColor));
+        aStyleSet.SetLightColor(Color(ColorTransparency, aStyle.maLightColor));
+        aStyleSet.SetLightBorderColor(Color(ColorTransparency, aStyle.maLightBorderColor));
+        aStyleSet.SetShadowColor(Color(ColorTransparency, aStyle.maShadowColor));
+        aStyleSet.SetDarkShadowColor(Color(ColorTransparency, aStyle.maDarkShadowColor));
+        aStyleSet.SetDefaultButtonTextColor(
+            Color(ColorTransparency, aStyle.maDefaultButtonTextColor));
+        aStyleSet.SetButtonTextColor(Color(ColorTransparency, aStyle.maButtonTextColor));
+        aStyleSet.SetDefaultActionButtonTextColor(
+            Color(ColorTransparency, aStyle.maDefaultActionButtonTextColor));
+        aStyleSet.SetActionButtonTextColor(
+            Color(ColorTransparency, aStyle.maActionButtonTextColor));
+        aStyleSet.SetFlatButtonTextColor(Color(ColorTransparency, aStyle.maFlatButtonTextColor));
+        aStyleSet.SetDefaultButtonRolloverTextColor(
+            Color(ColorTransparency, aStyle.maDefaultButtonRolloverTextColor));
+        aStyleSet.SetButtonRolloverTextColor(
+            Color(ColorTransparency, aStyle.maButtonRolloverTextColor));
         aStyleSet.SetDefaultActionButtonRolloverTextColor(
-            aStyle.maDefaultActionButtonRolloverTextColor);
-        aStyleSet.SetActionButtonRolloverTextColor(aStyle.maActionButtonRolloverTextColor);
-        aStyleSet.SetFlatButtonRolloverTextColor(aStyle.maFlatButtonRolloverTextColor);
+            Color(ColorTransparency, aStyle.maDefaultActionButtonRolloverTextColor));
+        aStyleSet.SetActionButtonRolloverTextColor(
+            Color(ColorTransparency, aStyle.maActionButtonRolloverTextColor));
+        aStyleSet.SetFlatButtonRolloverTextColor(
+            Color(ColorTransparency, aStyle.maFlatButtonRolloverTextColor));
         aStyleSet.SetDefaultButtonPressedRolloverTextColor(
-            aStyle.maDefaultButtonPressedRolloverTextColor);
-        aStyleSet.SetButtonPressedRolloverTextColor(aStyle.maButtonPressedRolloverTextColor);
+            Color(ColorTransparency, aStyle.maDefaultButtonPressedRolloverTextColor));
+        aStyleSet.SetButtonPressedRolloverTextColor(
+            Color(ColorTransparency, aStyle.maButtonPressedRolloverTextColor));
         aStyleSet.SetDefaultActionButtonPressedRolloverTextColor(
-            aStyle.maDefaultActionButtonPressedRolloverTextColor);
+            Color(ColorTransparency, aStyle.maDefaultActionButtonPressedRolloverTextColor));
         aStyleSet.SetActionButtonPressedRolloverTextColor(
-            aStyle.maActionButtonPressedRolloverTextColor);
+            Color(ColorTransparency, aStyle.maActionButtonPressedRolloverTextColor));
         aStyleSet.SetFlatButtonPressedRolloverTextColor(
-            aStyle.maFlatButtonPressedRolloverTextColor);
-        aStyleSet.SetRadioCheckTextColor(aStyle.maRadioCheckTextColor);
-        aStyleSet.SetGroupTextColor(aStyle.maGroupTextColor);
-        aStyleSet.SetLabelTextColor(aStyle.maLabelTextColor);
-        aStyleSet.SetWindowColor(aStyle.maWindowColor);
-        aStyleSet.SetWindowTextColor(aStyle.maWindowTextColor);
-        aStyleSet.SetDialogColor(aStyle.maDialogColor);
-        aStyleSet.SetDialogTextColor(aStyle.maDialogTextColor);
-        aStyleSet.SetWorkspaceColor(aStyle.maWorkspaceColor);
-        aStyleSet.SetMonoColor(aStyle.maMonoColor);
-        aStyleSet.SetFieldColor(Color(aStyle.maFieldColor));
-        aStyleSet.SetFieldTextColor(aStyle.maFieldTextColor);
-        aStyleSet.SetFieldRolloverTextColor(aStyle.maFieldRolloverTextColor);
-        aStyleSet.SetActiveColor(aStyle.maActiveColor);
-        aStyleSet.SetActiveTextColor(aStyle.maActiveTextColor);
-        aStyleSet.SetActiveBorderColor(aStyle.maActiveBorderColor);
-        aStyleSet.SetDeactiveColor(aStyle.maDeactiveColor);
-        aStyleSet.SetDeactiveTextColor(aStyle.maDeactiveTextColor);
-        aStyleSet.SetDeactiveBorderColor(aStyle.maDeactiveBorderColor);
-        aStyleSet.SetMenuColor(aStyle.maMenuColor);
-        aStyleSet.SetMenuBarColor(aStyle.maMenuBarColor);
-        aStyleSet.SetMenuBarRolloverColor(aStyle.maMenuBarRolloverColor);
-        aStyleSet.SetMenuBorderColor(aStyle.maMenuBorderColor);
-        aStyleSet.SetMenuTextColor(aStyle.maMenuTextColor);
-        aStyleSet.SetMenuBarTextColor(aStyle.maMenuBarTextColor);
-        aStyleSet.SetMenuBarRolloverTextColor(aStyle.maMenuBarRolloverTextColor);
-        aStyleSet.SetMenuBarHighlightTextColor(aStyle.maMenuBarHighlightTextColor);
-        aStyleSet.SetMenuHighlightColor(aStyle.maMenuHighlightColor);
-        aStyleSet.SetMenuHighlightTextColor(aStyle.maMenuHighlightTextColor);
-        aStyleSet.SetHighlightColor(aStyle.maHighlightColor);
-        aStyleSet.SetHighlightTextColor(aStyle.maHighlightTextColor);
-        aStyleSet.SetActiveTabColor(aStyle.maActiveTabColor);
-        aStyleSet.SetInactiveTabColor(aStyle.maInactiveTabColor);
-        aStyleSet.SetTabTextColor(aStyle.maTabTextColor);
-        aStyleSet.SetTabRolloverTextColor(aStyle.maTabRolloverTextColor);
-        aStyleSet.SetTabHighlightTextColor(aStyle.maTabHighlightTextColor);
-        aStyleSet.SetDisableColor(aStyle.maDisableColor);
-        aStyleSet.SetHelpColor(aStyle.maHelpColor);
-        aStyleSet.SetHelpTextColor(aStyle.maHelpTextColor);
-        aStyleSet.SetLinkColor(aStyle.maLinkColor);
-        aStyleSet.SetVisitedLinkColor(aStyle.maVisitedLinkColor);
-        aStyleSet.SetToolTextColor(aStyle.maToolTextColor);
-        aStyleSet.SetFontColor(aStyle.maFontColor);
+            Color(ColorTransparency, aStyle.maFlatButtonPressedRolloverTextColor));
+        aStyleSet.SetRadioCheckTextColor(Color(ColorTransparency, aStyle.maRadioCheckTextColor));
+        aStyleSet.SetGroupTextColor(Color(ColorTransparency, aStyle.maGroupTextColor));
+        aStyleSet.SetLabelTextColor(Color(ColorTransparency, aStyle.maLabelTextColor));
+        aStyleSet.SetWindowColor(Color(ColorTransparency, aStyle.maWindowColor));
+        aStyleSet.SetWindowTextColor(Color(ColorTransparency, aStyle.maWindowTextColor));
+        aStyleSet.SetDialogColor(Color(ColorTransparency, aStyle.maDialogColor));
+        aStyleSet.SetDialogTextColor(Color(ColorTransparency, aStyle.maDialogTextColor));
+        aStyleSet.SetWorkspaceColor(Color(ColorTransparency, aStyle.maWorkspaceColor));
+        aStyleSet.SetMonoColor(Color(ColorTransparency, aStyle.maMonoColor));
+        aStyleSet.SetFieldColor(Color(ColorTransparency, aStyle.maFieldColor));
+        aStyleSet.SetFieldTextColor(Color(ColorTransparency, aStyle.maFieldTextColor));
+        aStyleSet.SetFieldRolloverTextColor(
+            Color(ColorTransparency, aStyle.maFieldRolloverTextColor));
+        aStyleSet.SetActiveColor(Color(ColorTransparency, aStyle.maActiveColor));
+        aStyleSet.SetActiveTextColor(Color(ColorTransparency, aStyle.maActiveTextColor));
+        aStyleSet.SetActiveBorderColor(Color(ColorTransparency, aStyle.maActiveBorderColor));
+        aStyleSet.SetDeactiveColor(Color(ColorTransparency, aStyle.maDeactiveColor));
+        aStyleSet.SetDeactiveTextColor(Color(ColorTransparency, aStyle.maDeactiveTextColor));
+        aStyleSet.SetDeactiveBorderColor(Color(ColorTransparency, aStyle.maDeactiveBorderColor));
+        aStyleSet.SetMenuColor(Color(ColorTransparency, aStyle.maMenuColor));
+        aStyleSet.SetMenuBarColor(Color(ColorTransparency, aStyle.maMenuBarColor));
+        aStyleSet.SetMenuBarRolloverColor(Color(ColorTransparency, aStyle.maMenuBarRolloverColor));
+        aStyleSet.SetMenuBorderColor(Color(ColorTransparency, aStyle.maMenuBorderColor));
+        aStyleSet.SetMenuTextColor(Color(ColorTransparency, aStyle.maMenuTextColor));
+        aStyleSet.SetMenuBarTextColor(Color(ColorTransparency, aStyle.maMenuBarTextColor));
+        aStyleSet.SetMenuBarRolloverTextColor(
+            Color(ColorTransparency, aStyle.maMenuBarRolloverTextColor));
+        aStyleSet.SetMenuBarHighlightTextColor(
+            Color(ColorTransparency, aStyle.maMenuBarHighlightTextColor));
+        aStyleSet.SetMenuHighlightColor(Color(ColorTransparency, aStyle.maMenuHighlightColor));
+        aStyleSet.SetMenuHighlightTextColor(
+            Color(ColorTransparency, aStyle.maMenuHighlightTextColor));
+        aStyleSet.SetHighlightColor(Color(ColorTransparency, aStyle.maHighlightColor));
+        aStyleSet.SetHighlightTextColor(Color(ColorTransparency, aStyle.maHighlightTextColor));
+        aStyleSet.SetActiveTabColor(Color(ColorTransparency, aStyle.maActiveTabColor));
+        aStyleSet.SetInactiveTabColor(Color(ColorTransparency, aStyle.maInactiveTabColor));
+        aStyleSet.SetTabTextColor(Color(ColorTransparency, aStyle.maTabTextColor));
+        aStyleSet.SetTabRolloverTextColor(Color(ColorTransparency, aStyle.maTabRolloverTextColor));
+        aStyleSet.SetTabHighlightTextColor(
+            Color(ColorTransparency, aStyle.maTabHighlightTextColor));
+        aStyleSet.SetDisableColor(Color(ColorTransparency, aStyle.maDisableColor));
+        aStyleSet.SetHelpColor(Color(ColorTransparency, aStyle.maHelpColor));
+        aStyleSet.SetHelpTextColor(Color(ColorTransparency, aStyle.maHelpTextColor));
+        aStyleSet.SetLinkColor(Color(ColorTransparency, aStyle.maLinkColor));
+        aStyleSet.SetVisitedLinkColor(Color(ColorTransparency, aStyle.maVisitedLinkColor));
+        aStyleSet.SetToolTextColor(Color(ColorTransparency, aStyle.maToolTextColor));
+        aStyleSet.SetFontColor(Color(ColorTransparency, aStyle.maFontColor));
 
