| /* |
| * Copyright 2006 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkImageDecoder.h" |
| #include "SkImageEncoder.h" |
| #include "SkColor.h" |
| #include "SkColorPriv.h" |
| #include "SkDither.h" |
| #include "SkMath.h" |
| #include "SkRTConf.h" |
| #include "SkScaledBitmapSampler.h" |
| #include "SkStream.h" |
| #include "SkTemplates.h" |
| #include "SkUtils.h" |
| #include "transform_scanline.h" |
| extern "C" { |
| #include "png.h" |
| } |
| |
| /* 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 |
| |
| #if defined(SK_DEBUG) |
| #define DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS false |
| #else // !defined(SK_DEBUG) |
| #define DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS true |
| #endif // defined(SK_DEBUG) |
| SK_CONF_DECLARE(bool, c_suppressPNGImageDecoderWarnings, |
| "images.png.suppressDecoderWarnings", |
| DEFAULT_FOR_SUPPRESS_PNG_IMAGE_DECODER_WARNINGS, |
| "Suppress most PNG warnings when calling image decode " |
| "functions."); |
| |
| |
| |
| class SkPNGImageIndex { |
| public: |
| SkPNGImageIndex(SkStreamRewindable* stream, png_structp png_ptr, png_infop info_ptr) |
| : fStream(stream) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fColorType(kUnknown_SkColorType) { |
| SkASSERT(stream != NULL); |
| stream->ref(); |
| } |
| ~SkPNGImageIndex() { |
| if (fPng_ptr) { |
| png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL); |
| } |
| } |
| |
| SkAutoTUnref<SkStreamRewindable> fStream; |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| SkColorType fColorType; |
| }; |
| |
| class SkPNGImageDecoder : public SkImageDecoder { |
| public: |
| SkPNGImageDecoder() { |
| fImageIndex = NULL; |
| } |
| Format getFormat() const SK_OVERRIDE { |
| return kPNG_Format; |
| } |
| |
| virtual ~SkPNGImageDecoder() { |
| SkDELETE(fImageIndex); |
| } |
| |
| protected: |
| #ifdef SK_BUILD_FOR_ANDROID |
| bool onBuildTileIndex(SkStreamRewindable *stream, int *width, int *height) SK_OVERRIDE; |
| bool onDecodeSubset(SkBitmap* bitmap, const SkIRect& region) SK_OVERRIDE; |
| #endif |
| Result onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE; |
| |
| private: |
| SkPNGImageIndex* fImageIndex; |
| |
| bool onDecodeInit(SkStream* stream, png_structp *png_ptrp, png_infop *info_ptrp); |
| bool decodePalette(png_structp png_ptr, png_infop info_ptr, |
| bool * SK_RESTRICT hasAlphap, bool *reallyHasAlphap, |
| SkColorTable **colorTablep); |
| bool getBitmapColorType(png_structp, png_infop, SkColorType*, bool* hasAlpha, |
| SkPMColor* theTranspColor); |
| |
| typedef SkImageDecoder INHERITED; |
| }; |
| |
| #ifndef png_jmpbuf |
| # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| #endif |
| |
| #define PNG_BYTES_TO_CHECK 4 |
| |
| /* Automatically clean up after throwing an exception */ |
| struct PNGAutoClean { |
| PNGAutoClean(png_structp p, png_infop i): png_ptr(p), info_ptr(i) {} |
| ~PNGAutoClean() { |
| png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL); |
| } |
| private: |
| png_structp png_ptr; |
| png_infop info_ptr; |
| }; |
| |
| static void sk_read_fn(png_structp png_ptr, png_bytep data, png_size_t length) { |
| SkStream* sk_stream = (SkStream*) png_get_io_ptr(png_ptr); |
| size_t bytes = sk_stream->read(data, length); |
| if (bytes != length) { |
| png_error(png_ptr, "Read Error!"); |
| } |
| } |
| |
| #ifdef SK_BUILD_FOR_ANDROID |
| static void sk_seek_fn(png_structp png_ptr, png_uint_32 offset) { |
| SkStreamRewindable* sk_stream = (SkStreamRewindable*) png_get_io_ptr(png_ptr); |
| if (!sk_stream->rewind()) { |
| png_error(png_ptr, "Failed to rewind stream!"); |
| } |
| (void)sk_stream->skip(offset); |
| } |
| #endif |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) { |
| SkImageDecoder::Peeker* peeker = |
| (SkImageDecoder::Peeker*)png_get_user_chunk_ptr(png_ptr); |
| // peek() returning true means continue decoding |
| return peeker->peek((const char*)chunk->name, chunk->data, chunk->size) ? |
| 1 : -1; |
| } |
| #endif |
| |
| 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 skip_src_rows(png_structp png_ptr, uint8_t storage[], int count) { |
| for (int i = 0; i < count; i++) { |
| uint8_t* tmp = storage; |
| png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1); |
| } |
| } |
| |
| static bool pos_le(int value, int max) { |
| return value > 0 && value <= max; |
| } |
| |
| static bool substituteTranspColor(SkBitmap* bm, SkPMColor match) { |
| SkASSERT(bm->colorType() == kN32_SkColorType); |
| |
| bool reallyHasAlpha = false; |
| |
| for (int y = bm->height() - 1; y >= 0; --y) { |
| SkPMColor* p = bm->getAddr32(0, y); |
| for (int x = bm->width() - 1; x >= 0; --x) { |
| if (match == *p) { |
| *p = 0; |
| reallyHasAlpha = true; |
| } |
| p += 1; |
| } |
| } |
| return reallyHasAlpha; |
| } |
| |
| static bool canUpscalePaletteToConfig(SkColorType dstColorType, bool srcHasAlpha) { |
| switch (dstColorType) { |
| case kN32_SkColorType: |
| case kARGB_4444_SkColorType: |
| return true; |
| case kRGB_565_SkColorType: |
