bool decode(const SharedBuffer& data, bool sizeOnly)
{
m_decodingSizeOnly = sizeOnly;
// We need to do the setjmp here. Otherwise bad things will happen.
if (setjmp(JMPBUF(m_png)))
return m_decoder->setFailed();
const char* segment;
while (unsigned segmentLength = data.getSomeData(segment, m_readOffset)) {
m_readOffset += segmentLength;
m_currentBufferSize = m_readOffset;
png_process_data(m_png, m_info, reinterpret_cast<png_bytep>(const_cast<char*>(segment)), segmentLength);
if (sizeOnly ? m_decoder->isDecodedSizeAvailable() : m_decoder->frameIsCompleteAtIndex(0))
return true;
}
return false;
}
bool decode(const SharedBuffer& data, bool sizeOnly)
{
m_decodingSizeOnly = sizeOnly;
PNGImageDecoder* decoder = static_cast<PNGImageDecoder*>(png_get_progressive_ptr(m_png));
// We need to do the setjmp here. Otherwise bad things will happen.
if (setjmp(JMPBUF(m_png)))
return decoder->setFailed();
const char* segment;
while (unsigned segmentLength = data.getSomeData(segment, m_readOffset)) {
m_readOffset += segmentLength;
m_currentBufferSize = m_readOffset;
png_process_data(m_png, m_info, reinterpret_cast<png_bytep>(const_cast<char*>(segment)), segmentLength);
// We explicitly specify the superclass isSizeAvailable() because we
// merely want to check if we've managed to set the size, not
// (recursively) trigger additional decoding if we haven't.
if (sizeOnly ? decoder->ImageDecoder::isSizeAvailable() : decoder->isComplete())
return true;
}
return false;
}
void PNGImageDecoder::rowAvailable(unsigned char* rowBuffer, unsigned rowIndex, int)
{
if (m_frameBufferCache.isEmpty())
return;
// Initialize the framebuffer if needed.
ImageFrame& buffer = m_frameBufferCache[0];
if (buffer.status() == ImageFrame::FrameEmpty) {
png_structp png = m_reader->pngPtr();
if (!buffer.setSize(size().width(), size().height())) {
longjmp(JMPBUF(png), 1);
return;
}
unsigned colorChannels = m_reader->hasAlpha() ? 4 : 3;
if (PNG_INTERLACE_ADAM7 == png_get_interlace_type(png, m_reader->infoPtr())) {
m_reader->createInterlaceBuffer(colorChannels * size().width() * size().height());
if (!m_reader->interlaceBuffer()) {
longjmp(JMPBUF(png), 1);
return;
}
}
#if USE(QCMSLIB)
if (m_reader->colorTransform()) {
m_reader->createRowBuffer(colorChannels * size().width());
if (!m_reader->rowBuffer()) {
longjmp(JMPBUF(png), 1);
return;
}
}
#endif
buffer.setStatus(ImageFrame::FramePartial);
buffer.setHasAlpha(false);
// For PNGs, the frame always fills the entire image.
buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
}
/* libpng comments (here to explain what follows).
*
* this function is called for every row in the image. If the
* image is interlacing, and you turned on the interlace handler,
* this function will be called for every row in every pass.
* Some of these rows will not be changed from the previous pass.
* When the row is not changed, the new_row variable will be NULL.
* The rows and passes are called in order, so you don't really
* need the row_num and pass, but I'm supplying them because it
* may make your life easier.
*/
// Nothing to do if the row is unchanged, or the row is outside
// the image bounds: libpng may send extra rows, ignore them to
// make our lives easier.
if (!rowBuffer)
return;
int y = rowIndex;
if (y < 0 || y >= size().height())
return;
/* libpng comments (continued).
