bool PNGInstallChunkHandler(png_structp png, void* context, ChunkHandler handler, const char* chunkName) {
if (setjmp(png_jmpbuf(png))) {
return false;
}
png_set_read_user_chunk_fn(png, context, handler);
png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS, (png_bytep) chunkName, 1);
return true;
}
// Reads the header and initializes the output fields, if not NULL.
//
// @param stream Input data. Will be read to get enough information to properly
// setup the codec.
// @param chunkReader SkPngChunkReader, for reading unknown chunks. May be NULL.
// If not NULL, png_ptr will hold an *unowned* pointer to it. The caller is
// expected to continue to own it for the lifetime of the png_ptr.
// @param outCodec Optional output variable. If non-NULL, will be set to a new
// SkPngCodec on success.
// @param png_ptrp Optional output variable. If non-NULL, will be set to a new
// png_structp on success.
// @param info_ptrp Optional output variable. If non-NULL, will be set to a new
// png_infop on success;
// @return true on success, in which case the caller is responsible for calling
// png_destroy_read_struct(png_ptrp, info_ptrp).
// If it returns false, the passed in fields (except stream) are unchanged.
static bool read_header(SkStream* stream, SkPngChunkReader* chunkReader, SkCodec** outCodec,
png_structp* png_ptrp, png_infop* info_ptrp) {
// The image is known to be a PNG. Decode enough to know the SkImageInfo.
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr,
sk_error_fn, sk_warning_fn);
if (!png_ptr) {
return false;
}
AutoCleanPng autoClean(png_ptr, stream, chunkReader, outCodec);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == nullptr) {
return false;
}
autoClean.setInfoPtr(info_ptr);
// FIXME: Could we use the return value of setjmp to specify the type of
// error?
if (setjmp(png_jmpbuf(png_ptr))) {
return false;
}
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
// Hookup our chunkReader so we can see any user-chunks the caller may be interested in.
// This needs to be installed before we read the png header. Android may store ninepatch
// chunks in the header.
if (chunkReader) {
png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0);
png_set_read_user_chunk_fn(png_ptr, (png_voidp) chunkReader, sk_read_user_chunk);
}
#endif
const bool decodedBounds = autoClean.decodeBounds();
if (!decodedBounds) {
return false;
}
// On success, decodeBounds releases ownership of png_ptr and info_ptr.
if (png_ptrp) {
*png_ptrp = png_ptr;
}
if (info_ptrp) {
*info_ptrp = info_ptr;
}
// decodeBounds takes care of setting outCodec
if (outCodec) {
SkASSERT(*outCodec);
}
return true;
}
int main(int argc, char *argv[]) {
FILE *fp;
const char *filename;
unsigned char header[8];
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
int result = 1;
if (argc != 2) {
fprintf(stderr, "Usage: %s <png>\n", argv[0]);
return -1;
}
filename = argv[1];
fp = fopen(filename, "rb");
if (!fp) {
perror(filename);
return -1;
}
if (fread(header, 8, 1, fp) != 1)
FAIL("%s: Couldn't read header.", filename);
if (png_sig_cmp(header, 0, 8))
FAIL("%s: Not a PNG.", filename);
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (!png_ptr)
FAIL("Couldn't set up PNG reader.");
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
FAIL("Couldn't set up PNG info reader.");
if (setjmp(png_jmpbuf(png_ptr)))
goto done;
png_init_io(png_ptr, fp);
png_set_sig_bytes(png_ptr, 8);
png_set_read_user_chunk_fn(png_ptr, NULL, &read_chunk);
png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER, NULL, 0);
png_read_info(png_ptr, info_ptr);
puts(apng ? "APNG" : "PNG");
result = 0;
done:
if (png_ptr)
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
fclose(fp);
return result;
}
/* Test one file */
int
test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
{
static png_FILE_p fpin;
static png_FILE_p fpout; /* "static" prevents setjmp corruption */
