1 files changed, 124 insertions, 0 deletions
diff --git a/vcl/source/bitmap/alpha.cxx b/vcl/source/bitmap/alpha.cxx
new file mode 100644
index 000000000..deeba1280
--- /dev/null
+++ b/vcl/source/bitmap/alpha.cxx
@@ -0,0 +1,124 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <tools/color.hxx>
+#include <vcl/alpha.hxx>
+
+#include <bitmap/BitmapWriteAccess.hxx>
+#include <salinst.hxx>
+#include <svdata.hxx>
+#include <salbmp.hxx>
+#include <sal/log.hxx>
+
+AlphaMask::AlphaMask() = default;
+
+AlphaMask::AlphaMask( const Bitmap& rBitmap ) :
+    Bitmap( rBitmap )
+{
+    if( !rBitmap.IsEmpty() )
+        Convert( BmpConversion::N8BitNoConversion );
+}
+
+AlphaMask::AlphaMask( const AlphaMask& ) = default;
+
+AlphaMask::AlphaMask( AlphaMask&& ) = default;
+
+AlphaMask::AlphaMask( const Size& rSizePixel, const sal_uInt8* pEraseTransparency )
+    : Bitmap(rSizePixel, vcl::PixelFormat::N8_BPP, &Bitmap::GetGreyPalette(256))
+{
+    if( pEraseTransparency )
+        Bitmap::Erase( Color( *pEraseTransparency, *pEraseTransparency, *pEraseTransparency ) );
+}
+
+AlphaMask::~AlphaMask() = default;
+
+AlphaMask& AlphaMask::operator=( const Bitmap& rBitmap )
+{
+    *static_cast<Bitmap*>(this) = rBitmap;
+
+    if( !rBitmap.IsEmpty() )
+        Convert( BmpConversion::N8BitNoConversion );
+
+    return *this;
+}
+
+const Bitmap& AlphaMask::ImplGetBitmap() const
+{
+    return *this;
+}
+
+void AlphaMask::ImplSetBitmap( const Bitmap& rBitmap )
+{
+    SAL_WARN_IF(rBitmap.getPixelFormat() != vcl::PixelFormat::N8_BPP, "vcl.gdi", "Bitmap should be 8bpp, not " << vcl::pixelFormatBitCount(rBitmap.getPixelFormat()) << "bpp" );
+    SAL_WARN_IF( !rBitmap.HasGreyPalette8Bit(), "vcl.gdi", "Bitmap isn't greyscale" );
+    *static_cast<Bitmap*>(this) = rBitmap;
+}
+
+Bitmap const & AlphaMask::GetBitmap() const
+{
+    return ImplGetBitmap();
+}
+
+void AlphaMask::Erase( sal_uInt8 cTransparency )
+{
+    Bitmap::Erase( Color( cTransparency, cTransparency, cTransparency ) );
+}
+
+void AlphaMask::BlendWith(const Bitmap& rOther)
+{
+    std::shared_ptr<SalBitmap> xImpBmp(ImplGetSVData()->mpDefInst->CreateSalBitmap());
+    if (xImpBmp->Create(*ImplGetSalBitmap()) && xImpBmp->AlphaBlendWith(*rOther.ImplGetSalBitmap()))
+    {
+        ImplSetSalBitmap(xImpBmp);
+        return;
+    }
+    AlphaMask aOther(rOther); // to 8 bits
+    Bitmap::ScopedReadAccess pOtherAcc(aOther);
+    AlphaScopedWriteAccess pAcc(*this);
+    if (!(pOtherAcc && pAcc && pOtherAcc->GetBitCount() == 8 && pAcc->GetBitCount() == 8))
+        return;
+
+    const tools::Long nHeight = std::min(pOtherAcc->Height(), pAcc->Height());
+    const tools::Long nWidth = std::min(pOtherAcc->Width(), pAcc->Width());
+    for (tools::Long y = 0; y < nHeight; ++y)
+    {
+        Scanline scanline = pAcc->GetScanline( y );
+        ConstScanline otherScanline = pOtherAcc->GetScanline( y );
+        for (tools::Long x = 0; x < nWidth; ++x)
+        {
+            // Use sal_uInt16 for following multiplication
+            const sal_uInt16 nGrey1 = *scanline;
+            const sal_uInt16 nGrey2 = *otherScanline;
+            *scanline = static_cast<sal_uInt8>(nGrey1 + nGrey2 - nGrey1 * nGrey2 / 255);
+            ++scanline;
+            ++otherScanline;
+        }
+    }
+}
+
+void AlphaMask::ReleaseAccess( BitmapReadAccess* pAccess )
+{
+    if( pAccess )
+    {
+        Bitmap::ReleaseAccess( pAccess );
+        Convert( BmpConversion::N8BitNoConversion );
+    }
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */