| /* |
| * 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_Base.h" |
| #include "SkColorTable.h" |
| #include "SkMath.h" |
| #include "SkOpts.h" |
| #include "SkPngCodec.h" |
| #include "SkPoint3.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| #include "SkTemplates.h" |
| #include "SkUtils.h" |
| |
| #include "png.h" |
| |
| // This warning triggers false postives way too often in here. |
| #if defined(__GNUC__) && !defined(__clang__) |
| #pragma GCC diagnostic ignored "-Wclobbered" |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Callback functions |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| SkCodecPrintf("------ png error %s\n", msg); |
| longjmp(png_jmpbuf(png_ptr), 1); |
| } |
| |
| void sk_warning_fn(png_structp, png_const_charp msg) { |
| SkCodecPrintf("----- png warning %s\n", msg); |
| } |
| |
| static void sk_read_fn(png_structp png_ptr, png_bytep data, |
| png_size_t length) { |
| SkStream* stream = static_cast<SkStream*>(png_get_io_ptr(png_ptr)); |
| const size_t bytes = stream->read(data, length); |
| if (bytes != length) { |
| // FIXME: We want to report the fact that the stream was truncated. |
| // One way to do that might be to pass a enum to longjmp so setjmp can |
| // specify the failure. |
| png_error(png_ptr, "Read Error!"); |
| } |
| } |
| |
| #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: |
| AutoCleanPng(png_structp png_ptr) |
| : fPng_ptr(png_ptr) |
| , fInfo_ptr(nullptr) {} |
| |
| ~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; |
| } |
| |
| void release() { |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| |
| private: |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| }; |
| #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) |
| |
| // Note: SkColorTable claims to store SkPMColors, which is not necessarily the case here. |
| bool SkPngCodec::createColorTable(const SkImageInfo& dstInfo, int* ctableCount) { |
| |
| int numColors; |
| png_color* palette; |
| if (!png_get_PLTE(fPng_ptr, fInfo_ptr, &palette, &numColors)) { |
| return false; |
| } |
| |
| // Contents depend on tableColorType and our choice of if/when to premultiply: |
| // { kPremul, kUnpremul, kOpaque } x { RGBA, BGRA } |
| SkPMColor colorTable[256]; |
| SkColorType tableColorType = fColorXform ? kRGBA_8888_SkColorType : dstInfo.colorType(); |
| |
| png_bytep alphas; |
| int numColorsWithAlpha = 0; |
| if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) { |
| // If we are performing a color xform, it will handle the premultiply. Otherwise, |
| // we'll do it here. |
| bool premultiply = !fColorXform && needs_premul(dstInfo, this->getInfo()); |
| |
| // 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, tableColorType); |
| |
| 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. |
| colorTable[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(tableColorType)) { |
| SkOpts::RGB_to_RGB1(colorTable + numColorsWithAlpha, palette, |
| numColors - numColorsWithAlpha); |
| } else { |
| SkOpts::RGB_to_BGR1(colorTable + numColorsWithAlpha, palette, |
| numColors - numColorsWithAlpha); |
| } |
| } |
| |
| // If we are not decoding to F16, we can color xform now and store the results |
| // in the color table. |
| if (fColorXform && kRGBA_F16_SkColorType != dstInfo.colorType()) { |
| SkColorType xformColorType = is_rgba(dstInfo.colorType()) ? |
| kRGBA_8888_SkColorType : kBGRA_8888_SkColorType; |
