scroggo | f24f224 | 2015-03-03 08:59:20 -0800 | [diff] [blame^] | 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_libpng.h" |
| 9 | #include "SkColorPriv.h" |
| 10 | #include "SkColorTable.h" |
| 11 | #include "SkBitmap.h" |
| 12 | #include "SkMath.h" |
| 13 | #include "SkSize.h" |
| 14 | #include "SkStream.h" |
| 15 | #include "SkSwizzler.h" |
| 16 | |
| 17 | /////////////////////////////////////////////////////////////////////////////// |
| 18 | // Helper macros |
| 19 | /////////////////////////////////////////////////////////////////////////////// |
| 20 | |
| 21 | #ifndef png_jmpbuf |
| 22 | # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| 23 | #endif |
| 24 | |
| 25 | /* These were dropped in libpng >= 1.4 */ |
| 26 | #ifndef png_infopp_NULL |
| 27 | #define png_infopp_NULL NULL |
| 28 | #endif |
| 29 | |
| 30 | #ifndef png_bytepp_NULL |
| 31 | #define png_bytepp_NULL NULL |
| 32 | #endif |
| 33 | |
| 34 | #ifndef int_p_NULL |
| 35 | #define int_p_NULL NULL |
| 36 | #endif |
| 37 | |
| 38 | #ifndef png_flush_ptr_NULL |
| 39 | #define png_flush_ptr_NULL NULL |
| 40 | #endif |
| 41 | |
| 42 | /////////////////////////////////////////////////////////////////////////////// |
| 43 | // Callback functions |
| 44 | /////////////////////////////////////////////////////////////////////////////// |
| 45 | |
| 46 | static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| 47 | SkDebugf("------ png error %s\n", msg); |
| 48 | longjmp(png_jmpbuf(png_ptr), 1); |
| 49 | } |
| 50 | |
| 51 | static void sk_read_fn(png_structp png_ptr, png_bytep data, |
| 52 | png_size_t length) { |
| 53 | SkStream* stream = static_cast<SkStream*>(png_get_io_ptr(png_ptr)); |
| 54 | const size_t bytes = stream->read(data, length); |
| 55 | if (bytes != length) { |
| 56 | // FIXME: We want to report the fact that the stream was truncated. |
| 57 | // One way to do that might be to pass a enum to longjmp so setjmp can |
| 58 | // specify the failure. |
| 59 | png_error(png_ptr, "Read Error!"); |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | /////////////////////////////////////////////////////////////////////////////// |
| 64 | // Helpers |
| 65 | /////////////////////////////////////////////////////////////////////////////// |
| 66 | |
| 67 | class AutoCleanPng : public SkNoncopyable { |
| 68 | public: |
| 69 | AutoCleanPng(png_structp png_ptr) |
| 70 | : fPng_ptr(png_ptr) |
| 71 | , fInfo_ptr(NULL) {} |
| 72 | |
| 73 | ~AutoCleanPng() { |
| 74 | // fInfo_ptr will never be non-NULL unless fPng_ptr is. |
| 75 | if (fPng_ptr) { |
| 76 | png_infopp info_pp = fInfo_ptr ? &fInfo_ptr : NULL; |
| 77 | png_destroy_read_struct(&fPng_ptr, info_pp, png_infopp_NULL); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | void setInfoPtr(png_infop info_ptr) { |
| 82 | SkASSERT(NULL == fInfo_ptr); |
| 83 | fInfo_ptr = info_ptr; |
| 84 | } |
| 85 | |
| 86 | void detach() { |
| 87 | fPng_ptr = NULL; |
| 88 | fInfo_ptr = NULL; |
| 89 | } |
| 90 | |
| 91 | private: |
| 92 | png_structp fPng_ptr; |
| 93 | png_infop fInfo_ptr; |
| 94 | }; |
| 95 | #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) |
| 96 | |
