bool SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
#ifdef TIME_DECODE
AutoTimeMillis atm("JPEG Decode");
#endif
SkAutoMalloc srcStorage;
JPEGAutoClean autoClean;
jpeg_decompress_struct cinfo;
skjpeg_error_mgr sk_err;
skjpeg_source_mgr sk_stream(stream, this, false);
cinfo.err = jpeg_std_error(&sk_err);
sk_err.error_exit = skjpeg_error_exit;
// All objects need to be instantiated before this setjmp call so that
// they will be cleaned up properly if an error occurs.
if (setjmp(sk_err.fJmpBuf)) {
return return_false(cinfo, *bm, "setjmp");
}
jpeg_create_decompress(&cinfo);
autoClean.set(&cinfo);
#ifdef SK_BUILD_FOR_ANDROID
overwrite_mem_buffer_size(&cinfo);
#endif
//jpeg_stdio_src(&cinfo, file);
cinfo.src = &sk_stream;
int status = jpeg_read_header(&cinfo, true);
if (status != JPEG_HEADER_OK) {
return return_false(cinfo, *bm, "read_header");
}
/* Try to fulfill the requested sampleSize. Since jpeg can do it (when it
can) much faster that we, just use their num/denom api to approximate
the size.
*/
int sampleSize = this->getSampleSize();
if (this->getPreferQualityOverSpeed()) {
cinfo.dct_method = JDCT_ISLOW;
} else {
cinfo.dct_method = JDCT_IFAST;
}
cinfo.scale_num = 1;
cinfo.scale_denom = sampleSize;
/* this gives about 30% performance improvement. In theory it may
reduce the visual quality, in practice I'm not seeing a difference
*/
cinfo.do_fancy_upsampling = 0;
/* this gives another few percents */
cinfo.do_block_smoothing = 0;
/* default format is RGB */
cinfo.out_color_space = JCS_RGB;
SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false);
// only these make sense for jpegs
if (config != SkBitmap::kARGB_8888_Config &&
config != SkBitmap::kARGB_4444_Config &&
config != SkBitmap::kRGB_565_Config) {
config = SkBitmap::kARGB_8888_Config;
}
#ifdef ANDROID_RGB
cinfo.dither_mode = JDITHER_NONE;
if (config == SkBitmap::kARGB_8888_Config) {
cinfo.out_color_space = JCS_RGBA_8888;
} else if (config == SkBitmap::kRGB_565_Config) {
cinfo.out_color_space = JCS_RGB_565;
if (this->getDitherImage()) {
cinfo.dither_mode = JDITHER_ORDERED;
}
}
#endif
if (sampleSize == 1 && mode == SkImageDecoder::kDecodeBounds_Mode) {
bm->setConfig(config, cinfo.image_width, cinfo.image_height);
bm->setIsOpaque(true);
return true;
}
/* image_width and image_height are the original dimensions, available
after jpeg_read_header(). To see the scaled dimensions, we have to call
jpeg_start_decompress(), and then read output_width and output_height.
*/
if (!jpeg_start_decompress(&cinfo)) {
/* If we failed here, we may still have enough information to return
to the caller if they just wanted (subsampled bounds). If sampleSize
was 1, then we would have already returned. Thus we just check if
we're in kDecodeBounds_Mode, and that we have valid output sizes.
One reason to fail here is that we have insufficient stream data
to complete the setup. However, output dimensions seem to get
computed very early, which is why this special check can pay off.
*/
if (SkImageDecoder::kDecodeBounds_Mode == mode &&
valid_output_dimensions(cinfo)) {
SkScaledBitmapSampler smpl(cinfo.output_width, cinfo.output_height,
recompute_sampleSize(sampleSize, cinfo));
bm->setConfig(config, smpl.scaledWidth(), smpl.scaledHeight());
bm->setIsOpaque(true);
return true;
} else {
return return_false(cinfo, *bm, "start_decompress");
}
}
sampleSize = recompute_sampleSize(sampleSize, cinfo);
// should we allow the Chooser (if present) to pick a config for us???
if (!this->chooseFromOneChoice(config, cinfo.output_width,
cinfo.output_height)) {
return return_false(cinfo, *bm, "chooseFromOneChoice");
}
#ifdef ANDROID_RGB
/* short-circuit the SkScaledBitmapSampler when possible, as this gives
a significant performance boost.