*
* For the non-NULL rows of interlaced images, you must call
* png_progressive_combine_row() passing in the row and the
* old row. You can call this function for NULL rows (it will
* just return) and for non-interlaced images (it just does the
* memcpy for you) if it will make the code easier. Thus, you
* can just do this for all cases:
*
* png_progressive_combine_row(png_ptr, old_row, new_row);
*
* where old_row is what was displayed for previous rows. Note
* that the first pass (pass == 0 really) will completely cover
* the old row, so the rows do not have to be initialized. After
* the first pass (and only for interlaced images), you will have
* to pass the current row, and the function will combine the
* old row and the new row.
*/
bool hasAlpha = m_reader->hasAlpha();
png_bytep row = rowBuffer;
if (png_bytep interlaceBuffer = m_reader->interlaceBuffer()) {
unsigned colorChannels = hasAlpha ? 4 : 3;
row = interlaceBuffer + (rowIndex * colorChannels * size().width());
png_progressive_combine_row(m_reader->pngPtr(), row, rowBuffer);
}
#if USE(QCMSLIB)
if (qcms_transform* transform = m_reader->colorTransform()) {
qcms_transform_data(transform, row, m_reader->rowBuffer(), size().width());
row = m_reader->rowBuffer();
}
#endif
// Write the decoded row pixels to the frame buffer. The repetitive
// form of the row write loops is for speed.
ImageFrame::PixelData* address = buffer.getAddr(0, y);
unsigned alphaMask = 255;
int width = size().width();
png_bytep pixel = row;
if (hasAlpha) {
if (buffer.premultiplyAlpha()) {
for (int x = 0; x < width; ++x, pixel += 4) {
buffer.setRGBAPremultiply(address++, pixel[0], pixel[1], pixel[2], pixel[3]);
alphaMask &= pixel[3];
}
} else {
for (int x = 0; x < width; ++x, pixel += 4) {
buffer.setRGBARaw(address++, pixel[0], pixel[1], pixel[2], pixel[3]);
alphaMask &= pixel[3];
}
}
} else {
for (int x = 0; x < width; ++x, pixel += 3) {
buffer.setRGBARaw(address++, pixel[0], pixel[1], pixel[2], 255);
}
}
if (alphaMask != 255 && !buffer.hasAlpha())
buffer.setHasAlpha(true);
buffer.setPixelsChanged(true);
}
void PNGImageDecoder::headerAvailable()
{
png_structp png = m_reader->pngPtr();
png_infop info = m_reader->infoPtr();
png_uint_32 width = png_get_image_width(png, info);
png_uint_32 height = png_get_image_height(png, info);
// Protect against large PNGs. See http://bugzil.la/251381 for more details.
const unsigned long maxPNGSize = 1000000UL;
if (width > maxPNGSize || height > maxPNGSize) {
longjmp(JMPBUF(png), 1);
return;
}
// Set the image size now that the image header is available.
if (!setSize(width, height)) {
longjmp(JMPBUF(png), 1);
return;
}
int bitDepth, colorType, interlaceType, compressionType, filterType, channels;
png_get_IHDR(png, info, &width, &height, &bitDepth, &colorType, &interlaceType, &compressionType, &filterType);
// The options we set here match what Mozilla does.
// Expand to ensure we use 24-bit for RGB and 32-bit for RGBA.
if (colorType == PNG_COLOR_TYPE_PALETTE || (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8))
png_set_expand(png);
png_bytep trns = 0;
int trnsCount = 0;
if (png_get_valid(png, info, PNG_INFO_tRNS)) {
png_get_tRNS(png, info, &trns, &trnsCount, 0);
png_set_expand(png);
}
if (bitDepth == 16)
png_set_strip_16(png);
if (colorType == PNG_COLOR_TYPE_GRAY || colorType == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png);
#if USE(QCMSLIB)
if ((colorType & PNG_COLOR_MASK_COLOR) && !m_ignoreGammaAndColorProfile) {
// We only support color profiles for color PALETTE and RGB[A] PNG. Supporting
// color profiles for gray-scale images is slightly tricky, at least using the
// CoreGraphics ICC library, because we expand gray-scale images to RGB but we
// do not similarly transform the color profile. We'd either need to transform
// the color profile or we'd need to decode into a gray-scale image buffer and
// hand that to CoreGraphics.