| 97 | // call only if color_type is PALETTE. Returns true if the ctable has alpha |
| 98 | static bool has_transparency_in_palette(png_structp png_ptr, |
| 99 | png_infop info_ptr) { |
| 100 | if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| 101 | return false; |
| 102 | } |
| 103 | |
| 104 | png_bytep trans; |
| 105 | int num_trans; |
| 106 | png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, NULL); |
| 107 | return num_trans > 0; |
| 108 | } |
| 109 | |
| 110 | // Method for coverting to either an SkPMColor or a similarly packed |
| 111 | // unpremultiplied color. |
| 112 | typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b); |
| 113 | |
| 114 | // Note: SkColorTable claims to store SkPMColors, which is not necessarily |
| 115 | // the case here. |
| 116 | SkColorTable* decode_palette(png_structp png_ptr, png_infop info_ptr, |
| 117 | bool premultiply, SkAlphaType* outAlphaType) { |
| 118 | SkASSERT(outAlphaType != NULL); |
| 119 | int numPalette; |
| 120 | png_colorp palette; |
| 121 | png_bytep trans; |
| 122 | |
| 123 | if (!png_get_PLTE(png_ptr, info_ptr, &palette, &numPalette)) { |
| 124 | return NULL; |
| 125 | } |
| 126 | |
| 127 | /* BUGGY IMAGE WORKAROUND |
| 128 | |
| 129 | We hit some images (e.g. fruit_.png) who contain bytes that are == colortable_count |
| 130 | which is a problem since we use the byte as an index. To work around this we grow |
| 131 | the colortable by 1 (if its < 256) and duplicate the last color into that slot. |
| 132 | */ |
| 133 | const int colorCount = numPalette + (numPalette < 256); |
| 134 | // Note: These are not necessarily SkPMColors. |
| 135 | SkPMColor colorStorage[256]; // worst-case storage |
| 136 | SkPMColor* colorPtr = colorStorage; |
| 137 | |
| 138 | int numTrans; |
| 139 | if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| 140 | png_get_tRNS(png_ptr, info_ptr, &trans, &numTrans, NULL); |
| 141 | } else { |
| 142 | numTrans = 0; |
| 143 | } |
| 144 | |
| 145 | // check for bad images that might make us crash |
| 146 | if (numTrans > numPalette) { |
| 147 | numTrans = numPalette; |
| 148 | } |
| 149 | |
| 150 | int index = 0; |
| 151 | int transLessThanFF = 0; |
| 152 | |
| 153 | // Choose which function to use to create the color table. If the final destination's |
| 154 | // colortype is unpremultiplied, the color table will store unpremultiplied colors. |
| 155 | PackColorProc proc; |
| 156 | if (premultiply) { |
| 157 | proc = &SkPreMultiplyARGB; |
| 158 | } else { |
| 159 | proc = &SkPackARGB32NoCheck; |
| 160 | } |
| 161 | for (; index < numTrans; index++) { |
| 162 | transLessThanFF |= (int)*trans - 0xFF; |
| 163 | *colorPtr++ = proc(*trans++, palette->red, palette->green, palette->blue); |
| 164 | palette++; |
| 165 | } |
| 166 | |
| 167 | if (transLessThanFF < 0) { |
| 168 | *outAlphaType = premultiply ? kPremul_SkAlphaType : kUnpremul_SkAlphaType; |
| 169 | } else { |
| 170 | *outAlphaType = kOpaque_SkAlphaType; |
| 171 | } |
| 172 | |
| 173 | for (; index < numPalette; index++) { |
| 174 | *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue); |
| 175 | palette++; |
| 176 | } |
| 177 | |
