| /* |
| * 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 "SkCodec_libpng.h" |
| #include "SkColorPriv.h" |
| #include "SkColorTable.h" |
| #include "SkBitmap.h" |
| #include "SkMath.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Helper macros |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #ifndef png_jmpbuf |
| # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| #endif |
| |
| /* These were dropped in libpng >= 1.4 */ |
| #ifndef png_infopp_NULL |
| #define png_infopp_NULL NULL |
| #endif |
| |
| #ifndef png_bytepp_NULL |
| #define png_bytepp_NULL NULL |
| #endif |
| |
| #ifndef int_p_NULL |
| #define int_p_NULL NULL |
| #endif |
| |
| #ifndef png_flush_ptr_NULL |
| #define png_flush_ptr_NULL NULL |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Callback functions |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| SkDebugf("------ png error %s\n", msg); |
| longjmp(png_jmpbuf(png_ptr), 1); |
| } |
| |
| 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!"); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Helpers |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| class AutoCleanPng : public SkNoncopyable { |
| public: |
| AutoCleanPng(png_structp png_ptr) |
| : fPng_ptr(png_ptr) |
| , fInfo_ptr(NULL) {} |
| |
| ~AutoCleanPng() { |
| // fInfo_ptr will never be non-NULL unless fPng_ptr is. |
| if (fPng_ptr) { |
| png_infopp info_pp = fInfo_ptr ? &fInfo_ptr : NULL; |
| png_destroy_read_struct(&fPng_ptr, info_pp, png_infopp_NULL); |
| } |
| } |
| |
| void setInfoPtr(png_infop info_ptr) { |
| SkASSERT(NULL == fInfo_ptr); |
| fInfo_ptr = info_ptr; |
| } |
| |
| void detach() { |
| fPng_ptr = NULL; |
| fInfo_ptr = NULL; |
| } |
| |
| private: |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| }; |
| #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) |
| |
| // call only if color_type is PALETTE. Returns true if the ctable has alpha |
| static bool has_transparency_in_palette(png_structp png_ptr, |
| png_infop info_ptr) { |
| if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| return false; |
| } |
| |
| png_bytep trans; |
| int num_trans; |
| png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, NULL); |
| return num_trans > 0; |
| } |
| |
| // Method for coverting to either an SkPMColor or a similarly packed |
| // unpremultiplied color. |
| typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b); |
| |
| // Note: SkColorTable claims to store SkPMColors, which is not necessarily |
| // the case here. |
| SkColorTable* decode_palette(png_structp png_ptr, png_infop info_ptr, |
| bool premultiply, SkAlphaType* outAlphaType) { |
| SkASSERT(outAlphaType != NULL); |
| int numPalette; |
| png_colorp palette; |
| png_bytep trans; |
| |
| if (!png_get_PLTE(png_ptr, info_ptr, &palette, &numPalette)) { |
| return NULL; |
| } |
| |
| /* BUGGY IMAGE WORKAROUND |
| |
| We hit some images (e.g. fruit_.png) who contain bytes that are == colortable_count |
| which is a problem since we use the byte as an index. To work around this we grow |
| the colortable by 1 (if its < 256) and duplicate the last color into that slot. |
| */ |
| const int colorCount = numPalette + (numPalette < 256); |
| // Note: These are not necessarily SkPMColors. |
| SkPMColor colorStorage[256]; // worst-case storage |
| SkPMColor* colorPtr = colorStorage; |
| |
| int numTrans; |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| png_get_tRNS(png_ptr, info_ptr, &trans, &numTrans, NULL); |
| } else { |
| numTrans = 0; |
| } |
| |
| // check for bad images that might make us crash |
| if (numTrans > numPalette) { |
| numTrans = numPalette; |