*/
if (sampleSize == 1 &&
((config == SkBitmap::kARGB_8888_Config &&
cinfo.out_color_space == JCS_RGBA_8888) ||
(config == SkBitmap::kRGB_565_Config &&
cinfo.out_color_space == JCS_RGB_565)))
{
bm->lockPixels();
JSAMPLE* rowptr = (JSAMPLE*)bm->getPixels();
bm->unlockPixels();
bool reuseBitmap = (rowptr != NULL);
if (reuseBitmap && ((int) cinfo.output_width != bm->width() ||
(int) cinfo.output_height != bm->height())) {
// Dimensions must match
return false;
}
if (!reuseBitmap) {
bm->setConfig(config, cinfo.output_width, cinfo.output_height);
bm->setIsOpaque(true);
if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
if (!this->allocPixelRef(bm, NULL)) {
return return_false(cinfo, *bm, "allocPixelRef");
}
} else if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
SkAutoLockPixels alp(*bm);
rowptr = (JSAMPLE*)bm->getPixels();
INT32 const bpr = bm->rowBytes();
while (cinfo.output_scanline < cinfo.output_height) {
int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
// if row_count == 0, then we didn't get a scanline, so abort.
// if we supported partial images, we might return true in this case
if (0 == row_count) {
return return_false(cinfo, *bm, "read_scanlines");
}
if (this->shouldCancelDecode()) {
return return_false(cinfo, *bm, "shouldCancelDecode");
}
rowptr += bpr;
}
if (reuseBitmap) {
bm->notifyPixelsChanged();
}
jpeg_finish_decompress(&cinfo);
return true;
}
#endif
// check for supported formats
SkScaledBitmapSampler::SrcConfig sc;
if (3 == cinfo.out_color_components && JCS_RGB == cinfo.out_color_space) {
sc = SkScaledBitmapSampler::kRGB;
#ifdef ANDROID_RGB
} else if (JCS_RGBA_8888 == cinfo.out_color_space) {
sc = SkScaledBitmapSampler::kRGBX;
} else if (JCS_RGB_565 == cinfo.out_color_space) {
sc = SkScaledBitmapSampler::kRGB_565;
#endif
} else if (1 == cinfo.out_color_components &&
JCS_GRAYSCALE == cinfo.out_color_space) {
sc = SkScaledBitmapSampler::kGray;
} else {
return return_false(cinfo, *bm, "jpeg colorspace");
}
SkScaledBitmapSampler sampler(cinfo.output_width, cinfo.output_height,
sampleSize);
bm->lockPixels();
JSAMPLE* rowptr = (JSAMPLE*)bm->getPixels();
bool reuseBitmap = (rowptr != NULL);
bm->unlockPixels();
if (reuseBitmap && (sampler.scaledWidth() != bm->width() ||
sampler.scaledHeight() != bm->height())) {
// Dimensions must match
return false;
}
if (!reuseBitmap) {
bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight());
// jpegs are always opaque (i.e. have no per-pixel alpha)
bm->setIsOpaque(true);
if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
if (!this->allocPixelRef(bm, NULL)) {
return return_false(cinfo, *bm, "allocPixelRef");
}
} else if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
SkAutoLockPixels alp(*bm);
if (!sampler.begin(bm, sc, this->getDitherImage())) {
return return_false(cinfo, *bm, "sampler.begin");
}
uint8_t* srcRow = (uint8_t*)srcStorage.reset(cinfo.output_width * 4);
// Possibly skip initial rows [sampler.srcY0]
if (!skip_src_rows(&cinfo, srcRow, sampler.srcY0())) {
return return_false(cinfo, *bm, "skip rows");
}
// now loop through scanlines until y == bm->height() - 1
for (int y = 0;; y++) {
JSAMPLE* rowptr = (JSAMPLE*)srcRow;
int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
if (0 == row_count) {
return return_false(cinfo, *bm, "read_scanlines");
}
if (this->shouldCancelDecode()) {
return return_false(cinfo, *bm, "shouldCancelDecode");
}
sampler.next(srcRow);
if (bm->height() - 1 == y) {
// we're done
break;
}
if (!skip_src_rows(&cinfo, srcRow, sampler.srcDY() - 1)) {
return return_false(cinfo, *bm, "skip rows");
}
}
// we formally skip the rest, so we don't get a complaint from libjpeg