| // only return true if the src is opaque (since 565 is opaque) |
| return !srcHasAlpha; |
| default: |
| return false; |
| } |
| } |
| |
| // call only if color_type is PALETTE. Returns true if the ctable has alpha |
| static bool hasTransparencyInPalette(png_structp png_ptr, png_infop info_ptr) { |
| png_bytep trans; |
| int num_trans; |
| |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, NULL); |
| return num_trans > 0; |
| } |
| return false; |
| } |
| |
| void do_nothing_warning_fn(png_structp, png_const_charp) { |
| /* do nothing */ |
| } |
| |
| bool SkPNGImageDecoder::onDecodeInit(SkStream* sk_stream, png_structp *png_ptrp, |
| png_infop *info_ptrp) { |
| /* Create and initialize the png_struct with the desired error handler |
| * functions. If you want to use the default stderr and longjump method, |
| * you can supply NULL for the last three parameters. We also supply the |
| * the compiler header file version, so that we know if the application |
| * was compiled with a compatible version of the library. */ |
| |
| png_error_ptr user_warning_fn = |
| (c_suppressPNGImageDecoderWarnings) ? (&do_nothing_warning_fn) : NULL; |
| /* NULL means to leave as default library behavior. */ |
| /* c_suppressPNGImageDecoderWarnings default depends on SK_DEBUG. */ |
| /* To suppress warnings with a SK_DEBUG binary, set the |
| * environment variable "skia_images_png_suppressDecoderWarnings" |
| * to "true". Inside a program that links to skia: |
| * SK_CONF_SET("images.png.suppressDecoderWarnings", true); */ |
| |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, |
| NULL, sk_error_fn, user_warning_fn); |
| // png_voidp user_error_ptr, user_error_fn, user_warning_fn); |
| if (png_ptr == NULL) { |
| return false; |
| } |
| |
| *png_ptrp = png_ptr; |
| |
| /* Allocate/initialize the memory for image information. */ |
| png_infop info_ptr = png_create_info_struct(png_ptr); |
| if (info_ptr == NULL) { |
| png_destroy_read_struct(&png_ptr, png_infopp_NULL, png_infopp_NULL); |
| return false; |
| } |
| *info_ptrp = info_ptr; |
| |
| /* Set error handling if you are using the setjmp/longjmp method (this is |
| * the normal method of doing things with libpng). REQUIRED unless you |
| * set up your own error handlers in the png_create_read_struct() earlier. |
| */ |
| if (setjmp(png_jmpbuf(png_ptr))) { |
| png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL); |
| return false; |
| } |
| |
| /* If you are using replacement read functions, instead of calling |
| * png_init_io() here you would call: |
| */ |
| png_set_read_fn(png_ptr, (void *)sk_stream, sk_read_fn); |
| #ifdef SK_BUILD_FOR_ANDROID |
| png_set_seek_fn(png_ptr, sk_seek_fn); |
| #endif |
| /* where user_io_ptr is a structure you want available to the callbacks */ |
| /* If we have already read some of the signature */ |
| // png_set_sig_bytes(png_ptr, 0 /* sig_read */ ); |
| |
| #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED |
| // hookup our peeker so we can see any user-chunks the caller may be interested in |
| png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0); |
| if (this->getPeeker()) { |
| png_set_read_user_chunk_fn(png_ptr, (png_voidp)this->getPeeker(), 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, colorType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &colorType, int_p_NULL, int_p_NULL, int_p_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); |
| } |
| |
| return true; |
| } |
| |
| SkImageDecoder::Result SkPNGImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* decodedBitmap, |
| Mode mode) { |
| png_structp png_ptr; |
| png_infop info_ptr; |
| |
| if (!onDecodeInit(sk_stream, &png_ptr, &info_ptr)) { |
| return kFailure; |
| } |
| |
| PNGAutoClean autoClean(png_ptr, info_ptr); |
| |
| if (setjmp(png_jmpbuf(png_ptr))) { |
| return kFailure; |
| } |
| |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, pngColorType, interlaceType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &pngColorType, &interlaceType, int_p_NULL, int_p_NULL); |
| |
| SkColorType colorType; |
| bool hasAlpha = false; |
| SkPMColor theTranspColor = 0; // 0 tells us not to try to match |
| |
| if (!this->getBitmapColorType(png_ptr, info_ptr, &colorType, &hasAlpha, &theTranspColor)) { |
| return kFailure; |
| } |
| |
| SkAlphaType alphaType = this->getRequireUnpremultipliedColors() ? |
| kUnpremul_SkAlphaType : kPremul_SkAlphaType; |
| const int sampleSize = this->getSampleSize(); |
| SkScaledBitmapSampler sampler(origWidth, origHeight, sampleSize); |
| decodedBitmap->setInfo(SkImageInfo::Make(sampler.scaledWidth(), sampler.scaledHeight(), |
| colorType, alphaType)); |
| |
| if (SkImageDecoder::kDecodeBounds_Mode == mode) { |
| return kSuccess; |
| } |
| |
| // from here down we are concerned with colortables and pixels |
| |
| // we track if we actually see a non-opaque pixels, since sometimes a PNG sets its colortype |
| // to |= PNG_COLOR_MASK_ALPHA, but all of its pixels are in fact opaque. We care, since we |
