| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkBitmap.h" |
| #include "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkColorSpace.h" |
| #include "SkColorTable.h" |
| #include "SkMath.h" |
| #include "SkOpts.h" |
| #include "SkPngCodec.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| #include "SkTemplates.h" |
| #include "SkUtils.h" |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Callback functions |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| // When setjmp is first called, it returns 0, meaning longjmp was not called. |
| constexpr int kSetJmpOkay = 0; |
| // An error internal to libpng. |
| constexpr int kPngError = 1; |
| // Passed to longjmp when we have decoded as many lines as we need. |
| constexpr int kStopDecoding = 2; |
| |
| static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| SkCodecPrintf("------ png error %s\n", msg); |
| longjmp(png_jmpbuf(png_ptr), kPngError); |
| } |
| |
| void sk_warning_fn(png_structp, png_const_charp msg) { |
| SkCodecPrintf("----- png warning %s\n", msg); |
| } |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) { |
| SkPngChunkReader* chunkReader = (SkPngChunkReader*)png_get_user_chunk_ptr(png_ptr); |
| // readChunk() returning true means continue decoding |
| return chunkReader->readChunk((const char*)chunk->name, chunk->data, chunk->size) ? 1 : -1; |
| } |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Helpers |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| class AutoCleanPng : public SkNoncopyable { |
| public: |
| /* |
| * This class does not take ownership of stream or reader, but if codecPtr |
| * is non-NULL, and decodeBounds succeeds, it will have created a new |
| * SkCodec (pointed to by *codecPtr) which will own/ref them, as well as |
| * the png_ptr and info_ptr. |
| */ |
| AutoCleanPng(png_structp png_ptr, SkStream* stream, SkPngChunkReader* reader, |
| SkCodec** codecPtr) |
| : fPng_ptr(png_ptr) |
| , fInfo_ptr(nullptr) |
| , fDecodedBounds(false) |
| , fReadHeader(false) |
| , fStream(stream) |
| , fChunkReader(reader) |
| , fOutCodec(codecPtr) |
| {} |
| |
| ~AutoCleanPng() { |
| // fInfo_ptr will never be non-nullptr unless fPng_ptr is. |
| if (fPng_ptr) { |
| png_infopp info_pp = fInfo_ptr ? &fInfo_ptr : nullptr; |
| png_destroy_read_struct(&fPng_ptr, info_pp, nullptr); |
| } |
| } |
| |
| void setInfoPtr(png_infop info_ptr) { |
| SkASSERT(nullptr == fInfo_ptr); |
| fInfo_ptr = info_ptr; |
| } |
| |
| /** |
| * Reads enough of the input stream to decode the bounds. |
| * @return false if the stream is not a valid PNG (or too short). |
| * true if it read enough of the stream to determine the bounds. |
| * In the latter case, the stream may have been read beyond the |
| * point to determine the bounds, and the png_ptr will have saved |
| * any extra data. Further, if the codecPtr supplied to the |
| * constructor was not NULL, it will now point to a new SkCodec, |
| * which owns (or refs, in the case of the SkPngChunkReader) the |
| * inputs. If codecPtr was NULL, the png_ptr and info_ptr are |
| * unowned, and it is up to the caller to destroy them. |
| */ |
| bool decodeBounds(); |
| |
| private: |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| bool fDecodedBounds; |
| bool fReadHeader; |
| SkStream* fStream; |
| SkPngChunkReader* fChunkReader; |
| SkCodec** fOutCodec; |
| |
| /** |
| * Supplied to libpng to call when it has read enough data to determine |
| * bounds. |
| */ |
| static void InfoCallback(png_structp png_ptr, png_infop info_ptr) { |
| // png_get_progressive_ptr returns the pointer we set on the png_ptr with |
| // png_set_progressive_read_fn |
| static_cast<AutoCleanPng*>(png_get_progressive_ptr(png_ptr))->infoCallback(); |
| } |
| |
| void infoCallback(); |
| |
| void releasePngPtrs() { |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| }; |
| #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) |
| |