bool sRGB = false;
ColorProfile colorProfile;
getColorProfile(png, info, colorProfile, sRGB);
bool imageHasAlpha = (colorType & PNG_COLOR_MASK_ALPHA) || trnsCount;
m_reader->createColorTransform(colorProfile, imageHasAlpha, sRGB);
m_hasColorProfile = !!m_reader->colorTransform();
}
#endif
if (!m_hasColorProfile) {
// Deal with gamma and keep it under our control.
const double inverseGamma = 0.45455;
const double defaultGamma = 2.2;
double gamma;
if (!m_ignoreGammaAndColorProfile && png_get_gAMA(png, info, &gamma)) {
const double maxGamma = 21474.83;
if ((gamma <= 0.0) || (gamma > maxGamma)) {
gamma = inverseGamma;
png_set_gAMA(png, info, gamma);
}
png_set_gamma(png, defaultGamma, gamma);
} else {
png_set_gamma(png, defaultGamma, inverseGamma);
}
}
// Tell libpng to send us rows for interlaced pngs.
if (interlaceType == PNG_INTERLACE_ADAM7)
png_set_interlace_handling(png);
// Update our info now.
png_read_update_info(png, info);
channels = png_get_channels(png, info);
ASSERT(channels == 3 || channels == 4);
m_reader->setHasAlpha(channels == 4);
if (m_reader->decodingSizeOnly()) {
// If we only needed the size, halt the reader.
#if PNG_LIBPNG_VER_MAJOR > 1 || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 5)
// '0' argument to png_process_data_pause means: Do not cache unprocessed data.
m_reader->setReadOffset(m_reader->currentBufferSize() - png_process_data_pause(png, 0));
#else
m_reader->setReadOffset(m_reader->currentBufferSize() - png->buffer_size);
png->buffer_size = 0;
#endif
}
}
// Called if the decoding of the image fails.
static void PNGAPI decodingFailed(png_structp png, png_const_charp)
{
longjmp(JMPBUF(png), 1);
}
void PNGImageDecoder::rowAvailable(unsigned char* rowBuffer, unsigned rowIndex, int interlacePass)
{
if (m_frameBufferCache.isEmpty())
return;
// Initialize the framebuffer if needed.
ImageFrame& buffer = m_frameBufferCache[0];
if (buffer.status() == ImageFrame::FrameEmpty) {
if (!buffer.setSize(scaledSize().width(), scaledSize().height())) {
longjmp(JMPBUF(m_reader->pngPtr()), 1);
return;
}
buffer.setStatus(ImageFrame::FramePartial);
buffer.setHasAlpha(false);
buffer.setColorProfile(m_colorProfile);
// For PNGs, the frame always fills the entire image.
buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
if (png_get_interlace_type(m_reader->pngPtr(), m_reader->infoPtr()) != PNG_INTERLACE_NONE)
m_reader->createInterlaceBuffer((m_reader->hasAlpha() ? 4 : 3) * size().width() * size().height());
}
if (!rowBuffer)
return;
// libpng comments (pasted in here to explain what follows)
/*
* this function is called for every row in the image. If the
* image is interlacing, and you turned on the interlace handler,
* this function will be called for every row in every pass.
* Some of these rows will not be changed from the previous pass.
* When the row is not changed, the new_row variable will be NULL.
* The rows and passes are called in order, so you don't really
* need the row_num and pass, but I'm supplying them because it
* may make your life easier.
*
* For the non-NULL rows of interlaced images, you must call
* png_progressive_combine_row() passing in the row and the
* old row. You can call this function for NULL rows (it will
* just return) and for non-interlaced images (it just does the
* memcpy for you) if it will make the code easier. Thus, you
* can just do this for all cases:
*
* png_progressive_combine_row(png_ptr, old_row, new_row);
*
* where old_row is what was displayed for previous rows. Note
* that the first pass (pass == 0 really) will completely cover
* the old row, so the rows do not have to be initialized. After
* the first pass (and only for interlaced images), you will have
* to pass the current row, and the function will combine the
* old row and the new row.
