| |
| /* |
| * 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 "SkScaledBitmapSampler.h" |
| #include "SkStream.h" |
| #include "SkTemplates.h" |
| #include "SkUtils.h" |
| |
| extern "C" { |
| #include "png.h" |
| } |
| |
| class SkPNGImageDecoder : public SkImageDecoder { |
| public: |
| virtual Format getFormat() const { |
| return kPNG_Format; |
| } |
| |
| protected: |
| virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode); |
| }; |
| |
| #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, 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!"); |
| } |
| } |
| |
| 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; |
| } |
| |
| static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| #if 0 |
| SkDebugf("------ png error %s\n", msg); |
| #endif |
| 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, NULL, 1); |
| } |
| } |
| |
| static bool pos_le(int value, int max) { |
| return value > 0 && value <= max; |
| } |
| |
| static bool substituteTranspColor(SkBitmap* bm, SkPMColor match) { |
| SkASSERT(bm->config() == SkBitmap::kARGB_8888_Config); |
| |
| 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(SkBitmap::Config dstConfig, |
| bool srcHasAlpha) { |
| switch (dstConfig) { |
| case SkBitmap::kARGB_8888_Config: |
| case SkBitmap::kARGB_4444_Config: |
| return true; |
| case SkBitmap::kRGB_565_Config: |
| // 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; |
| } |
| |
| bool SkPNGImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* decodedBitmap, |
| Mode mode) { |
| // SkAutoTrace apr("SkPNGImageDecoder::onDecode"); |
| |
| /* 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_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, |
| NULL, sk_error_fn, NULL); |
| // png_voidp user_error_ptr, user_error_fn, user_warning_fn); |
| if (png_ptr == NULL) { |
| return false; |
| } |
| |
| /* 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, NULL, NULL); |
| return false; |
| } |
| |
| PNGAutoClean autoClean(png_ptr, 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))) { |
| 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); |
| /* 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 */ ); |
| |
| // 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); |
| } |
| |
| /* 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 bit_depth, color_type, interlace_type; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bit_depth, &color_type, |
| &interlace_type, NULL, NULL); |
| |
| /* tell libpng to strip 16 bit/color files down to 8 bits/color */ |
| if (bit_depth == 16) { |
| png_set_strip_16(png_ptr); |
| } |
| /* 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 (bit_depth < 8) { |
| png_set_packing(png_ptr); |
| } |
| /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */ |
| if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { |
| png_set_expand_gray_1_2_4_to_8(png_ptr); |
| } |
| |
| /* Make a grayscale image into RGB. */ |
| if (color_type == PNG_COLOR_TYPE_GRAY || |
| color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { |
| png_set_gray_to_rgb(png_ptr); |
| } |
| |
| SkBitmap::Config config; |
| bool hasAlpha = false; |
| bool doDither = this->getDitherImage(); |
| SkPMColor theTranspColor = 0; // 0 tells us not to try to match |
| |
| // check for sBIT chunk data, in case we should disable dithering because |
| // our data is not truely 8bits per component |
| if (doDither) { |
| png_color_8p sig_bit = NULL; |
| bool has_sbit = PNG_INFO_sBIT == png_get_sBIT(png_ptr, info_ptr, |
| &sig_bit); |
| #if 0 |
| if (has_sbit) { |
| 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 (has_sbit && pos_le(sig_bit->red, SK_R16_BITS) && |
| pos_le(sig_bit->green, SK_G16_BITS) && |
| pos_le(sig_bit->blue, SK_B16_BITS)) { |
| doDither = false; |
| } |
| } |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) { |