| bool AutoCleanPng::decodeBounds() { |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| return false; |
| } |
| |
| png_set_progressive_read_fn(fPng_ptr, this, InfoCallback, nullptr, nullptr); |
| |
| // Arbitrary buffer size, though note that it matches (below) |
| // SkPngCodec::processData(). FIXME: Can we better suit this to the size of |
| // the PNG header? |
| constexpr size_t kBufferSize = 4096; |
| char buffer[kBufferSize]; |
| |
| while (true) { |
| const size_t bytesRead = fStream->read(buffer, kBufferSize); |
| if (!bytesRead) { |
| // We have read to the end of the input without decoding bounds. |
| break; |
| } |
| |
| png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead); |
| if (fReadHeader) { |
| break; |
| } |
| } |
| |
| // For safety, clear the pointer to this object. |
| png_set_progressive_read_fn(fPng_ptr, nullptr, nullptr, nullptr, nullptr); |
| return fDecodedBounds; |
| } |
| |
| void SkPngCodec::processData() { |
| switch (setjmp(png_jmpbuf(fPng_ptr))) { |
| case kPngError: |
| // There was an error. Stop processing data. |
| // FIXME: Do we need to discard png_ptr? |
| return; |
| case kStopDecoding: |
| // We decoded all the lines we want. |
| return; |
| case kSetJmpOkay: |
| // Everything is okay. |
| break; |
| default: |
| // No other values should be passed to longjmp. |
| SkASSERT(false); |
| } |
| |
| // Arbitrary buffer size |
| constexpr size_t kBufferSize = 4096; |
| char buffer[kBufferSize]; |
| |
| while (true) { |
| const size_t bytesRead = this->stream()->read(buffer, kBufferSize); |
| png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead); |
| |
| if (!bytesRead) { |
| // We have read to the end of the input. Note that we quit *after* |
| // calling png_process_data, because decodeBounds may have told |
| // libpng to save the remainder of the buffer, in which case |
| // png_process_data will process the saved buffer, though the |
| // stream has no more to read. |
| break; |
| } |
| } |
| } |
| |
| // Note: SkColorTable claims to store SkPMColors, which is not necessarily |
| // the case here. |
| bool SkPngCodec::createColorTable(SkColorType dstColorType, bool premultiply, int* ctableCount) { |
| |
| int numColors; |
| png_color* palette; |
| if (!png_get_PLTE(fPng_ptr, fInfo_ptr, &palette, &numColors)) { |
| return false; |
| } |
| |
| // Note: These are not necessarily SkPMColors. |
| SkPMColor colorPtr[256]; |
| |
| png_bytep alphas; |
| int numColorsWithAlpha = 0; |
| if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) { |
| // Choose which function to use to create the color table. If the final destination's |
| // colortype is unpremultiplied, the color table will store unpremultiplied colors. |
| PackColorProc proc = choose_pack_color_proc(premultiply, dstColorType); |
| |
| for (int i = 0; i < numColorsWithAlpha; i++) { |
| // We don't have a function in SkOpts that combines a set of alphas with a set |
| // of RGBs. We could write one, but it's hardly worth it, given that this |
| // is such a small fraction of the total decode time. |
| colorPtr[i] = proc(alphas[i], palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| } |
| |
| if (numColorsWithAlpha < numColors) { |
| // The optimized code depends on a 3-byte png_color struct with the colors |
| // in RGB order. These checks make sure it is safe to use. |
| static_assert(3 == sizeof(png_color), "png_color struct has changed. Opts are broken."); |
| #ifdef SK_DEBUG |
| SkASSERT(&palette->red < &palette->green); |
| SkASSERT(&palette->green < &palette->blue); |
| #endif |
| |
| if (is_rgba(dstColorType)) { |
| SkOpts::RGB_to_RGB1(colorPtr + numColorsWithAlpha, palette, |
| numColors - numColorsWithAlpha); |
| } else { |
| SkOpts::RGB_to_BGR1(colorPtr + numColorsWithAlpha, palette, |
| numColors - numColorsWithAlpha); |
| } |
| } |
| |
| // Pad the color table with the last color in the table (or black) in the case that |
| // invalid pixel indices exceed the number of colors in the table. |