*/
png_structp png = m_reader->pngPtr();
bool hasAlpha = m_reader->hasAlpha();
unsigned colorChannels = hasAlpha ? 4 : 3;
png_bytep row;
png_bytep interlaceBuffer = m_reader->interlaceBuffer();
if (interlaceBuffer) {
row = interlaceBuffer + (rowIndex * colorChannels * size().width());
png_progressive_combine_row(png, row, rowBuffer);
} else
row = rowBuffer;
// Copy the data into our buffer.
int width = scaledSize().width();
int destY = scaledY(rowIndex);
// Check that the row is within the image bounds. LibPNG may supply an extra row.
if (destY < 0 || destY >= scaledSize().height())
return;
bool nonTrivialAlpha = false;
for (int x = 0; x < width; ++x) {
png_bytep pixel = row + (m_scaled ? m_scaledColumns[x] : x) * colorChannels;
unsigned alpha = hasAlpha ? pixel[3] : 255;
buffer.setRGBA(x, destY, pixel[0], pixel[1], pixel[2], alpha);
nonTrivialAlpha |= alpha < 255;
}
if (nonTrivialAlpha && !buffer.hasAlpha())
buffer.setHasAlpha(nonTrivialAlpha);
}
void PNGImageDecoder::headerAvailable()
{
png_structp png = m_reader->pngPtr();
png_infop info = m_reader->infoPtr();
png_uint_32 width = png_get_image_width(png, info);
png_uint_32 height = png_get_image_height(png, info);
// Protect against large images.
if (width > cMaxPNGSize || height > cMaxPNGSize) {
longjmp(JMPBUF(png), 1);
return;
}
// We can fill in the size now that the header is available. Avoid memory
// corruption issues by neutering setFailed() during this call; if we don't
// do this, failures will cause |m_reader| to be deleted, and our jmpbuf
// will cease to exist. Note that we'll still properly set the failure flag
// in this case as soon as we longjmp().
m_doNothingOnFailure = true;
bool result = setSize(width, height);
m_doNothingOnFailure = false;
if (!result) {
longjmp(JMPBUF(png), 1);
return;
}
int bitDepth, colorType, interlaceType, compressionType, filterType, channels;
png_get_IHDR(png, info, &width, &height, &bitDepth, &colorType, &interlaceType, &compressionType, &filterType);
if ((colorType == PNG_COLOR_TYPE_RGB || colorType == PNG_COLOR_TYPE_RGB_ALPHA) && !m_ignoreGammaAndColorProfile) {
// We currently support color profiles only for RGB and RGBA PNGs. Supporting
// color profiles for gray-scale images is slightly tricky, at least using the
// CoreGraphics ICC library, because we expand gray-scale images to RGB but we
// don't similarly transform the color profile. We'd either need to transform
// the color profile or we'd need to decode into a gray-scale image buffer and
// hand that to CoreGraphics.
m_colorProfile = readColorProfile(png, info);
}
// The options we set here match what Mozilla does.
// Expand to ensure we use 24-bit for RGB and 32-bit for RGBA.
if (colorType == PNG_COLOR_TYPE_PALETTE || (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8))
png_set_expand(png);
png_bytep trns = 0;
int trnsCount = 0;
if (png_get_valid(png, info, PNG_INFO_tRNS)) {
png_get_tRNS(png, info, &trns, &trnsCount, 0);
png_set_expand(png);
}
if (bitDepth == 16)
png_set_strip_16(png);
if (colorType == PNG_COLOR_TYPE_GRAY || colorType == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png);
// Deal with gamma and keep it under our control.
