reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 1 | /* libs/graphics/images/SkImageDecoder_libpng.cpp |
| 2 | ** |
| 3 | ** Copyright 2006, The Android Open Source Project |
| 4 | ** |
| 5 | ** Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | ** you may not use this file except in compliance with the License. |
| 7 | ** You may obtain a copy of the License at |
| 8 | ** |
| 9 | ** http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | ** |
| 11 | ** Unless required by applicable law or agreed to in writing, software |
| 12 | ** distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | ** See the License for the specific language governing permissions and |
| 15 | ** limitations under the License. |
| 16 | */ |
| 17 | |
| 18 | #include "SkImageDecoder.h" |
reed@android.com | b08eb2b | 2009-01-06 20:16:26 +0000 | [diff] [blame^] | 19 | #include "SkImageEncoder.h" |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 20 | #include "SkColor.h" |
| 21 | #include "SkColorPriv.h" |
| 22 | #include "SkDither.h" |
| 23 | #include "SkMath.h" |
| 24 | #include "SkScaledBitmapSampler.h" |
| 25 | #include "SkStream.h" |
| 26 | #include "SkTemplates.h" |
| 27 | #include "SkUtils.h" |
| 28 | |
| 29 | extern "C" { |
| 30 | #include "png.h" |
| 31 | } |
| 32 | |
| 33 | class SkPNGImageDecoder : public SkImageDecoder { |
| 34 | public: |
| 35 | virtual Format getFormat() const { |
| 36 | return kPNG_Format; |
| 37 | } |
| 38 | |
| 39 | protected: |
| 40 | virtual bool onDecode(SkStream* stream, SkBitmap* bm, |
| 41 | SkBitmap::Config pref, Mode); |
| 42 | }; |
| 43 | |
| 44 | #ifndef png_jmpbuf |
| 45 | # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| 46 | #endif |
| 47 | |
| 48 | #define PNG_BYTES_TO_CHECK 4 |
| 49 | |
| 50 | /* Automatically clean up after throwing an exception */ |
| 51 | struct PNGAutoClean { |
| 52 | PNGAutoClean(png_structp p, png_infop i): png_ptr(p), info_ptr(i) {} |
| 53 | ~PNGAutoClean() { |
| 54 | png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL); |
| 55 | } |
| 56 | private: |
| 57 | png_structp png_ptr; |
| 58 | png_infop info_ptr; |
| 59 | }; |
| 60 | |
| 61 | SkImageDecoder* SkImageDecoder_PNG_Factory(SkStream* stream) { |
| 62 | char buf[PNG_BYTES_TO_CHECK]; |
| 63 | if (stream->read(buf, PNG_BYTES_TO_CHECK) == PNG_BYTES_TO_CHECK && |
| 64 | !png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) { |
| 65 | return SkNEW(SkPNGImageDecoder); |
| 66 | } |
| 67 | return NULL; |
| 68 | } |
| 69 | |
| 70 | static void sk_read_fn(png_structp png_ptr, png_bytep data, png_size_t length) { |
| 71 | SkStream* sk_stream = (SkStream*) png_ptr->io_ptr; |
| 72 | size_t bytes = sk_stream->read(data, length); |
| 73 | if (bytes != length) { |
| 74 | png_error(png_ptr, "Read Error!"); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) { |
| 79 | SkImageDecoder::Peeker* peeker = |
| 80 | (SkImageDecoder::Peeker*)png_get_user_chunk_ptr(png_ptr); |
| 81 | // peek() returning true means continue decoding |
| 82 | return peeker->peek((const char*)chunk->name, chunk->data, chunk->size) ? |
| 83 | 1 : -1; |
| 84 | } |
| 85 | |
| 86 | static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| 87 | #if 0 |
| 88 | SkDebugf("------ png error %s\n", msg); |
| 89 | #endif |
| 90 | longjmp(png_jmpbuf(png_ptr), 1); |
| 91 | } |
| 92 | |
| 93 | static void skip_src_rows(png_structp png_ptr, uint8_t storage[], int count) { |
| 94 | for (int i = 0; i < count; i++) { |
| 95 | uint8_t* tmp = storage; |
| 96 | png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1); |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | static bool pos_le(int value, int max) { |
| 101 | return value > 0 && value <= max; |
| 102 | } |
| 103 | |
| 104 | static bool substituteTranspColor(SkBitmap* bm, SkPMColor match) { |
| 105 | SkASSERT(bm->config() == SkBitmap::kARGB_8888_Config); |
| 106 | |
| 107 | bool reallyHasAlpha = false; |
| 108 | |