png_structp read_ptr;
png_infop read_info_ptr, end_info_ptr;
#ifdef PNG_WRITE_SUPPORTED
png_structp write_ptr;
png_infop write_info_ptr;
png_infop write_end_info_ptr;
#else
png_structp write_ptr = NULL;
png_infop write_info_ptr = NULL;
png_infop write_end_info_ptr = NULL;
#endif
png_bytep row_buf;
png_uint_32 y;
png_uint_32 width, height;
int num_pass, pass;
int bit_depth, color_type;
#ifdef PNG_SETJMP_SUPPORTED
#ifdef USE_FAR_KEYWORD
jmp_buf jmpbuf;
#endif
#endif
#if defined(_WIN32_WCE)
TCHAR path[MAX_PATH];
#endif
char inbuf[256], outbuf[256];
row_buf = NULL;
#if defined(_WIN32_WCE)
MultiByteToWideChar(CP_ACP, 0, inname, -1, path, MAX_PATH);
if ((fpin = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL)) == INVALID_HANDLE_VALUE)
#else
if ((fpin = fopen(inname, "rb")) == NULL)
#endif
{
fprintf(STDERR, "Could not find input file %s\n", inname);
return (1);
}
#if defined(_WIN32_WCE)
MultiByteToWideChar(CP_ACP, 0, outname, -1, path, MAX_PATH);
if ((fpout = CreateFile(path, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL)) == INVALID_HANDLE_VALUE)
#else
if ((fpout = fopen(outname, "wb")) == NULL)
#endif
{
fprintf(STDERR, "Could not open output file %s\n", outname);
FCLOSE(fpin);
return (1);
}
png_debug(0, "Allocating read and write structures\n");
#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
read_ptr =
png_create_read_struct_2(PNG_LIBPNG_VER_STRING, png_voidp_NULL,
png_error_ptr_NULL, png_error_ptr_NULL, png_voidp_NULL,
(png_malloc_ptr)png_debug_malloc, (png_free_ptr)png_debug_free);
#else
read_ptr =
png_create_read_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL,
png_error_ptr_NULL, png_error_ptr_NULL);
#endif
#if defined(PNG_NO_STDIO)
png_set_error_fn(read_ptr, (png_voidp)inname, pngtest_error,
pngtest_warning);
#endif
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
user_chunk_data[0] = 0;
user_chunk_data[1] = 0;
user_chunk_data[2] = 0;
user_chunk_data[3] = 0;
png_set_read_user_chunk_fn(read_ptr, user_chunk_data,
read_user_chunk_callback);
#endif
#ifdef PNG_WRITE_SUPPORTED
#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
write_ptr =
png_create_write_struct_2(PNG_LIBPNG_VER_STRING, png_voidp_NULL,
png_error_ptr_NULL, png_error_ptr_NULL, png_voidp_NULL,
(png_malloc_ptr)png_debug_malloc, (png_free_ptr)png_debug_free);
#else
write_ptr =
png_create_write_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL,
png_error_ptr_NULL, png_error_ptr_NULL);
#endif
#if defined(PNG_NO_STDIO)
png_set_error_fn(write_ptr, (png_voidp)inname, pngtest_error,
pngtest_warning);
#endif
#endif
png_debug(0, "Allocating read_info, write_info and end_info structures\n");
read_info_ptr = png_create_info_struct(read_ptr);
end_info_ptr = png_create_info_struct(read_ptr);
#ifdef PNG_WRITE_SUPPORTED
write_info_ptr = png_create_info_struct(write_ptr);
write_end_info_ptr = png_create_info_struct(write_ptr);
#endif
#ifdef PNG_SETJMP_SUPPORTED
png_debug(0, "Setting jmpbuf for read struct\n");
#ifdef USE_FAR_KEYWORD
if (setjmp(jmpbuf))
#else
if (setjmp(png_jmpbuf(read_ptr)))
#endif
{
fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname);
png_free(read_ptr, row_buf);
row_buf = NULL;
png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
#ifdef PNG_WRITE_SUPPORTED
png_destroy_info_struct(write_ptr, &write_end_info_ptr);
png_destroy_write_struct(&write_ptr, &write_info_ptr);
#endif
FCLOSE(fpin);
FCLOSE(fpout);
return (1);
}
#ifdef USE_FAR_KEYWORD
png_memcpy(png_jmpbuf(read_ptr), jmpbuf, png_sizeof(jmp_buf));
#endif
#ifdef PNG_WRITE_SUPPORTED
png_debug(0, "Setting jmpbuf for write struct\n");
#ifdef USE_FAR_KEYWORD
if (setjmp(jmpbuf))
#else
if (setjmp(png_jmpbuf(write_ptr)))
#endif
{
fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname);
png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr);
png_destroy_info_struct(write_ptr, &write_end_info_ptr);
