slidesorter/cache/SlsBitmapCompressor.cxx

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 *
 * Licensed to the Apache Software Foundation (ASF) under one
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 * 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
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 *
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 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_sd.hxx"

#include "SlsBitmapCompressor.hxx"

#include <tools/stream.hxx>
#include <vcl/bitmapex.hxx>
#include <vcl/pngread.hxx>
#include <vcl/pngwrite.hxx>

namespace sd { namespace slidesorter { namespace cache {


//===== NoBitmapCompression ===================================================

/** This dummy replacement simply stores a shared pointer to the original
    preview bitmap.
*/
class NoBitmapCompression::DummyReplacement
    : public BitmapReplacement
{
public:
    Bitmap maPreview;
    Size maOriginalSize;

    DummyReplacement (const Bitmap& rPreview) : maPreview(rPreview)  { }
    virtual ~DummyReplacement(void) {}
    virtual sal_Int32 GetMemorySize (void) const { return maPreview.GetSizeBytes(); }
};


::boost::shared_ptr<BitmapReplacement> NoBitmapCompression::Compress (const Bitmap& rBitmap) const
{
    return ::boost::shared_ptr<BitmapReplacement>(new DummyReplacement(rBitmap));
}

Bitmap NoBitmapCompression::Decompress (const BitmapReplacement& rBitmapData) const
{
    return dynamic_cast<const DummyReplacement&>(rBitmapData).maPreview;
}


bool NoBitmapCompression::IsLossless (void) const
{
    return true;
}


//===== CompressionByDeletion =================================================

::boost::shared_ptr<BitmapReplacement> CompressionByDeletion::Compress (const Bitmap& ) const
{
    return ::boost::shared_ptr<BitmapReplacement>();
}


Bitmap CompressionByDeletion::Decompress (const BitmapReplacement& ) const
{
    // Return a NULL pointer.  This will eventually lead to a request for
    // the creation of a new one.
    return Bitmap();
}


bool CompressionByDeletion::IsLossless (void) const
{
    return false;
}


//===== ResolutionReduction ===================================================

/** Store a scaled down bitmap together with the original size.
*/
class ResolutionReduction::ResolutionReducedReplacement : public BitmapReplacement
{
public:
    Bitmap maPreview;
    Size maOriginalSize;

    virtual ~ResolutionReducedReplacement();
    virtual sal_Int32 GetMemorySize (void) const;
};

ResolutionReduction::ResolutionReducedReplacement::~ResolutionReducedReplacement()
{
}

sal_Int32 ResolutionReduction::ResolutionReducedReplacement::GetMemorySize (void) const
{
    return maPreview.GetSizeBytes();
}

::boost::shared_ptr<BitmapReplacement> ResolutionReduction::Compress (
    const Bitmap& rBitmap) const
{
    ResolutionReducedReplacement* pResult = new ResolutionReducedReplacement();
    pResult->maPreview = rBitmap;
    Size aSize (rBitmap.GetSizePixel());
    pResult->maOriginalSize = aSize;
    if (aSize.Width()>0 && aSize.Width()<mnWidth)
    {
        int nHeight = aSize.Height() * mnWidth / aSize.Width() ;
        pResult->maPreview.Scale(Size(mnWidth,nHeight));
    }

    return ::boost::shared_ptr<BitmapReplacement>(pResult);
}


Bitmap ResolutionReduction::Decompress (const BitmapReplacement& rBitmapData) const
{
    Bitmap aResult;

    const ResolutionReducedReplacement* pData (
        dynamic_cast<const ResolutionReducedReplacement*>(&rBitmapData));

    if ( ! pData->maPreview.IsEmpty())
    {
        aResult = pData->maPreview;
        if (pData->maOriginalSize.Width() > mnWidth)
            aResult.Scale(pData->maOriginalSize);
    }

    return aResult;
}


bool ResolutionReduction::IsLossless (void) const
{
    return false;
}


//===== PNGCompression ========================================================


class PngCompression::PngReplacement : public BitmapReplacement
{
public:
    void* mpData;
    sal_Int32 mnDataSize;
    Size maImageSize;
    PngReplacement (void)
        : mpData(NULL),
          mnDataSize(0),
          maImageSize(0,0)
    {}
    virtual ~PngReplacement (void)
    {
        delete [] (char*)mpData;
    }
    virtual sal_Int32 GetMemorySize (void) const
    {
        return mnDataSize;
    }
};


::boost::shared_ptr<BitmapReplacement> PngCompression::Compress (const Bitmap& rBitmap) const
{
    ::vcl::PNGWriter aWriter (rBitmap);
    SvMemoryStream aStream (32768, 32768);
    aWriter.Write(aStream);

    PngReplacement* pResult = new PngReplacement();
    pResult->maImageSize = rBitmap.GetSizePixel();
    pResult->mnDataSize = aStream.Tell();
    pResult->mpData = new char[pResult->mnDataSize];
    memcpy(pResult->mpData, aStream.GetData(), pResult->mnDataSize);

    return ::boost::shared_ptr<BitmapReplacement>(pResult);
}


Bitmap PngCompression::Decompress (
    const BitmapReplacement& rBitmapData) const
{
    Bitmap aResult;
    const PngReplacement* pData (dynamic_cast<const PngReplacement*>(&rBitmapData));
    if (pData != NULL)
    {
        SvMemoryStream aStream (pData->mpData, pData->mnDataSize, STREAM_READ);
        ::vcl::PNGReader aReader (aStream);
        aResult = aReader.Read().GetBitmap();
    }

    return aResult;
}


bool PngCompression::IsLossless (void) const
{
    return true;
}


} } } // end of namespace ::sd::slidesorter::cache