| const int maxColors = 1 << fBitDepth; |
| if (numColors < maxColors) { |
| SkPMColor lastColor = numColors > 0 ? colorPtr[numColors - 1] : SK_ColorBLACK; |
| sk_memset32(colorPtr + numColors, lastColor, maxColors - numColors); |
| } |
| |
| // Set the new color count. |
| if (ctableCount != nullptr) { |
| *ctableCount = maxColors; |
| } |
| |
| fColorTable.reset(new SkColorTable(colorPtr, maxColors)); |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Creation |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| bool SkPngCodec::IsPng(const char* buf, size_t bytesRead) { |
| return !png_sig_cmp((png_bytep) buf, (png_size_t)0, bytesRead); |
| } |
| |
| static float png_fixed_point_to_float(png_fixed_point x) { |
| // We multiply by the same factor that libpng used to convert |
| // fixed point -> double. Since we want floats, we choose to |
| // do the conversion ourselves rather than convert |
| // fixed point -> double -> float. |
| return ((float) x) * 0.00001f; |
| } |
| |
| static float png_inverted_fixed_point_to_float(png_fixed_point x) { |
| // This is necessary because the gAMA chunk actually stores 1/gamma. |
| return 1.0f / png_fixed_point_to_float(x); |
| } |
| |
| // Returns a colorSpace object that represents any color space information in |
| // the encoded data. If the encoded data contains no color space, this will |
| // return NULL. |
| sk_sp<SkColorSpace> read_color_space(png_structp png_ptr, png_infop info_ptr) { |
| |
| #if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6) |
| |
| // First check for an ICC profile |
| png_bytep profile; |
| png_uint_32 length; |
| // The below variables are unused, however, we need to pass them in anyway or |
| // png_get_iCCP() will return nothing. |
| // Could knowing the |name| of the profile ever be interesting? Maybe for debugging? |
| png_charp name; |
| // The |compression| is uninteresting since: |
| // (1) libpng has already decompressed the profile for us. |
| // (2) "deflate" is the only mode of decompression that libpng supports. |
| int compression; |
| if (PNG_INFO_iCCP == png_get_iCCP(png_ptr, info_ptr, &name, &compression, &profile, |
| &length)) { |
| return SkColorSpace::NewICC(profile, length); |
| } |
| |
| // Second, check for sRGB. |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) { |
| |
| // sRGB chunks also store a rendering intent: Absolute, Relative, |
| // Perceptual, and Saturation. |
| // FIXME (msarett): Extract this information from the sRGB chunk once |
| // we are able to handle this information in |
| // SkColorSpace. |
| return SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); |
| } |
| |
| // Next, check for chromaticities. |
| png_fixed_point XYZ[9]; |
| float toXYZD50[9]; |
| png_fixed_point gamma; |
| float gammas[3]; |
| if (png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &XYZ[0], &XYZ[1], &XYZ[2], &XYZ[3], &XYZ[4], |
| &XYZ[5], &XYZ[6], &XYZ[7], &XYZ[8])) { |
| |
| // FIXME (msarett): Here we are treating XYZ values as D50 even though the color |
| // temperature is unspecified. I suspect that this assumption |
| // is most often ok, but we could also calculate the color |
| // temperature (D value) and then convert the XYZ to D50. Maybe |
| // we should add a new constructor to SkColorSpace that accepts |
| // XYZ with D-Unkown? |
| for (int i = 0; i < 9; i++) { |
| toXYZD50[i] = png_fixed_point_to_float(XYZ[i]); |
| } |
| |
| if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { |
| float value = png_inverted_fixed_point_to_float(gamma); |
| gammas[0] = value; |
| gammas[1] = value; |
| gammas[2] = value; |
| |
| } else { |
| // Default to sRGB (gamma = 2.2f) if the image has color space information, |
| // but does not specify gamma. |
| gammas[0] = 2.2f; |
| gammas[1] = 2.2f; |
| gammas[2] = 2.2f; |
| } |
| |
| SkMatrix44 mat(SkMatrix44::kUninitialized_Constructor); |
| mat.set3x3ColMajorf(toXYZD50); |
| return SkColorSpace::NewRGB(gammas, mat); |
| } |
| |