| bool paletteHasAlpha = hasTransparencyInPalette(png_ptr, info_ptr); |
| config = this->getPrefConfig(kIndex_SrcDepth, paletteHasAlpha); |
| // now see if we can upscale to their requested config |
| if (!canUpscalePaletteToConfig(config, paletteHasAlpha)) { |
| config = SkBitmap::kIndex8_Config; |
| } |
| } 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 (color_type & PNG_COLOR_MASK_COLOR) { |
| if (16 == bit_depth) { |
| theTranspColor = SkPackARGB32(0xFF, transpColor->red >> 8, |
| transpColor->green >> 8, transpColor->blue >> 8); |
| } else { |
| theTranspColor = SkPackARGB32(0xFF, transpColor->red, |
| transpColor->green, transpColor->blue); |
| } |
| } else { // gray |
| if (16 == bit_depth) { |
| theTranspColor = SkPackARGB32(0xFF, transpColor->gray >> 8, |
| transpColor->gray >> 8, transpColor->gray >> 8); |
| } else { |
| theTranspColor = SkPackARGB32(0xFF, transpColor->gray, |
| transpColor->gray, transpColor->gray); |
| } |
| } |
| } |
| |
| if (valid || |
| PNG_COLOR_TYPE_RGB_ALPHA == color_type || |
| PNG_COLOR_TYPE_GRAY_ALPHA == color_type) { |
| hasAlpha = true; |
| } |
| config = this->getPrefConfig(k32Bit_SrcDepth, hasAlpha); |
| // now match the request against our capabilities |
| if (hasAlpha) { |
| if (config != SkBitmap::kARGB_4444_Config) { |
| config = SkBitmap::kARGB_8888_Config; |
| } |
| } else { |
| if (config != SkBitmap::kRGB_565_Config && |
| config != SkBitmap::kARGB_4444_Config) { |
| config = SkBitmap::kARGB_8888_Config; |
| } |
| } |
| } |
| |
| // sanity check for size |
| { |
| Sk64 size; |
| size.setMul(origWidth, origHeight); |
| if (size.isNeg() || !size.is32()) { |
| return false; |
| } |
| // now check that if we are 4-bytes per pixel, we also don't overflow |
| if (size.get32() > (0x7FFFFFFF >> 2)) { |
| return false; |
| } |
| } |
| |
| if (!this->chooseFromOneChoice(config, origWidth, origHeight)) { |
| return false; |
| } |
| |
| const int sampleSize = this->getSampleSize(); |
| SkScaledBitmapSampler sampler(origWidth, origHeight, sampleSize); |
| |
| decodedBitmap->setConfig(config, sampler.scaledWidth(), |
| sampler.scaledHeight(), 0); |
| if (SkImageDecoder::kDecodeBounds_Mode == mode) { |
| return true; |
| } |
| |
| // 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 (color_type == PNG_COLOR_TYPE_PALETTE) { |
| int num_palette; |
| png_colorp palette; |
| png_bytep trans; |
| int num_trans; |
| |
| png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette); |
| |
| /* 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 = num_palette + (num_palette < 256); |
| |
| colorTable = SkNEW_ARGS(SkColorTable, (colorCount)); |
| |
| SkPMColor* colorPtr = colorTable->lockColors(); |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, NULL); |
| hasAlpha = (num_trans > 0); |
| } else { |
| num_trans = 0; |
| colorTable->setFlags(colorTable->getFlags() | SkColorTable::kColorsAreOpaque_Flag); |
| } |
| // check for bad images that might make us crash |
| if (num_trans > num_palette) { |
| num_trans = num_palette; |
| } |
| |
| int index = 0; |
| int transLessThanFF = 0; |
| |
| for (; index < num_trans; index++) { |
| transLessThanFF |= (int)*trans - 0xFF; |
| *colorPtr++ = SkPreMultiplyARGB(*trans++, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| reallyHasAlpha |= (transLessThanFF < 0); |
| |
| for (; index < num_palette; index++) { |
| *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| |
| // see BUGGY IMAGE WORKAROUND comment above |
| if (num_palette < 256) { |
| *colorPtr = colorPtr[-1]; |
| } |
| colorTable->unlockColors(true); |
| } |
| |
| SkAutoUnref aur(colorTable); |
| |
| if (!this->allocPixelRef(decodedBitmap, |
| SkBitmap::kIndex8_Config == config ? |
| colorTable : NULL)) { |
| return false; |
| } |
| |
| SkAutoLockPixels alp(*decodedBitmap); |
| |
| /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ |
| // if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| // ; // png_set_swap_alpha(png_ptr); |
| |
| /* swap bytes of 16 bit files to least significant byte first */ |
| // png_set_swap(png_ptr); |
| |
| /* Add filler (or alpha) byte (before/after each RGB triplet) */ |
| if (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_GRAY) { |
| png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| } |
| |
| /* 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 = interlace_type != 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 (SkBitmap::kIndex8_Config == config && 1 == sampleSize) { |
| 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, NULL, 1); |
| } |
| } |
| } else { |
| SkScaledBitmapSampler::SrcConfig sc; |
| int srcBytesPerPixel = 4; |
| |
| if (colorTable != NULL) { |
| sc = SkScaledBitmapSampler::kIndex; |
| 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 |
| */ |
| SkAutoLockColors ctLock(colorTable); |
| if (!sampler.begin(decodedBitmap, sc, doDither, ctLock.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++) { |
| uint8_t* row = base; |
| for (png_uint_32 y = 0; y < origHeight; y++) { |
| uint8_t* bmRow = row; |
| png_read_rows(png_ptr, &bmRow, 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(); |
| 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, 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); |
| } |
| decodedBitmap->setIsOpaque(!reallyHasAlpha); |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #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!"); |
| } |
| } |
| |
| typedef void (*transform_scanline_proc)(const char* SK_RESTRICT src, |
| int width, char* SK_RESTRICT dst); |
| |
| static void transform_scanline_565(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| const uint16_t* SK_RESTRICT srcP = (const uint16_t*)src; |
| for (int i = 0; i < width; i++) { |
| unsigned c = *srcP++; |
| *dst++ = SkPacked16ToR32(c); |
| *dst++ = SkPacked16ToG32(c); |
| *dst++ = SkPacked16ToB32(c); |
| } |
| } |
| |
| static void transform_scanline_888(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; |
| for (int i = 0; i < width; i++) { |
| SkPMColor c = *srcP++; |
| *dst++ = SkGetPackedR32(c); |
| *dst++ = SkGetPackedG32(c); |
| *dst++ = SkGetPackedB32(c); |
| } |
| } |
| |
| static void transform_scanline_444(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; |
| for (int i = 0; i < width; i++) { |
| SkPMColor16 c = *srcP++; |
| *dst++ = SkPacked4444ToR32(c); |
| *dst++ = SkPacked4444ToG32(c); |
| *dst++ = SkPacked4444ToB32(c); |
| } |
| } |
| |
| static void transform_scanline_8888(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; |
| const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| SkUnPreMultiply::GetScaleTable(); |
| |
| for (int i = 0; i < width; i++) { |
| SkPMColor c = *srcP++; |
| unsigned a = SkGetPackedA32(c); |
| unsigned r = SkGetPackedR32(c); |
| unsigned g = SkGetPackedG32(c); |
| unsigned b = SkGetPackedB32(c); |
| |
| if (0 != a && 255 != a) { |
| SkUnPreMultiply::Scale scale = table[a]; |
| r = SkUnPreMultiply::ApplyScale(scale, r); |
| g = SkUnPreMultiply::ApplyScale(scale, g); |
| b = SkUnPreMultiply::ApplyScale(scale, b); |
| } |
| *dst++ = r; |
| *dst++ = g; |
| *dst++ = b; |
| *dst++ = a; |
| } |
| } |
| |
| static void transform_scanline_4444(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; |
| const SkUnPreMultiply::Scale* SK_RESTRICT table = |
| SkUnPreMultiply::GetScaleTable(); |
| |
| for (int i = 0; i < width; i++) { |
| SkPMColor16 c = *srcP++; |
| unsigned a = SkPacked4444ToA32(c); |
| unsigned r = SkPacked4444ToR32(c); |
| unsigned g = SkPacked4444ToG32(c); |
| unsigned b = SkPacked4444ToB32(c); |
| |
| if (0 != a && 255 != a) { |
| SkUnPreMultiply::Scale scale = table[a]; |
| r = SkUnPreMultiply::ApplyScale(scale, r); |
| g = SkUnPreMultiply::ApplyScale(scale, g); |
| b = SkUnPreMultiply::ApplyScale(scale, b); |