| // draw lots faster if we can flag the bitmap has being opaque |
| bool reallyHasAlpha = false; |
| SkColorTable* colorTable = NULL; |
| |
| if (pngColorType == PNG_COLOR_TYPE_PALETTE) { |
| decodePalette(png_ptr, info_ptr, &hasAlpha, &reallyHasAlpha, &colorTable); |
| } |
| |
| SkAutoUnref aur(colorTable); |
| |
| if (!this->allocPixelRef(decodedBitmap, |
| kIndex_8_SkColorType == colorType ? colorTable : NULL)) { |
| return kFailure; |
| } |
| |
| SkAutoLockPixels alp(*decodedBitmap); |
| |
| /* Turn on interlace handling. REQUIRED if you are not using |
| * png_read_image(). To see how to handle interlacing passes, |
| * see the png_read_row() method below: |
| */ |
| const int number_passes = (interlaceType != PNG_INTERLACE_NONE) ? |
| png_set_interlace_handling(png_ptr) : 1; |
| |
| /* Optional call to gamma correct and add the background to the palette |
| * and update info structure. REQUIRED if you are expecting libpng to |
| * update the palette for you (ie you selected such a transform above). |
| */ |
| png_read_update_info(png_ptr, info_ptr); |
| |
| if ((kAlpha_8_SkColorType == colorType || kIndex_8_SkColorType == colorType) && |
| 1 == sampleSize) { |
| if (kAlpha_8_SkColorType == colorType) { |
| // For an A8 bitmap, we assume there is an alpha for speed. It is |
| // possible the bitmap is opaque, but that is an unlikely use case |
| // since it would not be very interesting. |
| reallyHasAlpha = true; |
| // A8 is only allowed if the original was GRAY. |
| SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| } |
| for (int i = 0; i < number_passes; i++) { |
| for (png_uint_32 y = 0; y < origHeight; y++) { |
| uint8_t* bmRow = decodedBitmap->getAddr8(0, y); |
| png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| } |
| } |
| } else { |
| SkScaledBitmapSampler::SrcConfig sc; |
| int srcBytesPerPixel = 4; |
| |
| if (colorTable != NULL) { |
| sc = SkScaledBitmapSampler::kIndex; |
| srcBytesPerPixel = 1; |
| } else if (kAlpha_8_SkColorType == colorType) { |
| // A8 is only allowed if the original was GRAY. |
| SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| sc = SkScaledBitmapSampler::kGray; |
| srcBytesPerPixel = 1; |
| } else if (hasAlpha) { |
| sc = SkScaledBitmapSampler::kRGBA; |
| } else { |
| sc = SkScaledBitmapSampler::kRGBX; |
| } |
| |
| /* We have to pass the colortable explicitly, since we may have one |
| even if our decodedBitmap doesn't, due to the request that we |
| upscale png's palette to a direct model |
| */ |
| const SkPMColor* colors = colorTable ? colorTable->readColors() : NULL; |
| if (!sampler.begin(decodedBitmap, sc, *this, colors)) { |
| return kFailure; |
| } |
| const int height = decodedBitmap->height(); |
| |
| if (number_passes > 1) { |
| SkAutoMalloc storage(origWidth * origHeight * srcBytesPerPixel); |
| uint8_t* base = (uint8_t*)storage.get(); |
| size_t rowBytes = origWidth * srcBytesPerPixel; |
| |
| for (int i = 0; i < number_passes; i++) { |
| uint8_t* row = base; |
| for (png_uint_32 y = 0; y < origHeight; y++) { |
| uint8_t* bmRow = row; |
| png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| row += rowBytes; |
| } |
| } |
| // now sample it |
| base += sampler.srcY0() * rowBytes; |
| for (int y = 0; y < height; y++) { |
| reallyHasAlpha |= sampler.next(base); |
| base += sampler.srcDY() * rowBytes; |
| } |
| } else { |
| SkAutoMalloc storage(origWidth * srcBytesPerPixel); |
| uint8_t* srcRow = (uint8_t*)storage.get(); |
| skip_src_rows(png_ptr, srcRow, sampler.srcY0()); |
| |
| for (int y = 0; y < height; y++) { |
| uint8_t* tmp = srcRow; |
| png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1); |
| reallyHasAlpha |= sampler.next(srcRow); |
| if (y < height - 1) { |
| skip_src_rows(png_ptr, srcRow, sampler.srcDY() - 1); |
| } |
| } |
| |
| // skip the rest of the rows (if any) |
| png_uint_32 read = (height - 1) * sampler.srcDY() + |
| sampler.srcY0() + 1; |
| SkASSERT(read <= origHeight); |
| skip_src_rows(png_ptr, srcRow, origHeight - read); |
| } |
| } |
| |
| /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ |
| png_read_end(png_ptr, info_ptr); |
| |
| if (0 != theTranspColor) { |
| reallyHasAlpha |= substituteTranspColor(decodedBitmap, theTranspColor); |
| } |
| if (reallyHasAlpha && this->getRequireUnpremultipliedColors()) { |
| switch (decodedBitmap->colorType()) { |
| case kIndex_8_SkColorType: |
| // Fall through. |
| case kARGB_4444_SkColorType: |
| // We have chosen not to support unpremul for these colortypes. |
| return kFailure; |
| default: { |
| // Fall through to finish the decode. This colortype either |
| // supports unpremul or it is irrelevant because it has no |
| // alpha (or only alpha). |
| // These brackets prevent a warning. |
| } |
| } |
| } |
| |
| if (!reallyHasAlpha) { |
| decodedBitmap->setAlphaType(kOpaque_SkAlphaType); |
| } |
| return kSuccess; |
| } |
| |
| |
| |
| bool SkPNGImageDecoder::getBitmapColorType(png_structp png_ptr, png_infop info_ptr, |
| SkColorType* colorTypep, |
| bool* hasAlphap, |
| SkPMColor* SK_RESTRICT theTranspColorp) { |
