do not force pixel reading in VclCanvasBitmap ctor

BitmapReadAccess is not need by most calls in the class, and
creating it already in ctor forces reading of all pixels,
which is expensive e.g. when fetching them from the GPU.

Change-Id: Ie5da67d1c41ad798928646077b5b4c33147d0ea9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/128308
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

2 files changed, 81 insertions, 47 deletions

diff --git a/vcl/inc/canvasbitmap.hxx b/vcl/inc/canvasbitmap.hxx
index cb50e82bf8d9..54586a1ad60e 100644
--- a/vcl/inc/canvasbitmap.hxx
+++ b/vcl/inc/canvasbitmap.hxx
@@ -38,8 +38,10 @@ namespace vcl::unotools
         BitmapEx                                       m_aBmpEx;
         ::Bitmap                                       m_aBitmap;
         ::Bitmap                                       m_aAlpha;
-        Bitmap::ScopedReadAccess                       m_pBmpAcc;
-        Bitmap::ScopedReadAccess                       m_pAlphaAcc;
+        Bitmap::ScopedInfoAccess                       m_pBmpAcc;
+        Bitmap::ScopedInfoAccess                       m_pAlphaAcc;
+        std::optional<Bitmap::ScopedReadAccess>        m_pBmpReadAcc;
+        std::optional<Bitmap::ScopedReadAccess>        m_pAlphaReadAcc;
         css::uno::Sequence<sal_Int8>                   m_aComponentTags;
         css::uno::Sequence<sal_Int32>                  m_aComponentBitCounts;
         css::rendering::IntegerBitmapLayout            m_aLayout;
@@ -53,6 +55,8 @@ namespace vcl::unotools
         bool                                           m_bPalette;
 
         SAL_DLLPRIVATE void setComponentInfo( sal_uInt32 redShift, sal_uInt32 greenShift, sal_uInt32 blueShift );
+        Bitmap::ScopedReadAccess& getBitmapReadAccess();
+        Bitmap::ScopedReadAccess& getAlphaReadAccess();
 
         virtual ~VclCanvasBitmap() override;
 
diff --git a/vcl/source/helper/canvasbitmap.cxx b/vcl/source/helper/canvasbitmap.cxx
index 2eaa16223789..301237e18e43 100644
--- a/vcl/source/helper/canvasbitmap.cxx
+++ b/vcl/source/helper/canvasbitmap.cxx
@@ -94,6 +94,24 @@ void VclCanvasBitmap::setComponentInfo( sal_uInt32 redShift, sal_uInt32 greenShi
     pCounts[bluePos]  = bitcount(blueShift);
 }
 
+Bitmap::ScopedReadAccess& VclCanvasBitmap::getBitmapReadAccess()
+{
+    // BitmapReadAccess is more expensive than BitmapInfoAccess,
+    // as the latter requires also pixels, which may need converted
+    // from the system format (and even fetched). Most calls here
+    // need only info access, create read access only on demand.
+    if(!m_pBmpReadAcc)
+        m_pBmpReadAcc.emplace(m_aBitmap);
+    return m_pBmpReadAcc.value();
+}
+
+Bitmap::ScopedReadAccess& VclCanvasBitmap::getAlphaReadAccess()
+{
+    if(!m_pAlphaReadAcc)
+        m_pAlphaReadAcc.emplace(m_aAlpha);
+    return m_pAlphaReadAcc.value();
+}
+
 VclCanvasBitmap::VclCanvasBitmap( const BitmapEx& rBitmap ) :
     m_aBmpEx( rBitmap ),
     m_aBitmap( rBitmap.GetBitmap() ),
@@ -110,7 +128,7 @@ VclCanvasBitmap::VclCanvasBitmap( const BitmapEx& rBitmap ) :
     if( m_aBmpEx.IsAlpha() )
     {
         m_aAlpha = m_aBmpEx.GetAlpha().GetBitmap();
-        m_pAlphaAcc = Bitmap::ScopedReadAccess(m_aAlpha);
+        m_pAlphaAcc = Bitmap::ScopedInfoAccess(m_aAlpha);
     }
 
     m_aLayout.ScanLines      = 0;
@@ -391,20 +409,23 @@ uno::Sequence< sal_Int8 > SAL_CALL VclCanvasBitmap::getData( rendering::IntegerB
 
     if( !m_aBmpEx.IsAlpha() )
     {
-        OSL_ENSURE(m_pBmpAcc,"Invalid bmp read access");
+        Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+        OSL_ENSURE(pBmpAcc,"Invalid bmp read access");
 
         // can return bitmap data as-is
         for( tools::Long y=aRequestedBytes.Top(); y<aRequestedBytes.Bottom(); ++y )
         {
-            Scanline pScan = m_pBmpAcc->GetScanline(y);
+            Scanline pScan = pBmpAcc->GetScanline(y);
             memcpy(pOutBuf, pScan+aRequestedBytes.Left(), aRequestedBytes.getWidth());
             pOutBuf += nScanlineStride;
         }
     }
     else
     {
-        OSL_ENSURE(m_pBmpAcc,"Invalid bmp read access");
-        OSL_ENSURE(m_pAlphaAcc,"Invalid alpha read access");
+        Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+        Bitmap::ScopedReadAccess& pAlphaAcc = getAlphaReadAccess();
+        OSL_ENSURE(pBmpAcc,"Invalid bmp read access");
+        OSL_ENSURE(pAlphaAcc,"Invalid alpha read access");
 
         // interleave alpha with bitmap data - note, bitcount is
         // always integer multiple of 8
@@ -420,23 +441,23 @@ uno::Sequence< sal_Int8 > SAL_CALL VclCanvasBitmap::getData( rendering::IntegerB
                 // input less than a byte - copy via GetPixel()
                 for( tools::Long x=aRequestedArea.Left(); x<aRequestedArea.Right(); ++x )
                 {
-                    *pOutScan++ = m_pBmpAcc->GetPixelIndex(y,x);
-                    *pOutScan++ = m_pAlphaAcc->GetPixelIndex(y,x);
+                    *pOutScan++ = pBmpAcc->GetPixelIndex(y,x);
+                    *pOutScan++ = pAlphaAcc->GetPixelIndex(y,x);
                 }
             }
             else
             {
                 const tools::Long nNonAlphaBytes( m_nBitsPerInputPixel/8 );
                 const tools::Long nScanlineOffsetLeft(aRequestedArea.Left()*nNonAlphaBytes);
-                Scanline  pScan = m_pBmpAcc->GetScanline(y) + nScanlineOffsetLeft;
-                Scanline pScanlineAlpha = m_pAlphaAcc->GetScanline( y );
+                Scanline  pScan = pBmpAcc->GetScanline(y) + nScanlineOffsetLeft;
+                Scanline pScanlineAlpha = pAlphaAcc->GetScanline( y );
 
                 // input integer multiple of byte - copy directly
                 for( tools::Long x=aRequestedArea.Left(); x<aRequestedArea.Right(); ++x )
                 {
                     for( tools::Long i=0; i<nNonAlphaBytes; ++i )
                         *pOutScan++ = *pScan++;
-                    *pOutScan++ = m_pAlphaAcc->GetIndexFromData( pScanlineAlpha, x );
+                    *pOutScan++ = pAlphaAcc->GetIndexFromData( pScanlineAlpha, x );
                 }
             }
 
@@ -477,16 +498,19 @@ uno::Sequence< sal_Int8 > SAL_CALL VclCanvasBitmap::getPixel( rendering::Integer
     const tools::Long nScanlineLeftOffset( pos.X*m_nBitsPerInputPixel/8 );
     if( !m_aBmpEx.IsAlpha() )
     {
-        assert(m_pBmpAcc && "Invalid bmp read access");
+        Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+        assert(pBmpAcc && "Invalid bmp read access");
 
         // can return bitmap data as-is
-        Scanline pScan = m_pBmpAcc->GetScanline(pos.Y);
+        Scanline pScan = pBmpAcc->GetScanline(pos.Y);
         memcpy(pOutBuf, pScan+nScanlineLeftOffset, aRet.getLength() );
     }
     else
     {
-        assert(m_pBmpAcc && "Invalid bmp read access");
-        assert(m_pAlphaAcc && "Invalid alpha read access");
+        Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+        Bitmap::ScopedReadAccess& pAlphaAcc = getAlphaReadAccess();
+        assert(pBmpAcc && "Invalid bmp read access");
+        assert(pAlphaAcc && "Invalid alpha read access");
 