#ifdef PNG_WRITE_SUPPORTED
png_destroy_write_struct(&write_ptr, &write_info_ptr);
#endif
FCLOSE(fpin);
FCLOSE(fpout);
return (1);
}
#ifdef USE_FAR_KEYWORD
png_memcpy(png_jmpbuf(write_ptr), jmpbuf, png_sizeof(jmp_buf));
#endif
#endif
#endif
png_debug(0, "Initializing input and output streams\n");
#if !defined(PNG_NO_STDIO)
png_init_io(read_ptr, fpin);
# ifdef PNG_WRITE_SUPPORTED
png_init_io(write_ptr, fpout);
# endif
#else
png_set_read_fn(read_ptr, (png_voidp)fpin, pngtest_read_data);
# ifdef PNG_WRITE_SUPPORTED
png_set_write_fn(write_ptr, (png_voidp)fpout, pngtest_write_data,
# if defined(PNG_WRITE_FLUSH_SUPPORTED)
pngtest_flush);
# else
NULL);
# endif
# endif
#endif
if (status_dots_requested == 1)
{
#ifdef PNG_WRITE_SUPPORTED
png_set_write_status_fn(write_ptr, write_row_callback);
#endif
png_set_read_status_fn(read_ptr, read_row_callback);
}
else
{
#ifdef PNG_WRITE_SUPPORTED
png_set_write_status_fn(write_ptr, png_write_status_ptr_NULL);
#endif
png_set_read_status_fn(read_ptr, png_read_status_ptr_NULL);
}
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
{
int i;
for (i = 0; i<256; i++)
filters_used[i] = 0;
png_set_read_user_transform_fn(read_ptr, count_filters);
}
#endif
#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
zero_samples = 0;
png_set_write_user_transform_fn(write_ptr, count_zero_samples);
#endif
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
# ifndef PNG_HANDLE_CHUNK_ALWAYS
# define PNG_HANDLE_CHUNK_ALWAYS 3
# endif
png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS,
png_bytep_NULL, 0);
#endif
#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
# ifndef PNG_HANDLE_CHUNK_IF_SAFE
# define PNG_HANDLE_CHUNK_IF_SAFE 2
# endif
png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_IF_SAFE,
png_bytep_NULL, 0);
#endif
png_debug(0, "Reading info struct\n");
png_read_info(read_ptr, read_info_ptr);
png_debug(0, "Transferring info struct\n");
{
int interlace_type, compression_type, filter_type;
if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,
&color_type, &interlace_type, &compression_type, &filter_type))
{
png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
color_type, interlace_type, compression_type, filter_type);
#else
color_type, PNG_INTERLACE_NONE, compression_type, filter_type);
#endif
}
}
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_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;
}
*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))) {
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);
png_set_seek_fn(png_ptr, sk_seek_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);
/* 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);
}
return true;
}
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) {
// Reads the header and initializes the output fields, if not NULL.
//
// @param stream Input data. Will be read to get enough information to properly
// setup the codec.
// @param chunkReader SkPngChunkReader, for reading unknown chunks. May be NULL.
// If not NULL, png_ptr will hold an *unowned* pointer to it. The caller is
// expected to continue to own it for the lifetime of the png_ptr.
// @param outCodec Optional output variable. If non-NULL, will be set to a new
// SkPngCodec on success.
// @param png_ptrp Optional output variable. If non-NULL, will be set to a new
// png_structp on success.
// @param info_ptrp Optional output variable. If non-NULL, will be set to a new
// png_infop on success;
// @return true on success, in which case the caller is responsible for calling
// png_destroy_read_struct(png_ptrp, info_ptrp).
// If it returns false, the passed in fields (except stream) are unchanged.
static bool read_header(SkStream* stream, SkPngChunkReader* chunkReader, SkCodec** outCodec,
png_structp* png_ptrp, png_infop* info_ptrp) {
// The image is known to be a PNG. Decode enough to know the SkImageInfo.