| // Last, check for gamma. |
| if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { |
| |
| // Guess a default value for cHRM? Or should we just give up? |
| // Here we use the identity matrix as a default. |
| |
| // Set the gammas. |
| float value = png_inverted_fixed_point_to_float(gamma); |
| gammas[0] = value; |
| gammas[1] = value; |
| gammas[2] = value; |
| |
| return SkColorSpace::NewRGB(gammas, SkMatrix44::I()); |
| } |
| |
| #endif // LIBPNG >= 1.6 |
| |
| // Finally, what should we do if there is no color space information in the PNG? |
| // The specification says that this indicates "gamma is unknown" and that the |
| // "color is device dependent". I'm assuming we can represent this with NULL. |
| // But should we guess sRGB? Most images are sRGB, even if they don't specify. |
| return nullptr; |
| } |
| |
| class SkPngNormalDecoder : public SkPngCodec { |
| public: |
| SkPngNormalDecoder(int width, int height, const SkEncodedInfo& info, SkStream* stream, |
| SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth, |
| sk_sp<SkColorSpace> colorSpace) |
| : INHERITED(width, height, info, stream, reader, png_ptr, info_ptr, bitDepth, |
| std::move(colorSpace)) |
| , fLinesDecoded(0) |
| , fDst(nullptr) |
| , fRowBytes(0) |
| , fFirstRow(0) |
| , fLastRow(0) |
| {} |
| |
| static void AllRowsCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) { |
| GetDecoder(png_ptr)->allRowsCallback(row, rowNum); |
| } |
| |
| static void RowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) { |
| GetDecoder(png_ptr)->rowCallback(row, rowNum); |
| } |
| private: |
| int fLinesDecoded; // FIXME: Move to baseclass? |
| void* fDst; |
| size_t fRowBytes; |
| |
| // Variables for partial decode |
| int fFirstRow; // FIXME: Move to baseclass? |
| int fLastRow; |
| |
| typedef SkPngCodec INHERITED; |
| |
| static SkPngNormalDecoder* GetDecoder(png_structp png_ptr) { |
| return static_cast<SkPngNormalDecoder*>(png_get_progressive_ptr(png_ptr)); |
| } |
| |
| Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { |
| const int height = this->getInfo().height(); |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, AllRowsCallback, nullptr); |
| fDst = dst; |
| fRowBytes = rowBytes; |
| |
| fLinesDecoded = 0; |
| |
| this->processData(); |
| |
| if (fLinesDecoded == height) { |
| return SkCodec::kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fLinesDecoded; |
| } |
| |
| return SkCodec::kIncompleteInput; |
| } |
| |
| void allRowsCallback(png_bytep row, int rowNum) { |
| SkASSERT(rowNum - fFirstRow == fLinesDecoded); |
| fLinesDecoded++; |
| this->swizzler()->swizzle(fDst, row); |
| fDst = SkTAddOffset<void>(fDst, fRowBytes); |
| } |
| |
| void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override { |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, RowCallback, nullptr); |
| fFirstRow = firstRow; |
| fLastRow = lastRow; |
| fDst = dst; |
| fRowBytes = rowBytes; |
| fLinesDecoded = 0; |
| } |
| |
| SkCodec::Result decode(int* rowsDecoded) override { |
| this->processData(); |
| |
| if (fLinesDecoded == fLastRow - fFirstRow + 1) { |
| return SkCodec::kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fLinesDecoded; |
| } |
| |
| return SkCodec::kIncompleteInput; |
| } |
| |
| void rowCallback(png_bytep row, int rowNum) { |
| if (rowNum < fFirstRow) { |
| // Ignore this row. |
| return; |
| } |
| |
| SkASSERT(rowNum <= fLastRow); |
| |
| if (this->swizzler()->rowNeeded(fLinesDecoded)) { |
| this->swizzler()->swizzle(fDst, row); |
| fDst = SkTAddOffset<void>(fDst, fRowBytes); |
| } |
| |
| fLinesDecoded++; |
| |
| if (rowNum == fLastRow) { |
| // Fake error to stop decoding scanlines. |
| longjmp(png_jmpbuf(this->png_ptr()), kStopDecoding); |
| } |
| } |
| }; |
| |
| class SkPngInterlacedDecoder : public SkPngCodec { |
| public: |
| SkPngInterlacedDecoder(int width, int height, const SkEncodedInfo& info, SkStream* stream, |
| SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth, |