if (!skip_src_rows(&cinfo, srcRow,
cinfo.output_height - cinfo.output_scanline)) {
return return_false(cinfo, *bm, "skip rows");
}
if (reuseBitmap) {
bm->notifyPixelsChanged();
}
jpeg_finish_decompress(&cinfo);
// SkDebugf("------------------- bm2 size %d [%d %d] %d\n", bm->getSize(), bm->width(), bm->height(), bm->config());
return true;
}
bool SkPNGImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* decodedBitmap,
SkBitmap::Config prefConfig, 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, png_infopp_NULL, png_infopp_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, int_p_NULL, int_p_NULL);
SkBitmap::Config config;
bool hasAlpha = false;
bool doDither = this->getDitherImage();
// check for sBIT chunk data, in case we should disable dithering because
// our data is not truely 8bits per component
if (doDither) {
#if 0
SkDebugf("----- sBIT %d %d %d %d\n", info_ptr->sig_bit.red,
info_ptr->sig_bit.green, info_ptr->sig_bit.blue,
info_ptr->sig_bit.alpha);
#endif
// 0 seems to indicate no information available
if (pos_le(info_ptr->sig_bit.red, SK_R16_BITS) &&
pos_le(info_ptr->sig_bit.green, SK_G16_BITS) &&
pos_le(info_ptr->sig_bit.blue, SK_B16_BITS)) {
doDither = false;
}
}
if (color_type == PNG_COLOR_TYPE_PALETTE) {
config = SkBitmap::kIndex8_Config; // defer sniffing for hasAlpha
} else {
png_color_16p transColor;
png_get_tRNS(png_ptr, info_ptr, NULL, NULL, &transColor);
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ||
PNG_COLOR_TYPE_RGB_ALPHA == color_type ||
PNG_COLOR_TYPE_GRAY_ALPHA == color_type) {
hasAlpha = true;
config = SkBitmap::kARGB_8888_Config;
} else { // we get to choose the config
config = prefConfig;
if (config == SkBitmap::kNo_Config) {
config = SkImageDecoder::GetDeviceConfig();
}
if (config != SkBitmap::kRGB_565_Config &&
config != SkBitmap::kARGB_4444_Config) {
config = SkBitmap::kARGB_8888_Config;
}
}
}
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
/* 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_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);
}
// 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, colorTable)) {
delete colorTable;
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, png_bytepp_NULL, 1);
}
}
} else {
SkScaledBitmapSampler::SrcConfig sc;
int srcBytesPerPixel = 4;
if (SkBitmap::kIndex8_Config == config) {
sc = SkScaledBitmapSampler::kIndex;
srcBytesPerPixel = 1;
} else if (hasAlpha) {
sc = SkScaledBitmapSampler::kRGBA;
} else {
sc = SkScaledBitmapSampler::kRGBX;
}
SkAutoMalloc storage(origWidth * srcBytesPerPixel);
const int height = decodedBitmap->height();
for (int i = 0; i < number_passes; i++) {
if (!sampler.begin(decodedBitmap, sc, doDither)) {
return false;
}
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);
}
if (hasAlpha && !reallyHasAlpha) {
SkDEBUGF(("Image doesn't really have alpha [%d %d]\n",
origWidth, origHeight));
}
}
/* read rest of file, and get additional chunks in info_ptr - REQUIRED */
png_read_end(png_ptr, info_ptr);
decodedBitmap->setIsOpaque(!reallyHasAlpha);
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;
}
bool SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap* bm,
SkBitmap::Config prefConfig, Mode mode) {
#ifdef TIME_DECODE
AutoTimeMillis atm("JPEG Decode");
#endif
SkAutoMalloc srcStorage;
JPEGAutoClean autoClean;
jpeg_decompress_struct cinfo;
sk_error_mgr sk_err;
sk_source_mgr sk_stream(stream);
cinfo.err = jpeg_std_error(&sk_err);
sk_err.error_exit = sk_error_exit;
// All objects need to be instantiated before this setjmp call so that
// they will be cleaned up properly if an error occurs.
