handle strange brightness+contrast adjustment from msoffice (fdo#38410)

LO uses basically the formula "newpixel=(oldpixel-128)*contrast+128+brightness",
i.e. contrast is applied first. It looks like there's no "oficial" formula for this,
so a formula that applies brightness first would be ok too. MSO for some weird reason
apparently uses a formula that applies half of brightness before contrast and
half afterwards (insert funny political correctness or compromise joke here).
While the result is the same like with the LO formula if only either brightness
or contrast is adjusted, the result is different if both are involved. Just modify
the image using the MSO algorithm if this is the case.

Conflicts:
filter/source/msfilter/msdffimp.cxx
include/vcl/bitmap.hxx
include/vcl/bitmapex.hxx
include/vcl/gdimtf.hxx
vcl/source/gdi/bitmap3.cxx
vcl/source/gdi/bitmapex.cxx
vcl/source/gdi/gdimtf.cxx

Change-Id: I55fe8f395832685b90f024cf2f58b0797c1ba588

7 files changed, 61 insertions, 22 deletions

diff --git a/filter/source/msfilter/msdffimp.cxx b/filter/source/msfilter/msdffimp.cxx
index 09f15c05e1a4..f37a5551151b 100644
--- a/filter/source/msfilter/msdffimp.cxx
+++ b/filter/source/msfilter/msdffimp.cxx
@@ -3816,7 +3816,12 @@ SdrObject* SvxMSDffManager::ImportGraphic( SvStream& rSt, SfxItemSet& rSet, cons
 
             if ( nContrast || nBrightness || ( nGamma != 0x10000 ) || ( eDrawMode != GRAPHICDRAWMODE_STANDARD ) )
             {
-                if ( ( rObjData.nSpFlags & SP_FOLESHAPE ) == 0 )
+                // MSO uses a different algorithm for contrast+brightness, LO applies contrast before brightness,
+                // while MSO apparently applies half of brightness before contrast and half after. So if only
+                // contrast or brightness need to be altered, the result is the same, but if both are involved,
+                // there's no way to map that, so just force a conversion of the image.
+                bool needsConversion = nContrast != 0 && nBrightness != 0;
+                if ( ( rObjData.nSpFlags & SP_FOLESHAPE ) == 0 && !needsConversion )
                 {
                     if ( nBrightness )
                         rSet.Put( SdrGrafLuminanceItem( nBrightness ) );
@@ -3841,7 +3846,7 @@ SdrObject* SvxMSDffManager::ImportGraphic( SvStream& rSt, SfxItemSet& rSet, cons
                         {
                             BitmapEx    aBitmapEx( aGraf.GetBitmapEx() );
                             if ( nBrightness || nContrast || ( nGamma != 0x10000 ) )
-                                aBitmapEx.Adjust( nBrightness, (sal_Int16)nContrast, 0, 0, 0, (double)nGamma / 0x10000, sal_False );
+                                aBitmapEx.Adjust( nBrightness, (sal_Int16)nContrast, 0, 0, 0, (double)nGamma / 0x10000, false, true );
                             if ( eDrawMode == GRAPHICDRAWMODE_GREYS )
                                 aBitmapEx.Convert( BMP_CONVERSION_8BIT_GREYS );
                             else if ( eDrawMode == GRAPHICDRAWMODE_MONO )
@@ -3855,7 +3860,7 @@ SdrObject* SvxMSDffManager::ImportGraphic( SvStream& rSt, SfxItemSet& rSet, cons
                         {
                             GDIMetaFile aGdiMetaFile( aGraf.GetGDIMetaFile() );
                             if ( nBrightness || nContrast || ( nGamma != 0x10000 ) )
-                                aGdiMetaFile.Adjust( nBrightness, (sal_Int16)nContrast, 0, 0, 0, (double)nGamma / 0x10000, sal_False );
+                                aGdiMetaFile.Adjust( nBrightness, (sal_Int16)nContrast, 0, 0, 0, (double)nGamma / 0x10000, false, true );
                             if ( eDrawMode == GRAPHICDRAWMODE_GREYS )
                                 aGdiMetaFile.Convert( MTF_CONVERSION_8BIT_GREYS );
                             else if ( eDrawMode == GRAPHICDRAWMODE_MONO )
diff --git a/include/vcl/bitmap.hxx b/include/vcl/bitmap.hxx
index d555d04e0c1c..4759937e915a 100644
--- a/include/vcl/bitmap.hxx
+++ b/include/vcl/bitmap.hxx
@@ -796,6 +796,9 @@ public:
         If sal_True, invert the channel values with the logical 'not' operator
 