| SkAlphaType xformAlphaType = select_alpha_xform(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| fColorXform->apply(colorTable, colorTable, numColors, xformColorType, xformAlphaType); |
| } |
| |
| // 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 ? colorTable[numColors - 1] : SK_ColorBLACK; |
| sk_memset32(colorTable + numColors, lastColor, maxColors - numColors); |
| } |
| |
| // Set the new color count. |
| if (ctableCount != nullptr) { |
| *ctableCount = maxColors; |
| } |
| |
| fColorTable.reset(new SkColorTable(colorTable, 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); |
| } |
| |
| static constexpr float gSRGB_toXYZD50[] { |
| 0.4358f, 0.3853f, 0.1430f, // Rx, Gx, Bx |
| 0.2224f, 0.7170f, 0.0606f, // Ry, Gy, Gz |
| 0.0139f, 0.0971f, 0.7139f, // Rz, Gz, Bz |
| }; |
| |
| static bool convert_to_D50(SkMatrix44* toXYZD50, float toXYZ[9], float whitePoint[2]) { |
| float wX = whitePoint[0]; |
| float wY = whitePoint[1]; |
| if (wX < 0.0f || wY < 0.0f || (wX + wY > 1.0f)) { |
| return false; |
| } |
| |
| // Calculate the XYZ illuminant. Call this the src illuminant. |
| float wZ = 1.0f - wX - wY; |
| float scale = 1.0f / wY; |
| // TODO (msarett): |
| // What are common src illuminants? I'm guessing we will almost always see D65. Should |
| // we go ahead and save a precomputed D65->D50 Bradford matrix? Should we exit early if |
| // if the src illuminant is D50? |
| SkVector3 srcXYZ = SkVector3::Make(wX * scale, 1.0f, wZ * scale); |
| |
| // The D50 illuminant. |
| SkVector3 dstXYZ = SkVector3::Make(0.96422f, 1.0f, 0.82521f); |
| |
| // Calculate the chromatic adaptation matrix. We will use the Bradford method, thus |
| // the matrices below. The Bradford method is used by Adobe and is widely considered |
| // to be the best. |
| // http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html |
| SkMatrix mA, mAInv; |
| mA.setAll(0.8951f, 0.2664f, -0.1614f, -0.7502f, 1.7135f, 0.0367f, 0.0389f, -0.0685f, 1.0296f); |
| mAInv.setAll(0.9869929f, -0.1470543f, 0.1599627f, 0.4323053f, 0.5183603f, 0.0492912f, |
| -0.0085287f, 0.0400428f, 0.9684867f); |
| |
| // Map illuminant into cone response domain. |
| SkVector3 srcCone; |
| srcCone.fX = mA[0] * srcXYZ.fX + mA[1] * srcXYZ.fY + mA[2] * srcXYZ.fZ; |
| srcCone.fY = mA[3] * srcXYZ.fX + mA[4] * srcXYZ.fY + mA[5] * srcXYZ.fZ; |
| srcCone.fZ = mA[6] * srcXYZ.fX + mA[7] * srcXYZ.fY + mA[8] * srcXYZ.fZ; |
| SkVector3 dstCone; |
| dstCone.fX = mA[0] * dstXYZ.fX + mA[1] * dstXYZ.fY + mA[2] * dstXYZ.fZ; |
| dstCone.fY = mA[3] * dstXYZ.fX + mA[4] * dstXYZ.fY + mA[5] * dstXYZ.fZ; |
| dstCone.fZ = mA[6] * dstXYZ.fX + mA[7] * dstXYZ.fY + mA[8] * dstXYZ.fZ; |
| |
| SkMatrix DXToD50; |
| DXToD50.setIdentity(); |
| DXToD50[0] = dstCone.fX / srcCone.fX; |
| DXToD50[4] = dstCone.fY / srcCone.fY; |
| DXToD50[8] = dstCone.fZ / srcCone.fZ; |
| DXToD50.postConcat(mAInv); |
| DXToD50.preConcat(mA); |
| |
| SkMatrix toXYZ3x3; |
| toXYZ3x3.setAll(toXYZ[0], toXYZ[3], toXYZ[6], toXYZ[1], toXYZ[4], toXYZ[7], toXYZ[2], toXYZ[5], |
| toXYZ[8]); |
| toXYZ3x3.postConcat(DXToD50); |
| |
| toXYZD50->set3x3(toXYZ3x3[0], toXYZ3x3[3], toXYZ3x3[6], |
| toXYZ3x3[1], toXYZ3x3[4], toXYZ3x3[7], |
| toXYZ3x3[2], toXYZ3x3[5], toXYZ3x3[8]); |
| return true; |
| } |
| |
| // 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 toXYZFixed[9]; |
| float toXYZ[9]; |
| png_fixed_point whitePointFixed[2]; |
| float whitePoint[2]; |
| png_fixed_point gamma; |
| float gammas[3]; |
| if (png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &toXYZFixed[0], &toXYZFixed[1], &toXYZFixed[2], |