| sk_sp<SkColorSpace> colorSpace, int numberPasses) |
| : INHERITED(width, height, info, stream, reader, png_ptr, info_ptr, bitDepth, |
| std::move(colorSpace)) |
| , fNumberPasses(numberPasses) |
| , fFirstRow(0) |
| , fLastRow(0) |
| , fLinesDecoded(0) |
| , fInterlacedComplete(false) |
| , fPng_rowbytes(0) |
| {} |
| |
| static void InterlacedRowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int pass) { |
| auto decoder = static_cast<SkPngInterlacedDecoder*>(png_get_progressive_ptr(png_ptr)); |
| decoder->interlacedRowCallback(row, rowNum, pass); |
| } |
| |
| private: |
| const int fNumberPasses; |
| int fFirstRow; |
| int fLastRow; |
| void* fDst; |
| size_t fRowBytes; |
| int fLinesDecoded; |
| bool fInterlacedComplete; |
| size_t fPng_rowbytes; |
| SkAutoTMalloc<png_byte> fInterlaceBuffer; |
| |
| typedef SkPngCodec INHERITED; |
| |
| // FIXME: Currently sharing interlaced callback for all rows and subset. It's not |
| // as expensive as the subset version of non-interlaced, but it still does extra |
| // work. |
| void interlacedRowCallback(png_bytep row, int rowNum, int pass) { |
| if (rowNum < fFirstRow || rowNum > fLastRow) { |
| // Ignore this row |
| return; |
| } |
| |
| png_bytep oldRow = fInterlaceBuffer.get() + (rowNum - fFirstRow) * fPng_rowbytes; |
| png_progressive_combine_row(this->png_ptr(), oldRow, row); |
| |
| if (0 == pass) { |
| // The first pass initializes all rows. |
| SkASSERT(row); |
| SkASSERT(fLinesDecoded == rowNum - fFirstRow); |
| fLinesDecoded++; |
| } else { |
| SkASSERT(fLinesDecoded == fLastRow - fFirstRow + 1); |
| if (fNumberPasses - 1 == pass && rowNum == fLastRow) { |
| // Last pass, and we have read all of the rows we care about. Note that |
| // we do not care about reading anything beyond the end of the image (or |
| // beyond the last scanline requested). |
| fInterlacedComplete = true; |
| // Fake error to stop decoding scanlines. |
| longjmp(png_jmpbuf(this->png_ptr()), kStopDecoding); |
| } |
| } |
| } |
| |
| SkCodec::Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { |
| const int height = this->getInfo().height(); |
| this->setUpInterlaceBuffer(height); |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, nullptr); |
| |
| fFirstRow = 0; |
| fLastRow = height - 1; |
| fLinesDecoded = 0; |
| |
| this->processData(); |
| |
| png_bytep srcRow = fInterlaceBuffer.get(); |
| // FIXME: When resuming, this may rewrite rows that did not change. |
| for (int rowNum = 0; rowNum < fLinesDecoded; rowNum++) { |
| this->swizzler()->swizzle(dst, srcRow); |
| dst = SkTAddOffset<void>(dst, rowBytes); |
| srcRow = SkTAddOffset<png_byte>(srcRow, fPng_rowbytes); |
| } |
| if (fInterlacedComplete) { |
| return SkCodec::kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fLinesDecoded; |
| } |
| |
| return SkCodec::kIncompleteInput; |
| } |
| |
| void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override { |
| // FIXME: We could skip rows in the interlace buffer that we won't put in the output. |
| this->setUpInterlaceBuffer(lastRow - firstRow + 1); |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, nullptr); |
| fFirstRow = firstRow; |
| fLastRow = lastRow; |
| fDst = dst; |
| fRowBytes = rowBytes; |
| fLinesDecoded = 0; |
| } |
| |
| SkCodec::Result decode(int* rowsDecoded) override { |
| this->processData(); |
| |
| // Now call the callback on all the rows that were decoded. |
| if (!fLinesDecoded) { |
| return SkCodec::kIncompleteInput; |
| } |
| const int lastRow = fLinesDecoded + fFirstRow - 1; |
| SkASSERT(lastRow <= fLastRow); |
| |
| // FIXME: For resuming interlace, we may swizzle a row that hasn't changed. But it |
| // may be too tricky/expensive to handle that correctly. |
| png_bytep srcRow = fInterlaceBuffer.get(); |
| const int sampleY = this->swizzler()->sampleY(); |
| void* dst = fDst; |
| for (int rowNum = fFirstRow; rowNum <= lastRow; rowNum += sampleY) { |
| this->swizzler()->swizzle(dst, srcRow); |