         @return sal_True, if the operation was completed successfully.
+
+        @param msoBrightness
+        Use the same formula for brightness as used by MSOffice.
      */
     sal_Bool                    Adjust( short nLuminancePercent = 0,
                                     short nContrastPercent = 0,
@@ -803,7 +806,8 @@ public:
                                     short nChannelGPercent = 0,
                                     short nChannelBPercent = 0,
                                     double fGamma = 1.0,
-                                    sal_Bool bInvert = sal_False );
+                                    bool bInvert = false,
+                                    bool msoBrightness = false );
 
     /** Apply specified filter to the bitmap
 
diff --git a/include/vcl/bitmapex.hxx b/include/vcl/bitmapex.hxx
index 00a3c4e83886..b63c9d5f94d3 100644
--- a/include/vcl/bitmapex.hxx
+++ b/include/vcl/bitmapex.hxx
@@ -344,6 +344,10 @@ public:
         If sal_True, invert the channel values with the logical 'not' operator
 
         @return sal_True, if the operation was completed successfully.
+
+        @param msoFormula
+        Use the same formula for brightness as used by MSOffice.
+
      */
     sal_Bool                Adjust( short nLuminancePercent = 0,
                                 short nContrastPercent = 0,
@@ -351,7 +355,8 @@ public:
                                 short nChannelGPercent = 0,
                                 short nChannelBPercent = 0,
                                 double fGamma = 1.0,
-                                sal_Bool bInvert = sal_False );
+                                bool bInvert = false,
+                                bool msoBrightness = false );
 
     /** Apply specified filter to the bitmap
 
diff --git a/include/vcl/gdimtf.hxx b/include/vcl/gdimtf.hxx
index c790acdd7c43..6865001c2ca7 100644
--- a/include/vcl/gdimtf.hxx
+++ b/include/vcl/gdimtf.hxx
@@ -150,7 +150,7 @@ public:
     void            Adjust( short nLuminancePercent = 0, short nContrastPercent = 0,
                             short nChannelRPercent = 0,  short nChannelGPercent = 0,
                             short nChannelBPercent = 0,  double fGamma = 1.0,
-                            sal_Bool bInvert = sal_False
+                            bool bInvert = false, bool msoBrightness = false
                     );
 
     void            Convert( MtfConversion eConversion );
diff --git a/vcl/source/gdi/bitmap3.cxx b/vcl/source/gdi/bitmap3.cxx
index 5b56ae4d9b7b..354a03b5ece9 100644
--- a/vcl/source/gdi/bitmap3.cxx
+++ b/vcl/source/gdi/bitmap3.cxx
@@ -3271,7 +3271,7 @@ sal_Bool Bitmap::Vectorize( GDIMetaFile& rMtf, sal_uInt8 cReduce, sal_uLong nFla
 
 sal_Bool Bitmap::Adjust( short nLuminancePercent, short nContrastPercent,
                      short nChannelRPercent, short nChannelGPercent, short nChannelBPercent,
-                     double fGamma, sal_Bool bInvert )
+                     double fGamma, bool bInvert, bool msoBrightness )
 {
     sal_Bool bRet = sal_False;
 
@@ -3303,8 +3303,11 @@ sal_Bool Bitmap::Adjust( short nLuminancePercent, short nContrastPercent,
             else
                 fM = ( 128.0 + 1.27 * MinMax( nContrastPercent, -100L, 0L ) ) / 128.0;
 
-            // total offset = luminance offset + contrast offset
-            fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55 + 128.0 - fM * 128.0;
+            if(!msoBrightness)
+                // total offset = luminance offset + contrast offset
+                fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55 + 128.0 - fM * 128.0;
+            else
+                fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55;
 
             // channel offset = channel offset  + total offset
             fROff = nChannelRPercent * 2.55 + fOff;
@@ -3318,10 +3321,21 @@ sal_Bool Bitmap::Adjust( short nLuminancePercent, short nContrastPercent,
             // create mapping table
             for( nX = 0L; nX < 256L; nX++ )
             {
-                cMapR[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fROff ), 0L, 255L );
-                cMapG[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fGOff ), 0L, 255L );
-                cMapB[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fBOff ), 0L, 255L );
-
+                if(!msoBrightness)
+                {
+                    cMapR[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fROff ), 0L, 255L );
+                    cMapG[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fGOff ), 0L, 255L );
+                    cMapB[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fBOff ), 0L, 255L );
+                }
+                else
+                {
+                    // LO simply uses (in a somewhat optimized form) "newcolor = (oldcolor-128)*contrast+brightness+128"
+                    // as the formula, i.e. contrast first, brightness afterwards. MSOffice, for whatever weird reason,
+                    // use neither first, but apparently it applies half of brightness before contrast and half afterwards.
+                    cMapR[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fROff/2-128) * fM + 128 + fROff/2 ), 0L, 255L );
+                    cMapG[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fGOff/2-128) * fM + 128 + fGOff/2 ), 0L, 255L );
+                    cMapB[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fBOff/2-128) * fM + 128 + fBOff/2 ), 0L, 255L );
+                }
                 if( bGamma )
                 {
                     cMapR[ nX ] = GAMMA( cMapR[ nX ], fGamma );
diff --git a/vcl/source/gdi/bitmapex.cxx b/vcl/source/gdi/bitmapex.cxx
index f60c583f1dcd..87564d852be8 100644
--- a/vcl/source/gdi/bitmapex.cxx
+++ b/vcl/source/gdi/bitmapex.cxx
@@ -633,11 +633,11 @@ sal_Bool BitmapEx::Replace( const Color* pSearchColors, const Color* pReplaceCol
 