| 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); |
| |
| #ifdef PNG_sBIT_SUPPORTED |
| // check for sBIT chunk data, in case we should disable dithering because |
| // our data is not truely 8bits per component |
| png_color_8p sig_bit; |
| if (this->getDitherImage() && png_get_sBIT(png_ptr, info_ptr, &sig_bit)) { |
| #if 0 |
| SkDebugf("----- sBIT %d %d %d %d\n", sig_bit->red, sig_bit->green, |
| sig_bit->blue, sig_bit->alpha); |
| #endif |
| // 0 seems to indicate no information available |
| if (pos_le(sig_bit->red, SK_R16_BITS) && |
| pos_le(sig_bit->green, SK_G16_BITS) && |
| pos_le(sig_bit->blue, SK_B16_BITS)) { |
| this->setDitherImage(false); |
| } |
| } |
| #endif |
| |
| if (colorType == PNG_COLOR_TYPE_PALETTE) { |
| bool paletteHasAlpha = hasTransparencyInPalette(png_ptr, info_ptr); |
| *colorTypep = this->getPrefColorType(kIndex_SrcDepth, paletteHasAlpha); |
| // now see if we can upscale to their requested colortype |
| if (!canUpscalePaletteToConfig(*colorTypep, paletteHasAlpha)) { |
| *colorTypep = kIndex_8_SkColorType; |
| } |
| } else { |
| png_color_16p transpColor = NULL; |
| int numTransp = 0; |
| |
| png_get_tRNS(png_ptr, info_ptr, NULL, &numTransp, &transpColor); |
| |
| bool valid = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS); |
| |
| if (valid && numTransp == 1 && transpColor != NULL) { |
| /* Compute our transparent color, which we'll match against later. |
| We don't really handle 16bit components properly here, since we |
| do our compare *after* the values have been knocked down to 8bit |
| which means we will find more matches than we should. The real |
| fix seems to be to see the actual 16bit components, do the |
| compare, and then knock it down to 8bits ourselves. |
| */ |
| if (colorType & PNG_COLOR_MASK_COLOR) { |
| if (16 == bitDepth) { |
| *theTranspColorp = SkPackARGB32(0xFF, transpColor->red >> 8, |
| transpColor->green >> 8, |
| transpColor->blue >> 8); |
| } else { |
| /* We apply the mask because in a very small |
| number of corrupt PNGs, (transpColor->red > 255) |
| and (bitDepth == 8), for certain versions of libpng. */ |
| *theTranspColorp = SkPackARGB32(0xFF, |
| 0xFF & (transpColor->red), |
| 0xFF & (transpColor->green), |
| 0xFF & (transpColor->blue)); |
| } |
| } else { // gray |
| if (16 == bitDepth) { |
| *theTranspColorp = SkPackARGB32(0xFF, transpColor->gray >> 8, |
| transpColor->gray >> 8, |
| transpColor->gray >> 8); |
| } else { |
| /* We apply the mask because in a very small |
| number of corrupt PNGs, (transpColor->red > |
| 255) and (bitDepth == 8), for certain versions |
| of libpng. For safety we assume the same could |
| happen with a grayscale PNG. */ |
| *theTranspColorp = SkPackARGB32(0xFF, |
| 0xFF & (transpColor->gray), |
| 0xFF & (transpColor->gray), |
| 0xFF & (transpColor->gray)); |
| } |
| } |
| } |
| |
| if (valid || |
| PNG_COLOR_TYPE_RGB_ALPHA == colorType || |
| PNG_COLOR_TYPE_GRAY_ALPHA == colorType) { |
| *hasAlphap = true; |
| } |
| |
| SrcDepth srcDepth = k32Bit_SrcDepth; |
| if (PNG_COLOR_TYPE_GRAY == colorType) { |
| srcDepth = k8BitGray_SrcDepth; |
| // Remove this assert, which fails on desk_pokemonwiki.skp |
| //SkASSERT(!*hasAlphap); |
| } |
| |
| *colorTypep = this->getPrefColorType(srcDepth, *hasAlphap); |
| // now match the request against our capabilities |
| if (*hasAlphap) { |
| if (*colorTypep != kARGB_4444_SkColorType) { |
| *colorTypep = kN32_SkColorType; |
| } |
| } else { |
| if (kAlpha_8_SkColorType == *colorTypep) { |
| if (k8BitGray_SrcDepth != srcDepth) { |
| // Converting a non grayscale image to A8 is not currently supported. |
| *colorTypep = kN32_SkColorType; |
| } |
| } else if (*colorTypep != kRGB_565_SkColorType && |
| *colorTypep != kARGB_4444_SkColorType) { |
| *colorTypep = kN32_SkColorType; |
| } |
| } |
| } |
| |
| // 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 false; |
| } |
| } |
| |
| // If the image has alpha and the decoder wants unpremultiplied |
| // colors, the only supported colortype is 8888. |
| if (this->getRequireUnpremultipliedColors() && *hasAlphap) { |
| *colorTypep = kN32_SkColorType; |
| } |
| |
| if (fImageIndex != NULL) { |
| if (kUnknown_SkColorType == fImageIndex->fColorType) { |
| // This is the first time for this subset decode. From now on, |
| // all decodes must be in the same colortype. |
| fImageIndex->fColorType = *colorTypep; |
| } else if (fImageIndex->fColorType != *colorTypep) { |
| // Requesting a different colortype for a subsequent decode is not |
| // supported. Report failure before we make changes to png_ptr. |
| return false; |
| } |
| } |
| |
| bool convertGrayToRGB = PNG_COLOR_TYPE_GRAY == colorType && *colorTypep != 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. |
| if (colorType == PNG_COLOR_TYPE_RGB || convertGrayToRGB) { |
| png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| } |
| |
| return true; |
| } |
| |
| typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b); |
| |