| } |
| *dst++ = r; |
| *dst++ = g; |
| *dst++ = b; |
| *dst++ = a; |
| } |
| } |
| |
| static void transform_scanline_index8(const char* SK_RESTRICT src, int width, |
| char* SK_RESTRICT dst) { |
| memcpy(dst, src, width); |
| } |
| |
| static transform_scanline_proc choose_proc(SkBitmap::Config config, |
| 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 (SkBitmap::kIndex8_Config == config) { |
| hasAlpha = false; // we store false in the table entries for kIndex8 |
| } |
| |
| static const struct { |
| SkBitmap::Config fConfig; |
| bool fHasAlpha; |
| transform_scanline_proc fProc; |
| } gMap[] = { |
| { SkBitmap::kRGB_565_Config, false, transform_scanline_565 }, |
| { SkBitmap::kARGB_8888_Config, false, transform_scanline_888 }, |
| { SkBitmap::kARGB_8888_Config, true, transform_scanline_8888 }, |
| { SkBitmap::kARGB_4444_Config, false, transform_scanline_444 }, |
| { SkBitmap::kARGB_4444_Config, true, transform_scanline_4444 }, |
| { SkBitmap::kIndex8_Config, false, transform_scanline_index8 }, |
| }; |
| |
| for (int i = SK_ARRAY_COUNT(gMap) - 1; i >= 0; --i) { |
| if (gMap[i].fConfig == config && 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) { |
| SkAutoLockColors alc(ctable); |
| const SkPMColor* SK_RESTRICT colors = alc.colors(); |
| 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: |
| virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality); |
| private: |
| bool doEncode(SkWStream* stream, const SkBitmap& bm, |
| const bool& hasAlpha, int colorType, |
| int bitDepth, SkBitmap::Config config, |
| png_color_8& sig_bit); |
| }; |
| |
| bool SkPNGImageEncoder::onEncode(SkWStream* stream, const SkBitmap& bitmap, |
| int /*quality*/) { |
| SkBitmap::Config config = bitmap.getConfig(); |
| |
| const bool hasAlpha = !bitmap.isOpaque(); |
| int colorType = PNG_COLOR_MASK_COLOR; |
| int bitDepth = 8; // default for color |
| png_color_8 sig_bit; |
| |
| switch (config) { |
| case SkBitmap::kIndex8_Config: |
| colorType |= PNG_COLOR_MASK_PALETTE; |
| // fall through to the ARGB_8888 case |
| case SkBitmap::kARGB_8888_Config: |
| sig_bit.red = 8; |
| sig_bit.green = 8; |
| sig_bit.blue = 8; |
| sig_bit.alpha = 8; |
| break; |
| case SkBitmap::kARGB_4444_Config: |
| sig_bit.red = 4; |
| sig_bit.green = 4; |
| sig_bit.blue = 4; |
| sig_bit.alpha = 4; |
| break; |
| case SkBitmap::kRGB_565_Config: |
| 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 (NULL != 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, config, sig_bit); |
| } |
| |
| bool SkPNGImageEncoder::doEncode(SkWStream* stream, const SkBitmap& bitmap, |
| const bool& hasAlpha, int colorType, |
| int bitDepth, SkBitmap::Config config, |
| 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, 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, 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 (SkBitmap::kIndex8_Config == config) { |
| 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); |
| } |
| } |
| |
| png_set_sBIT(png_ptr, info_ptr, &sig_bit); |
| 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(config, 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); |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #include "SkTRegistry.h" |
| |
| #ifdef SK_ENABLE_LIBPNG |
| SkImageDecoder* sk_libpng_dfactory(SkStream*); |
| SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type); |
| #endif |
| |
| SkImageDecoder* sk_libpng_dfactory(SkStream* 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 SkNEW(SkPNGImageDecoder); |
| } |
| return NULL; |
| } |
| |
| SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) { |
| return (SkImageEncoder::kPNG_Type == t) ? SkNEW(SkPNGImageEncoder) : NULL; |
| } |
| |
| static SkTRegistry<SkImageEncoder*, SkImageEncoder::Type> gEReg(sk_libpng_efactory); |
| static SkTRegistry<SkImageDecoder*, SkStream*> gDReg(sk_libpng_dfactory); |