| 109 | for (int y = bm->height() - 1; y >= 0; --y) { |
| 110 | SkPMColor* p = bm->getAddr32(0, y); |
| 111 | for (int x = bm->width() - 1; x >= 0; --x) { |
| 112 | if (match == *p) { |
| 113 | *p = 0; |
| 114 | reallyHasAlpha = true; |
| 115 | } |
| 116 | p += 1; |
| 117 | } |
| 118 | } |
| 119 | return reallyHasAlpha; |
| 120 | } |
| 121 | |
| 122 | bool SkPNGImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* decodedBitmap, |
| 123 | SkBitmap::Config prefConfig, Mode mode) { |
| 124 | // SkAutoTrace apr("SkPNGImageDecoder::onDecode"); |
| 125 | |
| 126 | /* Create and initialize the png_struct with the desired error handler |
| 127 | * functions. If you want to use the default stderr and longjump method, |
| 128 | * you can supply NULL for the last three parameters. We also supply the |
| 129 | * the compiler header file version, so that we know if the application |
| 130 | * was compiled with a compatible version of the library. */ |
| 131 | png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, |
| 132 | NULL, sk_error_fn, NULL); |
| 133 | // png_voidp user_error_ptr, user_error_fn, user_warning_fn); |
| 134 | if (png_ptr == NULL) { |
| 135 | return false; |
| 136 | } |
| 137 | |
| 138 | /* Allocate/initialize the memory for image information. */ |
| 139 | png_infop info_ptr = png_create_info_struct(png_ptr); |
| 140 | if (info_ptr == NULL) { |
| 141 | png_destroy_read_struct(&png_ptr, png_infopp_NULL, png_infopp_NULL); |
| 142 | return false; |
| 143 | } |
| 144 | |
| 145 | PNGAutoClean autoClean(png_ptr, info_ptr); |
| 146 | |
| 147 | /* Set error handling if you are using the setjmp/longjmp method (this is |
| 148 | * the normal method of doing things with libpng). REQUIRED unless you |
| 149 | * set up your own error handlers in the png_create_read_struct() earlier. |
| 150 | */ |
| 151 | if (setjmp(png_jmpbuf(png_ptr))) { |
| 152 | return false; |
| 153 | } |
| 154 | |
| 155 | /* If you are using replacement read functions, instead of calling |
| 156 | * png_init_io() here you would call: |
| 157 | */ |
| 158 | png_set_read_fn(png_ptr, (void *)sk_stream, sk_read_fn); |
| 159 | /* where user_io_ptr is a structure you want available to the callbacks */ |
| 160 | /* If we have already read some of the signature */ |
| 161 | // png_set_sig_bytes(png_ptr, 0 /* sig_read */ ); |
| 162 | |
| 163 | // hookup our peeker so we can see any user-chunks the caller may be interested in |
| 164 | png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0); |
| 165 | if (this->getPeeker()) { |
| 166 | png_set_read_user_chunk_fn(png_ptr, (png_voidp)this->getPeeker(), sk_read_user_chunk); |
| 167 | } |
| 168 | |
| 169 | /* The call to png_read_info() gives us all of the information from the |
| 170 | * PNG file before the first IDAT (image data chunk). */ |
| 171 | png_read_info(png_ptr, info_ptr); |
| 172 | png_uint_32 origWidth, origHeight; |
| 173 | int bit_depth, color_type, interlace_type; |
| 174 | png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bit_depth, &color_type, |
| 175 | &interlace_type, int_p_NULL, int_p_NULL); |
| 176 | |
| 177 | /* tell libpng to strip 16 bit/color files down to 8 bits/color */ |
| 178 | if (bit_depth == 16) { |
| 179 | png_set_strip_16(png_ptr); |
| 180 | } |
| 181 | /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single |
| 182 | * byte into separate bytes (useful for paletted and grayscale images). */ |
| 183 | if (bit_depth < 8) { |
| 184 | png_set_packing(png_ptr); |
| 185 | } |
| 186 | /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */ |
| 187 | if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { |
| 188 | png_set_gray_1_2_4_to_8(png_ptr); |
| 189 | } |
| 190 | |
| 191 | /* Make a grayscale image into RGB. */ |
| 192 | if (color_type == PNG_COLOR_TYPE_GRAY || |
| 193 | color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { |
| 194 | png_set_gray_to_rgb(png_ptr); |
| 195 | } |
| 196 | |