| } |
| |
| int index = 0; |
| int transLessThanFF = 0; |
| |
| // 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; |
| if (premultiply) { |
| proc = &SkPreMultiplyARGB; |
| } else { |
| proc = &SkPackARGB32NoCheck; |
| } |
| for (; index < numTrans; index++) { |
| transLessThanFF |= (int)*trans - 0xFF; |
| *colorPtr++ = proc(*trans++, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| |
| if (transLessThanFF < 0) { |
| *outAlphaType = premultiply ? kPremul_SkAlphaType : kUnpremul_SkAlphaType; |
| } else { |
| *outAlphaType = kOpaque_SkAlphaType; |
| } |
| |
| for (; index < numPalette; index++) { |
| *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| |
| // see BUGGY IMAGE WORKAROUND comment above |
| if (numPalette < 256) { |
| *colorPtr = colorPtr[-1]; |
| } |
| |
| return SkNEW_ARGS(SkColorTable, (colorStorage, colorCount)); |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Creation |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #define PNG_BYTES_TO_CHECK 4 |
| |
| bool SkPngCodec::IsPng(SkStream* stream) { |
| char buf[PNG_BYTES_TO_CHECK]; |
| if (stream->read(buf, PNG_BYTES_TO_CHECK) != PNG_BYTES_TO_CHECK) { |
| return false; |
| } |
| if (png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) { |
| return false; |
| } |
| return true; |
| } |
| |
| SkCodec* SkPngCodec::NewFromStream(SkStream* stream) { |
| // The image is known to be a PNG. Decode enough to know the SkImageInfo. |
| // FIXME: Allow silencing warnings. |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, |
| sk_error_fn, NULL); |
| if (!png_ptr) { |
| return NULL; |
| } |
| |
| AutoCleanPng autoClean(png_ptr); |
| |
| png_infop info_ptr = png_create_info_struct(png_ptr); |
| if (info_ptr == NULL) { |
| return NULL; |
| } |
| |
| 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 NULL; |
| } |
| |
| png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn); |
| |
| // FIXME: This is where the old code hooks up the Peeker. Does it need to |
| // be set this early? (i.e. where are the user chunks? early in the stream, |
| // potentially?) |
| // If it does, we need to figure out a way to set it here. |
| |
| // 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, colorType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &colorType, int_p_NULL, int_p_NULL, int_p_NULL); |
| |
| // sanity check for size |
| { |
| int64_t size = sk_64_mul(origWidth, origHeight); |
| // now check that if we are 4-bytes per pixel, we also don't overflow |
| if (size < 0 || size > (0x7FFFFFFF >> 2)) { |
| return NULL; |
| } |
| } |
| |
| // Tell libpng to strip 16 bit/color files down to 8 bits/color |
| if (bitDepth == 16) { |
| png_set_strip_16(png_ptr); |
| } |
| #ifdef PNG_READ_PACK_SUPPORTED |
| // 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) { |
| png_set_packing(png_ptr); |
| } |
| #endif |
| // Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel. |
| if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) { |
| png_set_expand_gray_1_2_4_to_8(png_ptr); |
| } |
| |
| |
| // Now determine the default SkColorType and SkAlphaType. |
| SkColorType skColorType; |
| SkAlphaType skAlphaType; |
| switch (colorType) { |
| case PNG_COLOR_TYPE_PALETTE: |
| // Technically, this is true of the data, but I don't think we want |
| // to support it. |
| // skColorType = kIndex8_SkColorType; |
| skColorType = kN32_SkColorType; |
| skAlphaType = has_transparency_in_palette(png_ptr, info_ptr) ? |
| kUnpremul_SkAlphaType : kOpaque_SkAlphaType; |
| break; |
| case PNG_COLOR_TYPE_GRAY: |
| if (false) { |
| // FIXME: Is this the wrong default behavior? This means if the |
