Alpha channel in BitmapColor - change bIndex to alpha

We want to store the alpha channel in BitmapColor. To achieve this
we can repurpose bIndex attribute for alpha. Generally we don't
need bIndex at all as we can infer if we use index colors or not
from the context (using palette or not)

Change-Id: I18fe748beeca59e2869368a1c3c2ee9d2062b41e
Reviewed-on: https://gerrit.libreoffice.org/61057
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

4 files changed, 44 insertions, 29 deletions

diff --git a/vcl/qa/cppunit/bitmapcolor.cxx b/vcl/qa/cppunit/bitmapcolor.cxx
index 2953c0d0eab8..c8cae6aef973 100644
--- a/vcl/qa/cppunit/bitmapcolor.cxx
+++ b/vcl/qa/cppunit/bitmapcolor.cxx
@@ -35,9 +35,8 @@ public:
     void defaultConstructor();
     void colorValueConstructor();
     void colorClassConstructor();
-
+    void getColor();
     void setValue();
-
     void invert();
     void getLuminance();
 
@@ -45,6 +44,7 @@ public:
     CPPUNIT_TEST(defaultConstructor);
     CPPUNIT_TEST(colorValueConstructor);
     CPPUNIT_TEST(colorClassConstructor);
+    CPPUNIT_TEST(getColor);
     CPPUNIT_TEST(setValue);
     CPPUNIT_TEST(invert);
     CPPUNIT_TEST(getLuminance);
@@ -58,7 +58,7 @@ void BitmapColorTest::defaultConstructor()
     CPPUNIT_ASSERT_EQUAL_MESSAGE("Red wrong", static_cast<sal_uInt8>(0), aBmpColor.GetRed());
     CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", static_cast<sal_uInt8>(0), aBmpColor.GetGreen());
     CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(0), aBmpColor.GetBlue());
-    CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0), aBmpColor.GetAlpha());
 }
 
 void BitmapColorTest::colorValueConstructor()
@@ -70,7 +70,8 @@ void BitmapColorTest::colorValueConstructor()
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", static_cast<sal_uInt8>(0),
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(0), aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
     }
 
     {
@@ -81,7 +82,8 @@ void BitmapColorTest::colorValueConstructor()
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(128),
                                      aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
     }
 
     {
@@ -92,7 +94,8 @@ void BitmapColorTest::colorValueConstructor()
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(255),
                                      aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
     }
 }
 
@@ -106,7 +109,8 @@ void BitmapColorTest::colorClassConstructor()
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", static_cast<sal_uInt8>(0),
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(0), aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
     }
 
     {
@@ -118,7 +122,8 @@ void BitmapColorTest::colorClassConstructor()
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(127),
                                      aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
     }
 
     {
@@ -130,10 +135,35 @@ void BitmapColorTest::colorClassConstructor()
                                      aBmpColor.GetGreen());
         CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(255),
                                      aBmpColor.GetBlue());
-        CPPUNIT_ASSERT_EQUAL_MESSAGE("Index wrong", false, aBmpColor.IsIndex());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(0),
+                                     aBmpColor.GetAlpha());
+    }
+
+    // Transparency / Alpha
+    {
+        Color aColor(255, 128, 64, 0);
+        BitmapColor aBmpColor(aColor);
+
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Red wrong", static_cast<sal_uInt8>(128), aBmpColor.GetRed());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", static_cast<sal_uInt8>(64),
+                                     aBmpColor.GetGreen());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", static_cast<sal_uInt8>(0), aBmpColor.GetBlue());
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("Alpha wrong", static_cast<sal_uInt8>(255),
+                                     aBmpColor.GetAlpha());
     }
 }
 