| 197 | SkBitmap::Config config; |
| 198 | bool hasAlpha = false; |
| 199 | bool doDither = this->getDitherImage(); |
| 200 | SkPMColor theTranspColor = 0; // 0 tells us not to try to match |
| 201 | |
| 202 | // check for sBIT chunk data, in case we should disable dithering because |
| 203 | // our data is not truely 8bits per component |
| 204 | if (doDither) { |
| 205 | #if 0 |
| 206 | SkDebugf("----- sBIT %d %d %d %d\n", info_ptr->sig_bit.red, |
| 207 | info_ptr->sig_bit.green, info_ptr->sig_bit.blue, |
| 208 | info_ptr->sig_bit.alpha); |
| 209 | #endif |
| 210 | // 0 seems to indicate no information available |
| 211 | if (pos_le(info_ptr->sig_bit.red, SK_R16_BITS) && |
| 212 | pos_le(info_ptr->sig_bit.green, SK_G16_BITS) && |
| 213 | pos_le(info_ptr->sig_bit.blue, SK_B16_BITS)) { |
| 214 | doDither = false; |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | if (color_type == PNG_COLOR_TYPE_PALETTE) { |
| 219 | config = SkBitmap::kIndex8_Config; // defer sniffing for hasAlpha |
| 220 | } else { |
| 221 | png_color_16p transpColor = NULL; |
| 222 | int numTransp = 0; |
| 223 | |
| 224 | png_get_tRNS(png_ptr, info_ptr, NULL, &numTransp, &transpColor); |
| 225 | |
| 226 | bool valid = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS); |
| 227 | |
| 228 | if (valid && numTransp == 1 && transpColor != NULL) { |
| 229 | /* Compute our transparent color, which we'll match against later. |
| 230 | We don't really handle 16bit components properly here, since we |
| 231 | do our compare *after* the values have been knocked down to 8bit |
| 232 | which means we will find more matches than we should. The real |
| 233 | fix seems to be to see the actual 16bit components, do the |
| 234 | compare, and then knock it down to 8bits ourselves. |
| 235 | */ |
| 236 | if (color_type & PNG_COLOR_MASK_COLOR) { |
| 237 | if (16 == bit_depth) { |
| 238 | theTranspColor = SkPackARGB32(0xFF, transpColor->red >> 8, |
| 239 | transpColor->green >> 8, transpColor->blue >> 8); |
| 240 | } else { |
| 241 | theTranspColor = SkPackARGB32(0xFF, transpColor->red, |
| 242 | transpColor->green, transpColor->blue); |
| 243 | } |
| 244 | } else { // gray |
| 245 | if (16 == bit_depth) { |
| 246 | theTranspColor = SkPackARGB32(0xFF, transpColor->gray >> 8, |
| 247 | transpColor->gray >> 8, transpColor->gray >> 8); |
| 248 | } else { |
| 249 | theTranspColor = SkPackARGB32(0xFF, transpColor->gray, |
| 250 | transpColor->gray, transpColor->gray); |
| 251 | } |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | if (valid || |
| 256 | PNG_COLOR_TYPE_RGB_ALPHA == color_type || |
| 257 | PNG_COLOR_TYPE_GRAY_ALPHA == color_type) { |
| 258 | hasAlpha = true; |
| 259 | config = SkBitmap::kARGB_8888_Config; |
| 260 | } else { // we get to choose the config |
| 261 | config = prefConfig; |
| 262 | if (config == SkBitmap::kNo_Config) { |
| 263 | config = SkImageDecoder::GetDeviceConfig(); |
| 264 | } |
| 265 | if (config != SkBitmap::kRGB_565_Config && |
| 266 | config != SkBitmap::kARGB_4444_Config) { |
| 267 | config = SkBitmap::kARGB_8888_Config; |
| 268 | } |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | if (!this->chooseFromOneChoice(config, origWidth, origHeight)) { |
| 273 | return false; |
| 274 | } |
| 275 | |
| 276 | const int sampleSize = this->getSampleSize(); |
| 277 | SkScaledBitmapSampler sampler(origWidth, origHeight, sampleSize); |
| 278 | |
| 279 | decodedBitmap->setConfig(config, sampler.scaledWidth(), |
| 280 | sampler.scaledHeight(), 0); |
| 281 | if (SkImageDecoder::kDecodeBounds_Mode == mode) { |
| 282 | return true; |
| 283 | } |
| 284 | |
| 285 | // from here down we are concerned with colortables and pixels |
| 286 | |
| 287 | // we track if we actually see a non-opaque pixels, since sometimes a PNG sets its colortype |
| 288 | // to |= PNG_COLOR_MASK_ALPHA, but all of its pixels are in fact opaque. We care, since we |
| 289 | // draw lots faster if we can flag the bitmap has being opaque |
