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1 /*
2  * Copyright 2015 The Android Open Source Project
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 #ifndef SkCodecPriv_DEFINED
9 #define SkCodecPriv_DEFINED
10 
11 #include "include/codec/SkEncodedOrigin.h"
12 #include "include/core/SkImageInfo.h"
13 #include "include/core/SkTypes.h"
14 #include "include/private/SkColorData.h"
15 #include "include/private/SkEncodedInfo.h"
16 #include "src/codec/SkColorTable.h"
17 
18 #ifdef SK_PRINT_CODEC_MESSAGES
19     #define SkCodecPrintf SkDebugf
20 #else
21     #define SkCodecPrintf(...)
22 #endif
23 
24 // Defined in SkCodec.cpp
25 bool sk_select_xform_format(SkColorType colorType, bool forColorTable,
26                             skcms_PixelFormat* outFormat);
27 
28 // FIXME: Consider sharing with dm, nanbench, and tools.
get_scale_from_sample_size(int sampleSize)29 static inline float get_scale_from_sample_size(int sampleSize) {
30     return 1.0f / ((float) sampleSize);
31 }
32 
is_valid_subset(const SkIRect & subset,const SkISize & imageDims)33 static inline bool is_valid_subset(const SkIRect& subset, const SkISize& imageDims) {
34     return SkIRect::MakeSize(imageDims).contains(subset);
35 }
36 
37 /*
38  * returns a scaled dimension based on the original dimension and the sampleSize
39  * NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder
40  * FIXME: I think we should call this get_sampled_dimension().
41  */
get_scaled_dimension(int srcDimension,int sampleSize)42 static inline int get_scaled_dimension(int srcDimension, int sampleSize) {
43     if (sampleSize > srcDimension) {
44         return 1;
45     }
46     return srcDimension / sampleSize;
47 }
48 
49 /*
50  * Returns the first coordinate that we will keep during a scaled decode.
51  * The output can be interpreted as an x-coordinate or a y-coordinate.
52  *
53  * This does not need to be called and is not called when sampleFactor == 1.
54  */
get_start_coord(int sampleFactor)55 static inline int get_start_coord(int sampleFactor) { return sampleFactor / 2; };
56 
57 /*
58  * Given a coordinate in the original image, this returns the corresponding
59  * coordinate in the scaled image.  This function is meaningless if
60  * IsCoordNecessary returns false.
61  * The output can be interpreted as an x-coordinate or a y-coordinate.
62  *
63  * This does not need to be called and is not called when sampleFactor == 1.
64  */
get_dst_coord(int srcCoord,int sampleFactor)65 static inline int get_dst_coord(int srcCoord, int sampleFactor) { return srcCoord / sampleFactor; };
66 
67 /*
68  * When scaling, we will discard certain y-coordinates (rows) and
69  * x-coordinates (columns).  This function returns true if we should keep the
70  * coordinate and false otherwise.
71  * The inputs may be x-coordinates or y-coordinates.
72  *
73  * This does not need to be called and is not called when sampleFactor == 1.
74  */
is_coord_necessary(int srcCoord,int sampleFactor,int scaledDim)75 static inline bool is_coord_necessary(int srcCoord, int sampleFactor, int scaledDim) {
76     // Get the first coordinate that we want to keep
77     int startCoord = get_start_coord(sampleFactor);
78 
79     // Return false on edge cases
80     if (srcCoord < startCoord || get_dst_coord(srcCoord, sampleFactor) >= scaledDim) {
81         return false;
82     }
83 
84     // Every sampleFactor rows are necessary
85     return ((srcCoord - startCoord) % sampleFactor) == 0;
86 }
87 
valid_alpha(SkAlphaType dstAlpha,bool srcIsOpaque)88 static inline bool valid_alpha(SkAlphaType dstAlpha, bool srcIsOpaque) {
89     if (kUnknown_SkAlphaType == dstAlpha) {
90         return false;
91     }
92 
93     if (srcIsOpaque) {
94         if (kOpaque_SkAlphaType != dstAlpha) {
95             SkCodecPrintf("Warning: an opaque image should be decoded as opaque "
96                           "- it is being decoded as non-opaque, which will draw slower\n");
97         }
98         return true;
99     }
100 
101     return dstAlpha != kOpaque_SkAlphaType;
102 }
103 
104 /*
105  * If there is a color table, get a pointer to the colors, otherwise return nullptr
106  */
get_color_ptr(SkColorTable * colorTable)107 static inline const SkPMColor* get_color_ptr(SkColorTable* colorTable) {
108      return nullptr != colorTable ? colorTable->readColors() : nullptr;
109 }
110 
111 /*
112  * Compute row bytes for an image using pixels per byte
113  */
compute_row_bytes_ppb(int width,uint32_t pixelsPerByte)114 static inline size_t compute_row_bytes_ppb(int width, uint32_t pixelsPerByte) {
115     return (width + pixelsPerByte - 1) / pixelsPerByte;
116 }
117 
118 /*
119  * Compute row bytes for an image using bytes per pixel
120  */
compute_row_bytes_bpp(int width,uint32_t bytesPerPixel)121 static inline size_t compute_row_bytes_bpp(int width, uint32_t bytesPerPixel) {
122     return width * bytesPerPixel;
123 }
