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 "SkColorPriv.h"
12 #include "SkColorSpaceXform.h"
13 #include "SkColorTable.h"
14 #include "SkImageInfo.h"
15 #include "SkTypes.h"
16
17 #ifdef SK_PRINT_CODEC_MESSAGES
18 #define SkCodecPrintf SkDebugf
19 #else
20 #define SkCodecPrintf(...)
21 #endif
22
23 // FIXME: Consider sharing with dm, nanbench, and tools.
get_scale_from_sample_size(int sampleSize)24 static inline float get_scale_from_sample_size(int sampleSize) {
25 return 1.0f / ((float) sampleSize);
26 }
27
is_valid_subset(const SkIRect & subset,const SkISize & imageDims)28 static inline bool is_valid_subset(const SkIRect& subset, const SkISize& imageDims) {
29 return SkIRect::MakeSize(imageDims).contains(subset);
30 }
31
32 /*
33 * returns a scaled dimension based on the original dimension and the sampleSize
34 * NOTE: we round down here for scaled dimension to match the behavior of SkImageDecoder
35 * FIXME: I think we should call this get_sampled_dimension().
36 */
get_scaled_dimension(int srcDimension,int sampleSize)37 static inline int get_scaled_dimension(int srcDimension, int sampleSize) {
38 if (sampleSize > srcDimension) {
39 return 1;
40 }
41 return srcDimension / sampleSize;
42 }
43
44 /*
45 * Returns the first coordinate that we will keep during a scaled decode.
46 * The output can be interpreted as an x-coordinate or a y-coordinate.
47 *
48 * This does not need to be called and is not called when sampleFactor == 1.
49 */
get_start_coord(int sampleFactor)50 static inline int get_start_coord(int sampleFactor) { return sampleFactor / 2; };
51
52 /*
53 * Given a coordinate in the original image, this returns the corresponding
54 * coordinate in the scaled image. This function is meaningless if
55 * IsCoordNecessary returns false.
56 * The output can be interpreted as an x-coordinate or a y-coordinate.
57 *
58 * This does not need to be called and is not called when sampleFactor == 1.
59 */
get_dst_coord(int srcCoord,int sampleFactor)60 static inline int get_dst_coord(int srcCoord, int sampleFactor) { return srcCoord / sampleFactor; };
61
62 /*
63 * When scaling, we will discard certain y-coordinates (rows) and
64 * x-coordinates (columns). This function returns true if we should keep the
65 * coordinate and false otherwise.
66 * The inputs may be x-coordinates or y-coordinates.
67 *
68 * This does not need to be called and is not called when sampleFactor == 1.
69 */
is_coord_necessary(int srcCoord,int sampleFactor,int scaledDim)70 static inline bool is_coord_necessary(int srcCoord, int sampleFactor, int scaledDim) {
71 // Get the first coordinate that we want to keep
72 int startCoord = get_start_coord(sampleFactor);
73
74 // Return false on edge cases
75 if (srcCoord < startCoord || get_dst_coord(srcCoord, sampleFactor) >= scaledDim) {
76 return false;
77 }
78
79 // Every sampleFactor rows are necessary
80 return ((srcCoord - startCoord) % sampleFactor) == 0;
81 }
82
valid_alpha(SkAlphaType dstAlpha,SkAlphaType srcAlpha)83 static inline bool valid_alpha(SkAlphaType dstAlpha, SkAlphaType srcAlpha) {
84 if (kUnknown_SkAlphaType == dstAlpha) {
85 return false;
86 }
87
88 if (srcAlpha != dstAlpha) {
89 if (kOpaque_SkAlphaType == srcAlpha) {
90 // If the source is opaque, we can support any.
91 SkCodecPrintf("Warning: an opaque image should be decoded as opaque "
92 "- it is being decoded as non-opaque, which will draw slower\n");
93 return true;
94 }
95
96 // The source is not opaque
97 switch (dstAlpha) {
98 case kPremul_SkAlphaType:
99 case kUnpremul_SkAlphaType:
100 // The source is not opaque, so either of these is okay
101 break;
102 default:
103 // We cannot decode a non-opaque image to opaque (or unknown)
104 return false;
105 }
106 }
107 return true;
108 }
109
110 /*
111 * Original version of conversion_possible that does not account for color spaces.
112 * Used by codecs that have not been updated to support color spaces.