| dst = SkTAddOffset<void>(dst, fRowBytes); |
| srcRow = SkTAddOffset<png_byte>(srcRow, fPng_rowbytes * sampleY); |
| } |
| |
| if (fInterlacedComplete) { |
| return SkCodec::kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fLinesDecoded; |
| } |
| return SkCodec::kIncompleteInput; |
| } |
| |
| void setUpInterlaceBuffer(int height) { |
| fPng_rowbytes = png_get_rowbytes(this->png_ptr(), this->info_ptr()); |
| fInterlaceBuffer.reset(fPng_rowbytes * height); |
| fInterlacedComplete = false; |
| } |
| }; |
| |
| // Reads the header and initializes the output fields, if not NULL. |
| // |
| // @param stream Input data. Will be read to get enough information to properly |
| // setup the codec. |
| // @param chunkReader SkPngChunkReader, for reading unknown chunks. May be NULL. |
| // If not NULL, png_ptr will hold an *unowned* pointer to it. The caller is |
| // expected to continue to own it for the lifetime of the png_ptr. |
| // @param outCodec Optional output variable. If non-NULL, will be set to a new |
| // SkPngCodec on success. |
| // @param png_ptrp Optional output variable. If non-NULL, will be set to a new |
| // png_structp on success. |
| // @param info_ptrp Optional output variable. If non-NULL, will be set to a new |
| // png_infop on success; |
| // @return true on success, in which case the caller is responsible for calling |
| // png_destroy_read_struct(png_ptrp, info_ptrp). |
| // If it returns false, the passed in fields (except stream) are unchanged. |
| static bool read_header(SkStream* stream, SkPngChunkReader* chunkReader, SkCodec** outCodec, |
| png_structp* png_ptrp, png_infop* info_ptrp) { |
| // The image is known to be a PNG. Decode enough to know the SkImageInfo. |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, |
| sk_error_fn, sk_warning_fn); |
| if (!png_ptr) { |
| return false; |
| } |
| |
| AutoCleanPng autoClean(png_ptr, stream, chunkReader, outCodec); |
| |
| png_infop info_ptr = png_create_info_struct(png_ptr); |
| if (info_ptr == nullptr) { |
| return false; |
| } |
| |
| autoClean.setInfoPtr(info_ptr); |
| |
| // FIXME: Could we use the return value of setjmp to specify the type of |
| // error? |
| if (setjmp(png_jmpbuf(png_ptr))) { |
| return false; |
| } |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| // Hookup our chunkReader so we can see any user-chunks the caller may be interested in. |
| // This needs to be installed before we read the png header. Android may store ninepatch |
| // chunks in the header. |
| if (chunkReader) { |
| png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0); |
| png_set_read_user_chunk_fn(png_ptr, (png_voidp) chunkReader, sk_read_user_chunk); |
| } |
| #endif |
| |
| const bool decodedBounds = autoClean.decodeBounds(); |
| |
| if (!decodedBounds) { |
| return false; |
| } |
| |
| // On success, decodeBounds releases ownership of png_ptr and info_ptr. |
| if (png_ptrp) { |
| *png_ptrp = png_ptr; |
| } |
| if (info_ptrp) { |
| *info_ptrp = info_ptr; |
| } |
| |
| // decodeBounds takes care of setting outCodec |
| if (outCodec) { |
| SkASSERT(*outCodec); |
| } |
| return true; |
| } |
| |
| void AutoCleanPng::infoCallback() { |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, encodedColorType; |
| png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth, |
| &encodedColorType, nullptr, nullptr, nullptr); |
| |
| // Tell libpng to strip 16 bit/color files down to 8 bits/color. |
| // TODO: Should we handle this in SkSwizzler? Could this also benefit |
| // RAW decodes? |
| if (bitDepth == 16) { |
| SkASSERT(PNG_COLOR_TYPE_PALETTE != encodedColorType); |
| png_set_strip_16(fPng_ptr); |
| } |
| |
| // Now determine the default colorType and alphaType and set the required transforms. |
| // Often, we depend on SkSwizzler to perform any transforms that we need. However, we |
| // still depend on libpng for many of the rare and PNG-specific cases. |
| SkEncodedInfo::Color color; |
| SkEncodedInfo::Alpha alpha; |
