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1 /* | |
2 * Copyright 2015 Google Inc. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license that can be | |
5 * found in the LICENSE file. | |
6 */ | |
7 | |
8 #include "SkCodec.h" | |
9 #include "SkColorTable.h" | |
10 #include "SkImageInfo.h" | |
11 #include "SkMaskSwizzler.h" | |
12 #include "SkStream.h" | |
13 #include "SkSwizzler.h" | |
14 #include "SkTypes.h" | |
15 | |
16 // TODO: rename SkCodec_libbmp files to SkBmpCodec | |
17 /* | |
18 * | |
19 * This class implements the decoding for bmp images | |
20 * | |
21 */ | |
22 class SkBmpCodec : public SkCodec { | |
23 public: | |
24 | |
25 /* | |
26 * | |
27 * Describes if rows of the input start at the top or bottom of the image | |
28 * | |
29 */ | |
30 enum RowOrder { | |
31 kTopDown_RowOrder, | |
32 kBottomUp_RowOrder | |
33 }; | |
34 | |
35 /* | |
36 * | |
37 * Checks the start of the stream to see if the image is a bmp | |
38 * | |
39 */ | |
40 static bool IsBmp(SkStream*); | |
41 | |
42 /* | |
43 * | |
44 * Assumes IsBmp was called and returned true | |
45 * Creates a bmp decoder | |
46 * Reads enough of the stream to determine the image format | |
47 * | |
48 */ | |
49 static SkCodec* NewFromStream(SkStream*); | |
50 | |
51 /* | |
52 * | |
53 * Creates a bmp decoder for a bmp embedded in ico | |
54 * Reads enough of the stream to determine the image format | |
55 * | |
56 */ | |
57 static SkCodec* NewFromIco(SkStream*); | |
58 | |
59 protected: | |
60 | |
61 /* | |
62 * | |
63 * Initiates the bmp decode | |
64 * | |
65 */ | |
66 Result onGetPixels(const SkImageInfo& dstInfo, void* dst, | |
67 size_t dstRowBytes, const Options&, SkPMColor*, | |
68 int*) override; | |
69 | |
70 SkEncodedFormat onGetEncodedFormat() const override { return kBMP_SkEncodedF
ormat; } | |
71 | |
72 private: | |
73 | |
74 /* | |
75 * | |
76 * Used to define the input format of the bmp | |
77 * | |
78 */ | |
79 enum BitmapInputFormat { | |
80 kStandard_BitmapInputFormat, | |
81 kRLE_BitmapInputFormat, | |
82 kBitMask_BitmapInputFormat, | |
83 kUnknown_BitmapInputFormat | |
84 }; | |
85 | |
86 /* | |
87 * | |
88 * Creates the color table | |
89 * Sets colorCount to the new color count if it is non-NULL | |
90 */ | |
91 bool createColorTable(SkAlphaType alphaType, int* colorCount); | |
92 | |
93 /* | |
94 * | |
95 * Creates a bmp decoder | |
96 * Reads enough of the stream to determine the image format | |
97 * | |
98 */ | |
99 static SkCodec* NewFromStream(SkStream*, bool isIco); | |
100 | |
101 /* | |
102 * | |
103 * Read enough of the stream to initialize the SkBmpCodec. Returns a bool | |
104 * representing success or failure. If it returned true, and codecOut was | |
105 * not NULL, it will be set to a new SkBmpCodec. | |
106 * Does *not* take ownership of the passed in SkStream. | |
107 * | |
108 */ | |
109 static bool ReadHeader(SkStream*, bool isIco, SkCodec** codecOut); | |
110 | |
111 /* | |
112 * | |
113 * Performs the bitmap decoding for bit masks input format | |
114 * | |
115 */ | |
116 Result decodeMask(const SkImageInfo& dstInfo, void* dst, | |
117 size_t dstRowBytes, const Options& opts); | |
118 | |
119 /* | |
120 * | |
121 * Set an RLE pixel using the color table | |
122 * | |
123 */ | |
124 void setRLEPixel(void* dst, size_t dstRowBytes, | |
125 const SkImageInfo& dstInfo, uint32_t x, uint32_t y, | |
126 uint8_t index); | |
127 /* | |
128 * | |
129 * Set an RLE24 pixel from R, G, B values | |
130 * | |
131 */ | |
132 void setRLE24Pixel(void* dst, size_t dstRowBytes, | |
133 const SkImageInfo& dstInfo, uint32_t x, uint32_t y, | |
134 uint8_t red, uint8_t green, uint8_t blue); | |
135 | |
136 /* | |
137 * | |
138 * Performs the bitmap decoding for RLE input format | |
139 * | |
140 */ | |
141 Result decodeRLE(const SkImageInfo& dstInfo, void* dst, | |
142 size_t dstRowBytes, const Options& opts); | |
143 | |
144 /* | |
145 * | |
146 * Performs the bitmap decoding for standard input format | |
147 * | |
148 */ | |
149 Result decode(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, con
st Options& opts); | |
150 | |
151 /* | |
152 * | |
153 * Creates an instance of the decoder | |
154 * Called only by NewFromStream | |
155 * | |
156 * @param srcInfo contains the source width and height | |
157 * @param stream the stream of image data | |
158 * @param bitsPerPixel the number of bits used to store each pixel | |
159 * @param format the format of the bmp file | |
160 * @param masks optional color masks for certain bmp formats, passes | |
161 ownership to SkBmpCodec | |
162 * @param numColors the number of colors in the color table | |
163 * @param bytesPerColor the number of bytes in the stream used to represent | |
164 each color in the color table | |
165 * @param offset the offset of the image pixel data from the end of the | |
166 * headers | |
167 * @param rowOrder indicates whether rows are ordered top-down or bottom-up | |
168 * @param RLEBytes used only for RLE decodes, as we must decode all | |
169 * of the data at once rather than row by row | |
170 * it indicates the amount of data left in the stream | |
171 * after decoding the headers | |
172 * | |
173 */ | |
174 SkBmpCodec(const SkImageInfo& srcInfo, SkStream* stream, | |
175 uint16_t bitsPerPixel, BitmapInputFormat format, | |
176 SkMasks* masks, uint32_t numColors, uint32_t bytesPerColor, | |
177 uint32_t offset, RowOrder rowOrder, size_t RLEBytes, | |
178 bool isIco); | |
179 | |
180 // Fields | |
181 const uint16_t fBitsPerPixel; | |
182 const BitmapInputFormat fInputFormat; | |
183 SkAutoTDelete<SkMasks> fMasks; // owned | |
184 SkAutoTUnref<SkColorTable> fColorTable; // owned | |
185 uint32_t fNumColors; | |
186 const uint32_t fBytesPerColor; | |
187 const uint32_t fOffset; | |
188 const RowOrder fRowOrder; | |
189 const size_t fRLEBytes; | |
190 const bool fIsIco; | |
191 | |
192 typedef SkCodec INHERITED; | |
193 }; | |
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