 sal_Bool BitmapEx::Adjust( short nLuminancePercent, short nContrastPercent,
                        short nChannelRPercent, short nChannelGPercent, short nChannelBPercent,
-                       double fGamma, sal_Bool bInvert )
+                       double fGamma, bool bInvert, bool msoBrightness )
 {
     return( !!aBitmap ? aBitmap.Adjust( nLuminancePercent, nContrastPercent,
                                         nChannelRPercent, nChannelGPercent, nChannelBPercent,
-                                        fGamma, bInvert ) : sal_False );
+                                        fGamma, bInvert, msoBrightness ) : false );
 }
 
 sal_Bool BitmapEx::Filter( BmpFilter eFilter, const BmpFilterParam* pFilterParam, const Link* pProgress )
diff --git a/vcl/source/gdi/gdimtf.cxx b/vcl/source/gdi/gdimtf.cxx
index 90e691beeed9..17cbb3765bf6 100644
--- a/vcl/source/gdi/gdimtf.cxx
+++ b/vcl/source/gdi/gdimtf.cxx
@@ -2175,7 +2175,7 @@ void GDIMetaFile::ImplExchangeColors( ColorExchangeFnc pFncCol, const void* pCol
 
 void GDIMetaFile::Adjust( short nLuminancePercent, short nContrastPercent,
                           short nChannelRPercent, short nChannelGPercent,
-                          short nChannelBPercent, double fGamma, sal_Bool bInvert )
+                          short nChannelBPercent, double fGamma, bool bInvert, bool msoBrightness )
 {
     // nothing to do? => return quickly
     if( nLuminancePercent || nContrastPercent ||
@@ -2196,8 +2196,11 @@ void GDIMetaFile::Adjust( short nLuminancePercent, short nContrastPercent,
         else
             fM = ( 128.0 + 1.27 * MinMax( nContrastPercent, -100L, 0L ) ) / 128.0;
 
-        // total offset = luminance offset + contrast offset
-        fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55 + 128.0 - fM * 128.0;
+        if(!msoBrightness)
+            // total offset = luminance offset + contrast offset
+            fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55 + 128.0 - fM * 128.0;
+        else
+            fOff = MinMax( nLuminancePercent, -100L, 100L ) * 2.55;
 
         // channel offset = channel offset  + total offset
         fROff = nChannelRPercent * 2.55 + fOff;
@@ -2211,10 +2214,18 @@ void GDIMetaFile::Adjust( short nLuminancePercent, short nContrastPercent,
         // create mapping table
         for( long nX = 0L; nX < 256L; nX++ )
         {
-            aColParam.pMapR[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fROff ), 0L, 255L );
-            aColParam.pMapG[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fGOff ), 0L, 255L );
-            aColParam.pMapB[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fBOff ), 0L, 255L );
-
+            if(!msoBrightness)
+            {
+                aColParam.pMapR[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fROff ), 0L, 255L );
+                aColParam.pMapG[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fGOff ), 0L, 255L );
+                aColParam.pMapB[ nX ] = (sal_uInt8) MinMax( FRound( nX * fM + fBOff ), 0L, 255L );
+            }
+            else
+            {
+                aColParam.pMapR[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fROff/2-128) * fM + 128 + fROff/2 ), 0L, 255L );
+                aColParam.pMapG[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fGOff/2-128) * fM + 128 + fGOff/2 ), 0L, 255L );
+                aColParam.pMapB[ nX ] = (sal_uInt8) MinMax( FRound( (nX+fBOff/2-128) * fM + 128 + fBOff/2 ), 0L, 255L );
+            }
             if( bGamma )
             {
                 aColParam.pMapR[ nX ] = GAMMA( aColParam.pMapR[ nX ], fGamma );