| 178 | // see BUGGY IMAGE WORKAROUND comment above |
| 179 | if (numPalette < 256) { |
| 180 | *colorPtr = colorPtr[-1]; |
| 181 | } |
| 182 | |
| 183 | return SkNEW_ARGS(SkColorTable, (colorStorage, colorCount)); |
| 184 | } |
| 185 | |
| 186 | /////////////////////////////////////////////////////////////////////////////// |
| 187 | // Creation |
| 188 | /////////////////////////////////////////////////////////////////////////////// |
| 189 | |
| 190 | #define PNG_BYTES_TO_CHECK 4 |
| 191 | |
| 192 | bool SkPngCodec::IsPng(SkStream* stream) { |
| 193 | char buf[PNG_BYTES_TO_CHECK]; |
| 194 | if (stream->read(buf, PNG_BYTES_TO_CHECK) != PNG_BYTES_TO_CHECK) { |
| 195 | return false; |
| 196 | } |
| 197 | if (png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) { |
| 198 | return false; |
| 199 | } |
| 200 | return true; |
| 201 | } |
| 202 | |
| 203 | SkCodec* SkPngCodec::NewFromStream(SkStream* stream) { |
| 204 | // The image is known to be a PNG. Decode enough to know the SkImageInfo. |
| 205 | // FIXME: Allow silencing warnings. |
| 206 | png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, |
| 207 | sk_error_fn, NULL); |
| 208 | if (!png_ptr) { |
| 209 | return NULL; |
| 210 | } |
| 211 | |
| 212 | AutoCleanPng autoClean(png_ptr); |
| 213 | |
| 214 | png_infop info_ptr = png_create_info_struct(png_ptr); |
| 215 | if (info_ptr == NULL) { |
| 216 | return NULL; |
| 217 | } |
| 218 | |
| 219 | autoClean.setInfoPtr(info_ptr); |
| 220 | |
| 221 | // FIXME: Could we use the return value of setjmp to specify the type of |
| 222 | // error? |
| 223 | if (setjmp(png_jmpbuf(png_ptr))) { |
| 224 | return NULL; |
| 225 | } |
| 226 | |
| 227 | png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn); |
| 228 | |
| 229 | // FIXME: This is where the old code hooks up the Peeker. Does it need to |
| 230 | // be set this early? (i.e. where are the user chunks? early in the stream, |
| 231 | // potentially?) |
| 232 | // If it does, we need to figure out a way to set it here. |
| 233 | |
| 234 | // The call to png_read_info() gives us all of the information from the |
| 235 | // PNG file before the first IDAT (image data chunk). |
| 236 | png_read_info(png_ptr, info_ptr); |
| 237 | png_uint_32 origWidth, origHeight; |
| 238 | int bitDepth, colorType; |
| 239 | png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| 240 | &colorType, int_p_NULL, int_p_NULL, int_p_NULL); |
| 241 | |
| 242 | // sanity check for size |
| 243 | { |
| 244 | int64_t size = sk_64_mul(origWidth, origHeight); |
| 245 | // now check that if we are 4-bytes per pixel, we also don't overflow |
| 246 | if (size < 0 || size > (0x7FFFFFFF >> 2)) { |
| 247 | return NULL; |
| 248 | } |
| 249 | } |
| 250 | |
| 251 | // Tell libpng to strip 16 bit/color files down to 8 bits/color |
| 252 | if (bitDepth == 16) { |
| 253 | png_set_strip_16(png_ptr); |
| 254 | } |
| 255 | #ifdef PNG_READ_PACK_SUPPORTED |
| 256 | // Extract multiple pixels with bit depths of 1, 2, and 4 from a single |
| 257 | // byte into separate bytes (useful for paletted and grayscale images). |
| 258 | if (bitDepth < 8) { |
| 259 | png_set_packing(png_ptr); |
| 260 | } |
| 261 | #endif |