| &toXYZFixed[3], &toXYZFixed[4], &toXYZFixed[5], &toXYZFixed[6], |
| &toXYZFixed[7], &toXYZFixed[8]) && |
| png_get_cHRM_fixed(png_ptr, info_ptr, &whitePointFixed[0], &whitePointFixed[1], nullptr, |
| nullptr, nullptr, nullptr, nullptr, nullptr)) |
| { |
| for (int i = 0; i < 9; i++) { |
| toXYZ[i] = png_fixed_point_to_float(toXYZFixed[i]); |
| } |
| whitePoint[0] = png_fixed_point_to_float(whitePointFixed[0]); |
| whitePoint[1] = png_fixed_point_to_float(whitePointFixed[1]); |
| |
| SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor); |
| if (!convert_to_D50(&toXYZD50, toXYZ, whitePoint)) { |
| toXYZD50.set3x3RowMajorf(gSRGB_toXYZD50); |
| } |
| |
| 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; |
| |
| return SkColorSpace_Base::NewRGB(gammas, toXYZD50); |
| } |
| |
| // Default to sRGB gamma if the image has color space information, |
| // but does not specify gamma. |
| return SkColorSpace::NewRGB(SkColorSpace::kSRGB_RenderTargetGamma, toXYZD50); |
| } |
| |
| // Last, check for gamma. |
| if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { |
| |
| // Set the gammas. |
| float value = png_inverted_fixed_point_to_float(gamma); |
| gammas[0] = value; |
| gammas[1] = value; |
| gammas[2] = value; |
| |
| // Since there is no cHRM, we will guess sRGB gamut. |
| SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor); |
| toXYZD50.set3x3RowMajorf(gSRGB_toXYZD50); |
| |
| return SkColorSpace_Base::NewRGB(gammas, toXYZD50); |
| } |
| |
| #endif // LIBPNG >= 1.6 |
| |
| // Report that there is no color space information in the PNG. SkPngCodec is currently |
| // implemented to guess sRGB in this case. |
| return nullptr; |
| } |
| |
| static int bytes_per_pixel(int bitsPerPixel) { |
| // Note that we will have to change this implementation if we start |
| // supporting outputs from libpng that are less than 8-bits per component. |
| return bitsPerPixel / 8; |
| } |
| |
| void SkPngCodec::allocateStorage(const SkImageInfo& dstInfo) { |
| switch (fXformMode) { |
| case kSwizzleOnly_XformMode: |
| fStorage.reset(SkAlign4(fSrcRowBytes)); |
| fSwizzlerSrcRow = fStorage.get(); |
| break; |
| case kColorOnly_XformMode: |
| // Intentional fall through. A swizzler hasn't been created yet, but one will |
| // be created later if we are sampling. We'll go ahead and allocate |
| // enough memory to swizzle if necessary. |
| case kSwizzleColor_XformMode: { |
| size_t colorXformBytes = dstInfo.width() * sizeof(uint32_t); |
| fStorage.reset(SkAlign4(fSrcRowBytes) + colorXformBytes); |
| fSwizzlerSrcRow = fStorage.get(); |
| fColorXformSrcRow = SkTAddOffset<uint32_t>(fSwizzlerSrcRow, SkAlign4(fSrcRowBytes)); |
| break; |
| } |
| } |
| } |
| |
| void SkPngCodec::applyXformRow(void* dst, const void* src, SkColorType colorType, |
| SkAlphaType alphaType, int width) { |
| switch (fXformMode) { |
| case kSwizzleOnly_XformMode: |
| fSwizzler->swizzle(dst, (const uint8_t*) src); |
| break; |
| case kColorOnly_XformMode: |
| fColorXform->apply(dst, (const uint32_t*) src, width, colorType, alphaType); |
| break; |
| case kSwizzleColor_XformMode: |
| fSwizzler->swizzle(fColorXformSrcRow, (const uint8_t*) src); |
| fColorXform->apply(dst, fColorXformSrcRow, width, colorType, alphaType); |
| break; |
| } |
| } |
| |
| class SkPngNormalCodec : public SkPngCodec { |
| public: |
| SkPngNormalCodec(const SkEncodedInfo& encodedInfo, const SkImageInfo& imageInfo, |