| bool SkPNGImageDecoder::decodePalette(png_structp png_ptr, png_infop info_ptr, |
| bool *hasAlphap, bool *reallyHasAlphap, |
| SkColorTable **colorTablep) { |
| int numPalette; |
| png_colorp palette; |
| png_bytep trans; |
| int numTrans; |
| |
| png_get_PLTE(png_ptr, info_ptr, &palette, &numPalette); |
| |
| /* 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. |
| */ |
| int colorCount = numPalette + (numPalette < 256); |
| SkPMColor colorStorage[256]; // worst-case storage |
| SkPMColor* colorPtr = colorStorage; |
| |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| png_get_tRNS(png_ptr, info_ptr, &trans, &numTrans, NULL); |
| *hasAlphap = (numTrans > 0); |
| } 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 (this->getRequireUnpremultipliedColors()) { |
| proc = &SkPackARGB32NoCheck; |
| } else { |
| proc = &SkPreMultiplyARGB; |
| } |
| for (; index < numTrans; index++) { |
| transLessThanFF |= (int)*trans - 0xFF; |
| *colorPtr++ = proc(*trans++, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| bool reallyHasAlpha = (transLessThanFF < 0); |
| |
| 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]; |
| } |
| |
| *colorTablep = SkNEW_ARGS(SkColorTable, (colorStorage, colorCount)); |
| *reallyHasAlphap = reallyHasAlpha; |
| return true; |
| } |
| |
| #ifdef SK_BUILD_FOR_ANDROID |
| |
| bool SkPNGImageDecoder::onBuildTileIndex(SkStreamRewindable* sk_stream, int *width, int *height) { |
| png_structp png_ptr; |
| png_infop info_ptr; |
| |
| if (!onDecodeInit(sk_stream, &png_ptr, &info_ptr)) { |
| return false; |
| } |
| |
| if (setjmp(png_jmpbuf(png_ptr)) != 0) { |
| png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL); |
| return false; |
| } |
| |
| 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); |
| |
| *width = origWidth; |
| *height = origHeight; |
| |
| png_build_index(png_ptr); |
| |
| if (fImageIndex) { |
| SkDELETE(fImageIndex); |
| } |
| fImageIndex = SkNEW_ARGS(SkPNGImageIndex, (sk_stream, png_ptr, info_ptr)); |
| |
| return true; |
| } |
| |
| bool SkPNGImageDecoder::onDecodeSubset(SkBitmap* bm, const SkIRect& region) { |
| if (NULL == fImageIndex) { |
| return false; |
| } |
| |
| png_structp png_ptr = fImageIndex->fPng_ptr; |
| png_infop info_ptr = fImageIndex->fInfo_ptr; |
| if (setjmp(png_jmpbuf(png_ptr))) { |
| return false; |
| } |
| |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, pngColorType, interlaceType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &pngColorType, &interlaceType, int_p_NULL, int_p_NULL); |
| |
| SkIRect rect = SkIRect::MakeWH(origWidth, origHeight); |
| |
| if (!rect.intersect(region)) { |
| // If the requested region is entirely outside the image, just |
| // returns false |
| return false; |
| } |
| |
| SkColorType colorType; |
| bool hasAlpha = false; |
| SkPMColor theTranspColor = 0; // 0 tells us not to try to match |
| |
| if (!this->getBitmapColorType(png_ptr, info_ptr, &colorType, &hasAlpha, &theTranspColor)) { |
| return false; |
| } |
| |
| const int sampleSize = this->getSampleSize(); |
| SkScaledBitmapSampler sampler(origWidth, rect.height(), sampleSize); |
| |
| SkBitmap decodedBitmap; |
| decodedBitmap.setInfo(SkImageInfo::Make(sampler.scaledWidth(), sampler.scaledHeight(), |
| colorType, kPremul_SkAlphaType)); |
| |
| // from here down we are concerned with colortables and pixels |
| |
| // we track if we actually see a non-opaque pixels, since sometimes a PNG sets its colortype |
| // to |= PNG_COLOR_MASK_ALPHA, but all of its pixels are in fact opaque. We care, since we |
| // draw lots faster if we can flag the bitmap has being opaque |
| bool reallyHasAlpha = false; |
| SkColorTable* colorTable = NULL; |
| |
| if (pngColorType == PNG_COLOR_TYPE_PALETTE) { |
| decodePalette(png_ptr, info_ptr, &hasAlpha, &reallyHasAlpha, &colorTable); |
| } |
| |
| SkAutoUnref aur(colorTable); |
| |
| // Check ahead of time if the swap(dest, src) is possible. |
| // If yes, then we will stick to AllocPixelRef since it's cheaper with the swap happening. |
| // If no, then we will use alloc to allocate pixels to prevent garbage collection. |
| int w = rect.width() / sampleSize; |
| int h = rect.height() / sampleSize; |
| const bool swapOnly = (rect == region) && (w == decodedBitmap.width()) && |
| (h == decodedBitmap.height()) && bm->isNull(); |
| const bool needColorTable = kIndex_8_SkColorType == colorType; |
| if (swapOnly) { |
| if (!this->allocPixelRef(&decodedBitmap, needColorTable ? colorTable : NULL)) { |
| return false; |
| } |
| } else { |
| if (!decodedBitmap.tryAllocPixels(NULL, needColorTable ? colorTable : NULL)) { |
| return false; |
| } |
| } |
| SkAutoLockPixels alp(decodedBitmap); |
| |
| /* Turn on interlace handling. REQUIRED if you are not using |
| * png_read_image(). To see how to handle interlacing passes, |
| * see the png_read_row() method below: |
| */ |
| const int number_passes = (interlaceType != PNG_INTERLACE_NONE) ? |
| png_set_interlace_handling(png_ptr) : 1; |
| |
| /* Optional call to gamma correct and add the background to the palette |