| 262 | // Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel. |
| 263 | if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) { |
| 264 | png_set_expand_gray_1_2_4_to_8(png_ptr); |
| 265 | } |
| 266 | |
| 267 | |
| 268 | // Now determine the default SkColorType and SkAlphaType. |
| 269 | SkColorType skColorType; |
| 270 | SkAlphaType skAlphaType; |
| 271 | switch (colorType) { |
| 272 | case PNG_COLOR_TYPE_PALETTE: |
| 273 | // Technically, this is true of the data, but I don't think we want |
| 274 | // to support it. |
| 275 | // skColorType = kIndex8_SkColorType; |
| 276 | skColorType = kN32_SkColorType; |
| 277 | skAlphaType = has_transparency_in_palette(png_ptr, info_ptr) ? |
| 278 | kUnpremul_SkAlphaType : kOpaque_SkAlphaType; |
| 279 | break; |
| 280 | case PNG_COLOR_TYPE_GRAY: |
| 281 | if (false) { |
| 282 | // FIXME: Is this the wrong default behavior? This means if the |
| 283 | // caller supplies the info we gave them, they'll get Alpha 8. |
| 284 | skColorType = kAlpha_8_SkColorType; |
| 285 | // FIXME: Strangely, the canonical type for Alpha 8 is Premul. |
| 286 | skAlphaType = kPremul_SkAlphaType; |
| 287 | } else { |
| 288 | skColorType = kN32_SkColorType; |
| 289 | skAlphaType = kOpaque_SkAlphaType; |
| 290 | } |
| 291 | break; |
| 292 | default: |
| 293 | // Note: This *almost* mimics the code in SkImageDecoder_libpng. |
| 294 | // has_transparency_in_palette makes an additional check - whether |
| 295 | // numTrans is greater than 0. Why does the other code not make that |
| 296 | // check? |
| 297 | if (has_transparency_in_palette(png_ptr, info_ptr) |
| 298 | || PNG_COLOR_TYPE_RGB_ALPHA == colorType |
| 299 | || PNG_COLOR_TYPE_GRAY_ALPHA == colorType) |
| 300 | { |
| 301 | skAlphaType = kUnpremul_SkAlphaType; |
| 302 | } else { |
| 303 | skAlphaType = kOpaque_SkAlphaType; |
| 304 | } |
| 305 | skColorType = kN32_SkColorType; |
| 306 | break; |
| 307 | } |
| 308 | |
| 309 | { |
| 310 | // FIXME: Again, this block needs to go into onGetPixels. |
| 311 | bool convertGrayToRGB = PNG_COLOR_TYPE_GRAY == colorType && skColorType != kAlpha_8_SkColorType; |
| 312 | |
| 313 | // Unless the user is requesting A8, convert a grayscale image into RGB. |
| 314 | // GRAY_ALPHA will always be converted to RGB |
| 315 | if (convertGrayToRGB || colorType == PNG_COLOR_TYPE_GRAY_ALPHA) { |
| 316 | png_set_gray_to_rgb(png_ptr); |
| 317 | } |
| 318 | |
| 319 | // Add filler (or alpha) byte (after each RGB triplet) if necessary. |
| 320 | // FIXME: It seems like we could just use RGB as the SrcConfig here. |
| 321 | if (colorType == PNG_COLOR_TYPE_RGB || convertGrayToRGB) { |
| 322 | png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | // FIXME: Also need to check for sRGB (skbug.com/3471). |
| 327 | |
| 328 | SkImageInfo info = SkImageInfo::Make(origWidth, origHeight, skColorType, |
| 329 | skAlphaType); |
| 330 | SkCodec* codec = SkNEW_ARGS(SkPngCodec, (info, stream, png_ptr, info_ptr)); |
| 331 | autoClean.detach(); |
| 332 | return codec; |
| 333 | } |
| 334 | |
| 335 | SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream, |
| 336 | png_structp png_ptr, png_infop info_ptr) |