if (setjmp(sk_err.fJmpBuf)) {
return false;
}
jpeg_create_decompress(&cinfo);
autoClean.set(&cinfo);
//jpeg_stdio_src(&cinfo, file);
cinfo.src = &sk_stream;
jpeg_read_header(&cinfo, true);
/* Try to fulfill the requested sampleSize. Since jpeg can do it (when it
can) much faster that we, just use their num/denom api to approximate
the size.
*/
int sampleSize = this->getSampleSize();
cinfo.dct_method = JDCT_IFAST;
cinfo.scale_num = 1;
cinfo.scale_denom = sampleSize;
/* image_width and image_height are the original dimensions, available
after jpeg_read_header(). To see the scaled dimensions, we have to call
jpeg_start_decompress(), and then read output_width and output_height.
*/
jpeg_start_decompress(&cinfo);
/* If we need to better match the request, we might examine the image and
output dimensions, and determine if the downsampling jpeg provided is
not sufficient. If so, we can recompute a modified sampleSize value to
make up the difference.
To skip this additional scaling, just set sampleSize = 1; below.
*/
sampleSize = sampleSize * cinfo.output_width / cinfo.image_width;
// check for supported formats
bool isRGB; // as opposed to gray8
if (3 == cinfo.num_components && JCS_RGB == cinfo.out_color_space) {
isRGB = true;
} else if (1 == cinfo.num_components &&
JCS_GRAYSCALE == cinfo.out_color_space) {
isRGB = false; // could use Index8 config if we want...
} else {
SkDEBUGF(("SkJPEGImageDecoder: unsupported jpeg colorspace %d with %d components\n",
cinfo.jpeg_color_space, cinfo.num_components));
return false;
}
SkBitmap::Config config = prefConfig;
// if no user preference, see what the device recommends
if (config == SkBitmap::kNo_Config)
config = SkImageDecoder::GetDeviceConfig();
// only these make sense for jpegs
if (config != SkBitmap::kARGB_8888_Config &&
config != SkBitmap::kARGB_4444_Config &&
config != SkBitmap::kRGB_565_Config) {
config = SkBitmap::kARGB_8888_Config;
}
// should we allow the Chooser (if present) to pick a config for us???
if (!this->chooseFromOneChoice(config, cinfo.output_width,
cinfo.output_height)) {
return false;
}
SkScaledBitmapSampler sampler(cinfo.output_width, cinfo.output_height,
sampleSize);
bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight());
// jpegs are always opauqe (i.e. have no per-pixel alpha)
bm->setIsOpaque(true);
if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return true;
}
if (!this->allocPixelRef(bm, NULL)) {
return false;
}
SkAutoLockPixels alp(*bm);
if (!sampler.begin(bm,
isRGB ? SkScaledBitmapSampler::kRGB :
SkScaledBitmapSampler::kGray,
this->getDitherImage())) {
return false;
}
uint8_t* srcRow = (uint8_t*)srcStorage.alloc(cinfo.output_width * 3);
skip_src_rows(&cinfo, srcRow, sampler.srcY0());
for (int y = 0;; y++) {
JSAMPLE* rowptr = (JSAMPLE*)srcRow;
int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
SkASSERT(row_count == 1);
sampler.next(srcRow);
if (bm->height() - 1 == y) {
break;
}
skip_src_rows(&cinfo, srcRow, sampler.srcDY() - 1);
}
// ??? If I don't do this, I get an error from finish_decompress
skip_src_rows(&cinfo, srcRow, cinfo.output_height - cinfo.output_scanline);
jpeg_finish_decompress(&cinfo);
return true;
}