| * and update info structure. REQUIRED if you are expecting libpng to |
| * update the palette for you (ie you selected such a transform above). |
| */ |
| |
| // Direct access to png_ptr fields is deprecated in libpng > 1.2. |
| #if defined(PNG_1_0_X) || defined (PNG_1_2_X) |
| png_ptr->pass = 0; |
| #else |
| // FIXME: This sets pass as desired, but also sets iwidth. Is that ok? |
| png_set_interlaced_pass(png_ptr, 0); |
| #endif |
| png_read_update_info(png_ptr, info_ptr); |
| |
| int actualTop = rect.fTop; |
| |
| if ((kAlpha_8_SkColorType == colorType || kIndex_8_SkColorType == colorType) |
| && 1 == sampleSize) { |
| if (kAlpha_8_SkColorType == colorType) { |
| // For an A8 bitmap, we assume there is an alpha for speed. It is |
| // possible the bitmap is opaque, but that is an unlikely use case |
| // since it would not be very interesting. |
| reallyHasAlpha = true; |
| // A8 is only allowed if the original was GRAY. |
| SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| } |
| |
| for (int i = 0; i < number_passes; i++) { |
| png_configure_decoder(png_ptr, &actualTop, i); |
| for (int j = 0; j < rect.fTop - actualTop; j++) { |
| uint8_t* bmRow = decodedBitmap.getAddr8(0, 0); |
| png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| } |
| png_uint_32 bitmapHeight = (png_uint_32) decodedBitmap.height(); |
| for (png_uint_32 y = 0; y < bitmapHeight; y++) { |
| uint8_t* bmRow = decodedBitmap.getAddr8(0, y); |
| png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| } |
| } |
| } else { |
| SkScaledBitmapSampler::SrcConfig sc; |
| int srcBytesPerPixel = 4; |
| |
| if (colorTable != NULL) { |
| sc = SkScaledBitmapSampler::kIndex; |
| srcBytesPerPixel = 1; |
| } else if (kAlpha_8_SkColorType == colorType) { |
| // A8 is only allowed if the original was GRAY. |
| SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType); |
| sc = SkScaledBitmapSampler::kGray; |
| srcBytesPerPixel = 1; |
| } else if (hasAlpha) { |
| sc = SkScaledBitmapSampler::kRGBA; |
| } else { |
| sc = SkScaledBitmapSampler::kRGBX; |
| } |
| |
| /* We have to pass the colortable explicitly, since we may have one |
| even if our decodedBitmap doesn't, due to the request that we |
| upscale png's palette to a direct model |
| */ |
| const SkPMColor* colors = colorTable ? colorTable->readColors() : NULL; |
| if (!sampler.begin(&decodedBitmap, sc, *this, colors)) { |
| return false; |
| } |
| const int height = decodedBitmap.height(); |
| |
| if (number_passes > 1) { |
| SkAutoMalloc storage(origWidth * origHeight * srcBytesPerPixel); |
| uint8_t* base = (uint8_t*)storage.get(); |
| size_t rb = origWidth * srcBytesPerPixel; |
| |
| for (int i = 0; i < number_passes; i++) { |
| png_configure_decoder(png_ptr, &actualTop, i); |
| for (int j = 0; j < rect.fTop - actualTop; j++) { |
| png_read_rows(png_ptr, &base, png_bytepp_NULL, 1); |
| } |
| uint8_t* row = base; |
| for (int32_t y = 0; y < rect.height(); y++) { |
| uint8_t* bmRow = row; |
| png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1); |
| row += rb; |
| } |
| } |
| // now sample it |
| base += sampler.srcY0() * rb; |
| for (int y = 0; y < height; y++) { |
| reallyHasAlpha |= sampler.next(base); |
| base += sampler.srcDY() * rb; |
| } |
| } else { |
| SkAutoMalloc storage(origWidth * srcBytesPerPixel); |
| uint8_t* srcRow = (uint8_t*)storage.get(); |
| |
| png_configure_decoder(png_ptr, &actualTop, 0); |
| skip_src_rows(png_ptr, srcRow, sampler.srcY0()); |
| |
| for (int i = 0; i < rect.fTop - actualTop; i++) { |
| png_read_rows(png_ptr, &srcRow, png_bytepp_NULL, 1); |
| } |
| for (int y = 0; y < height; y++) { |
| uint8_t* tmp = srcRow; |
| png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1); |
| reallyHasAlpha |= sampler.next(srcRow); |
| if (y < height - 1) { |
| skip_src_rows(png_ptr, srcRow, sampler.srcDY() - 1); |
| } |
| } |
| } |
| } |
| |
| if (0 != theTranspColor) { |
| reallyHasAlpha |= substituteTranspColor(&decodedBitmap, theTranspColor); |
| } |
| if (reallyHasAlpha && this->getRequireUnpremultipliedColors()) { |
| switch (decodedBitmap.colorType()) { |
| case kIndex_8_SkColorType: |
| // Fall through. |
| case kARGB_4444_SkColorType: |
| // We have chosen not to support unpremul for these colortypess. |
| return false; |
| default: { |
| // Fall through to finish the decode. This config either |
| // supports unpremul or it is irrelevant because it has no |
| // alpha (or only alpha). |
| // These brackets prevent a warning. |
| } |
| } |
| } |
| SkAlphaType alphaType = kOpaque_SkAlphaType; |
| if (reallyHasAlpha) { |
| if (this->getRequireUnpremultipliedColors()) { |
| alphaType = kUnpremul_SkAlphaType; |
| } else { |
| alphaType = kPremul_SkAlphaType; |
| } |
| } |
| decodedBitmap.setAlphaType(alphaType); |
| |
| if (swapOnly) { |
| bm->swap(decodedBitmap); |
| return true; |
| } |
| return this->cropBitmap(bm, &decodedBitmap, sampleSize, region.x(), region.y(), |
| region.width(), region.height(), 0, rect.y()); |