         rSettings.SetStyleSettings(aStyleSet);
 
diff --git a/vcl/headless/svpgdi.cxx b/vcl/headless/svpgdi.cxx
index 4bbd6f76ec5c..60366f1184de 100644
--- a/vcl/headless/svpgdi.cxx
+++ b/vcl/headless/svpgdi.cxx
@@ -2308,7 +2308,7 @@ Color SvpSalGraphics::getPixel( tools::Long nX, tools::Long nY )
     sal_uInt8 b = unpremultiply_table[a][data[SVP_CAIRO_BLUE]];
     sal_uInt8 g = unpremultiply_table[a][data[SVP_CAIRO_GREEN]];
     sal_uInt8 r = unpremultiply_table[a][data[SVP_CAIRO_RED]];
-    Color aColor(0xFF - a, r, g, b);
+    Color aColor(ColorAlpha, a, r, g, b);
     cairo_surface_destroy(target);
 
     return aColor;
diff --git a/vcl/inc/bitmap/ScanlineTools.hxx b/vcl/inc/bitmap/ScanlineTools.hxx
index 1e3ab5023638..c343cf34f61e 100644
--- a/vcl/inc/bitmap/ScanlineTools.hxx
+++ b/vcl/inc/bitmap/ScanlineTools.hxx
@@ -39,7 +39,7 @@ public:
 