| 290 | bool reallyHasAlpha = false; |
| 291 | |
| 292 | SkColorTable* colorTable = NULL; |
| 293 | |
| 294 | if (color_type == PNG_COLOR_TYPE_PALETTE) { |
| 295 | int num_palette; |
| 296 | png_colorp palette; |
| 297 | png_bytep trans; |
| 298 | int num_trans; |
| 299 | |
| 300 | png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette); |
| 301 | |
| 302 | /* BUGGY IMAGE WORKAROUND |
| 303 | |
| 304 | We hit some images (e.g. fruit_.png) who contain bytes that are == colortable_count |
| 305 | which is a problem since we use the byte as an index. To work around this we grow |
| 306 | the colortable by 1 (if its < 256) and duplicate the last color into that slot. |
| 307 | */ |
| 308 | int colorCount = num_palette + (num_palette < 256); |
| 309 | |
| 310 | colorTable = SkNEW_ARGS(SkColorTable, (colorCount)); |
| 311 | |
| 312 | SkPMColor* colorPtr = colorTable->lockColors(); |
| 313 | if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| 314 | png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, NULL); |
| 315 | hasAlpha = (num_trans > 0); |
| 316 | } else { |
| 317 | num_trans = 0; |
| 318 | colorTable->setFlags(colorTable->getFlags() | SkColorTable::kColorsAreOpaque_Flag); |
| 319 | } |
| 320 | // check for bad images that might make us crash |
| 321 | if (num_trans > num_palette) { |
| 322 | num_trans = num_palette; |
| 323 | } |
| 324 | |
| 325 | int index = 0; |
| 326 | int transLessThanFF = 0; |
| 327 | |
| 328 | for (; index < num_trans; index++) { |
| 329 | transLessThanFF |= (int)*trans - 0xFF; |
| 330 | *colorPtr++ = SkPreMultiplyARGB(*trans++, palette->red, palette->green, palette->blue); |
| 331 | palette++; |
| 332 | } |
| 333 | reallyHasAlpha |= (transLessThanFF < 0); |
| 334 | |
| 335 | for (; index < num_palette; index++) { |
| 336 | *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue); |
| 337 | palette++; |
| 338 | } |
| 339 | |
| 340 | // see BUGGY IMAGE WORKAROUND comment above |
| 341 | if (num_palette < 256) { |
| 342 | *colorPtr = colorPtr[-1]; |
| 343 | } |
| 344 | colorTable->unlockColors(true); |
| 345 | } |
| 346 | |
| 347 | SkAutoUnref aur(colorTable); |
| 348 | |
| 349 | if (!this->allocPixelRef(decodedBitmap, colorTable)) { |
| 350 | return false; |
| 351 | } |
| 352 | |
| 353 | SkAutoLockPixels alp(*decodedBitmap); |
| 354 | |
| 355 | /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ |
| 356 | // if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 357 | // ; // png_set_swap_alpha(png_ptr); |
| 358 | |
| 359 | /* swap bytes of 16 bit files to least significant byte first */ |
| 360 | // png_set_swap(png_ptr); |
| 361 | |
| 362 | /* Add filler (or alpha) byte (before/after each RGB triplet) */ |
| 363 | if (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_GRAY) { |
| 364 | png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| 365 | } |
| 366 | |
| 367 | /* Turn on interlace handling. REQUIRED if you are not using |
| 368 | * png_read_image(). To see how to handle interlacing passes, |
| 369 | * see the png_read_row() method below: |
| 370 | */ |
| 371 | const int number_passes = interlace_type != PNG_INTERLACE_NONE ? |
| 372 | png_set_interlace_handling(png_ptr) : 1; |
| 373 | |
| 374 | /* Optional call to gamma correct and add the background to the palette |
| 375 | * and update info structure. REQUIRED if you are expecting libpng to |
| 376 | * update the palette for you (ie you selected such a transform above). |
| 377 | */ |
| 378 | png_read_update_info(png_ptr, info_ptr); |
| 379 | |
| 380 | if (SkBitmap::kIndex8_Config == config && 1 == sampleSize) { |
| 381 | for (int i = 0; i < number_passes; i++) { |
| 382 | for (png_uint_32 y = 0; y < origHeight; y++) { |
| 383 | uint8_t* bmRow = decodedBitmap->getAddr8(0, y); |
| 384 | png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| 385 | } |
| 386 | } |
| 387 | } else { |
| 388 | SkScaledBitmapSampler::SrcConfig sc; |
