just calculate the scanline positions

rather than generating a big offset table to dramatically reduce the amount of
memory loading graphics takes

Change-Id: I8a4b1dc5cbcb686d6b8570f2eeef61ee0fe25515
Reviewed-on: https://gerrit.libreoffice.org/35005Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

include/vcl/bitmapaccess.hxx

@@ -115,7 +115,6 @@ protected:
     FncSetPixel mFncSetPixel;
 
     SAL_DLLPRIVATE void ImplInitScanBuffer( Bitmap& rBitmap );
-    SAL_DLLPRIVATE void ImplClearScanBuffer();
     SAL_DLLPRIVATE bool ImplSetAccessPointers( ScanlineFormat nFormat );
 
 public:
@@ -303,13 +302,11 @@ inline const BitmapColor& BitmapInfoAccess::GetPaletteColor( sal_uInt16 nColor )
     return mpBuffer->maPalette[nColor];
 }
 
-
 inline const BitmapColor& BitmapInfoAccess::GetBestPaletteColor(const BitmapColor& rBitmapColor) const
 {
     return GetPaletteColor(GetBestPaletteIndex(rBitmapColor));
 }
 
-
 inline ColorMask& BitmapInfoAccess::GetColorMask() const
 {
     assert(mpBuffer && "Access is not valid!");
@@ -317,7 +314,6 @@ inline ColorMask& BitmapInfoAccess::GetColorMask() const
     return mpBuffer->maColorMask;
 }
 
-
 inline Scanline BitmapReadAccess::GetBuffer() const
 {
     assert(mpBuffer && "Access is not valid!");
@@ -325,32 +321,32 @@ inline Scanline BitmapReadAccess::GetBuffer() const
     return mpBuffer ? mpBuffer->mpBits : nullptr;
 }
 
-
 inline Scanline BitmapReadAccess::GetScanline(long nY) const
 {
-    assert(mpBuffer && mpScanBuf && "Access is not valid!");
+    assert(mpBuffer && "Access is not valid!");
     assert(nY < mpBuffer->mnHeight && "y-coordinate out of range!");
 
-    return mpScanBuf[nY];
+    if (mpBuffer->mnFormat & ScanlineFormat::TopDown)
+    {
+        return mpBuffer->mpBits + (nY * mpBuffer->mnScanlineSize);
+    }
+    return mpBuffer->mpBits + ((mpBuffer->mnHeight - 1 - nY) * mpBuffer->mnScanlineSize);
 }
 
-
 inline BitmapColor BitmapReadAccess::GetPixel(long nY, long nX) const
 {
-    assert(mpBuffer && mpScanBuf && "Access is not valid!");
+    assert(mpBuffer && "Access is not valid!");
     assert(nX < mpBuffer->mnWidth && "x-coordinate out of range!");
     assert(nY < mpBuffer->mnHeight && "y-coordinate out of range!");
 
-    return mFncGetPixel(mpScanBuf[nY], nX, maColorMask );
+    return mFncGetPixel(GetScanline(nY), nX, maColorMask );
 }
 
-
 inline sal_uInt8 BitmapReadAccess::GetPixelIndex(long nY, long nX) const
 {
     return GetPixel(nY, nX).GetBlueOrIndex();
 }
 
-
 inline BitmapColor BitmapReadAccess::GetPixelFromData(const sal_uInt8* pData, long nX) const
 {
     assert(pData && "Access is not valid!");
@@ -358,7 +354,6 @@ inline BitmapColor BitmapReadAccess::GetPixelFromData(const sal_uInt8* pData, lo
     return mFncGetPixel( pData, nX, maColorMask );
 }
 
-
 inline void BitmapReadAccess::SetPixelOnData(sal_uInt8* pData, long nX, const BitmapColor& rBitmapColor)
 {
     assert(pData && "Access is not valid!");
@@ -413,7 +408,7 @@ inline void BitmapWriteAccess::SetPixel(long nY, long nX, const BitmapColor& rBi
     assert(nX < mpBuffer->mnWidth && "x-coordinate out of range!");
     assert(nY < mpBuffer->mnHeight && "y-coordinate out of range!");
 
-    mFncSetPixel(mpScanBuf[nY], nX, rBitmapColor, maColorMask);
+    mFncSetPixel(GetScanline(nY), nX, rBitmapColor, maColorMask);
 }
 