     virtual Color readPixel() override
     {
-        const Color aColor(pData[4], pData[1], pData[2], pData[3]);
+        const Color aColor(ColorTransparency, pData[4], pData[1], pData[2], pData[3]);
         pData += 4;
         return aColor;
     }
diff --git a/vcl/qa/cppunit/BitmapExTest.cxx b/vcl/qa/cppunit/BitmapExTest.cxx
index 5e18b990f77d..5e0fe1dddfc6 100644
--- a/vcl/qa/cppunit/BitmapExTest.cxx
+++ b/vcl/qa/cppunit/BitmapExTest.cxx
@@ -37,17 +37,18 @@ void BitmapExTest::testGetPixelColor24_8()
     Bitmap aBitmap(Size(3, 3), 24);
     {
         BitmapScopedWriteAccess pWriteAccess(aBitmap);
-        pWriteAccess->Erase(Color(0x00, 0x00, 0xFF, 0x00));
+        pWriteAccess->Erase(Color(ColorTransparency, 0x00, 0x00, 0xFF, 0x00));
     }
     AlphaMask aMask(Size(3, 3));
     {
         AlphaScopedWriteAccess pWriteAccess(aMask);
-        pWriteAccess->Erase(Color(0x00, 0xAA, 0xAA, 0xAA));
+        pWriteAccess->Erase(Color(ColorTransparency, 0x00, 0xAA, 0xAA, 0xAA));
     }
 
     BitmapEx aBitmapEx(aBitmap, aMask);
 
-    CPPUNIT_ASSERT_EQUAL(Color(0xAA, 0x00, 0xFF, 0x00), aBitmapEx.GetPixelColor(0, 0));
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0xAA, 0x00, 0xFF, 0x00),
+                         aBitmapEx.GetPixelColor(0, 0));
 }
 
 void BitmapExTest::testGetPixelColor32()
@@ -61,12 +62,13 @@ void BitmapExTest::testGetPixelColor32()
     Bitmap aBitmap(Size(3, 3), 32);
     {
         BitmapScopedWriteAccess pWriteAccess(aBitmap);
-        pWriteAccess->Erase(Color(0xAA, 0x00, 0xFF, 0x00));
+        pWriteAccess->Erase(Color(ColorTransparency, 0xAA, 0x00, 0xFF, 0x00));
     }
 
     BitmapEx aBitmapEx(aBitmap);
 
-    CPPUNIT_ASSERT_EQUAL(Color(0xAA, 0x00, 0xFF, 0x00), aBitmapEx.GetPixelColor(0, 0));
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0xAA, 0x00, 0xFF, 0x00),
+                         aBitmapEx.GetPixelColor(0, 0));
 }
 
 void BitmapExTest::testTransformBitmapEx()
diff --git a/vcl/qa/cppunit/BitmapProcessorTest.cxx b/vcl/qa/cppunit/BitmapProcessorTest.cxx
index 2cc0cbe783d6..07e49b47ca1b 100644
--- a/vcl/qa/cppunit/BitmapProcessorTest.cxx
+++ b/vcl/qa/cppunit/BitmapProcessorTest.cxx
@@ -35,7 +35,7 @@ void BitmapProcessorTest::testDisabledImage()
         Bitmap aBitmap(Size(3, 3), 24);
         {
             BitmapScopedWriteAccess pWriteAccess(aBitmap);
-            pWriteAccess->Erase(Color(0x00, 0x00, 0xFF, 0x00));
+            pWriteAccess->Erase(Color(ColorTransparency, 0x00, 0x00, 0xFF, 0x00));
         }
         BitmapEx aBitmapEx(aBitmap);
         BitmapDisabledImageFilter aDisabledImageFilter;
@@ -52,12 +52,12 @@ void BitmapProcessorTest::testDisabledImage()
         Bitmap aBitmap(Size(3, 3), 24);
         {
             BitmapScopedWriteAccess pWriteAccess(aBitmap);
-            pWriteAccess->Erase(Color(0x00, 0x00, 0xFF, 0x00));
+            pWriteAccess->Erase(Color(ColorTransparency, 0x00, 0x00, 0xFF, 0x00));
         }
         AlphaMask aMask(Size(3, 3));
         {
             AlphaScopedWriteAccess pWriteAccess(aMask);
-            pWriteAccess->Erase(Color(0x00, 0xAA, 0xAA, 0xAA));
+            pWriteAccess->Erase(Color(ColorTransparency, 0x00, 0xAA, 0xAA, 0xAA));
         }
 
         BitmapEx aBitmapEx(aBitmap, aMask);
diff --git a/vcl/qa/cppunit/BitmapTest.cxx b/vcl/qa/cppunit/BitmapTest.cxx
index 56395358863b..0c96977a880a 100644
--- a/vcl/qa/cppunit/BitmapTest.cxx
+++ b/vcl/qa/cppunit/BitmapTest.cxx
@@ -562,7 +562,7 @@ void BitmapTest::testErase()
     {
         Bitmap::ScopedReadAccess pReadAccess(aBitmap);
         BitmapColor aColor(pReadAccess->GetPixel(0, 0));
-        CPPUNIT_ASSERT_EQUAL(BitmapColor(0x11, 0x22, 0x33, 0x00), aColor);
+        CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x11, 0x22, 0x33, 0x00), aColor);
     }
 }
 
@@ -577,20 +577,20 @@ void BitmapTest::testBitmap32()
     Bitmap aBitmap(Size(3, 3), 32);
     {
         BitmapScopedWriteAccess pWriteAccess(aBitmap);
-        pWriteAccess->Erase(Color(0xFF, 0x11, 0x22, 0x33));
-        pWriteAccess->SetPixel(1, 1, BitmapColor(0x44, 0xFF, 0xBB, 0x00));
-        pWriteAccess->SetPixel(2, 2, BitmapColor(0x99, 0x77, 0x66, 0x55));
+        pWriteAccess->Erase(Color(ColorTransparency, 0xFF, 0x11, 0x22, 0x33));
+        pWriteAccess->SetPixel(1, 1, BitmapColor(ColorTransparency, 0x44, 0xFF, 0xBB, 0x00));
+        pWriteAccess->SetPixel(2, 2, BitmapColor(ColorTransparency, 0x99, 0x77, 0x66, 0x55));
     }
     {
         Bitmap::ScopedReadAccess pReadAccess(aBitmap);
         BitmapColor aColor = pReadAccess->GetPixel(0, 0);
-        CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x00, 0xFF), aColor);
+        CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x00, 0xFF), aColor);
 