| } |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #include "SkColorPriv.h" |
| #include "SkUnPreMultiply.h" |
| |
| static void sk_write_fn(png_structp png_ptr, png_bytep data, png_size_t len) { |
| SkWStream* sk_stream = (SkWStream*)png_get_io_ptr(png_ptr); |
| if (!sk_stream->write(data, len)) { |
| png_error(png_ptr, "sk_write_fn Error!"); |
| } |
| } |
| |
| static transform_scanline_proc choose_proc(SkColorType ct, bool hasAlpha) { |
| // we don't care about search on alpha if we're kIndex8, since only the |
| // colortable packing cares about that distinction, not the pixels |
| if (kIndex_8_SkColorType == ct) { |
| hasAlpha = false; // we store false in the table entries for kIndex8 |
| } |
| |
| static const struct { |
| SkColorType fColorType; |
| bool fHasAlpha; |
| transform_scanline_proc fProc; |
| } gMap[] = { |
| { kRGB_565_SkColorType, false, transform_scanline_565 }, |
| { kN32_SkColorType, false, transform_scanline_888 }, |
| { kN32_SkColorType, true, transform_scanline_8888 }, |
| { kARGB_4444_SkColorType, false, transform_scanline_444 }, |
| { kARGB_4444_SkColorType, true, transform_scanline_4444 }, |
| { kIndex_8_SkColorType, false, transform_scanline_memcpy }, |
| }; |
| |
| for (int i = SK_ARRAY_COUNT(gMap) - 1; i >= 0; --i) { |
| if (gMap[i].fColorType == ct && gMap[i].fHasAlpha == hasAlpha) { |
| return gMap[i].fProc; |
| } |
| } |
| sk_throw(); |
| return NULL; |
| } |
| |
| // return the minimum legal bitdepth (by png standards) for this many colortable |
| // entries. SkBitmap always stores in 8bits per pixel, but for colorcount <= 16, |
| // we can use fewer bits per in png |
| static int computeBitDepth(int colorCount) { |
| #if 0 |
| int bits = SkNextLog2(colorCount); |
| SkASSERT(bits >= 1 && bits <= 8); |
| // now we need bits itself to be a power of 2 (e.g. 1, 2, 4, 8) |
| return SkNextPow2(bits); |
| #else |
| // for the moment, we don't know how to pack bitdepth < 8 |
| return 8; |
| #endif |
| } |
| |
| /* Pack palette[] with the corresponding colors, and if hasAlpha is true, also |
| pack trans[] and return the number of trans[] entries written. If hasAlpha |
| is false, the return value will always be 0. |
| |
| Note: this routine takes care of unpremultiplying the RGB values when we |
| have alpha in the colortable, since png doesn't support premul colors |
| */ |
| static inline int pack_palette(SkColorTable* ctable, |
| png_color* SK_RESTRICT palette, |
| png_byte* SK_RESTRICT trans, bool hasAlpha) { |
| const SkPMColor* SK_RESTRICT colors = ctable ? ctable->readColors() : NULL; |
| const int ctCount = ctable->count(); |
| int i, num_trans = 0; |
| |
| if (hasAlpha) { |
| /* first see if we have some number of fully opaque at the end of the |
| ctable. PNG allows num_trans < num_palette, but all of the trans |
| entries must come first in the palette. If I was smarter, I'd |
| reorder the indices and ctable so that all non-opaque colors came |
| first in the palette. But, since that would slow down the encode, |
| I'm leaving the indices and ctable order as is, and just looking |
| at the tail of the ctable for opaqueness. |
| */ |
| num_trans = ctCount; |
| for (i = ctCount - 1; i >= 0; --i) { |
| if (SkGetPackedA32(colors[i]) != 0xFF) { |
| break; |
| } |
| num_trans -= 1; |
| } |
| |
| const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| SkUnPreMultiply::GetScaleTable(); |
| |
| for (i = 0; i < num_trans; i++) { |
| const SkPMColor c = *colors++; |
| const unsigned a = SkGetPackedA32(c); |
| const SkUnPreMultiply::Scale s = table[a]; |
| trans[i] = a; |
| palette[i].red = SkUnPreMultiply::ApplyScale(s, SkGetPackedR32(c)); |
| palette[i].green = SkUnPreMultiply::ApplyScale(s,SkGetPackedG32(c)); |
| palette[i].blue = SkUnPreMultiply::ApplyScale(s, SkGetPackedB32(c)); |
| } |
| // now fall out of this if-block to use common code for the trailing |
| // opaque entries |
| } |
| |
| // these (remaining) entries are opaque |
| for (i = num_trans; i < ctCount; i++) { |
| SkPMColor c = *colors++; |
| palette[i].red = SkGetPackedR32(c); |
| palette[i].green = SkGetPackedG32(c); |
| palette[i].blue = SkGetPackedB32(c); |
| } |
| return num_trans; |
| } |
| |
| class SkPNGImageEncoder : public SkImageEncoder { |
| protected: |
| bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality) SK_OVERRIDE; |
| private: |
| bool doEncode(SkWStream* stream, const SkBitmap& bm, |
| const bool& hasAlpha, int colorType, |
| int bitDepth, SkColorType ct, |
| png_color_8& sig_bit); |
| |
| typedef SkImageEncoder INHERITED; |
| }; |
| |
| bool SkPNGImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bitmap, int /*quality*/) { |
| SkColorType ct = bitmap.colorType(); |
| |
| const bool hasAlpha = !bitmap.isOpaque(); |
| int colorType = PNG_COLOR_MASK_COLOR; |
| int bitDepth = 8; // default for color |
| png_color_8 sig_bit; |
| |
| switch (ct) { |
| case kIndex_8_SkColorType: |
| colorType |= PNG_COLOR_MASK_PALETTE; |
| // fall through to the ARGB_8888 case |
| case kN32_SkColorType: |
| sig_bit.red = 8; |
| sig_bit.green = 8; |