124 
125 /*
126  * Compute row bytes for an image
127  */
compute_row_bytes(int width,uint32_t bitsPerPixel)128 static inline size_t compute_row_bytes(int width, uint32_t bitsPerPixel) {
129     if (bitsPerPixel < 16) {
130         SkASSERT(0 == 8 % bitsPerPixel);
131         const uint32_t pixelsPerByte = 8 / bitsPerPixel;
132         return compute_row_bytes_ppb(width, pixelsPerByte);
133     } else {
134         SkASSERT(0 == bitsPerPixel % 8);
135         const uint32_t bytesPerPixel = bitsPerPixel / 8;
136         return compute_row_bytes_bpp(width, bytesPerPixel);
137     }
138 }
139 
140 /*
141  * Get a byte from a buffer
142  * This method is unsafe, the caller is responsible for performing a check
143  */
get_byte(const uint8_t * buffer,uint32_t i)144 static inline uint8_t get_byte(const uint8_t* buffer, uint32_t i) {
145     return buffer[i];
146 }
147 
148 /*
149  * Get a short from a buffer
150  * This method is unsafe, the caller is responsible for performing a check
151  */
get_short(const uint8_t * buffer,uint32_t i)152 static inline uint16_t get_short(const uint8_t* buffer, uint32_t i) {
153     uint16_t result;
154     memcpy(&result, &(buffer[i]), 2);
155 #ifdef SK_CPU_BENDIAN
156     return SkEndianSwap16(result);
157 #else
158     return result;
159 #endif
160 }
161 
162 /*
163  * Get an int from a buffer
164  * This method is unsafe, the caller is responsible for performing a check
165  */
get_int(const uint8_t * buffer,uint32_t i)166 static inline uint32_t get_int(const uint8_t* buffer, uint32_t i) {
167     uint32_t result;
168     memcpy(&result, &(buffer[i]), 4);
169 #ifdef SK_CPU_BENDIAN
170     return SkEndianSwap32(result);
171 #else
172     return result;
173 #endif
174 }
175 
176 /*
177  * @param data           Buffer to read bytes from
178  * @param isLittleEndian Output parameter
179  *                       Indicates if the data is little endian
180  *                       Is unaffected on false returns
181  */
is_valid_endian_marker(const uint8_t * data,bool * isLittleEndian)182 static inline bool is_valid_endian_marker(const uint8_t* data, bool* isLittleEndian) {
183     // II indicates Intel (little endian) and MM indicates motorola (big endian).
184     if (('I' != data[0] || 'I' != data[1]) && ('M' != data[0] || 'M' != data[1])) {
185         return false;
186     }
187 
188     *isLittleEndian = ('I' == data[0]);
189     return true;
190 }
191 
get_endian_short(const uint8_t * data,bool littleEndian)192 static inline uint16_t get_endian_short(const uint8_t* data, bool littleEndian) {
193     if (littleEndian) {
194         return (data[1] << 8) | (data[0]);
195     }
196 
197     return (data[0] << 8) | (data[1]);
198 }
199 
get_endian_int(const uint8_t * data,bool littleEndian)200 static inline uint32_t get_endian_int(const uint8_t* data, bool littleEndian) {
201     if (littleEndian) {
202         return (data[3] << 24) | (data[2] << 16) | (data[1] << 8) | (data[0]);
203     }
204 
205     return (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | (data[3]);
206 }
207 
premultiply_argb_as_rgba(U8CPU a,U8CPU r,U8CPU g,U8CPU b)208 static inline SkPMColor premultiply_argb_as_rgba(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
209     if (a != 255) {
210         r = SkMulDiv255Round(r, a);
211         g = SkMulDiv255Round(g, a);
212         b = SkMulDiv255Round(b, a);
213     }
214 
215     return SkPackARGB_as_RGBA(a, r, g, b);
216 }
217 
premultiply_argb_as_bgra(U8CPU a,U8CPU r,U8CPU g,U8CPU b)218 static inline SkPMColor premultiply_argb_as_bgra(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
219     if (a != 255) {
220         r = SkMulDiv255Round(r, a);
221         g = SkMulDiv255Round(g, a);
222         b = SkMulDiv255Round(b, a);
223     }
224 
225     return SkPackARGB_as_BGRA(a, r, g, b);
226 }
227 
is_rgba(SkColorType colorType)228 static inline bool is_rgba(SkColorType colorType) {
229 #ifdef SK_PMCOLOR_IS_RGBA
230     return (kBGRA_8888_SkColorType != colorType);
231 #else
232     return (kRGBA_8888_SkColorType == colorType);
233 #endif
234 }
235 
236 // Method for coverting to a 32 bit pixel.
237 typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
238 
choose_pack_color_proc(bool isPremul,SkColorType colorType)239 static inline PackColorProc choose_pack_color_proc(bool isPremul, SkColorType colorType) {
240     bool isRGBA = is_rgba(colorType);
241     if (isPremul) {
242         if (isRGBA) {
243             return &premultiply_argb_as_rgba;
244         } else {
245             return &premultiply_argb_as_bgra;
246         }
247     } else {
248         if (isRGBA) {
249             return &SkPackARGB_as_RGBA;
250         } else {
251             return &SkPackARGB_as_BGRA;
252         }
253     }
254 }
255 
256 bool is_orientation_marker(const uint8_t* data, size_t data_length, SkEncodedOrigin* orientation);
257 
258 #endif // SkCodecPriv_DEFINED
259