| // caller supplies the info we gave them, they'll get Alpha 8. |
| skColorType = kAlpha_8_SkColorType; |
| // FIXME: Strangely, the canonical type for Alpha 8 is Premul. |
| skAlphaType = kPremul_SkAlphaType; |
| } else { |
| skColorType = kN32_SkColorType; |
| skAlphaType = kOpaque_SkAlphaType; |
| } |
| break; |
| default: |
| // Note: This *almost* mimics the code in SkImageDecoder_libpng. |
| // has_transparency_in_palette makes an additional check - whether |
| // numTrans is greater than 0. Why does the other code not make that |
| // check? |
| if (has_transparency_in_palette(png_ptr, info_ptr) |
| || PNG_COLOR_TYPE_RGB_ALPHA == colorType |
| || PNG_COLOR_TYPE_GRAY_ALPHA == colorType) |
| { |
| skAlphaType = kUnpremul_SkAlphaType; |
| } else { |
| skAlphaType = kOpaque_SkAlphaType; |
| } |
| skColorType = kN32_SkColorType; |
| break; |
| } |
| |
| { |
| // FIXME: Again, this block needs to go into onGetPixels. |
| bool convertGrayToRGB = PNG_COLOR_TYPE_GRAY == colorType && skColorType != kAlpha_8_SkColorType; |
| |
| // Unless the user is requesting A8, convert a grayscale image into RGB. |
| // GRAY_ALPHA will always be converted to RGB |
| if (convertGrayToRGB || colorType == PNG_COLOR_TYPE_GRAY_ALPHA) { |
| png_set_gray_to_rgb(png_ptr); |
| } |
| |
| // Add filler (or alpha) byte (after each RGB triplet) if necessary. |
| // FIXME: It seems like we could just use RGB as the SrcConfig here. |
| if (colorType == PNG_COLOR_TYPE_RGB || convertGrayToRGB) { |
| png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| } |
| } |
| |
| // FIXME: Also need to check for sRGB (skbug.com/3471). |
| |
| SkImageInfo info = SkImageInfo::Make(origWidth, origHeight, skColorType, |
| skAlphaType); |
| SkCodec* codec = SkNEW_ARGS(SkPngCodec, (info, stream, png_ptr, info_ptr)); |
| autoClean.detach(); |
| return codec; |
| } |
| |
| SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream, |
| png_structp png_ptr, png_infop info_ptr) |
| : INHERITED(info, stream) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) {} |
| |
| SkPngCodec::~SkPngCodec() { |
| png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL); |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Getting the pixels |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static bool premul_and_unpremul(SkAlphaType A, SkAlphaType B) { |
| return kPremul_SkAlphaType == A && kUnpremul_SkAlphaType == B; |
| } |
| |
| static bool conversion_possible(const SkImageInfo& A, const SkImageInfo& B) { |
| // TODO: Support other conversions |
| if (A.colorType() != B.colorType()) { |
| return false; |
| } |
| if (A.profileType() != B.profileType()) { |
| return false; |
| } |
| if (A.alphaType() == B.alphaType()) { |
| return true; |
| } |
| return premul_and_unpremul(A.alphaType(), B.alphaType()) |
| || premul_and_unpremul(B.alphaType(), A.alphaType()); |
| } |
| |
| SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst, |
| size_t rowBytes, SkPMColor ctable[], |
| int* ctableCount) { |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| if (requestedInfo.dimensions() != this->getOriginalInfo().dimensions()) { |
| return kInvalidScale; |
| } |
| if (!conversion_possible(requestedInfo, this->getOriginalInfo())) { |
| return kInvalidConversion; |
| } |
| |
| SkBitmap decodedBitmap; |
| // If installPixels would have failed, getPixels should have failed before |
| // calling onGetPixels. |
| SkAssertResult(decodedBitmap.installPixels(requestedInfo, dst, rowBytes)); |
| |
| // Initialize all non-trivial objects before setjmp. |
| SkAutoTUnref<SkColorTable> colorTable; |
| SkAutoTDelete<SkSwizzler> swizzler; |