+void BitmapColorTest::getColor()
+{
+    BitmapColor aBitmapColor(255, 128, 64, 32);
+    Color aColor = aBitmapColor.GetColor();
+
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Red wrong", sal_uInt8(255), aColor.GetRed());
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Green wrong", sal_uInt8(128), aColor.GetGreen());
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Blue wrong", sal_uInt8(64), aColor.GetBlue());
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Transparecy wrong", sal_uInt8(32), aColor.GetTransparency());
+}
+
 void BitmapColorTest::setValue()
 {
     BitmapColor aBmpColor;
diff --git a/vcl/source/bitmap/BitmapTools.cxx b/vcl/source/bitmap/BitmapTools.cxx
index aaa678b888dd..13a133295b06 100644
--- a/vcl/source/bitmap/BitmapTools.cxx
+++ b/vcl/source/bitmap/BitmapTools.cxx
@@ -652,18 +652,7 @@ css::uno::Sequence< sal_Int8 > GetMaskDIB(BitmapEx const & aBmpEx)
 
 static sal_uInt8 lcl_GetColor(BitmapColor const& rColor)
 {
-    sal_uInt8 nTemp(0);
-    if (rColor.IsIndex())
-    {
-        nTemp = rColor.GetIndex();
-    }
-    else
-    {
-        nTemp = rColor.GetBlue();
-        // greyscale expected here, or what would non-grey colors mean?
-        assert(rColor.GetRed() == nTemp && rColor.GetGreen() == nTemp);
-    }
-    return nTemp;
+    return rColor.GetBlueOrIndex();
 }
 
 
diff --git a/vcl/source/gdi/bmpacc2.cxx b/vcl/source/gdi/bmpacc2.cxx
index 1d7cec5f4c79..25606c09509e 100644
--- a/vcl/source/gdi/bmpacc2.cxx
+++ b/vcl/source/gdi/bmpacc2.cxx
@@ -79,11 +79,7 @@ BitmapColor BitmapReadAccess::GetPixelForN8BitPal(ConstScanline pScanline, long
 
 void BitmapReadAccess::SetPixelForN8BitPal(Scanline pScanline, long nX, const BitmapColor& rBitmapColor, const ColorMask&)
 {
-    if (rBitmapColor.IsIndex())
-        pScanline[ nX ] = rBitmapColor.GetIndex();
-    else
-        // Let's hope that the RGB color values equal, so it doesn't matter what do we pick
-        pScanline[ nX ] = rBitmapColor.GetBlueOrIndex();
+    pScanline[ nX ] = rBitmapColor.GetBlueOrIndex();
 }
 
 BitmapColor BitmapReadAccess::GetPixelForN8BitTcMask(ConstScanline pScanline, long nX, const ColorMask& rMask)
diff --git a/vcl/unx/generic/print/genpspgraphics.cxx b/vcl/unx/generic/print/genpspgraphics.cxx
index f74ecffdb990..88e7fcdf901a 100644
--- a/vcl/unx/generic/print/genpspgraphics.cxx
+++ b/vcl/unx/generic/print/genpspgraphics.cxx
@@ -192,7 +192,7 @@ SalPrinterBmp::GetPixelRGB (sal_uInt32 nRow, sal_uInt32 nColumn) const
     Scanline pScan = mpScanAccess + nRow * mnScanOffset;
     BitmapColor aColor = mpFncGetPixel (pScan, nColumn, mpBmpBuffer->maColorMask);
 
-    if (aColor.IsIndex())
+    if (!!mpBmpBuffer->maPalette)
         GetPaletteColor(aColor.GetIndex());
 
     return ((aColor.GetBlue())        & 0x000000ff)
@@ -206,7 +206,7 @@ SalPrinterBmp::GetPixelGray (sal_uInt32 nRow, sal_uInt32 nColumn) const
     Scanline pScan = mpScanAccess + nRow * mnScanOffset;
     BitmapColor aColor = mpFncGetPixel (pScan, nColumn, mpBmpBuffer->maColorMask);
 
-    if (aColor.IsIndex())
+    if (!!mpBmpBuffer->maPalette)
         aColor = mpBmpBuffer->maPalette[aColor.GetIndex()];
 
     return (  aColor.GetBlue()  *  28UL
@@ -221,7 +221,7 @@ SalPrinterBmp::GetPixelIdx (sal_uInt32 nRow, sal_uInt32 nColumn) const
     Scanline pScan = mpScanAccess + nRow * mnScanOffset;
     BitmapColor aColor = mpFncGetPixel (pScan, nColumn, mpBmpBuffer->maColorMask);
 
-    if (aColor.IsIndex())
+    if (!!mpBmpBuffer->maPalette)
         return aColor.GetIndex();
     else
         return 0;