| sig_bit.blue = 8; |
| sig_bit.alpha = 8; |
| break; |
| case kARGB_4444_SkColorType: |
| sig_bit.red = 4; |
| sig_bit.green = 4; |
| sig_bit.blue = 4; |
| sig_bit.alpha = 4; |
| break; |
| case kRGB_565_SkColorType: |
| sig_bit.red = 5; |
| sig_bit.green = 6; |
| sig_bit.blue = 5; |
| sig_bit.alpha = 0; |
| break; |
| default: |
| return false; |
| } |
| |
| if (hasAlpha) { |
| // don't specify alpha if we're a palette, even if our ctable has alpha |
| if (!(colorType & PNG_COLOR_MASK_PALETTE)) { |
| colorType |= PNG_COLOR_MASK_ALPHA; |
| } |
| } else { |
| sig_bit.alpha = 0; |
| } |
| |
| SkAutoLockPixels alp(bitmap); |
| // readyToDraw checks for pixels (and colortable if that is required) |
| if (!bitmap.readyToDraw()) { |
| return false; |
| } |
| |
| // we must do this after we have locked the pixels |
| SkColorTable* ctable = bitmap.getColorTable(); |
| if (ctable) { |
| if (ctable->count() == 0) { |
| return false; |
| } |
| // check if we can store in fewer than 8 bits |
| bitDepth = computeBitDepth(ctable->count()); |
| } |
| |
| return doEncode(stream, bitmap, hasAlpha, colorType, bitDepth, ct, sig_bit); |
| } |
| |
| bool SkPNGImageEncoder::doEncode(SkWStream* stream, const SkBitmap& bitmap, |
| const bool& hasAlpha, int colorType, |
| int bitDepth, SkColorType ct, |
| png_color_8& sig_bit) { |
| |
| png_structp png_ptr; |
| png_infop info_ptr; |
| |
| png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, sk_error_fn, |
| NULL); |
| if (NULL == png_ptr) { |
| return false; |
| } |
| |
| info_ptr = png_create_info_struct(png_ptr); |
| if (NULL == info_ptr) { |
| png_destroy_write_struct(&png_ptr, png_infopp_NULL); |
| return false; |
| } |
| |
| /* Set error handling. REQUIRED if you aren't supplying your own |
| * error handling functions in the png_create_write_struct() call. |
| */ |
| if (setjmp(png_jmpbuf(png_ptr))) { |
| png_destroy_write_struct(&png_ptr, &info_ptr); |
| return false; |
| } |
| |
| png_set_write_fn(png_ptr, (void*)stream, sk_write_fn, png_flush_ptr_NULL); |
| |
| /* Set the image information here. Width and height are up to 2^31, |
| * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on |
| * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY, |
| * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB, |
| * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or |
| * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST |
| * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED |
| */ |
| |
| png_set_IHDR(png_ptr, info_ptr, bitmap.width(), bitmap.height(), |
| bitDepth, colorType, |
| PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, |
| PNG_FILTER_TYPE_BASE); |
| |
| // set our colortable/trans arrays if needed |
| png_color paletteColors[256]; |
| png_byte trans[256]; |
| if (kIndex_8_SkColorType == ct) { |
| SkColorTable* ct = bitmap.getColorTable(); |
| int numTrans = pack_palette(ct, paletteColors, trans, hasAlpha); |
| png_set_PLTE(png_ptr, info_ptr, paletteColors, ct->count()); |
| if (numTrans > 0) { |
| png_set_tRNS(png_ptr, info_ptr, trans, numTrans, NULL); |
| } |
| } |
| #ifdef PNG_sBIT_SUPPORTED |
| png_set_sBIT(png_ptr, info_ptr, &sig_bit); |
| #endif |
| png_write_info(png_ptr, info_ptr); |
| |
| const char* srcImage = (const char*)bitmap.getPixels(); |
| SkAutoSMalloc<1024> rowStorage(bitmap.width() << 2); |
| char* storage = (char*)rowStorage.get(); |
| transform_scanline_proc proc = choose_proc(ct, hasAlpha); |
| |
| for (int y = 0; y < bitmap.height(); y++) { |
| png_bytep row_ptr = (png_bytep)storage; |
| proc(srcImage, bitmap.width(), storage); |
| png_write_rows(png_ptr, &row_ptr, 1); |
| srcImage += bitmap.rowBytes(); |
| } |
| |
| png_write_end(png_ptr, info_ptr); |
| |
| /* clean up after the write, and free any memory allocated */ |
| png_destroy_write_struct(&png_ptr, &info_ptr); |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| DEFINE_DECODER_CREATOR(PNGImageDecoder); |
| DEFINE_ENCODER_CREATOR(PNGImageEncoder); |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static bool is_png(SkStreamRewindable* stream) { |
| char buf[PNG_BYTES_TO_CHECK]; |
| if (stream->read(buf, PNG_BYTES_TO_CHECK) == PNG_BYTES_TO_CHECK && |
| !png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) { |
| return true; |
| } |
| return false; |
| } |
| |
| SkImageDecoder* sk_libpng_dfactory(SkStreamRewindable* stream) { |
| if (is_png(stream)) { |
| return SkNEW(SkPNGImageDecoder); |
| } |
| return NULL; |
| } |
| |
| static SkImageDecoder::Format get_format_png(SkStreamRewindable* stream) { |
| if (is_png(stream)) { |
| return SkImageDecoder::kPNG_Format; |
| } |
| return SkImageDecoder::kUnknown_Format; |
| } |
| |
| SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) { |
| return (SkImageEncoder::kPNG_Type == t) ? SkNEW(SkPNGImageEncoder) : NULL; |
| } |
| |
| static SkImageDecoder_DecodeReg gDReg(sk_libpng_dfactory); |
| static SkImageDecoder_FormatReg gFormatReg(get_format_png); |
| static SkImageEncoder_EncodeReg gEReg(sk_libpng_efactory); |