         aColor = pReadAccess->GetPixel(1, 1);
-        CPPUNIT_ASSERT_EQUAL(BitmapColor(0x44, 0xFF, 0xBB, 0x00), aColor);
+        CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x44, 0xFF, 0xBB, 0x00), aColor);
 
         aColor = pReadAccess->GetPixel(2, 2);
-        CPPUNIT_ASSERT_EQUAL(BitmapColor(0x99, 0x77, 0x66, 0x55), aColor);
+        CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x99, 0x77, 0x66, 0x55), aColor);
     }
 }
 
diff --git a/vcl/qa/cppunit/ScanlineToolsTest.cxx b/vcl/qa/cppunit/ScanlineToolsTest.cxx
index bf053d3bc890..c6751b827ca1 100644
--- a/vcl/qa/cppunit/ScanlineToolsTest.cxx
+++ b/vcl/qa/cppunit/ScanlineToolsTest.cxx
@@ -42,8 +42,9 @@ void ScanlineToolsTest::ScanlineTransformer_32_ARGB()
     pScanlineTransformer->startLine(aScanLine.data());
 
     std::vector<Color> aColors{
-        Color(0, 10, 250, 120),  Color(50, 30, 230, 110), Color(100, 50, 210, 100),
-        Color(150, 70, 190, 90), Color(200, 90, 170, 80),
+        Color(ColorTransparency, 0, 10, 250, 120),   Color(ColorTransparency, 50, 30, 230, 110),
+        Color(ColorTransparency, 100, 50, 210, 100), Color(ColorTransparency, 150, 70, 190, 90),
+        Color(ColorTransparency, 200, 90, 170, 80),
     };
 
     for (Color const& aColor : aColors)
@@ -70,8 +71,9 @@ void ScanlineToolsTest::ScanlineTransformer_24_BGR()
     pScanlineTransformer->startLine(aScanLine.data());
 
     std::vector<Color> aColors{
-        Color(0, 10, 250, 120),  Color(50, 30, 230, 110), Color(100, 50, 210, 100),
-        Color(150, 70, 190, 90), Color(200, 90, 170, 80),
+        Color(ColorTransparency, 0, 10, 250, 120),   Color(ColorTransparency, 50, 30, 230, 110),
+        Color(ColorTransparency, 100, 50, 210, 100), Color(ColorTransparency, 150, 70, 190, 90),
+        Color(ColorTransparency, 200, 90, 170, 80),
     };
 
     for (Color const& aColor : aColors)
@@ -91,8 +93,9 @@ void ScanlineToolsTest::ScanlineTransformer_24_BGR()
 void ScanlineToolsTest::ScanlineTransformer_8bit_Palette()
 {
     std::vector<Color> aColors{
-        Color(0, 10, 250, 120),  Color(50, 30, 230, 110), Color(100, 50, 210, 100),
-        Color(150, 70, 190, 90), Color(200, 90, 170, 80),
+        Color(ColorTransparency, 0, 10, 250, 120),   Color(ColorTransparency, 50, 30, 230, 110),
+        Color(ColorTransparency, 100, 50, 210, 100), Color(ColorTransparency, 150, 70, 190, 90),
+        Color(ColorTransparency, 200, 90, 170, 80),
     };
 
     BitmapPalette aPalette(256);
diff --git a/vcl/qa/cppunit/bitmapcolor.cxx b/vcl/qa/cppunit/bitmapcolor.cxx
index 7329564d46c4..f62e19dabcd5 100644
--- a/vcl/qa/cppunit/bitmapcolor.cxx
+++ b/vcl/qa/cppunit/bitmapcolor.cxx
@@ -137,7 +137,7 @@ void BitmapColorTest::colorClassConstructor()
 
     // Transparency / Alpha
     {
-        BitmapColor aBmpColor(Color(255, 128, 64, 0));
+        BitmapColor aBmpColor(Color(ColorTransparency, 255, 128, 64, 0));
 
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Red wrong", static_cast<sal_uInt8>(128), aBmpColor.GetRed());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", static_cast<sal_uInt8>(64),
diff --git a/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx b/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
index 201d10e56fd3..bbf8a38da0f6 100644
--- a/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
+++ b/vcl/qa/cppunit/bitmaprender/BitmapRenderTest.cxx
@@ -152,20 +152,23 @@ void BitmapRenderTest::testDrawAlphaBitmapEx()
     }
 
     // Check the bitmap has pixels we expect
-    CPPUNIT_ASSERT_EQUAL(Color(0xFF, 0x00, 0x00, 0x00), aBitmapEx.GetPixelColor(0, 0));
-    CPPUNIT_ASSERT_EQUAL(Color(0x00, 0xFF, 0xFF, 0x00), aBitmapEx.GetPixelColor(1, 1));
-    CPPUNIT_ASSERT_EQUAL(Color(0x7F, 0x00, 0xFF, 0x00), aBitmapEx.GetPixelColor(2, 2));
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0xFF, 0x00, 0x00, 0x00),
+                         aBitmapEx.GetPixelColor(0, 0));
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0x00, 0xFF, 0xFF, 0x00),
+                         aBitmapEx.GetPixelColor(1, 1));
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0x7F, 0x00, 0xFF, 0x00),
+                         aBitmapEx.GetPixelColor(2, 2));
 
     pVDev->DrawBitmapEx(Point(), aBitmapEx);
 
-    CPPUNIT_ASSERT_EQUAL(Color(0x00, 0xFF, 0xFF, 0xFF), pVDev->GetPixel(Point(0, 0)));
-    CPPUNIT_ASSERT_EQUAL(Color(0x00, 0xFF, 0xFF, 0x00), pVDev->GetPixel(Point(1, 1)));
+    CPPUNIT_ASSERT_EQUAL(Color(0xFF, 0xFF, 0xFF), pVDev->GetPixel(Point(0, 0)));
+    CPPUNIT_ASSERT_EQUAL(Color(0xFF, 0xFF, 0x00), pVDev->GetPixel(Point(1, 1)));
 
 #if defined(_WIN32) || defined(MACOSX) || defined(IOS)
     // sometimes on Windows we get rounding error in blending so let's ignore this on Windows for now.
-    CPPUNIT_ASSERT_LESS(2, deltaColor(Color(0x00, 0x7F, 0xFF, 0x7F), pVDev->GetPixel(Point(2, 2))));
+    CPPUNIT_ASSERT_LESS(2, deltaColor(Color(0x7F, 0xFF, 0x7F), pVDev->GetPixel(Point(2, 2))));
 #else
-    CPPUNIT_ASSERT_EQUAL(Color(0x00, 0x7F, 0xFF, 0x7F), pVDev->GetPixel(Point(2, 2)));
+    CPPUNIT_ASSERT_EQUAL(Color(0x7F, 0xFF, 0x7F), pVDev->GetPixel(Point(2, 2)));
 #endif
 }
 