| switch (encodedColorType) { |
| case PNG_COLOR_TYPE_PALETTE: |
| // Extract multiple pixels with bit depths of 1, 2, and 4 from a single |
| // byte into separate bytes (useful for paletted and grayscale images). |
| if (bitDepth < 8) { |
| // TODO: Should we use SkSwizzler here? |
| png_set_packing(fPng_ptr); |
| } |
| |
| color = SkEncodedInfo::kPalette_Color; |
| // Set the alpha depending on if a transparency chunk exists. |
| alpha = png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS) ? |
| SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha; |
| break; |
| case PNG_COLOR_TYPE_RGB: |
| if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) { |
| // Convert to RGBA if transparency chunk exists. |
| png_set_tRNS_to_alpha(fPng_ptr); |
| color = SkEncodedInfo::kRGBA_Color; |
| alpha = SkEncodedInfo::kBinary_Alpha; |
| } else { |
| color = SkEncodedInfo::kRGB_Color; |
| alpha = SkEncodedInfo::kOpaque_Alpha; |
| } |
| break; |
| case PNG_COLOR_TYPE_GRAY: |
| // Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel. |
| if (bitDepth < 8) { |
| // TODO: Should we use SkSwizzler here? |
| png_set_expand_gray_1_2_4_to_8(fPng_ptr); |
| } |
| |
| if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) { |
| png_set_tRNS_to_alpha(fPng_ptr); |
| color = SkEncodedInfo::kGrayAlpha_Color; |
| alpha = SkEncodedInfo::kBinary_Alpha; |
| } else { |
| color = SkEncodedInfo::kGray_Color; |
| alpha = SkEncodedInfo::kOpaque_Alpha; |
| } |
| break; |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| color = SkEncodedInfo::kGrayAlpha_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| break; |
| case PNG_COLOR_TYPE_RGBA: |
| color = SkEncodedInfo::kRGBA_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| break; |
| default: |
| // All the color types have been covered above. |
| SkASSERT(false); |
| color = SkEncodedInfo::kRGBA_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| } |
| |
| const int numberPasses = png_set_interlace_handling(fPng_ptr); |
| |
| fReadHeader = true; |
| #if PNG_LIBPNG_VER_MAJOR > 1 || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 5) |
| // 1 tells libpng to save any extra data. We may be able to be more efficient by saving |
| // it ourselves. |
| png_process_data_pause(fPng_ptr, 1); |
| fDecodedBounds = true; |
| #else |
| // We may have read more than the header. Empty buffer and move to the end of the |
| // header so future calls can read the rows. |
| fDecodedBounds = fStream->move(-fPng_ptr->buffer_size); |
| fPng_ptr->buffer_size = 0; |
| if (!fDecodedBounds) { |
| // Stream could not be moved to the correct place. |
| return; |
| } |
| #endif |
| if (fOutCodec) { |
| SkASSERT(nullptr == *fOutCodec); |
| sk_sp<SkColorSpace> colorSpace = read_color_space(fPng_ptr, fInfo_ptr); |
| if (!colorSpace) { |
| // Treat unmarked pngs as sRGB. |
| colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); |
| } |
| SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, 8); |
| if (1 == numberPasses) { |
| *fOutCodec = new SkPngNormalDecoder(origWidth, origHeight, info, fStream, |
| fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, std::move(colorSpace)); |
| } else { |
| *fOutCodec = new SkPngInterlacedDecoder(origWidth, origHeight, info, fStream, |
| fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, std::move(colorSpace), |
| numberPasses); |
| } |
| } |
| |
| |
| // Release the pointers, which are now owned by the codec or the caller is expected to |
| // take ownership. |
| this->releasePngPtrs(); |
| } |
| |
| SkPngCodec::SkPngCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream, |
| SkPngChunkReader* chunkReader, png_structp png_ptr, png_infop info_ptr, |
| int bitDepth, sk_sp<SkColorSpace> colorSpace) |
| : INHERITED(width, height, info, stream, colorSpace) |
| , fPngChunkReader(SkSafeRef(chunkReader)) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fBitDepth(bitDepth) |
| {} |
| |
| SkPngCodec::~SkPngCodec() { |
| this->destroyReadStruct(); |
