bool SkPNGImageDecoder::onBuildTileIndex(SkStream* sk_stream, int *width,
int *height) {
png_structp png_ptr;
png_infop info_ptr;
this->index = new SkPNGImageIndex();
if (onDecodeInit(sk_stream, &png_ptr, &info_ptr) == false) {
return false;
}
// 2013.02.07, jiseon.kwon, set error handling in onBuildTileIndex [START]
if (setjmp(png_jmpbuf(png_ptr))) {
return false;
}
// 2013.02.07, jiseon.kwon, set error handling in onBuildTileIndex [END]
int bit_depth, color_type, interlace_type;
png_uint_32 origWidth, origHeight;
png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bit_depth,
&color_type, &interlace_type, int_p_NULL, int_p_NULL);
*width = origWidth;
*height = origHeight;
png_build_index(png_ptr);
this->index->png_ptr = png_ptr;
this->index->info_ptr = info_ptr;
return true;
}
bool SkPNGImageDecoder::buildTileIndex(SkStream* sk_stream,
int *width, int *height, bool isShareable) {
png_structp png_ptr;
png_infop info_ptr;
this->index = new SkPNGImageIndex();
if (!isShareable) {
size_t len, inputLen = 0;
size_t bufferSize = 4096;
void *tmp = sk_malloc_throw(bufferSize);
while ((len = sk_stream->read((char*) tmp + inputLen,
bufferSize - inputLen)) != 0) {
inputLen += len;
if (inputLen == bufferSize) {
bufferSize *= 2;
tmp = sk_realloc_throw(tmp, bufferSize);
}
}
tmp = sk_realloc_throw(tmp, inputLen);
SkMemoryStream *mem_stream = new SkMemoryStream(tmp, inputLen, true);
this->index->inputStream = mem_stream;
sk_stream = mem_stream;
}
if (onDecodeInit(sk_stream, &png_ptr, &info_ptr) == false) {
return false;
}
int bit_depth, color_type, interlace_type;
png_uint_32 origWidth, origHeight;
png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bit_depth,
&color_type, &interlace_type, int_p_NULL, int_p_NULL);
*width = origWidth;
*height = origHeight;
png_build_index(png_ptr);
this->index->png_ptr = png_ptr;
this->index->info_ptr = info_ptr;
return true;
}
bool 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) == false) {
return false;
}
if (setjmp(png_jmpbuf(png_ptr))) {
return false;
}
PNGAutoClean autoClean(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, int_p_NULL, int_p_NULL);
SkBitmap::Config config;
bool hasAlpha = false;
bool doDither = this->getDitherImage();
SkPMColor theTranspColor = 0; // 0 tells us not to try to match
if (getBitmapConfig(png_ptr, info_ptr, &config, &hasAlpha,
&doDither, &theTranspColor) == false) {
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) {
decodePalette(png_ptr, info_ptr, &hasAlpha,
&reallyHasAlpha, &colorTable);
}
SkAutoUnref aur(colorTable);
if (!this->allocPixelRef(decodedBitmap,
SkBitmap::kIndex8_Config == config ?
colorTable : NULL)) {
return false;
}
SkAutoLockPixels alp(*decodedBitmap);
/* 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, png_bytepp_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, 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();
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);
}
decodedBitmap->setIsOpaque(!reallyHasAlpha);
return true;
}