| SkStream* stream, SkPngChunkReader* chunkReader, png_structp png_ptr, |
| png_infop info_ptr, int bitDepth) |
| : INHERITED(encodedInfo, imageInfo, stream, chunkReader, png_ptr, info_ptr, bitDepth, 1) |
| {} |
| |
| Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) override { |
| if (!conversion_possible(dstInfo, this->getInfo()) || |
| !this->initializeXforms(dstInfo, options, ctable, ctableCount)) |
| { |
| return kInvalidConversion; |
| } |
| |
| this->allocateStorage(dstInfo); |
| return kSuccess; |
| } |
| |
| int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, int startRow) |
| override { |
| SkASSERT(0 == startRow); |
| |
| // Assume that an error in libpng indicates an incomplete input. |
| int y = 0; |
| if (setjmp(png_jmpbuf((png_struct*)fPng_ptr))) { |
| SkCodecPrintf("Failed to read row.\n"); |
| return y; |
| } |
| |
| SkAlphaType xformAlphaType = select_alpha_xform(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| int width = fSwizzler ? fSwizzler->swizzleWidth() : dstInfo.width(); |
| |
| for (; y < count; y++) { |
| png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr); |
| this->applyXformRow(dst, fSwizzlerSrcRow, dstInfo.colorType(), xformAlphaType, width); |
| dst = SkTAddOffset<void>(dst, rowBytes); |
| } |
| |
| return y; |
| } |
| |
| int onGetScanlines(void* dst, int count, size_t rowBytes) override { |
| return this->readRows(this->dstInfo(), dst, rowBytes, count, 0); |
| } |
| |
| bool onSkipScanlines(int count) override { |
| if (setjmp(png_jmpbuf((png_struct*)fPng_ptr))) { |
| SkCodecPrintf("Failed to skip row.\n"); |
| return false; |
| } |
| |
| for (int row = 0; row < count; row++) { |
| png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr); |
| } |
| return true; |
| } |
| |
| typedef SkPngCodec INHERITED; |
| }; |
| |
| class SkPngInterlacedCodec : public SkPngCodec { |
| public: |
| SkPngInterlacedCodec(const SkEncodedInfo& encodedInfo, const SkImageInfo& imageInfo, |
| SkStream* stream, SkPngChunkReader* chunkReader, png_structp png_ptr, |
| png_infop info_ptr, int bitDepth, int numberPasses) |
| : INHERITED(encodedInfo, imageInfo, stream, chunkReader, png_ptr, info_ptr, bitDepth, |
| numberPasses) |
| , fCanSkipRewind(false) |
| { |
| SkASSERT(numberPasses != 1); |
| } |
| |
| Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) override { |
| if (!conversion_possible(dstInfo, this->getInfo()) || |
| !this->initializeXforms(dstInfo, options, ctable, ctableCount)) |
| { |
| return kInvalidConversion; |
| } |
| |
| this->allocateStorage(dstInfo); |
| fCanSkipRewind = true; |
| return SkCodec::kSuccess; |
| } |
| |
| int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, int startRow) |
| override { |
| if (setjmp(png_jmpbuf((png_struct*)fPng_ptr))) { |
| SkCodecPrintf("Failed to get scanlines.\n"); |
| // FIXME (msarett): Returning 0 is pessimistic. If we can complete a single pass, |
| // we may be able to report that all of the memory has been initialized. Even if we |
| // fail on the first pass, we can still report than some scanlines are initialized. |
| return 0; |
| } |
| |
| SkAutoTMalloc<uint8_t> storage(count * fSrcRowBytes); |
| uint8_t* srcRow; |
| for (int i = 0; i < fNumberPasses; i++) { |
| // Discard rows that we planned to skip. |
| for (int y = 0; y < startRow; y++){ |
| png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr); |
| } |
| // Read rows we care about into storage. |
| srcRow = storage.get(); |
| for (int y = 0; y < count; y++) { |