113 *
114 * Most of our codecs support the same conversions:
115 * - opaque to any alpha type
116 * - 565 only if opaque
117 * - premul to unpremul and vice versa
118 * - always support RGBA, BGRA
119 * - otherwise match the src color type
120 */
conversion_possible_ignore_color_space(const SkImageInfo & dst,const SkImageInfo & src)121 static inline bool conversion_possible_ignore_color_space(const SkImageInfo& dst,
122 const SkImageInfo& src) {
123 // Ensure the alpha type is valid
124 if (!valid_alpha(dst.alphaType(), src.alphaType())) {
125 return false;
126 }
127
128 // Check for supported color types
129 switch (dst.colorType()) {
130 case kRGBA_8888_SkColorType:
131 case kBGRA_8888_SkColorType:
132 return true;
133 case kRGB_565_SkColorType:
134 return kOpaque_SkAlphaType == src.alphaType();
135 default:
136 return dst.colorType() == src.colorType();
137 }
138 }
139
140 /*
141 * If there is a color table, get a pointer to the colors, otherwise return nullptr
142 */
get_color_ptr(SkColorTable * colorTable)143 static inline const SkPMColor* get_color_ptr(SkColorTable* colorTable) {
144 return nullptr != colorTable ? colorTable->readColors() : nullptr;
145 }
146
select_xform_format(SkColorType colorType)147 static inline SkColorSpaceXform::ColorFormat select_xform_format(SkColorType colorType) {
148 switch (colorType) {
149 case kRGBA_8888_SkColorType:
150 return SkColorSpaceXform::kRGBA_8888_ColorFormat;
151 case kBGRA_8888_SkColorType:
152 return SkColorSpaceXform::kBGRA_8888_ColorFormat;
153 case kRGBA_F16_SkColorType:
154 return SkColorSpaceXform::kRGBA_F16_ColorFormat;
155 default:
156 SkASSERT(false);
157 return SkColorSpaceXform::kRGBA_8888_ColorFormat;
158 }
159 }
160
161 /*
162 * Given that the encoded image uses a color table, return the fill value
163 */
get_color_table_fill_value(SkColorType dstColorType,SkAlphaType alphaType,const SkPMColor * colorPtr,uint8_t fillIndex,SkColorSpaceXform * colorXform)164 static inline uint64_t get_color_table_fill_value(SkColorType dstColorType, SkAlphaType alphaType,
165 const SkPMColor* colorPtr, uint8_t fillIndex, SkColorSpaceXform* colorXform) {
166 SkASSERT(nullptr != colorPtr);
167 switch (dstColorType) {
168 case kRGBA_8888_SkColorType:
169 case kBGRA_8888_SkColorType:
170 return colorPtr[fillIndex];
171 case kRGB_565_SkColorType:
172 return SkPixel32ToPixel16(colorPtr[fillIndex]);
173 case kIndex_8_SkColorType:
174 return fillIndex;
175 case kRGBA_F16_SkColorType: {
176 SkASSERT(colorXform);
177 uint64_t dstColor;
178 uint32_t srcColor = colorPtr[fillIndex];
179 colorXform->apply(&dstColor, &srcColor, 1, select_xform_format(dstColorType),
180 SkColorSpaceXform::kRGBA_8888_ColorFormat, alphaType);
181 return dstColor;
182 }
183 default:
184 SkASSERT(false);
185 return 0;
186 }
187 }
188
189 /*
190 *
191 * Copy the codec color table back to the client when kIndex8 color type is requested
192 */
copy_color_table(const SkImageInfo & dstInfo,SkColorTable * colorTable,SkPMColor * inputColorPtr,int * inputColorCount)193 static inline void copy_color_table(const SkImageInfo& dstInfo, SkColorTable* colorTable,
194 SkPMColor* inputColorPtr, int* inputColorCount) {
195 if (kIndex_8_SkColorType == dstInfo.colorType()) {
196 SkASSERT(nullptr != inputColorPtr);
197 SkASSERT(nullptr != inputColorCount);
198 SkASSERT(nullptr != colorTable);
199 memcpy(inputColorPtr, colorTable->readColors(), *inputColorCount * sizeof(SkPMColor));
200 }
201 }
202
203 /*
204 * Compute row bytes for an image using pixels per byte
205 */
compute_row_bytes_ppb(int width,uint32_t pixelsPerByte)206 static inline size_t compute_row_bytes_ppb(int width, uint32_t pixelsPerByte) {
207 return (width + pixelsPerByte - 1) / pixelsPerByte;