@@ -211,14 +214,14 @@ void BitmapRenderTest::testAlphaVirtualDevice()
 #endif
 
     // Draw an semi-transparent pixel
-    pAlphaVirtualDevice->DrawPixel(Point(0, 0), Color(0x44, 0x22, 0xff, 0x55));
+    pAlphaVirtualDevice->DrawPixel(Point(0, 0), Color(ColorTransparency, 0x44, 0x22, 0xff, 0x55));
 
     aColor = pAlphaVirtualDevice->GetPixel(Point(0, 0));
     // Read back the semi-transparent pixel
 #if defined _WIN32
-    CPPUNIT_ASSERT_LESS(6, deltaColor(Color(0x4422FF55), aColor));
+    CPPUNIT_ASSERT_LESS(6, deltaColor(Color(ColorTransparency, 0x4422FF55), aColor));
 #else
-    CPPUNIT_ASSERT_EQUAL(Color(0x4422FF55), aColor);
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0x4422FF55), aColor);
 #endif
 
     // Read back the BitmapEx and check the semi-transparent pixel
@@ -228,9 +231,9 @@ void BitmapRenderTest::testAlphaVirtualDevice()
 
     aColor = aBitmap.GetPixelColor(0, 0);
 #if defined _WIN32
-    CPPUNIT_ASSERT_LESS(6, deltaColor(Color(0x4422FF55), aColor));
+    CPPUNIT_ASSERT_LESS(6, deltaColor(Color(ColorTransparency, 0x4422FF55), aColor));
 #else
-    CPPUNIT_ASSERT_EQUAL(Color(0x4422FF55), aColor);
+    CPPUNIT_ASSERT_EQUAL(Color(ColorTransparency, 0x4422FF55), aColor);
 #endif
 }
 
diff --git a/vcl/qa/cppunit/png/PngFilterTest.cxx b/vcl/qa/cppunit/png/PngFilterTest.cxx
index 42a25652134f..28e6c719f6fd 100644
--- a/vcl/qa/cppunit/png/PngFilterTest.cxx
+++ b/vcl/qa/cppunit/png/PngFilterTest.cxx
@@ -70,15 +70,23 @@ void PngFilterTest::testPng()
 
             if (pAccess->GetBitCount() == 24 || pAccess->GetBitCount() == 32)
             {
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 3));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 3));
-
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x00, 0x00), pAccess->GetPixel(1, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x00, 0x00), pAccess->GetPixel(1, 2));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x00, 0x00), pAccess->GetPixel(2, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x00, 0x00), pAccess->GetPixel(2, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 3));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 3));
+
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(2, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(2, 2));
             }
             else
             {
@@ -102,15 +110,23 @@ void PngFilterTest::testPng()
             CPPUNIT_ASSERT_EQUAL(tools::Long(4), pAccess->Height());
             if (pAccess->GetBitCount() == 24 || pAccess->GetBitCount() == 32)
             {
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 3));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 3));
-
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0x00, 0x00, 0x00), pAccess->GetPixel(1, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0xFF, 0x00, 0x00), pAccess->GetPixel(1, 2));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0xFF, 0x00), pAccess->GetPixel(2, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0x00, 0x00), pAccess->GetPixel(2, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 3));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 3));
+
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0xFF, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0xFF, 0x00),
+                                     pAccess->GetPixel(2, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0x00, 0x00),
+                                     pAccess->GetPixel(2, 2));
             }
             else
             {
@@ -134,15 +150,23 @@ void PngFilterTest::testPng()
 
             if (pAccess->GetBitCount() == 24)
             {
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 3));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(3, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x00), pAccess->GetPixel(0, 3));
-
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0x00, 0x00, 0x00), pAccess->GetPixel(1, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0xFF, 0x00, 0x00), pAccess->GetPixel(1, 2));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0xFF, 0x00), pAccess->GetPixel(2, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0x00, 0x00), pAccess->GetPixel(2, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 3));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(3, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x00),
+                                     pAccess->GetPixel(0, 3));
+
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0x00, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0xFF, 0x00, 0x00),
+                                     pAccess->GetPixel(1, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0xFF, 0x00),
+                                     pAccess->GetPixel(2, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0x00, 0x00),
+                                     pAccess->GetPixel(2, 2));
 
                 AlphaMask aAlpha = aBitmapEx.GetAlpha();
                 {
@@ -151,36 +175,44 @@ void PngFilterTest::testPng()
                     CPPUNIT_ASSERT_EQUAL(tools::Long(4), pAlphaAccess->Width());
                     CPPUNIT_ASSERT_EQUAL(tools::Long(4), pAlphaAccess->Height());
 
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x80, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x80, 0x00),
                                          pAlphaAccess->GetPixel(0, 0));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x80, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x80, 0x00),
                                          pAlphaAccess->GetPixel(3, 3));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x80, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x80, 0x00),
                                          pAlphaAccess->GetPixel(3, 0));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x80, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x80, 0x00),
                                          pAlphaAccess->GetPixel(0, 3));
 
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x40, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x40, 0x00),
                                          pAlphaAccess->GetPixel(1, 1));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0xC0, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0xC0, 0x00),
                                          pAlphaAccess->GetPixel(1, 2));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0xC0, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0xC0, 0x00),
                                          pAlphaAccess->GetPixel(2, 1));
-                    CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0x40, 0x00),
+                    CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0x40, 0x00),
                                          pAlphaAccess->GetPixel(2, 2));
                 }
             }
             else if (pAccess->GetBitCount() == 32)
             {
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x80), pAccess->GetPixel(0, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x80), pAccess->GetPixel(3, 3));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x80), pAccess->GetPixel(3, 0));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0xFF, 0x80), pAccess->GetPixel(0, 3));
-
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0x00, 0x00, 0x40), pAccess->GetPixel(1, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0xFF, 0x00, 0xC0), pAccess->GetPixel(1, 2));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0x00, 0x00, 0xFF, 0xC0), pAccess->GetPixel(2, 1));
-                CPPUNIT_ASSERT_EQUAL(BitmapColor(0xFF, 0xFF, 0x00, 0x40), pAccess->GetPixel(2, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x80),
+                                     pAccess->GetPixel(0, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x80),
+                                     pAccess->GetPixel(3, 3));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x80),
+                                     pAccess->GetPixel(3, 0));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0xFF, 0x80),
+                                     pAccess->GetPixel(0, 3));
+
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0x00, 0x00, 0x40),
+                                     pAccess->GetPixel(1, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0xFF, 0x00, 0xC0),
+                                     pAccess->GetPixel(1, 2));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0x00, 0x00, 0xFF, 0xC0),
+                                     pAccess->GetPixel(2, 1));
+                CPPUNIT_ASSERT_EQUAL(BitmapColor(ColorTransparency, 0xFF, 0xFF, 0x00, 0x40),
+                                     pAccess->GetPixel(2, 2));
             }
             else
             {
diff --git a/vcl/qt5/Qt5AccessibleWidget.cxx b/vcl/qt5/Qt5AccessibleWidget.cxx
index 1f33cec86e3c..879c451ec277 100644
--- a/vcl/qt5/Qt5AccessibleWidget.cxx
+++ b/vcl/qt5/Qt5AccessibleWidget.cxx
@@ -666,7 +666,7 @@ QColor Qt5AccessibleWidget::foregroundColor() const
         return QColor();
 
     Reference<XAccessibleComponent> xAccessibleComponent(xAc, UNO_QUERY);
-    return toQColor(xAccessibleComponent->getForeground());
+    return toQColor(Color(ColorTransparency, xAccessibleComponent->getForeground()));
 }
 
 QColor Qt5AccessibleWidget::backgroundColor() const
@@ -676,7 +676,7 @@ QColor Qt5AccessibleWidget::backgroundColor() const
         return QColor();
 
     Reference<XAccessibleComponent> xAccessibleComponent(xAc, UNO_QUERY);
-    return toQColor(xAccessibleComponent->getBackground());
+    return toQColor(Color(ColorTransparency, xAccessibleComponent->getBackground()));
 }
 
 void* Qt5AccessibleWidget::interface_cast(QAccessible::InterfaceType t)
diff --git a/vcl/qt5/Qt5Graphics_GDI.cxx b/vcl/qt5/Qt5Graphics_GDI.cxx
index 559ff4baca39..a40a96e9fb29 100644
--- a/vcl/qt5/Qt5Graphics_GDI.cxx
+++ b/vcl/qt5/Qt5Graphics_GDI.cxx
@@ -516,7 +516,10 @@ std::shared_ptr<SalBitmap> Qt5Graphics::getBitmap(tools::Long nX, tools::Long nY
     return std::make_shared<Qt5Bitmap>(m_pQImage->copy(nX, nY, nWidth, nHeight));
 }
 
-Color Qt5Graphics::getPixel(tools::Long nX, tools::Long nY) { return m_pQImage->pixel(nX, nY); }
+Color Qt5Graphics::getPixel(tools::Long nX, tools::Long nY)
+{
+    return Color(ColorTransparency, m_pQImage->pixel(nX, nY));
+}
 
 void Qt5Graphics::invert(tools::Long nX, tools::Long nY, tools::Long nWidth, tools::Long nHeight,
                          SalInvert nFlags)
diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index 8266fe938bbf..f9fdfcaa1300 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -216,7 +216,7 @@ SkColor toSkColorWithIntensity(Color color, int intensity)
 
 Color fromSkColor(SkColor color)
 {
-    return Color(255 - SkColorGetA(color), SkColorGetR(color), SkColorGetG(color),
+    return Color(ColorAlpha, SkColorGetA(color), SkColorGetR(color), SkColorGetG(color),
                  SkColorGetB(color));
 }
 
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index 77bb784241f0..70405e2b5111 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -939,7 +939,7 @@ void SkiaSalBitmap::PerformErase()
         abort();
     Color fastColor = mEraseColor;
     if (!!mPalette)
-        fastColor = mPalette.GetBestIndex(fastColor);
+        fastColor = Color(ColorTransparency, mPalette.GetBestIndex(fastColor));
     if (!ImplFastEraseBitmap(*bitmapBuffer, fastColor))
     {
         FncSetPixel setPixel = BitmapReadAccess::SetPixelFunction(bitmapBuffer->mnFormat);
diff --git a/vcl/source/app/settings.cxx b/vcl/source/app/settings.cxx
index 2f0495c58446..556e1f7e69cf 100644
--- a/vcl/source/app/settings.cxx
+++ b/vcl/source/app/settings.cxx
@@ -2301,7 +2301,7 @@ static void setupPersonaHeaderFooter( WhichPersona eWhich, OUString& rHeaderFoot
         if ( nIndex > 0 )
         {
             OUString aColor = aPersonaSettings.getToken( 0, ';', ++nIndex );
-            rMenuBarTextColor = Color( aColor.toUInt32( 16 ) );
+            rMenuBarTextColor = Color( ColorTransparency, aColor.toUInt32( 16 ) );
         }
     }
 
diff --git a/vcl/source/bitmap/BitmapBasicMorphologyFilter.cxx b/vcl/source/bitmap/BitmapBasicMorphologyFilter.cxx
index f3b371e03f1c..8bc038b486f9 100644
--- a/vcl/source/bitmap/BitmapBasicMorphologyFilter.cxx
+++ b/vcl/source/bitmap/BitmapBasicMorphologyFilter.cxx
@@ -38,7 +38,7 @@ struct FilterSharedData
         , mpWriteAccess(rWriteAccess.get())
         , mnRadius(nRadius)
         , mnOutsideVal(nOutsideVal)
-        , maOutsideColor(nOutsideVal, nOutsideVal, nOutsideVal, nOutsideVal)
+        , maOutsideColor(ColorTransparency, nOutsideVal, nOutsideVal, nOutsideVal, nOutsideVal)
     {
     }
 };
@@ -92,8 +92,9 @@ template <typename MorphologyOp, int nComponentWidth> struct Value
 
 template <typename MorphologyOp> struct Value<MorphologyOp, 0>
 {
-    static constexpr Color initColor{ MorphologyOp::initVal, MorphologyOp::initVal,
-                                      MorphologyOp::initVal, MorphologyOp::initVal };
+    static constexpr Color initColor{ ColorTransparency, MorphologyOp::initVal,
+                                      MorphologyOp::initVal, MorphologyOp::initVal,
+                                      MorphologyOp::initVal };
 
     Color aResult;
 
