sd/source/ui/slidesorter/cache/SlsBitmapCompressor.hxx

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  30
  31 #ifndef SD_SLIDESORTER_BITMAP_COMPRESSOR_HXX
  32 #define SD_SLIDESORTER_BITMAP_COMPRESSOR_HXX
  33
  34 #include <sal/types.h>
  35 #include <tools/gen.hxx>
  36 #include <boost/shared_ptr.hpp>
  37
  38 class BitmapEx;
  39
  40 namespace sd { namespace slidesorter { namespace cache {
  41
  42 class BitmapReplacement;
  43
  44
  45 /** This interface class provides the minimal method set for classes that
  46     implement the compression and decompression of preview bitmaps.
  47 */
  48 class BitmapCompressor
  49 {
  50 public:
  51     /** Compress the given bitmap into a replacement format that is specific
  52         to the compressor class.
  53     */
  54     virtual ::boost::shared_ptr<BitmapReplacement> Compress (
  55         const ::boost::shared_ptr<BitmapEx>& rpBitmap) const = 0;
  56
  57     /** Decompress the given replacement data into a preview bitmap.
  58         Depending on the compression technique the returned bitmap may
  59         differ from the original bitmap given to the Compress() method.  It
  60         may even of the wrong size or empty or the NULL pointer.  It is the
  61         task of the caller to create a new preview bitmap if the returned
  62         one is not as desired.
  63     */
  64     virtual ::boost::shared_ptr<BitmapEx> Decompress (const BitmapReplacement& rBitmapData)const=0;
  65
  66     /** Return whether the compression and decompression is lossless.  This
  67         value is used by the caller of Decompress() to decide whether to use
  68         the returned bitmap as is or if a new preview has to be created.
  69     */
  70     virtual bool IsLossless (void) const = 0;
  71 };
  72
  73
  74
  75 /** Interface for preview bitmap replacements.  Each bitmap
  76     compressor/decompressor has to provide an implementation that is
  77     suitable to store the compressed bitmaps.
  78 */
  79 class BitmapReplacement
  80 {
  81 public:
  82     virtual sal_Int32 GetMemorySize (void) const { return 0; }
  83 };
  84
  85
  86
  87
  88 /** This is one trivial bitmap compressor.  It stores bitmaps unmodified
  89     instead of compressing them.
  90     This compressor is lossless.
  91 */
  92 class NoBitmapCompression
  93     : public BitmapCompressor
  94 {
  95     class DummyReplacement;
  96 public:
  97     virtual ::boost::shared_ptr<BitmapReplacement> Compress (
  98         const ::boost::shared_ptr<BitmapEx>& rpBitmap) const;
  99     virtual ::boost::shared_ptr<BitmapEx> Decompress (const BitmapReplacement& rBitmapData) const;
 100     virtual bool IsLossless (void) const;
 101 };
 102
 103
 104
 105
 106 /** This is another trivial bitmap compressor.  Instead of compressing a
 107     bitmap, it throws the bitmap away.  Its Decompress() method returns a
 108     NULL pointer.  The caller has to create a new preview bitmap instead.
 109     This compressor clearly is not lossless.
 110 */
 111 class CompressionByDeletion
 112     : public BitmapCompressor
 113 {
 114 public:
 115     virtual ::boost::shared_ptr<BitmapReplacement> Compress (
 116         const ::boost::shared_ptr<BitmapEx>& rpBitmap) const;
 117     virtual ::boost::shared_ptr<BitmapEx> Decompress (const BitmapReplacement& rBitmapData) const;
 118     virtual bool IsLossless (void) const;
 119 };
 120
 121
 122
 123
 124 /** Compress a preview bitmap by reducing its resolution.  While the aspect
 125     ratio is maintained the horizontal resolution is scaled down to 100
 126     pixels.
 127     This compressor is not lossless.
 128 */
 129 class ResolutionReduction
 130     : public BitmapCompressor
 131 {
 132     class ResolutionReducedReplacement;
 133     static const sal_Int32 mnWidth = 100;
 134 public:
 135     virtual ::boost::shared_ptr<BitmapReplacement> Compress (
 136         const ::boost::shared_ptr<BitmapEx>& rpBitmap) const;
 137     /** Scale the replacement bitmap up to the original size.
 138     */
 139     virtual ::boost::shared_ptr<BitmapEx> Decompress (const BitmapReplacement& rBitmapData) const;
 140     virtual bool IsLossless (void) const;
 141 };
 142
 143
 144
 145
 146 /** Compress preview bitmaps using the PNG format.
 147     This compressor is lossless.
 148 */
 149 class PngCompression
 150     : public BitmapCompressor
 151 {
 152     class PngReplacement;
 153 public:
 154     virtual ::boost::shared_ptr<BitmapReplacement> Compress (
 155         const ::boost::shared_ptr<BitmapEx>& rpBitmap) const;
 156     virtual ::boost::shared_ptr<BitmapEx> Decompress (const BitmapReplacement& rBitmapData) const;
 157     virtual bool IsLossless (void) const;
 158 };
 159
 160
 161 } } } // end of namespace ::sd::slidesorter::cache
 162
 163 #endif