double gamma;
if (!m_ignoreGammaAndColorProfile && png_get_gAMA(png, info, &gamma)) {
if ((gamma <= 0.0) || (gamma > cMaxGamma)) {
gamma = cInverseGamma;
png_set_gAMA(png, info, gamma);
}
png_set_gamma(png, cDefaultGamma, gamma);
} else
png_set_gamma(png, cDefaultGamma, cInverseGamma);
// Tell libpng to send us rows for interlaced pngs.
if (interlaceType == PNG_INTERLACE_ADAM7)
png_set_interlace_handling(png);
// Update our info now.
png_read_update_info(png, info);
channels = png_get_channels(png, info);
ASSERT(channels == 3 || channels == 4);
m_reader->setHasAlpha(channels == 4);
if (m_reader->decodingSizeOnly()) {
// If we only needed the size, halt the reader.
#if defined(PNG_LIBPNG_VER_MAJOR) && defined(PNG_LIBPNG_VER_MINOR) && (PNG_LIBPNG_VER_MAJOR > 1 || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 5))
// '0' argument to png_process_data_pause means: Do not cache unprocessed data.
m_reader->setReadOffset(m_reader->currentBufferSize() - png_process_data_pause(png, 0));
#else
m_reader->setReadOffset(m_reader->currentBufferSize() - png->buffer_size);
png->buffer_size = 0;
#endif
}
}
void PNGImageDecoder::headerAvailable()
{
png_structp png = m_reader->pngPtr();
png_infop info = m_reader->infoPtr();
png_uint_32 width = png->width;
png_uint_32 height = png->height;
// Protect against large images.
if (png->width > cMaxPNGSize || png->height > cMaxPNGSize) {
longjmp(JMPBUF(png), 1);
return;
}
// We can fill in the size now that the header is available. Avoid memory
// corruption issues by neutering setFailed() during this call; if we don't
// do this, failures will cause |m_reader| to be deleted, and our jmpbuf
// will cease to exist. Note that we'll still properly set the failure flag
// in this case as soon as we longjmp().
m_doNothingOnFailure = true;
bool result = setSize(width, height);
m_doNothingOnFailure = false;
if (!result) {
longjmp(JMPBUF(png), 1);
return;
}
int bitDepth, colorType, interlaceType, compressionType, filterType, channels;
png_get_IHDR(png, info, &width, &height, &bitDepth, &colorType, &interlaceType, &compressionType, &filterType);
// The options we set here match what Mozilla does.
// Expand to ensure we use 24-bit for RGB and 32-bit for RGBA.
if (colorType == PNG_COLOR_TYPE_PALETTE || (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8))
png_set_expand(png);
png_bytep trns = 0;
int trnsCount = 0;
if (png_get_valid(png, info, PNG_INFO_tRNS)) {
png_get_tRNS(png, info, &trns, &trnsCount, 0);
png_set_expand(png);
}
if (bitDepth == 16)
png_set_strip_16(png);
if (colorType == PNG_COLOR_TYPE_GRAY || colorType == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png);
// Deal with gamma and keep it under our control.
double gamma;
if (png_get_gAMA(png, info, &gamma)) {
if ((gamma <= 0.0) || (gamma > cMaxGamma)) {
gamma = cInverseGamma;
png_set_gAMA(png, info, gamma);
}
png_set_gamma(png, cDefaultGamma, gamma);
} else
png_set_gamma(png, cDefaultGamma, cInverseGamma);
// Tell libpng to send us rows for interlaced pngs.
if (interlaceType == PNG_INTERLACE_ADAM7)
png_set_interlace_handling(png);
// Update our info now.
png_read_update_info(png, info);
channels = png_get_channels(png, info);
ASSERT(channels == 3 || channels == 4);
m_reader->setHasAlpha(channels == 4);
if (m_reader->decodingSizeOnly()) {
// If we only needed the size, halt the reader.
m_reader->setReadOffset(m_reader->currentBufferSize() - png->buffer_size);
png->buffer_size = 0;
}
}