@@ -107,7 +108,7 @@ template <typename MorphologyOp> struct Value<MorphologyOp, 0>
                sal_uInt8* /*pHint*/ = nullptr)
     {
         const auto& rSource = pReadAccess->GetColor(y, x);
-        aResult = Color(255 - MorphologyOp::apply(rSource.GetAlpha(), aResult.GetAlpha()),
+        aResult = Color(ColorAlpha, MorphologyOp::apply(rSource.GetAlpha(), aResult.GetAlpha()),
                         MorphologyOp::apply(rSource.GetRed(), aResult.GetRed()),
                         MorphologyOp::apply(rSource.GetGreen(), aResult.GetGreen()),
                         MorphologyOp::apply(rSource.GetBlue(), aResult.GetBlue()));
diff --git a/vcl/source/bitmap/BitmapDisabledImageFilter.cxx b/vcl/source/bitmap/BitmapDisabledImageFilter.cxx
index 9c4e469191a8..82b6c7f07d5e 100644
--- a/vcl/source/bitmap/BitmapDisabledImageFilter.cxx
+++ b/vcl/source/bitmap/BitmapDisabledImageFilter.cxx
@@ -40,7 +40,7 @@ BitmapEx BitmapDisabledImageFilter::execute(BitmapEx const& rBitmapEx) const
                 // Get the luminance from RGB color and remap the value from 0-255 to 160-224
                 const BitmapColor aColor = pRead->GetPixelFromData(pReadScan, nX);
                 sal_uInt8 nLum(aColor.GetLuminance() / 4 + 160);
-                BitmapColor aGreyValue(nLum, nLum, nLum, 255 - aColor.GetAlpha());
+                BitmapColor aGreyValue(ColorAlpha, nLum, nLum, nLum, aColor.GetAlpha());
                 pGrey->SetPixelOnData(pGreyScan, nX, aGreyValue);
             }
         }
diff --git a/vcl/source/bitmap/BitmapReadAccess.cxx b/vcl/source/bitmap/BitmapReadAccess.cxx
index 0a39835a364c..a978e3f77388 100644
--- a/vcl/source/bitmap/BitmapReadAccess.cxx
+++ b/vcl/source/bitmap/BitmapReadAccess.cxx
@@ -405,8 +405,8 @@ BitmapColor BitmapReadAccess::GetPixelForN32BitTcAbgr(ConstScanline pScanline, t
     sal_uInt8 g = *pScanline++;
     sal_uInt8 r = *pScanline;
 
-    return BitmapColor(vcl::bitmap::unpremultiply(r, a), vcl::bitmap::unpremultiply(g, a),
-                       vcl::bitmap::unpremultiply(b, a), 0xFF - a);
+    return BitmapColor(ColorAlpha, vcl::bitmap::unpremultiply(r, a),
+                       vcl::bitmap::unpremultiply(g, a), vcl::bitmap::unpremultiply(b, a), a);
 }
 
 BitmapColor BitmapReadAccess::GetPixelForN32BitTcXbgr(ConstScanline pScanline, tools::Long nX,
@@ -454,8 +454,8 @@ BitmapColor BitmapReadAccess::GetPixelForN32BitTcArgb(ConstScanline pScanline, t
     sal_uInt8 g = *pScanline++;
     sal_uInt8 b = *pScanline;
 
-    return BitmapColor(vcl::bitmap::unpremultiply(r, a), vcl::bitmap::unpremultiply(g, a),
-                       vcl::bitmap::unpremultiply(b, a), 0xFF - a);
+    return BitmapColor(ColorAlpha, vcl::bitmap::unpremultiply(r, a),
+                       vcl::bitmap::unpremultiply(g, a), vcl::bitmap::unpremultiply(b, a), a);
 }
 
 BitmapColor BitmapReadAccess::GetPixelForN32BitTcXrgb(ConstScanline pScanline, tools::Long nX,
@@ -503,8 +503,8 @@ BitmapColor BitmapReadAccess::GetPixelForN32BitTcBgra(ConstScanline pScanline, t
     sal_uInt8 r = *pScanline++;
     sal_uInt8 a = *pScanline;
 
-    return BitmapColor(vcl::bitmap::unpremultiply(r, a), vcl::bitmap::unpremultiply(g, a),
-                       vcl::bitmap::unpremultiply(b, a), 0xFF - a);
+    return BitmapColor(ColorAlpha, vcl::bitmap::unpremultiply(r, a),
+                       vcl::bitmap::unpremultiply(g, a), vcl::bitmap::unpremultiply(b, a), a);
 }
 
 BitmapColor BitmapReadAccess::GetPixelForN32BitTcBgrx(ConstScanline pScanline, tools::Long nX,
@@ -552,8 +552,8 @@ BitmapColor BitmapReadAccess::GetPixelForN32BitTcRgba(ConstScanline pScanline, t
     sal_uInt8 b = *pScanline++;
     sal_uInt8 a = *pScanline;
 
-    return BitmapColor(vcl::bitmap::unpremultiply(r, a), vcl::bitmap::unpremultiply(g, a),
-                       vcl::bitmap::unpremultiply(b, a), 0xFF - a);
+    return BitmapColor(ColorAlpha, vcl::bitmap::unpremultiply(r, a),
+                       vcl::bitmap::unpremultiply(g, a), vcl::bitmap::unpremultiply(b, a), a);
 }
 
 BitmapColor BitmapReadAccess::GetPixelForN32BitTcRgbx(ConstScanline pScanline, tools::Long nX,
diff --git a/vcl/source/gdi/gdimtf.cxx b/vcl/source/gdi/gdimtf.cxx
index 8d65c7b1a31f..e42e7feedb87 100644
--- a/vcl/source/gdi/gdimtf.cxx
+++ b/vcl/source/gdi/gdimtf.cxx
@@ -1725,7 +1725,7 @@ tools::Rectangle GDIMetaFile::GetBoundRect( OutputDevice& i_rReference, tools::R
 
 Color GDIMetaFile::ImplColAdjustFnc( const Color& rColor, const void* pColParam )
 {
-    return Color( 255 - rColor.GetAlpha(),
+    return Color( ColorAlpha, rColor.GetAlpha(),
                   static_cast<const ImplColAdjustParam*>(pColParam)->pMapR[ rColor.GetRed() ],
                   static_cast<const ImplColAdjustParam*>(pColParam)->pMapG[ rColor.GetGreen() ],
                   static_cast<const ImplColAdjustParam*>(pColParam)->pMapB[ rColor.GetBlue() ] );
@@ -1751,7 +1751,7 @@ Color GDIMetaFile::ImplColConvertFnc( const Color& rColor, const void* pColParam
     if( MtfConversion::N1BitThreshold == static_cast<const ImplColConvertParam*>(pColParam)->eConversion )
         cLum = ( cLum < 128 ) ? 0 : 255;
 