| 337 | : INHERITED(info, stream) |
| 338 | , fPng_ptr(png_ptr) |
| 339 | , fInfo_ptr(info_ptr) {} |
| 340 | |
| 341 | SkPngCodec::~SkPngCodec() { |
| 342 | png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL); |
| 343 | } |
| 344 | |
| 345 | /////////////////////////////////////////////////////////////////////////////// |
| 346 | // Getting the pixels |
| 347 | /////////////////////////////////////////////////////////////////////////////// |
| 348 | |
| 349 | static bool premul_and_unpremul(SkAlphaType A, SkAlphaType B) { |
| 350 | return kPremul_SkAlphaType == A && kUnpremul_SkAlphaType == B; |
| 351 | } |
| 352 | |
| 353 | static bool conversion_possible(const SkImageInfo& A, const SkImageInfo& B) { |
| 354 | // TODO: Support other conversions |
| 355 | if (A.colorType() != B.colorType()) { |
| 356 | return false; |
| 357 | } |
| 358 | if (A.profileType() != B.profileType()) { |
| 359 | return false; |
| 360 | } |
| 361 | if (A.alphaType() == B.alphaType()) { |
| 362 | return true; |
| 363 | } |
| 364 | return premul_and_unpremul(A.alphaType(), B.alphaType()) |
| 365 | || premul_and_unpremul(B.alphaType(), A.alphaType()); |
| 366 | } |
| 367 | |
| 368 | SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst, |
| 369 | size_t rowBytes, SkPMColor ctable[], |
| 370 | int* ctableCount) { |
| 371 | if (!this->rewindIfNeeded()) { |
| 372 | return kCouldNotRewind; |
| 373 | } |
| 374 | if (requestedInfo.dimensions() != this->getOriginalInfo().dimensions()) { |
| 375 | return kInvalidScale; |
| 376 | } |
| 377 | if (!conversion_possible(requestedInfo, this->getOriginalInfo())) { |
| 378 | return kInvalidConversion; |
| 379 | } |
| 380 | |
| 381 | SkBitmap decodedBitmap; |
| 382 | // If installPixels would have failed, getPixels should have failed before |
| 383 | // calling onGetPixels. |
| 384 | SkAssertResult(decodedBitmap.installPixels(requestedInfo, dst, rowBytes)); |
| 385 | |
| 386 | // Initialize all non-trivial objects before setjmp. |
| 387 | SkAutoTUnref<SkColorTable> colorTable; |
| 388 | SkAutoTDelete<SkSwizzler> swizzler; |
| 389 | SkAutoMalloc storage; // Scratch memory for pre-swizzled rows. |
| 390 | |
| 391 | // FIXME: Could we use the return value of setjmp to specify the type of |
| 392 | // error? |
| 393 | if (setjmp(png_jmpbuf(fPng_ptr))) { |
| 394 | SkDebugf("setjmp long jump!\n"); |
| 395 | return kInvalidInput; |
| 396 | } |
| 397 | |
| 398 | // FIXME: We already retrieved this information. Store it in SkPngCodec? |
| 399 | png_uint_32 origWidth, origHeight; |
| 400 | int bitDepth, pngColorType, interlaceType; |
| 401 | png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth, |
| 402 | &pngColorType, &interlaceType, int_p_NULL, int_p_NULL); |
| 403 | |
| 404 | const int numberPasses = (interlaceType != PNG_INTERLACE_NONE) ? |
| 405 | png_set_interlace_handling(fPng_ptr) : 1; |
| 406 | |
| 407 | SkSwizzler::SrcConfig sc; |
| 408 | bool reallyHasAlpha = false; |
| 409 | if (PNG_COLOR_TYPE_PALETTE == pngColorType) { |
| 410 | sc = SkSwizzler::kIndex; |
| 411 | SkAlphaType at = requestedInfo.alphaType(); |
| 412 | colorTable.reset(decode_palette(fPng_ptr, fInfo_ptr, |