| SkAutoMalloc storage; // Scratch memory for pre-swizzled rows. |
| |
| // FIXME: Could we use the return value of setjmp to specify the type of |
| // error? |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| SkDebugf("setjmp long jump!\n"); |
| return kInvalidInput; |
| } |
| |
| // FIXME: We already retrieved this information. Store it in SkPngCodec? |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, pngColorType, interlaceType; |
| png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth, |
| &pngColorType, &interlaceType, int_p_NULL, int_p_NULL); |
| |
| const int numberPasses = (interlaceType != PNG_INTERLACE_NONE) ? |
| png_set_interlace_handling(fPng_ptr) : 1; |
| |
| SkSwizzler::SrcConfig sc; |
| bool reallyHasAlpha = false; |
| if (PNG_COLOR_TYPE_PALETTE == pngColorType) { |
| sc = SkSwizzler::kIndex; |
| SkAlphaType at = requestedInfo.alphaType(); |
| colorTable.reset(decode_palette(fPng_ptr, fInfo_ptr, |
| kPremul_SkAlphaType == at, |
| &at)); |
| if (!colorTable) { |
| return kInvalidInput; |
| } |
| |
| reallyHasAlpha = (at != kOpaque_SkAlphaType); |
| |
| if (at != requestedInfo.alphaType()) { |
| // It turns out the image is opaque. |
| SkASSERT(kOpaque_SkAlphaType == at); |
| } |
| } else if (kAlpha_8_SkColorType == requestedInfo.colorType()) { |
| // Note: we check the destination, since otherwise we would have |
| // told png to upscale. |
| SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| sc = SkSwizzler::kGray; |
| } else if (this->getOriginalInfo().alphaType() == kOpaque_SkAlphaType) { |
| sc = SkSwizzler::kRGBX; |
| } else { |
| sc = SkSwizzler::kRGBA; |
| } |
| const SkPMColor* colors = colorTable ? colorTable->readColors() : NULL; |
| // TODO: Support skipZeroes. |
| swizzler.reset(SkSwizzler::CreateSwizzler(sc, colors, requestedInfo, |
| dst, rowBytes, false)); |
| if (!swizzler) { |
| // FIXME: CreateSwizzler could fail for another reason. |
| return kUnimplemented; |
| } |
| |
| // FIXME: Here is where we should likely insert some of the modifications |
| // made in the factory. |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| if (numberPasses > 1) { |
| const int width = requestedInfo.width(); |
| const int height = requestedInfo.height(); |
| const int bpp = SkSwizzler::BytesPerPixel(sc); |
| const size_t rowBytes = width * bpp; |
| |
| storage.reset(width * height * bpp); |
| uint8_t* const base = static_cast<uint8_t*>(storage.get()); |
| |
| for (int i = 0; i < numberPasses; i++) { |
| uint8_t* row = base; |
| for (int y = 0; y < height; y++) { |
| uint8_t* bmRow = row; |
| png_read_rows(fPng_ptr, &bmRow, png_bytepp_NULL, 1); |
| row += rowBytes; |
| } |
| } |
| |
| // Now swizzle it. |
| uint8_t* row = base; |
| for (int y = 0; y < height; y++) { |
| reallyHasAlpha |= swizzler->next(row); |
| row += rowBytes; |
| } |
| } else { |
| storage.reset(requestedInfo.width() * SkSwizzler::BytesPerPixel(sc)); |
| uint8_t* srcRow = static_cast<uint8_t*>(storage.get()); |
| for (int y = 0; y < requestedInfo.height(); y++) { |
| png_read_rows(fPng_ptr, &srcRow, png_bytepp_NULL, 1); |
| reallyHasAlpha |= swizzler->next(srcRow); |
| } |
| } |
| |
| /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ |
| png_read_end(fPng_ptr, fInfo_ptr); |
| |
| // FIXME: do we need substituteTranspColor? |
| |
| if (reallyHasAlpha && requestedInfo.alphaType() != kOpaque_SkAlphaType) { |
| // FIXME: We want to alert the caller. Is this the right way? |
| SkImageInfo* modInfo = const_cast<SkImageInfo*>(&requestedInfo); |
| *modInfo = requestedInfo.makeAlphaType(kOpaque_SkAlphaType); |
| } |
| return kSuccess; |
| } |