| 389 | int srcBytesPerPixel = 4; |
| 390 | |
| 391 | if (SkBitmap::kIndex8_Config == config) { |
| 392 | sc = SkScaledBitmapSampler::kIndex; |
| 393 | srcBytesPerPixel = 1; |
| 394 | } else if (hasAlpha) { |
| 395 | sc = SkScaledBitmapSampler::kRGBA; |
| 396 | } else { |
| 397 | sc = SkScaledBitmapSampler::kRGBX; |
| 398 | } |
| 399 | |
| 400 | SkAutoMalloc storage(origWidth * srcBytesPerPixel); |
| 401 | const int height = decodedBitmap->height(); |
| 402 | |
| 403 | for (int i = 0; i < number_passes; i++) { |
| 404 | if (!sampler.begin(decodedBitmap, sc, doDither)) { |
| 405 | return false; |
| 406 | } |
| 407 | |
| 408 | uint8_t* srcRow = (uint8_t*)storage.get(); |
| 409 | skip_src_rows(png_ptr, srcRow, sampler.srcY0()); |
| 410 | |
| 411 | for (int y = 0; y < height; y++) { |
| 412 | uint8_t* tmp = srcRow; |
| 413 | png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1); |
| 414 | reallyHasAlpha |= sampler.next(srcRow); |
| 415 | if (y < height - 1) { |
| 416 | skip_src_rows(png_ptr, srcRow, sampler.srcDY() - 1); |
| 417 | } |
| 418 | } |
| 419 | |
| 420 | // skip the rest of the rows (if any) |
| 421 | png_uint_32 read = (height - 1) * sampler.srcDY() + |
| 422 | sampler.srcY0() + 1; |
| 423 | SkASSERT(read <= origHeight); |
| 424 | skip_src_rows(png_ptr, srcRow, origHeight - read); |
| 425 | } |
| 426 | |
| 427 | if (hasAlpha && !reallyHasAlpha) { |
| 428 | #if 0 |
| 429 | SkDEBUGF(("Image doesn't really have alpha [%d %d]\n", |
| 430 | origWidth, origHeight)); |
| 431 | #endif |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ |
| 436 | png_read_end(png_ptr, info_ptr); |
| 437 | |
| 438 | if (0 != theTranspColor) { |
| 439 | reallyHasAlpha |= substituteTranspColor(decodedBitmap, theTranspColor); |
| 440 | } |
| 441 | decodedBitmap->setIsOpaque(!reallyHasAlpha); |
| 442 | return true; |
| 443 | } |
| 444 | |
| 445 | /////////////////////////////////////////////////////////////////////////////// |
| 446 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 447 | #include "SkColorPriv.h" |
| 448 | #include "SkUnPreMultiply.h" |
| 449 | |
| 450 | static void sk_write_fn(png_structp png_ptr, png_bytep data, png_size_t len) { |
| 451 | SkWStream* sk_stream = (SkWStream*)png_ptr->io_ptr; |
| 452 | if (!sk_stream->write(data, len)) { |
| 453 | png_error(png_ptr, "sk_write_fn Error!"); |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | typedef void (*transform_scanline_proc)(const char* SK_RESTRICT src, |
| 458 | int width, char* SK_RESTRICT dst); |
| 459 | |
| 460 | static void transform_scanline_565(const char* SK_RESTRICT src, int width, |
| 461 | char* SK_RESTRICT dst) { |
| 462 | const uint16_t* SK_RESTRICT srcP = (const uint16_t*)src; |
| 463 | for (int i = 0; i < width; i++) { |
| 464 | unsigned c = *srcP++; |
| 465 | *dst++ = SkPacked16ToR32(c); |
| 466 | *dst++ = SkPacked16ToG32(c); |
| 467 | *dst++ = SkPacked16ToB32(c); |
| 468 | } |
| 469 | } |
| 470 | |
| 471 | static void transform_scanline_888(const char* SK_RESTRICT src, int width, |
| 472 | char* SK_RESTRICT dst) { |
| 473 | const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; |
| 474 | for (int i = 0; i < width; i++) { |
| 475 | SkPMColor c = *srcP++; |
| 476 | *dst++ = SkGetPackedR32(c); |
| 477 | *dst++ = SkGetPackedG32(c); |
| 478 | *dst++ = SkGetPackedB32(c); |
| 479 | } |
| 480 | } |
| 481 | |
| 482 | static void transform_scanline_444(const char* SK_RESTRICT src, int width, |
| 483 | char* SK_RESTRICT dst) { |
| 484 | const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; |
| 485 | for (int i = 0; i < width; i++) { |
| 486 | SkPMColor16 c = *srcP++; |
| 487 | *dst++ = SkPacked4444ToR32(c); |
| 488 | *dst++ = SkPacked4444ToG32(c); |
| 489 | *dst++ = SkPacked4444ToB32(c); |
| 490 | } |
| 491 | } |
| 492 | |
| 493 | static void transform_scanline_8888(const char* SK_RESTRICT src, int width, |
| 494 | char* SK_RESTRICT dst) { |
