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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 : #ifndef SD_SLIDESORTER_BITMAP_COMPRESSOR_HXX
21 : #define SD_SLIDESORTER_BITMAP_COMPRESSOR_HXX
22 :
23 : #include <sal/types.h>
24 : #include <tools/gen.hxx>
25 : #include <boost/shared_ptr.hpp>
26 :
27 :
28 : class Bitmap;
29 :
30 : namespace sd { namespace slidesorter { namespace cache {
31 :
32 : class BitmapReplacement;
33 :
34 :
35 : /** This interface class provides the minimal method set for classes that
36 : implement the compression and decompression of preview bitmaps.
37 : */
38 0 : class BitmapCompressor
39 : {
40 : public:
41 : /** Compress the given bitmap into a replacement format that is specific
42 : to the compressor class.
43 : */
44 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const = 0;
45 :
46 : /** Decompress the given replacement data into a preview bitmap.
47 : Depending on the compression technique the returned bitmap may
48 : differ from the original bitmap given to the Compress() method. It
49 : may even of the wrong size or empty or the NULL pointer. It is the
50 : task of the caller to create a new preview bitmap if the returned
51 : one is not as desired.
52 : */
53 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData)const=0;
54 :
55 : /** Return whether the compression and decompression is lossless. This
56 : value is used by the caller of Decompress() to decide whether to use
57 : the returned bitmap as is or if a new preview has to be created.
58 : */
59 : virtual bool IsLossless (void) const = 0;
60 :
61 : protected:
62 0 : ~BitmapCompressor() {}
63 : };
64 :
65 :
66 :
67 : /** Interface for preview bitmap replacements. Each bitmap
68 : compressor/decompressor has to provide an implementation that is
69 : suitable to store the compressed bitmaps.
70 : */
71 0 : class BitmapReplacement
72 : {
73 : public:
74 0 : virtual sal_Int32 GetMemorySize (void) const { return 0; }
75 :
76 : protected:
77 0 : ~BitmapReplacement() {}
78 : };
79 :
80 :
81 :
82 :
83 : /** This is one trivial bitmap compressor. It stores bitmaps unmodified
84 : instead of compressing them.
85 : This compressor is lossless.
86 : */
87 0 : class NoBitmapCompression
88 : : public BitmapCompressor
89 : {
90 : class DummyReplacement;
91 : public:
92 0 : virtual ~NoBitmapCompression() {}
93 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rpBitmap) const;
94 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const;
95 : virtual bool IsLossless (void) const;
96 : };
97 :
98 :
99 :
100 :
101 : /** This is another trivial bitmap compressor. Instead of compressing a
102 : bitmap, it throws the bitmap away. Its Decompress() method returns a
103 : NULL pointer. The caller has to create a new preview bitmap instead.
104 : This compressor clearly is not lossless.
105 : */
106 0 : class CompressionByDeletion
107 : : public BitmapCompressor
108 : {
109 : public:
110 0 : virtual ~CompressionByDeletion() {}
111 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const;
112 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const;
113 : virtual bool IsLossless (void) const;
114 : };
115 :
116 :
117 :
118 :
119 : /** Compress a preview bitmap by reducing its resolution. While the aspect
120 : ratio is maintained the horizontal resolution is scaled down to 100
121 : pixels.
122 : This compressor is not lossless.
123 : */
124 0 : class ResolutionReduction
125 : : public BitmapCompressor
126 : {
127 : class ResolutionReducedReplacement;
128 : static const sal_Int32 mnWidth = 100;
129 : public:
130 0 : virtual ~ResolutionReduction() {}
131 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rpBitmap) const;
132 : /** Scale the replacement bitmap up to the original size.
133 : */
134 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const;
135 : virtual bool IsLossless (void) const;
136 : };
137 :
138 :
139 :
140 :
141 : /** Compress preview bitmaps using the PNG format.
142 : This compressor is lossless.
143 : */
144 0 : class PngCompression
145 : : public BitmapCompressor
146 : {
147 : class PngReplacement;
148 : public:
149 0 : virtual ~PngCompression() {}
150 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const;
151 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const;
152 : virtual bool IsLossless (void) const;
153 : };
154 :
155 :
156 : } } } // end of namespace ::sd::slidesorter::cache
157 :
158 : #endif
159 :
160 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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