208 }
209
210 /*
211 * Compute row bytes for an image using bytes per pixel
212 */
compute_row_bytes_bpp(int width,uint32_t bytesPerPixel)213 static inline size_t compute_row_bytes_bpp(int width, uint32_t bytesPerPixel) {
214 return width * bytesPerPixel;
215 }
216
217 /*
218 * Compute row bytes for an image
219 */
compute_row_bytes(int width,uint32_t bitsPerPixel)220 static inline size_t compute_row_bytes(int width, uint32_t bitsPerPixel) {
221 if (bitsPerPixel < 16) {
222 SkASSERT(0 == 8 % bitsPerPixel);
223 const uint32_t pixelsPerByte = 8 / bitsPerPixel;
224 return compute_row_bytes_ppb(width, pixelsPerByte);
225 } else {
226 SkASSERT(0 == bitsPerPixel % 8);
227 const uint32_t bytesPerPixel = bitsPerPixel / 8;
228 return compute_row_bytes_bpp(width, bytesPerPixel);
229 }
230 }
231
232 /*
233 * Get a byte from a buffer
234 * This method is unsafe, the caller is responsible for performing a check
235 */
get_byte(uint8_t * buffer,uint32_t i)236 static inline uint8_t get_byte(uint8_t* buffer, uint32_t i) {
237 return buffer[i];
238 }
239
240 /*
241 * Get a short from a buffer
242 * This method is unsafe, the caller is responsible for performing a check
243 */
get_short(uint8_t * buffer,uint32_t i)244 static inline uint16_t get_short(uint8_t* buffer, uint32_t i) {
245 uint16_t result;
246 memcpy(&result, &(buffer[i]), 2);
247 #ifdef SK_CPU_BENDIAN
248 return SkEndianSwap16(result);
249 #else
250 return result;
251 #endif
252 }
253
254 /*
255 * Get an int from a buffer
256 * This method is unsafe, the caller is responsible for performing a check
257 */
get_int(uint8_t * buffer,uint32_t i)258 static inline uint32_t get_int(uint8_t* buffer, uint32_t i) {
259 uint32_t result;
260 memcpy(&result, &(buffer[i]), 4);
261 #ifdef SK_CPU_BENDIAN
262 return SkEndianSwap32(result);
263 #else
264 return result;
265 #endif
266 }
267
268 /*
269 * @param data Buffer to read bytes from
270 * @param isLittleEndian Output parameter
271 * Indicates if the data is little endian
272 * Is unaffected on false returns
273 */
is_valid_endian_marker(const uint8_t * data,bool * isLittleEndian)274 static inline bool is_valid_endian_marker(const uint8_t* data, bool* isLittleEndian) {
275 // II indicates Intel (little endian) and MM indicates motorola (big endian).
276 if (('I' != data[0] || 'I' != data[1]) && ('M' != data[0] || 'M' != data[1])) {
277 return false;
278 }
279
280 *isLittleEndian = ('I' == data[0]);
281 return true;
282 }
283
get_endian_short(const uint8_t * data,bool littleEndian)284 static inline uint16_t get_endian_short(const uint8_t* data, bool littleEndian) {
285 if (littleEndian) {
286 return (data[1] << 8) | (data[0]);
287 }
288
289 return (data[0] << 8) | (data[1]);
290 }
291
premultiply_argb_as_rgba(U8CPU a,U8CPU r,U8CPU g,U8CPU b)292 static inline SkPMColor premultiply_argb_as_rgba(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
293 if (a != 255) {
294 r = SkMulDiv255Round(r, a);
295 g = SkMulDiv255Round(g, a);
296 b = SkMulDiv255Round(b, a);
297 }
298
299 return SkPackARGB_as_RGBA(a, r, g, b);
300 }
301
premultiply_argb_as_bgra(U8CPU a,U8CPU r,U8CPU g,U8CPU b)302 static inline SkPMColor premultiply_argb_as_bgra(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
303 if (a != 255) {
304 r = SkMulDiv255Round(r, a);
305 g = SkMulDiv255Round(g, a);
306 b = SkMulDiv255Round(b, a);
307 }
308
309 return SkPackARGB_as_BGRA(a, r, g, b);
310 }
311
is_rgba(SkColorType colorType)312 static inline bool is_rgba(SkColorType colorType) {
313 #ifdef SK_PMCOLOR_IS_RGBA
314 return (kBGRA_8888_SkColorType != colorType);
315 #else
316 return (kRGBA_8888_SkColorType == colorType);
317 #endif
318 }
319
320 // Method for coverting to a 32 bit pixel.