| 495 | const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; |
| 496 | const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| 497 | SkUnPreMultiply::GetScaleTable(); |
| 498 | |
| 499 | for (int i = 0; i < width; i++) { |
| 500 | SkPMColor c = *srcP++; |
| 501 | unsigned a = SkGetPackedA32(c); |
| 502 | unsigned r = SkGetPackedR32(c); |
| 503 | unsigned g = SkGetPackedG32(c); |
| 504 | unsigned b = SkGetPackedB32(c); |
| 505 | |
| 506 | if (0 != a && 255 != a) { |
| 507 | SkUnPreMultiply::Scale scale = table[a]; |
| 508 | r = SkUnPreMultiply::ApplyScale(scale, r); |
| 509 | g = SkUnPreMultiply::ApplyScale(scale, g); |
| 510 | b = SkUnPreMultiply::ApplyScale(scale, b); |
| 511 | } |
| 512 | *dst++ = r; |
| 513 | *dst++ = g; |
| 514 | *dst++ = b; |
| 515 | *dst++ = a; |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | static void transform_scanline_4444(const char* SK_RESTRICT src, int width, |
| 520 | char* SK_RESTRICT dst) { |
| 521 | const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; |
| 522 | const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| 523 | SkUnPreMultiply::GetScaleTable(); |
| 524 | |
| 525 | for (int i = 0; i < width; i++) { |
| 526 | SkPMColor16 c = *srcP++; |
| 527 | unsigned a = SkPacked4444ToA32(c); |
| 528 | unsigned r = SkPacked4444ToR32(c); |
| 529 | unsigned g = SkPacked4444ToG32(c); |
| 530 | unsigned b = SkPacked4444ToB32(c); |
| 531 | |
| 532 | if (0 != a && 255 != a) { |
| 533 | SkUnPreMultiply::Scale scale = table[a]; |
| 534 | r = SkUnPreMultiply::ApplyScale(scale, r); |
| 535 | g = SkUnPreMultiply::ApplyScale(scale, g); |
| 536 | b = SkUnPreMultiply::ApplyScale(scale, b); |
| 537 | } |
| 538 | *dst++ = r; |
| 539 | *dst++ = g; |
| 540 | *dst++ = b; |
| 541 | *dst++ = a; |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | static void transform_scanline_index8(const char* SK_RESTRICT src, int width, |
| 546 | char* SK_RESTRICT dst) { |
| 547 | memcpy(dst, src, width); |
| 548 | } |
| 549 | |
| 550 | static transform_scanline_proc choose_proc(SkBitmap::Config config, |
| 551 | bool hasAlpha) { |
| 552 | // we don't care about search on alpha if we're kIndex8, since only the |
| 553 | // colortable packing cares about that distinction, not the pixels |
| 554 | if (SkBitmap::kIndex8_Config == config) { |
| 555 | hasAlpha = false; // we store false in the table entries for kIndex8 |
| 556 | } |
| 557 | |
| 558 | static const struct { |
| 559 | SkBitmap::Config fConfig; |
| 560 | bool fHasAlpha; |
| 561 | transform_scanline_proc fProc; |
| 562 | } gMap[] = { |
| 563 | { SkBitmap::kRGB_565_Config, false, transform_scanline_565 }, |
| 564 | { SkBitmap::kARGB_8888_Config, false, transform_scanline_888 }, |
| 565 | { SkBitmap::kARGB_8888_Config, true, transform_scanline_8888 }, |
| 566 | { SkBitmap::kARGB_4444_Config, false, transform_scanline_444 }, |
| 567 | { SkBitmap::kARGB_4444_Config, true, transform_scanline_4444 }, |
| 568 | { SkBitmap::kIndex8_Config, false, transform_scanline_index8 }, |
| 569 | }; |
| 570 | |
| 571 | for (int i = SK_ARRAY_COUNT(gMap) - 1; i >= 0; --i) { |
| 572 | if (gMap[i].fConfig == config && gMap[i].fHasAlpha == hasAlpha) { |
| 573 | return gMap[i].fProc; |
| 574 | } |
| 575 | } |
| 576 | sk_throw(); |
| 577 | return NULL; |
| 578 | } |
| 579 | |
| 580 | // return the minimum legal bitdepth (by png standards) for this many colortable |
| 581 | // entries. SkBitmap always stores in 8bits per pixel, but for colorcount <= 16, |
| 582 | // we can use fewer bits per in png |
| 583 | static int computeBitDepth(int colorCount) { |
| 584 | #if 0 |
| 585 | int bits = SkNextLog2(colorCount); |
| 586 | SkASSERT(bits >= 1 && bits <= 8); |
| 587 | // now we need bits itself to be a power of 2 (e.g. 1, 2, 4, 8) |
| 588 | return SkNextPow2(bits); |
| 589 | #else |
| 590 | // for the moment, we don't know how to pack bitdepth < 8 |
| 591 | return 8; |
| 592 | #endif |
| 593 | } |
| 594 | |