 

vcl/source/gdi/bmpacc.cxx

@@ -102,7 +102,6 @@ sal_uInt16 BitmapInfoAccess::GetBestPaletteIndex( const BitmapColor& rBitmapColo
 
 BitmapReadAccess::BitmapReadAccess( Bitmap& rBitmap, BitmapAccessMode nMode ) :
             BitmapInfoAccess( rBitmap, nMode ),
-            mpScanBuf       ( nullptr ),
             mFncGetPixel    ( nullptr ),
             mFncSetPixel    ( nullptr )
 {
@@ -111,7 +110,6 @@ BitmapReadAccess::BitmapReadAccess( Bitmap& rBitmap, BitmapAccessMode nMode ) :
 
 BitmapReadAccess::BitmapReadAccess( Bitmap& rBitmap ) :
             BitmapInfoAccess( rBitmap, BitmapAccessMode::Read ),
-            mpScanBuf       ( nullptr ),
             mFncGetPixel    ( nullptr ),
             mFncSetPixel    ( nullptr )
 {
@@ -120,7 +118,6 @@ BitmapReadAccess::BitmapReadAccess( Bitmap& rBitmap ) :
 
 BitmapReadAccess::~BitmapReadAccess()
 {
-    ImplClearScanBuffer();
 }
 
 void BitmapReadAccess::ImplInitScanBuffer( Bitmap& rBitmap )
@@ -134,45 +131,15 @@ void BitmapReadAccess::ImplInitScanBuffer( Bitmap& rBitmap )
 
     maColorMask = mpBuffer->maColorMask;
 
-    bool bOk(true);
-    const long nHeight = mpBuffer->mnHeight;
-    Scanline pTmpLine = mpBuffer->mpBits;
-    try
-    {
-        mpScanBuf = new Scanline[ nHeight ];
-        if( mpBuffer->mnFormat & ScanlineFormat::TopDown )
-        {
-            for( long nY = 0; nY < nHeight; nY++, pTmpLine += mpBuffer->mnScanlineSize )
-                mpScanBuf[ nY ] = pTmpLine;
-        }
-        else
-        {
-            for( long nY = nHeight - 1; nY >= 0; nY--, pTmpLine += mpBuffer->mnScanlineSize )
-                mpScanBuf[ nY ] = pTmpLine;
-        }
-        bOk = ImplSetAccessPointers(RemoveScanline(mpBuffer->mnFormat));
-    }
-    catch (const std::bad_alloc&)
-    {
-        bOk = false;
-    }
+    bool bOk = ImplSetAccessPointers(RemoveScanline(mpBuffer->mnFormat));
 
     if (!bOk)
     {
-        delete[] mpScanBuf;
-        mpScanBuf = nullptr;
-
         xImpBmp->ImplReleaseBuffer( mpBuffer, mnAccessMode );
         mpBuffer = nullptr;
     }
 }
 
-void BitmapReadAccess::ImplClearScanBuffer()
-{
-    delete[] mpScanBuf;
-    mpScanBuf = nullptr;
-}
-
 bool BitmapReadAccess::ImplSetAccessPointers( ScanlineFormat nFormat )
 {
     bool bRet = true;
@@ -405,7 +372,7 @@ void BitmapWriteAccess::CopyScanline( long nY, const BitmapReadAccess& rReadAcc
     if( ( GetScanlineFormat() == rReadAcc.GetScanlineFormat() ) &&
         ( GetScanlineSize() >= rReadAcc.GetScanlineSize() ) )
     {
-        memcpy( mpScanBuf[ nY ], rReadAcc.GetScanline( nY ), rReadAcc.GetScanlineSize() );
+        memcpy(GetScanline(nY), rReadAcc.GetScanline(nY), rReadAcc.GetScanlineSize());
     }
     else
         // TODO: use fastbmp infrastructure
@@ -428,7 +395,7 @@ void BitmapWriteAccess::CopyScanline( long nY, ConstScanline aSrcScanline,
     if( nCount )
     {
         if( GetScanlineFormat() == RemoveScanline( nSrcScanlineFormat ) )
-            memcpy( mpScanBuf[ nY ], aSrcScanline, nCount );
+            memcpy(GetScanline(nY), aSrcScanline, nCount);
         else
         {
             DBG_ASSERT( nFormat != ScanlineFormat::N8BitTcMask &&