         // interleave alpha with bitmap data - note, bitcount is
         // always integer multiple of 8
@@ -496,18 +520,18 @@ uno::Sequence< sal_Int8 > SAL_CALL VclCanvasBitmap::getPixel( rendering::Integer
         if( m_nBitsPerInputPixel < 8 )
         {
             // input less than a byte - copy via GetPixel()
-            *pOutBuf++ = m_pBmpAcc->GetPixelIndex(pos.Y,pos.X);
-            *pOutBuf   = m_pAlphaAcc->GetPixelIndex(pos.Y,pos.X);
+            *pOutBuf++ = pBmpAcc->GetPixelIndex(pos.Y,pos.X);
+            *pOutBuf   = pAlphaAcc->GetPixelIndex(pos.Y,pos.X);
         }
         else
         {
             const tools::Long nNonAlphaBytes( m_nBitsPerInputPixel/8 );
-            Scanline  pScan = m_pBmpAcc->GetScanline(pos.Y);
+            Scanline  pScan = pBmpAcc->GetScanline(pos.Y);
 
             // input integer multiple of byte - copy directly
             memcpy(pOutBuf, pScan+nScanlineLeftOffset, nNonAlphaBytes );
             pOutBuf += nNonAlphaBytes;
-            *pOutBuf++ = m_pAlphaAcc->GetPixelIndex(pos.Y,pos.X);
+            *pOutBuf++ = pAlphaAcc->GetPixelIndex(pos.Y,pos.X);
         }
     }
 
@@ -1014,7 +1038,8 @@ uno::Sequence<rendering::RGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToRGB
     uno::Sequence< rendering::RGBColor > aRes(nNumColors);
     rendering::RGBColor* pOut( aRes.getArray() );
 
-    ENSURE_OR_THROW(m_pBmpAcc,
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+    ENSURE_OR_THROW(pBmpAcc,
                     "Unable to get BitmapAccess");
 
     if( m_aBmpEx.IsAlpha() )
@@ -1025,8 +1050,8 @@ uno::Sequence<rendering::RGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToRGB
             // if palette, index is guaranteed to be 8 bit
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor(*pIn) :
-                m_pBmpAcc->GetPixelFromData(pIn,0);
+                pBmpAcc->GetPaletteColor(*pIn) :
+                pBmpAcc->GetPixelFromData(pIn,0);
 
             // TODO(F3): Convert result to sRGB color space
             *pOut++ = rendering::RGBColor(toDoubleColor(aCol.GetRed()),
@@ -1042,8 +1067,8 @@ uno::Sequence<rendering::RGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToRGB
         {
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor( m_pBmpAcc->GetPixelFromData( pIn, i ).GetIndex()) :
-                m_pBmpAcc->GetPixelFromData(pIn, i);
+                pBmpAcc->GetPaletteColor( pBmpAcc->GetPixelFromData( pIn, i ).GetIndex()) :
+                pBmpAcc->GetPixelFromData(pIn, i);
 
             // TODO(F3): Convert result to sRGB color space
             *pOut++ = rendering::RGBColor(toDoubleColor(aCol.GetRed()),
@@ -1066,7 +1091,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToAR
     uno::Sequence< rendering::ARGBColor > aRes(nNumColors);
     rendering::ARGBColor* pOut( aRes.getArray() );
 
-    ENSURE_OR_THROW(m_pBmpAcc,
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+    ENSURE_OR_THROW(pBmpAcc,
                     "Unable to get BitmapAccess");
 
     if( m_aBmpEx.IsAlpha() )
@@ -1079,8 +1105,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToAR
             // if palette, index is guaranteed to be 8 bit
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor(*pIn) :
-                m_pBmpAcc->GetPixelFromData(pIn,0);
+                pBmpAcc->GetPaletteColor(*pIn) :
+                pBmpAcc->GetPixelFromData(pIn,0);
 
             // TODO(F3): Convert result to sRGB color space
             *pOut++ = rendering::ARGBColor(1.0 - toDoubleColor(nAlphaFactor*pIn[nNonAlphaBytes]),
@@ -1096,8 +1122,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToAR
         {
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor( m_pBmpAcc->GetPixelFromData( pIn, i ).GetIndex() ) :
-                m_pBmpAcc->GetPixelFromData(pIn, i);
+                pBmpAcc->GetPaletteColor( pBmpAcc->GetPixelFromData( pIn, i ).GetIndex() ) :
+                pBmpAcc->GetPixelFromData(pIn, i);
 