| 595 | /* Pack palette[] with the corresponding colors, and if hasAlpha is true, also |
| 596 | pack trans[] and return the number of trans[] entries written. If hasAlpha |
| 597 | is false, the return value will always be 0. |
| 598 | |
| 599 | Note: this routine takes care of unpremultiplying the RGB values when we |
| 600 | have alpha in the colortable, since png doesn't support premul colors |
| 601 | */ |
| 602 | static int pack_palette(SkColorTable* ctable, png_color* SK_RESTRICT palette, |
| 603 | png_byte* SK_RESTRICT trans, bool hasAlpha) { |
| 604 | SkAutoLockColors alc(ctable); |
| 605 | const SkPMColor* SK_RESTRICT colors = alc.colors(); |
| 606 | const int ctCount = ctable->count(); |
| 607 | int i, num_trans = 0; |
| 608 | |
| 609 | if (hasAlpha) { |
| 610 | /* first see if we have some number of fully opaque at the end of the |
| 611 | ctable. PNG allows num_trans < num_palette, but all of the trans |
| 612 | entries must come first in the palette. If I was smarter, I'd |
| 613 | reorder the indices and ctable so that all non-opaque colors came |
| 614 | first in the palette. But, since that would slow down the encode, |
| 615 | I'm leaving the indices and ctable order as is, and just looking |
| 616 | at the tail of the ctable for opaqueness. |
| 617 | */ |
| 618 | num_trans = ctCount; |
| 619 | for (i = ctCount - 1; i >= 0; --i) { |
| 620 | if (SkGetPackedA32(colors[i]) != 0xFF) { |
| 621 | break; |
| 622 | } |
| 623 | num_trans -= 1; |
| 624 | } |
| 625 | |
| 626 | const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| 627 | SkUnPreMultiply::GetScaleTable(); |
| 628 | |
| 629 | for (i = 0; i < num_trans; i++) { |
| 630 | const SkPMColor c = *colors++; |
| 631 | const unsigned a = SkGetPackedA32(c); |
| 632 | const SkUnPreMultiply::Scale s = table[a]; |
| 633 | trans[i] = a; |
| 634 | palette[i].red = SkUnPreMultiply::ApplyScale(s, SkGetPackedR32(c)); |
| 635 | palette[i].green = SkUnPreMultiply::ApplyScale(s,SkGetPackedG32(c)); |
| 636 | palette[i].blue = SkUnPreMultiply::ApplyScale(s, SkGetPackedB32(c)); |
| 637 | } |
| 638 | // now fall out of this if-block to use common code for the trailing |
| 639 | // opaque entries |
| 640 | } |
| 641 | |
| 642 | // these (remaining) entries are opaque |
| 643 | for (i = num_trans; i < ctCount; i++) { |
| 644 | SkPMColor c = *colors++; |
| 645 | palette[i].red = SkGetPackedR32(c); |
| 646 | palette[i].green = SkGetPackedG32(c); |
| 647 | palette[i].blue = SkGetPackedB32(c); |
| 648 | } |
| 649 | return num_trans; |
| 650 | } |
| 651 | |
| 652 | class SkPNGImageEncoder : public SkImageEncoder { |
| 653 | protected: |
| 654 | virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality); |
| 655 | }; |
| 656 | |
| 657 | bool SkPNGImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bitmap, |
| 658 | int /*quality*/) { |
| 659 | SkBitmap::Config config = bitmap.getConfig(); |
| 660 | |
| 661 | const bool hasAlpha = !bitmap.isOpaque(); |
| 662 | int colorType = PNG_COLOR_MASK_COLOR; |
| 663 | int bitDepth = 8; // default for color |
| 664 | png_color_8 sig_bit; |
| 665 | |
| 666 | switch (config) { |
| 667 | case SkBitmap::kIndex8_Config: |
| 668 | colorType |= PNG_COLOR_MASK_PALETTE; |
| 669 | // fall through to the ARGB_8888 case |
| 670 | case SkBitmap::kARGB_8888_Config: |
| 671 | sig_bit.red = 8; |
| 672 | sig_bit.green = 8; |
| 673 | sig_bit.blue = 8; |
| 674 | sig_bit.alpha = 8; |
| 675 | break; |
| 676 | case SkBitmap::kARGB_4444_Config: |
| 677 | sig_bit.red = 4; |
| 678 | sig_bit.green = 4; |
| 679 | sig_bit.blue = 4; |
| 680 | sig_bit.alpha = 4; |
| 681 | break; |
| 682 | case SkBitmap::kRGB_565_Config: |
| 683 | sig_bit.red = 5; |
| 684 | sig_bit.green = 6; |
| 685 | sig_bit.blue = 5; |
| 686 | sig_bit.alpha = 0; |
| 687 | break; |
| 688 | default: |
| 689 | return false; |
| 690 | } |
| 691 | |
| 692 | if (hasAlpha) { |
| 693 | // don't specify alpha if we're a palette, even if our ctable has alpha |