| 413 | kPremul_SkAlphaType == at, |
| 414 | &at)); |
| 415 | if (!colorTable) { |
| 416 | return kInvalidInput; |
| 417 | } |
| 418 | |
| 419 | reallyHasAlpha = (at != kOpaque_SkAlphaType); |
| 420 | |
| 421 | if (at != requestedInfo.alphaType()) { |
| 422 | // It turns out the image is opaque. |
| 423 | SkASSERT(kOpaque_SkAlphaType == at); |
| 424 | } |
| 425 | } else if (kAlpha_8_SkColorType == requestedInfo.colorType()) { |
| 426 | // Note: we check the destination, since otherwise we would have |
| 427 | // told png to upscale. |
| 428 | SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| 429 | sc = SkSwizzler::kGray; |
| 430 | } else if (this->getOriginalInfo().alphaType() == kOpaque_SkAlphaType) { |
| 431 | sc = SkSwizzler::kRGBX; |
| 432 | } else { |
| 433 | sc = SkSwizzler::kRGBA; |
| 434 | } |
| 435 | const SkPMColor* colors = colorTable ? colorTable->readColors() : NULL; |
| 436 | // TODO: Support skipZeroes. |
| 437 | swizzler.reset(SkSwizzler::CreateSwizzler(sc, colors, requestedInfo, |
| 438 | dst, rowBytes, false)); |
| 439 | if (!swizzler) { |
| 440 | // FIXME: CreateSwizzler could fail for another reason. |
| 441 | return kUnimplemented; |
| 442 | } |
| 443 | |
| 444 | // FIXME: Here is where we should likely insert some of the modifications |
| 445 | // made in the factory. |
| 446 | png_read_update_info(fPng_ptr, fInfo_ptr); |
| 447 | |
| 448 | if (numberPasses > 1) { |
| 449 | const int width = requestedInfo.width(); |
| 450 | const int height = requestedInfo.height(); |
| 451 | const int bpp = SkSwizzler::BytesPerPixel(sc); |
| 452 | const size_t rowBytes = width * bpp; |
| 453 | |
| 454 | storage.reset(width * height * bpp); |
| 455 | uint8_t* const base = static_cast<uint8_t*>(storage.get()); |
| 456 | |
| 457 | for (int i = 0; i < numberPasses; i++) { |
| 458 | uint8_t* row = base; |
| 459 | for (int y = 0; y < height; y++) { |
| 460 | uint8_t* bmRow = row; |
| 461 | png_read_rows(fPng_ptr, &bmRow, png_bytepp_NULL, 1); |
| 462 | row += rowBytes; |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | // Now swizzle it. |
| 467 | uint8_t* row = base; |
| 468 | for (int y = 0; y < height; y++) { |
| 469 | reallyHasAlpha |= swizzler->next(row); |
| 470 | row += rowBytes; |
| 471 | } |
| 472 | } else { |
| 473 | storage.reset(requestedInfo.width() * SkSwizzler::BytesPerPixel(sc)); |
| 474 | uint8_t* srcRow = static_cast<uint8_t*>(storage.get()); |
| 475 | for (int y = 0; y < requestedInfo.height(); y++) { |
| 476 | png_read_rows(fPng_ptr, &srcRow, png_bytepp_NULL, 1); |
| 477 | reallyHasAlpha |= swizzler->next(srcRow); |
| 478 | } |
| 479 | } |
| 480 | |
| 481 | /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ |
| 482 | png_read_end(fPng_ptr, fInfo_ptr); |
| 483 | |
| 484 | // FIXME: do we need substituteTranspColor? |
| 485 | |
| 486 | if (reallyHasAlpha && requestedInfo.alphaType() != kOpaque_SkAlphaType) { |
| 487 | // FIXME: We want to alert the caller. Is this the right way? |
| 488 | SkImageInfo* modInfo = const_cast<SkImageInfo*>(&requestedInfo); |
| 489 | *modInfo = requestedInfo.makeAlphaType(kOpaque_SkAlphaType); |
| 490 | } |
| 491 | return kSuccess; |
| 492 | } |