| png_read_row(fPng_ptr, srcRow, nullptr); |
| srcRow += fSrcRowBytes; |
| } |
| // Discard rows that we don't need. |
| for (int y = 0; y < this->getInfo().height() - startRow - count; y++) { |
| png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr); |
| } |
| } |
| |
| SkAlphaType xformAlphaType = select_alpha_xform(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| int width = fSwizzler ? fSwizzler->swizzleWidth() : dstInfo.width(); |
| srcRow = storage.get(); |
| for (int y = 0; y < count; y++) { |
| this->applyXformRow(dst, srcRow, dstInfo.colorType(), xformAlphaType, width); |
| srcRow = SkTAddOffset<uint8_t>(srcRow, fSrcRowBytes); |
| dst = SkTAddOffset<void>(dst, rowBytes); |
| } |
| |
| return count; |
| } |
| |
| int onGetScanlines(void* dst, int count, size_t rowBytes) override { |
| // rewind stream if have previously called onGetScanlines, |
| // since we need entire progressive image to get scanlines |
| if (fCanSkipRewind) { |
| // We already rewound in onStartScanlineDecode, so there is no reason to rewind. |
| // Next time onGetScanlines is called, we will need to rewind. |
| fCanSkipRewind = false; |
| } else { |
| // rewindIfNeeded resets fCurrScanline, since it assumes that start |
| // needs to be called again before scanline decoding. PNG scanline |
| // decoding is the exception, since it needs to rewind between |
| // calls to getScanlines. Keep track of fCurrScanline, to undo the |
| // reset. |
| const int currScanline = this->nextScanline(); |
| // This method would never be called if currScanline is -1 |
| SkASSERT(currScanline != -1); |
| |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| this->updateCurrScanline(currScanline); |
| } |
| |
| return this->readRows(this->dstInfo(), dst, rowBytes, count, this->nextScanline()); |
| } |
| |
| bool onSkipScanlines(int count) override { |
| // The non-virtual version will update fCurrScanline. |
| return true; |
| } |
| |
| SkScanlineOrder onGetScanlineOrder() const override { |
| return kNone_SkScanlineOrder; |
| } |
| |
| private: |
| // FIXME: This imitates behavior in SkCodec::rewindIfNeeded. That function |
| // is called whenever some action is taken that reads the stream and |
| // therefore the next call will require a rewind. So it modifies a boolean |
| // to note that the *next* time it is called a rewind is needed. |
| // SkPngInterlacedCodec has an extra wrinkle - calling |
| // onStartScanlineDecode followed by onGetScanlines does *not* require a |
| // rewind. Since rewindIfNeeded does not have this flexibility, we need to |
| // add another layer. |
| bool fCanSkipRewind; |
| |
| typedef SkPngCodec INHERITED; |
| }; |
| |
| // 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); |
| |
| 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; |
| } |
| |
| png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn); |
| |
| #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 |
| |
| // The call to png_read_info() gives us all of the information from the |
| // PNG file before the first IDAT (image data chunk). |
| png_read_info(png_ptr, info_ptr); |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, encodedColorType; |
| png_get_IHDR(png_ptr, info_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(png_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(png_ptr); |
| } |
| |
| color = SkEncodedInfo::kPalette_Color; |
| // Set the alpha depending on if a transparency chunk exists. |
| alpha = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ? |
| SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha; |
| break; |
| case PNG_COLOR_TYPE_RGB: |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| // Convert to RGBA if transparency chunk exists. |
| png_set_tRNS_to_alpha(png_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(png_ptr); |
| } |
| |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| png_set_tRNS_to_alpha(png_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; |
| } |
| |
| int numberPasses = png_set_interlace_handling(png_ptr); |
| |
| autoClean.release(); |
| if (png_ptrp) { |
| *png_ptrp = png_ptr; |
| } |
| if (info_ptrp) { |
| *info_ptrp = info_ptr; |
| } |
| |
| if (outCodec) { |
| sk_sp<SkColorSpace> colorSpace = read_color_space(png_ptr, info_ptr); |
| if (!colorSpace) { |
| // Treat unmarked pngs as sRGB. |
| colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); |
| } |
| |
| SkEncodedInfo encodedInfo = SkEncodedInfo::Make(color, alpha, 8); |
| SkImageInfo imageInfo = encodedInfo.makeImageInfo(origWidth, origHeight, colorSpace); |
| |
| if (SkEncodedInfo::kOpaque_Alpha == alpha) { |
| png_color_8p sigBits; |
| if (png_get_sBIT(png_ptr, info_ptr, &sigBits)) { |
| if (5 == sigBits->red && 6 == sigBits->green && 5 == sigBits->blue) { |
| // Recommend a decode to 565 if the sBIT indicates 565. |
| imageInfo = imageInfo.makeColorType(kRGB_565_SkColorType); |
| } |
| } |
| } |
| |
| if (1 == numberPasses) { |
| *outCodec = new SkPngNormalCodec(encodedInfo, imageInfo, stream, |
| chunkReader, png_ptr, info_ptr, bitDepth); |
| } else { |
| *outCodec = new SkPngInterlacedCodec(encodedInfo, imageInfo, stream, |
| chunkReader, png_ptr, info_ptr, bitDepth, numberPasses); |
| } |
| } |
| |
| return true; |
| } |
| |
| SkPngCodec::SkPngCodec(const SkEncodedInfo& encodedInfo, const SkImageInfo& imageInfo, |
| SkStream* stream, SkPngChunkReader* chunkReader, void* png_ptr, |
| void* info_ptr, int bitDepth, int numberPasses) |
| : INHERITED(encodedInfo, imageInfo, stream) |
| , fPngChunkReader(SkSafeRef(chunkReader)) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fSwizzlerSrcRow(nullptr) |
| , fColorXformSrcRow(nullptr) |
| , fSrcRowBytes(imageInfo.width() * (bytes_per_pixel(this->getEncodedInfo().bitsPerPixel()))) |
| , fNumberPasses(numberPasses) |
| , 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((png_struct**)&fPng_ptr, (png_info**)&fInfo_ptr, nullptr); |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Getting the pixels |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| bool SkPngCodec::initializeXforms(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) { |
| if (setjmp(png_jmpbuf((png_struct*)fPng_ptr))) { |
| SkCodecPrintf("Failed on png_read_update_info.\n"); |
| return false; |
| } |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| // Reset fSwizzler and fColorXform. We can't do this in onRewind() because the |
| // interlaced scanline decoder may need to rewind. |
| fSwizzler.reset(nullptr); |
| fColorXform = nullptr; |
| |
| if (needs_color_xform(dstInfo, this->getInfo())) { |
| fColorXform = SkColorSpaceXform::New(sk_ref_sp(this->getInfo().colorSpace()), |
| sk_ref_sp(dstInfo.colorSpace())); |
| SkASSERT(fColorXform); |
| } |
| |
| // If the image is RGBA and we have a color xform, we can skip the swizzler. |
| // FIXME (msarett): |
| // Support more input types to fColorXform (ex: RGB, Gray) and skip the swizzler more often. |