| 694 | if (!(colorType & PNG_COLOR_MASK_PALETTE)) { |
| 695 | colorType |= PNG_COLOR_MASK_ALPHA; |
| 696 | } |
| 697 | } else { |
| 698 | sig_bit.alpha = 0; |
| 699 | } |
| 700 | |
| 701 | SkAutoLockPixels alp(bitmap); |
| 702 | // readyToDraw checks for pixels (and colortable if that is required) |
| 703 | if (!bitmap.readyToDraw()) { |
| 704 | return false; |
| 705 | } |
| 706 | |
| 707 | // we must do this after we have locked the pixels |
| 708 | SkColorTable* ctable = bitmap.getColorTable(); |
| 709 | if (NULL != ctable) { |
| 710 | if (ctable->count() == 0) { |
| 711 | return false; |
| 712 | } |
| 713 | // check if we can store in fewer than 8 bits |
| 714 | bitDepth = computeBitDepth(ctable->count()); |
| 715 | } |
| 716 | |
| 717 | png_structp png_ptr; |
| 718 | png_infop info_ptr; |
| 719 | |
| 720 | png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, sk_error_fn, |
| 721 | NULL); |
| 722 | if (NULL == png_ptr) { |
| 723 | return false; |
| 724 | } |
| 725 | |
| 726 | info_ptr = png_create_info_struct(png_ptr); |
| 727 | if (NULL == info_ptr) { |
| 728 | png_destroy_write_struct(&png_ptr, png_infopp_NULL); |
| 729 | return false; |
| 730 | } |
| 731 | |
| 732 | /* Set error handling. REQUIRED if you aren't supplying your own |
| 733 | * error handling functions in the png_create_write_struct() call. |
| 734 | */ |
| 735 | if (setjmp(png_jmpbuf(png_ptr))) { |
| 736 | png_destroy_write_struct(&png_ptr, &info_ptr); |
| 737 | return false; |
| 738 | } |
| 739 | |
| 740 | png_set_write_fn(png_ptr, (void*)stream, sk_write_fn, png_flush_ptr_NULL); |
| 741 | |
| 742 | /* Set the image information here. Width and height are up to 2^31, |
| 743 | * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on |
| 744 | * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY, |
| 745 | * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB, |
| 746 | * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or |
| 747 | * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST |
| 748 | * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED |
| 749 | */ |
| 750 | |
| 751 | png_set_IHDR(png_ptr, info_ptr, bitmap.width(), bitmap.height(), |
| 752 | bitDepth, colorType, |
| 753 | PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, |
| 754 | PNG_FILTER_TYPE_BASE); |
| 755 | |
| 756 | #if 0 // need to support this some day |
| 757 | /* set the palette if there is one. REQUIRED for indexed-color images */ |
| 758 | palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH |
| 759 | * png_sizeof (png_color)); |
| 760 | /* ... set palette colors ... */ |
| 761 | png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH); |
| 762 | /* You must not free palette here, because png_set_PLTE only makes a link to |
| 763 | the palette that you malloced. Wait until you are about to destroy |
| 764 | the png structure. */ |
| 765 | #endif |
| 766 | |
| 767 | png_set_sBIT(png_ptr, info_ptr, &sig_bit); |
| 768 | png_write_info(png_ptr, info_ptr); |
| 769 | |
| 770 | const char* srcImage = (const char*)bitmap.getPixels(); |
| 771 | SkAutoSMalloc<1024> rowStorage(bitmap.width() << 2); |
| 772 | char* storage = (char*)rowStorage.get(); |
| 773 | transform_scanline_proc proc = choose_proc(config, hasAlpha); |
| 774 | |
| 775 | for (int y = 0; y < bitmap.height(); y++) { |
| 776 | png_bytep row_ptr = (png_bytep)storage; |
| 777 | proc(srcImage, bitmap.width(), storage); |
| 778 | png_write_rows(png_ptr, &row_ptr, 1); |
| 779 | srcImage += bitmap.rowBytes(); |
| 780 | } |
| 781 | |
| 782 | png_write_end(png_ptr, info_ptr); |
| 783 | |
| 784 | /* clean up after the write, and free any memory allocated */ |
| 785 | png_destroy_write_struct(&png_ptr, &info_ptr); |
| 786 | return true; |
| 787 | } |
| 788 | |
| 789 | SkImageEncoder* SkImageEncoder_PNG_Factory(); |
| 790 | SkImageEncoder* SkImageEncoder_PNG_Factory() { |
| 791 | return SkNEW(SkPNGImageEncoder); |
| 792 | } |
| 793 | |