             // TODO(F3): Convert result to sRGB color space
             *pOut++ = rendering::ARGBColor(1.0,
@@ -1121,7 +1147,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToPA
     uno::Sequence< rendering::ARGBColor > aRes(nNumColors);
     rendering::ARGBColor* pOut( aRes.getArray() );
 
-    ENSURE_OR_THROW(m_pBmpAcc,
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
+    ENSURE_OR_THROW(pBmpAcc,
                     "Unable to get BitmapAccess");
 
     if( m_aBmpEx.IsAlpha() )
@@ -1134,8 +1161,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToPA
             // if palette, index is guaranteed to be 8 bit
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor(*pIn) :
-                m_pBmpAcc->GetPixelFromData(pIn,0);
+                pBmpAcc->GetPaletteColor(*pIn) :
+                pBmpAcc->GetPixelFromData(pIn,0);
 
             // TODO(F3): Convert result to sRGB color space
             const double nAlpha( 1.0 - toDoubleColor(nAlphaFactor*pIn[nNonAlphaBytes]) );
@@ -1152,8 +1179,8 @@ uno::Sequence<rendering::ARGBColor> SAL_CALL VclCanvasBitmap::convertIntegerToPA
         {
             const BitmapColor aCol =
                 m_bPalette ?
-                m_pBmpAcc->GetPaletteColor( m_pBmpAcc->GetPixelFromData( pIn, i ).GetIndex() ) :
-                m_pBmpAcc->GetPixelFromData(pIn, i);
+                pBmpAcc->GetPaletteColor( pBmpAcc->GetPixelFromData( pIn, i ).GetIndex() ) :
+                pBmpAcc->GetPixelFromData(pIn, i);
 
             // TODO(F3): Convert result to sRGB color space
             *pOut++ = rendering::ARGBColor(1.0,
@@ -1175,6 +1202,7 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromRGB( con
 
     uno::Sequence< sal_Int8 > aRes(nNumBytes);
     sal_uInt8* pColors=reinterpret_cast<sal_uInt8*>(aRes.getArray());
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
 
     if( m_aBmpEx.IsAlpha() )
     {
@@ -1187,10 +1215,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromRGB( con
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
             pColors   += nNonAlphaBytes;
             *pColors++ = sal_uInt8(255);
         }
@@ -1205,10 +1233,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromRGB( con
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
         }
     }
 
@@ -1224,6 +1252,7 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromARGB( co
 
     uno::Sequence< sal_Int8 > aRes(nNumBytes);
     sal_uInt8* pColors=reinterpret_cast<sal_uInt8*>(aRes.getArray());
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
 
     if( m_aBmpEx.IsAlpha() )
     {
@@ -1236,10 +1265,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromARGB( co
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
             pColors   += nNonAlphaBytes;
             *pColors++ = 255 - toByteColor(rgbColor[i].Alpha);
         }
@@ -1254,10 +1283,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromARGB( co
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
         }
     }
 
@@ -1273,6 +1302,7 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromPARGB( c
 
     uno::Sequence< sal_Int8 > aRes(nNumBytes);
     sal_uInt8* pColors=reinterpret_cast<sal_uInt8*>(aRes.getArray());
+    Bitmap::ScopedReadAccess& pBmpAcc = getBitmapReadAccess();
 
     if( m_aBmpEx.IsAlpha() )
     {
@@ -1286,10 +1316,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromPARGB( c
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
             pColors   += nNonAlphaBytes;
             *pColors++ = 255 - toByteColor(nAlpha);
         }
@@ -1304,10 +1334,10 @@ uno::Sequence< ::sal_Int8 > SAL_CALL VclCanvasBitmap::convertIntegerFromPARGB( c
             const BitmapColor aCol2 =
                 m_bPalette ?
                 BitmapColor(
-                    sal::static_int_cast<sal_uInt8>(m_pBmpAcc->GetBestPaletteIndex( aCol ))) :
+                    sal::static_int_cast<sal_uInt8>(pBmpAcc->GetBestPaletteIndex( aCol ))) :
                 aCol;
 
-            m_pBmpAcc->SetPixelOnData(pColors,i,aCol2);
+            pBmpAcc->SetPixelOnData(pColors,i,aCol2);
         }
     }