321 typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
322
choose_pack_color_proc(bool isPremul,SkColorType colorType)323 static inline PackColorProc choose_pack_color_proc(bool isPremul, SkColorType colorType) {
324 bool isRGBA = is_rgba(colorType);
325 if (isPremul) {
326 if (isRGBA) {
327 return &premultiply_argb_as_rgba;
328 } else {
329 return &premultiply_argb_as_bgra;
330 }
331 } else {
332 if (isRGBA) {
333 return &SkPackARGB_as_RGBA;
334 } else {
335 return &SkPackARGB_as_BGRA;
336 }
337 }
338 }
339
needs_premul(const SkImageInfo & dstInfo,const SkImageInfo & srcInfo)340 static inline bool needs_premul(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo) {
341 return kPremul_SkAlphaType == dstInfo.alphaType() &&
342 kUnpremul_SkAlphaType == srcInfo.alphaType();
343 }
344
needs_color_xform(const SkImageInfo & dstInfo,const SkImageInfo & srcInfo)345 static inline bool needs_color_xform(const SkImageInfo& dstInfo, const SkImageInfo& srcInfo) {
346 // Color xform is necessary in order to correctly perform premultiply in linear space.
347 bool needsPremul = needs_premul(dstInfo, srcInfo);
348
349 // F16 is by definition a linear space, so we always must perform a color xform.
350 bool isF16 = kRGBA_F16_SkColorType == dstInfo.colorType();
351
352 // Need a color xform when dst space does not match the src.
353 bool srcDstNotEqual = !SkColorSpace::Equals(srcInfo.colorSpace(), dstInfo.colorSpace());
354
355 // We never perform a color xform in legacy mode.
356 bool isLegacy = nullptr == dstInfo.colorSpace();
357
358 return !isLegacy && (needsPremul || isF16 || srcDstNotEqual);
359 }
360
select_xform_alpha(SkAlphaType dstAlphaType,SkAlphaType srcAlphaType)361 static inline SkAlphaType select_xform_alpha(SkAlphaType dstAlphaType, SkAlphaType srcAlphaType) {
362 return (kOpaque_SkAlphaType == srcAlphaType) ? kOpaque_SkAlphaType : dstAlphaType;
363 }
364
365 /*
366 * Alpha Type Conversions
367 * - kOpaque to kOpaque, kUnpremul, kPremul is valid
368 * - kUnpremul to kUnpremul, kPremul is valid
369 *
370 * Color Type Conversions
371 * - Always support kRGBA_8888, kBGRA_8888
372 * - Support kRGBA_F16 when there is a linear dst color space
373 * - Support kIndex8 if it matches the src
374 * - Support k565 if kOpaque and color correction is not required
375 * - Support k565 if it matches the src, kOpaque, and color correction is not required
376 */
conversion_possible(const SkImageInfo & dst,const SkImageInfo & src)377 static inline bool conversion_possible(const SkImageInfo& dst, const SkImageInfo& src) {
378 // Ensure the alpha type is valid.
379 if (!valid_alpha(dst.alphaType(), src.alphaType())) {
380 return false;
381 }
382
383 // Check for supported color types.
384 switch (dst.colorType()) {
385 case kRGBA_8888_SkColorType:
386 case kBGRA_8888_SkColorType:
387 return true;
388 case kRGBA_F16_SkColorType:
389 return dst.colorSpace() && dst.colorSpace()->gammaIsLinear();
390 case kIndex_8_SkColorType:
391 return kIndex_8_SkColorType == src.colorType();
392 case kRGB_565_SkColorType:
393 return kOpaque_SkAlphaType == src.alphaType() && !needs_color_xform(dst, src);
394 case kGray_8_SkColorType:
395 return kGray_8_SkColorType == src.colorType() &&
396 kOpaque_SkAlphaType == src.alphaType() && !needs_color_xform(dst, src);
397 default:
398 return false;
399 }
400 }
401
402 #endif // SkCodecPriv_DEFINED
403