| } |
| |
| void SkPngCodec::destroyReadStruct() { |
| if (fPng_ptr) { |
| // We will never have a nullptr fInfo_ptr with a non-nullptr fPng_ptr |
| SkASSERT(fInfo_ptr); |
| png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, nullptr); |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Getting the pixels |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| bool SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo, |
| const Options& options, |
| SkPMColor ctable[], |
| int* ctableCount) { |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| return false; |
| } |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) { |
| if (!this->createColorTable(requestedInfo.colorType(), |
| kPremul_SkAlphaType == requestedInfo.alphaType(), ctableCount)) { |
| return false; |
| } |
| } |
| |
| // Copy the color table to the client if they request kIndex8 mode |
| copy_color_table(requestedInfo, fColorTable, ctable, ctableCount); |
| |
| // Create the swizzler. SkPngCodec retains ownership of the color table. |
| const SkPMColor* colors = get_color_ptr(fColorTable.get()); |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, requestedInfo, |
| options)); |
| SkASSERT(fSwizzler); |
| |
| return true; |
| } |
| |
| |
| bool SkPngCodec::onRewind() { |
| // This sets fPng_ptr and fInfo_ptr to nullptr. If read_header |
| // succeeds, they will be repopulated, and if it fails, they will |
| // remain nullptr. Any future accesses to fPng_ptr and fInfo_ptr will |
| // come through this function which will rewind and again attempt |
| // to reinitialize them. |
| this->destroyReadStruct(); |
| |
| png_structp png_ptr; |
| png_infop info_ptr; |
| if (!read_header(this->stream(), fPngChunkReader.get(), nullptr, &png_ptr, &info_ptr)) { |
| return false; |
| } |
| |
| fPng_ptr = png_ptr; |
| fInfo_ptr = info_ptr; |
| return true; |
| } |
| |
| SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst, |
| size_t dstRowBytes, const Options& options, |
| SkPMColor ctable[], int* ctableCount, |
| int* rowsDecoded) { |
| if (!conversion_possible(requestedInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| if (options.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| |
| // Note that ctable and ctableCount may be modified if there is a color table |
| if (!this->initializeSwizzler(requestedInfo, options, ctable, ctableCount)) { |
| return kInvalidInput; // or parameters? |
| } |
| |
| return this->decodeAllRows(dst, dstRowBytes, rowsDecoded); |
| } |
| |
| SkCodec::Result SkPngCodec::onStartIncrementalDecode(const SkImageInfo& dstInfo, |
| void* dst, size_t rowBytes, const SkCodec::Options& options, |
| SkPMColor* ctable, int* ctableCount) { |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| |
| if (!this->initializeSwizzler(dstInfo, options, ctable, ctableCount)) { |
| return kInvalidInput; |
| } |
| |
| int firstRow, lastRow; |
| if (options.fSubset) { |
| firstRow = options.fSubset->top(); |
| lastRow = options.fSubset->bottom() - 1; |
| } else { |
| firstRow = 0; |
| lastRow = dstInfo.height() - 1; |
| } |
| this->setRange(firstRow, lastRow, dst, rowBytes); |
| return kSuccess; |
| } |
| |
| SkCodec::Result SkPngCodec::onIncrementalDecode(int* rowsDecoded) { |
| return this->decode(rowsDecoded); |
| } |
| |
| uint32_t SkPngCodec::onGetFillValue(SkColorType colorType) const { |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| if (colorPtr) { |
| return get_color_table_fill_value(colorType, colorPtr, 0); |
| } |
| return INHERITED::onGetFillValue(colorType); |
| } |
| |
| SkCodec* SkPngCodec::NewFromStream(SkStream* stream, SkPngChunkReader* chunkReader) { |
| SkAutoTDelete<SkStream> streamDeleter(stream); |
| |
| SkCodec* outCodec = nullptr; |
| if (read_header(stream, chunkReader, &outCodec, nullptr, nullptr)) { |
| // Codec has taken ownership of the stream. |
| SkASSERT(outCodec); |
| streamDeleter.release(); |
| return outCodec; |
| } |
| |
| return nullptr; |
| } |