-    return Color( 255 - rColor.GetAlpha(), cLum, cLum, cLum );
+    return Color( ColorTransparency, 255 - rColor.GetAlpha(), cLum, cLum, cLum );
 }
 
 BitmapEx GDIMetaFile::ImplBmpConvertFnc( const BitmapEx& rBmpEx, const void* pBmpParam )
diff --git a/vcl/source/graphic/GraphicObject2.cxx b/vcl/source/graphic/GraphicObject2.cxx
index 82ce4dd07fcf..f2a67a6f8203 100644
--- a/vcl/source/graphic/GraphicObject2.cxx
+++ b/vcl/source/graphic/GraphicObject2.cxx
@@ -476,7 +476,7 @@ void GraphicObject::ImplTransformBitmap( BitmapEx&          rBmpEx,
             }
 
             aBmpEx2.Scale(Size(nPadTotalWidth, nPadTotalHeight));
-            aBmpEx2.Erase( Color(0xFF,0,0,0) );
+            aBmpEx2.Erase( Color(ColorAlpha,0,0,0,0) );
             aBmpEx2.CopyPixel( tools::Rectangle( Point(nPadLeft, nPadTop), aBmpSize ), tools::Rectangle( Point(0, 0), aBmpSize ), &rBmpEx );
             rBmpEx = aBmpEx2;
         }
diff --git a/vcl/source/helper/canvastools.cxx b/vcl/source/helper/canvastools.cxx
index dc57592944ab..c1ee370537cc 100644
--- a/vcl/source/helper/canvastools.cxx
+++ b/vcl/source/helper/canvastools.cxx
@@ -609,7 +609,7 @@ namespace vcl::unotools
             const rendering::ARGBColor aARGBColor(
                 xColorSpace->convertToARGB(rColor)[0]);
 
-            return Color( 255-toByteColor(aARGBColor.Alpha),
+            return Color( ColorAlpha, toByteColor(aARGBColor.Alpha),
                           toByteColor(aARGBColor.Red),
                           toByteColor(aARGBColor.Green),
                           toByteColor(aARGBColor.Blue) );
diff --git a/vcl/source/pdf/PDFiumLibrary.cxx b/vcl/source/pdf/PDFiumLibrary.cxx
index bdd3fed7b4d4..42fb1370ce9f 100644
--- a/vcl/source/pdf/PDFiumLibrary.cxx
+++ b/vcl/source/pdf/PDFiumLibrary.cxx
@@ -657,7 +657,7 @@ Color PDFiumPageObject::getFillColor()
     unsigned int nR, nG, nB, nA;
     if (FPDFPageObj_GetFillColor(mpPageObject, &nR, &nG, &nB, &nA))
     {
-        aColor = Color(0xFF - nA, nR, nG, nB);
+        aColor = Color(ColorAlpha, nA, nR, nG, nB);
     }
     return aColor;
 }
@@ -668,7 +668,7 @@ Color PDFiumPageObject::getStrokeColor()
     unsigned int nR, nG, nB, nA;
     if (FPDFPageObj_GetStrokeColor(mpPageObject, &nR, &nG, &nB, &nA))
     {
-        aColor = Color(0xFF - nA, nR, nG, nB);
+        aColor = Color(ColorAlpha, nA, nR, nG, nB);
     }
     return aColor;
 }
@@ -857,7 +857,7 @@ Color PDFiumAnnotationImpl::getColor()
     unsigned int nR, nG, nB, nA;
     if (FPDFAnnot_GetColor(mpAnnotation, FPDFANNOT_COLORTYPE_Color, &nR, &nG, &nB, &nA))
     {
-        aColor = Color(0xFF - nA, nR, nG, nB);
+        aColor = Color(ColorAlpha, nA, nR, nG, nB);
     }
     return aColor;
 }
@@ -868,7 +868,7 @@ Color PDFiumAnnotationImpl::getInteriorColor()
     unsigned int nR, nG, nB, nA;
     if (FPDFAnnot_GetColor(mpAnnotation, FPDFANNOT_COLORTYPE_InteriorColor, &nR, &nG, &nB, &nA))
     {
-        aColor = Color(0xFF - nA, nR, nG, nB);
+        aColor = Color(ColorAlpha, nA, nR, nG, nB);
     }
     return aColor;
 }
diff --git a/vcl/source/window/menubarwindow.cxx b/vcl/source/window/menubarwindow.cxx
index 6c47c8a0ac01..c29a827b2c38 100644
--- a/vcl/source/window/menubarwindow.cxx
+++ b/vcl/source/window/menubarwindow.cxx
@@ -92,7 +92,7 @@ void DecoToolBox::SetImages( tools::Long nMaxHeight, bool bForce )
 
     lastSize = nMaxHeight - border;
 
-    Color       aEraseColor( 255, 255, 255, 255 );
+    Color       aEraseColor( ColorTransparency, 255, 255, 255, 255 );
     BitmapEx    aBmpExDst( maImage.GetBitmapEx() );
     BitmapEx    aBmpExSrc( aBmpExDst );
 
diff --git a/vcl/unx/generic/app/saldisp.cxx b/vcl/unx/generic/app/saldisp.cxx
index efc154e14cb6..26624925dfe8 100644
--- a/vcl/unx/generic/app/saldisp.cxx
+++ b/vcl/unx/generic/app/saldisp.cxx
@@ -2430,7 +2430,7 @@ SalVisual::SalVisual( const XVisualInfo* pXVI )
 Color SalVisual::GetTCColor( Pixel nPixel ) const
 {
     if( SALCOLOR == eRGBMode_ )
-        return static_cast<Color>(nPixel);
+        return Color(ColorTransparency, nPixel);
 
     if( SALCOLORREVERSE == eRGBMode_ )
         return Color( (nPixel & 0x0000FF),
@@ -2715,7 +2715,7 @@ Color SalColormap::GetColor( Pixel nPixel ) const
     if( !m_hColormap )
     {
         SAL_WARN("vcl", "SalColormap::GetColor() !m_hColormap");
-        return nPixel;
+        return Color(ColorTransparency, nPixel);
     }
 
     // DirectColor, StaticColor, StaticGray, GrayScale
@@ -2791,7 +2791,7 @@ Pixel SalColormap::GetPixel( Color nColor ) const
                     {
                         XColor aInversColor;
 
-                        Color nInversColor = sal_uInt32(nColor) ^ 0xFFFFFF;
+                        Color nInversColor(ColorTransparency, sal_uInt32(nColor) ^ 0xFFFFFF);
 
                         GetXPixel( aInversColor,
                                    nInversColor.GetRed(),