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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 INCLUDED_SD_SOURCE_UI_SLIDESORTER_CACHE_SLSBITMAPCOMPRESSOR_HXX
21 : #define INCLUDED_SD_SOURCE_UI_SLIDESORTER_CACHE_SLSBITMAPCOMPRESSOR_HXX
22 :
23 : #include <sal/types.h>
24 : #include <boost/shared_ptr.hpp>
25 :
26 : class Bitmap;
27 :
28 : namespace sd { namespace slidesorter { namespace cache {
29 :
30 : class BitmapReplacement;
31 :
32 : /** This interface class provides the minimal method set for classes that
33 : implement the compression and decompression of preview bitmaps.
34 : */
35 64 : class BitmapCompressor
36 : {
37 : public:
38 : /** Compress the given bitmap into a replacement format that is specific
39 : to the compressor class.
40 : */
41 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const = 0;
42 :
43 : /** Decompress the given replacement data into a preview bitmap.
44 : Depending on the compression technique the returned bitmap may
45 : differ from the original bitmap given to the Compress() method. It
46 : may even of the wrong size or empty or the NULL pointer. It is the
47 : task of the caller to create a new preview bitmap if the returned
48 : one is not as desired.
49 : */
50 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData)const=0;
51 :
52 : /** Return whether the compression and decompression is lossless. This
53 : value is used by the caller of Decompress() to decide whether to use
54 : the returned bitmap as is or if a new preview has to be created.
55 : */
56 : virtual bool IsLossless() const = 0;
57 :
58 : protected:
59 64 : ~BitmapCompressor() {}
60 : };
61 :
62 : /** Interface for preview bitmap replacements. Each bitmap
63 : compressor/decompressor has to provide an implementation that is
64 : suitable to store the compressed bitmaps.
65 : */
66 0 : class BitmapReplacement
67 : {
68 : public:
69 0 : virtual sal_Int32 GetMemorySize() const { return 0; }
70 :
71 : protected:
72 0 : ~BitmapReplacement() {}
73 : };
74 :
75 : /** This is one trivial bitmap compressor. It stores bitmaps unmodified
76 : instead of compressing them.
77 : This compressor is lossless.
78 : */
79 0 : class NoBitmapCompression
80 : : public BitmapCompressor
81 : {
82 : class DummyReplacement;
83 : public:
84 0 : virtual ~NoBitmapCompression() {}
85 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rpBitmap) const SAL_OVERRIDE;
86 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const SAL_OVERRIDE;
87 : virtual bool IsLossless() const SAL_OVERRIDE;
88 : };
89 :
90 : /** This is another trivial bitmap compressor. Instead of compressing a
91 : bitmap, it throws the bitmap away. Its Decompress() method returns a
92 : NULL pointer. The caller has to create a new preview bitmap instead.
93 : This compressor clearly is not lossless.
94 : */
95 0 : class CompressionByDeletion
96 : : public BitmapCompressor
97 : {
98 : public:
99 0 : virtual ~CompressionByDeletion() {}
100 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const SAL_OVERRIDE;
101 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const SAL_OVERRIDE;
102 : virtual bool IsLossless() const SAL_OVERRIDE;
103 : };
104 :
105 : /** Compress a preview bitmap by reducing its resolution. While the aspect
106 : ratio is maintained the horizontal resolution is scaled down to 100
107 : pixels.
108 : This compressor is not lossless.
109 : */
110 0 : class ResolutionReduction
111 : : public BitmapCompressor
112 : {
113 : class ResolutionReducedReplacement;
114 : static const sal_Int32 mnWidth = 100;
115 : public:
116 0 : virtual ~ResolutionReduction() {}
117 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rpBitmap) const SAL_OVERRIDE;
118 : /** Scale the replacement bitmap up to the original size.
119 : */
120 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const SAL_OVERRIDE;
121 : virtual bool IsLossless() const SAL_OVERRIDE;
122 : };
123 :
124 : /** Compress preview bitmaps using the PNG format.
125 : This compressor is lossless.
126 : */
127 64 : class PngCompression
128 : : public BitmapCompressor
129 : {
130 : class PngReplacement;
131 : public:
132 128 : virtual ~PngCompression() {}
133 : virtual ::boost::shared_ptr<BitmapReplacement> Compress (const Bitmap& rBitmap) const SAL_OVERRIDE;
134 : virtual Bitmap Decompress (const BitmapReplacement& rBitmapData) const SAL_OVERRIDE;
135 : virtual bool IsLossless() const SAL_OVERRIDE;
136 : };
137 :
138 : } } } // end of namespace ::sd::slidesorter::cache
139 :
140 : #endif
141 :
142 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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