| if (fColorXform && SkEncodedInfo::kRGBA_Color == this->getEncodedInfo().color() && |
| !options.fSubset) |
| { |
| fXformMode = kColorOnly_XformMode; |
| return true; |
| } |
| |
| if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) { |
| if (!this->createColorTable(dstInfo, ctableCount)) { |
| return false; |
| } |
| } |
| |
| // Copy the color table to the client if they request kIndex8 mode. |
| copy_color_table(dstInfo, fColorTable, ctable, ctableCount); |
| |
| this->initializeSwizzler(dstInfo, options); |
| return true; |
| } |
| |
| static inline bool apply_xform_on_decode(SkColorType dstColorType, SkEncodedInfo::Color srcColor) { |
| // We will apply the color xform when reading the color table, unless F16 is requested. |
| return SkEncodedInfo::kPalette_Color != srcColor || kRGBA_F16_SkColorType == dstColorType; |
| } |
| |
| void SkPngCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options) { |
| SkImageInfo swizzlerInfo = dstInfo; |
| Options swizzlerOptions = options; |
| fXformMode = kSwizzleOnly_XformMode; |
| if (fColorXform && apply_xform_on_decode(dstInfo.colorType(), this->getEncodedInfo().color())) { |
| swizzlerInfo = swizzlerInfo.makeColorType(kRGBA_8888_SkColorType); |
| if (kPremul_SkAlphaType == dstInfo.alphaType()) { |
| swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType); |
| } |
| |
| fXformMode = kSwizzleColor_XformMode; |
| |
| // Here, we swizzle into temporary memory, which is not zero initialized. |
| // FIXME (msarett): |
| // Is this a problem? |
| swizzlerOptions.fZeroInitialized = kNo_ZeroInitialized; |
| } |
| |
| const SkPMColor* colors = get_color_ptr(fColorTable.get()); |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, swizzlerInfo, |
| swizzlerOptions)); |
| SkASSERT(fSwizzler); |
| } |
| |
| SkSampler* SkPngCodec::getSampler(bool createIfNecessary) { |
| if (fSwizzler || !createIfNecessary) { |
| return fSwizzler; |
| } |
| |
| this->initializeSwizzler(this->dstInfo(), this->options()); |
| return fSwizzler; |
| } |
| |
| 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& dstInfo, void* dst, |
| size_t rowBytes, const Options& options, |
| SkPMColor ctable[], int* ctableCount, |
| int* rowsDecoded) { |
| if (!conversion_possible(dstInfo, this->getInfo()) || |
| !this->initializeXforms(dstInfo, options, ctable, ctableCount)) |
| { |
| return kInvalidConversion; |
| } |
| |
| if (options.fSubset) { |
| return kUnimplemented; |
| } |
| |
| this->allocateStorage(dstInfo); |
| int count = this->readRows(dstInfo, dst, rowBytes, dstInfo.height(), 0); |
| if (count > dstInfo.height()) { |
| *rowsDecoded = count; |
| return kIncompleteInput; |
| } |
| |
| return kSuccess; |
| } |
| |
| uint64_t SkPngCodec::onGetFillValue(const SkImageInfo& dstInfo) const { |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| if (colorPtr) { |
| SkAlphaType alphaType = select_alpha_xform(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| return get_color_table_fill_value(dstInfo.colorType(), alphaType, colorPtr, 0, |
| fColorXform.get()); |
| } |
| return INHERITED::onGetFillValue(dstInfo); |
| } |
| |
| SkCodec* SkPngCodec::NewFromStream(SkStream* stream, SkPngChunkReader* chunkReader) { |
| SkAutoTDelete<SkStream> streamDeleter(stream); |
| |
| SkCodec* outCodec; |
| if (read_header(stream, chunkReader, &outCodec, nullptr, nullptr)) { |
| // Codec has taken ownership of the stream. |
| SkASSERT(outCodec); |
| streamDeleter.release(); |
| return outCodec; |
| } |
| |
| return nullptr; |
| } |