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr,
sk_error_fn, sk_warning_fn);
if (!png_ptr) {
return false;
}
AutoCleanPng autoClean(png_ptr);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == nullptr) {
return false;
}
autoClean.setInfoPtr(info_ptr);
// FIXME: Could we use the return value of setjmp to specify the type of
// error?
if (setjmp(png_jmpbuf(png_ptr))) {
return false;
}
png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn);
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
// Hookup our chunkReader so we can see any user-chunks the caller may be interested in.
// This needs to be installed before we read the png header. Android may store ninepatch
// chunks in the header.
if (chunkReader) {
png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0);
png_set_read_user_chunk_fn(png_ptr, (png_voidp) chunkReader, 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, encodedColorType;
png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
&encodedColorType, nullptr, nullptr, nullptr);
// Tell libpng to strip 16 bit/color files down to 8 bits/color.
// TODO: Should we handle this in SkSwizzler? Could this also benefit
// RAW decodes?
if (bitDepth == 16) {
SkASSERT(PNG_COLOR_TYPE_PALETTE != encodedColorType);
png_set_strip_16(png_ptr);
}
// Now determine the default colorType and alphaType and set the required transforms.
// Often, we depend on SkSwizzler to perform any transforms that we need. However, we
// still depend on libpng for many of the rare and PNG-specific cases.
SkEncodedInfo::Color color;
SkEncodedInfo::Alpha alpha;
switch (encodedColorType) {
case PNG_COLOR_TYPE_PALETTE:
// 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) {
// TODO: Should we use SkSwizzler here?
png_set_packing(png_ptr);
}
color = SkEncodedInfo::kPalette_Color;
// Set the alpha depending on if a transparency chunk exists.
alpha = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ?
SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha;
break;
case PNG_COLOR_TYPE_RGB:
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
// Convert to RGBA if transparency chunk exists.
png_set_tRNS_to_alpha(png_ptr);
color = SkEncodedInfo::kRGBA_Color;
alpha = SkEncodedInfo::kBinary_Alpha;
} else {
color = SkEncodedInfo::kRGB_Color;
alpha = SkEncodedInfo::kOpaque_Alpha;
}
break;
case PNG_COLOR_TYPE_GRAY:
// Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel.
if (bitDepth < 8) {
// TODO: Should we use SkSwizzler here?
png_set_expand_gray_1_2_4_to_8(png_ptr);
}
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
png_set_tRNS_to_alpha(png_ptr);
color = SkEncodedInfo::kGrayAlpha_Color;
alpha = SkEncodedInfo::kBinary_Alpha;
} else {
color = SkEncodedInfo::kGray_Color;
alpha = SkEncodedInfo::kOpaque_Alpha;
}
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
color = SkEncodedInfo::kGrayAlpha_Color;
alpha = SkEncodedInfo::kUnpremul_Alpha;
break;
case PNG_COLOR_TYPE_RGBA:
color = SkEncodedInfo::kRGBA_Color;
alpha = SkEncodedInfo::kUnpremul_Alpha;
break;
default:
// All the color types have been covered above.
SkASSERT(false);
color = SkEncodedInfo::kRGBA_Color;
alpha = SkEncodedInfo::kUnpremul_Alpha;
}
int numberPasses = png_set_interlace_handling(png_ptr);
autoClean.release();
if (png_ptrp) {
*png_ptrp = png_ptr;
}
if (info_ptrp) {
*info_ptrp = info_ptr;
}
if (outCodec) {
sk_sp<SkColorSpace> colorSpace = read_color_space(png_ptr, info_ptr);
if (!colorSpace) {
// Treat unmarked pngs as sRGB.
colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
}
SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, 8);
if (1 == numberPasses) {
*outCodec = new SkPngScanlineDecoder(origWidth, origHeight, info, stream,
chunkReader, png_ptr, info_ptr, bitDepth, colorSpace);
} else {
*outCodec = new SkPngInterlacedScanlineDecoder(origWidth, origHeight, info, stream,
chunkReader, png_ptr, info_ptr, bitDepth, numberPasses, colorSpace);
}
}
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;
}
//---------------------------------------------------------------------------
void __fastcall TDeePNG::LoadFromStream(Classes::TStream * Stream)
{
// LoadFromStream
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
png_infop end_info = NULL;
png_bytep *row_pointers = NULL;
BYTE *image = NULL;
png_uint_32 i;
try
{
// create png_struct
png_ptr = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
(png_voidp)this, DeePNG_error, DeePNG_warning,
(png_voidp)this, DeePNG_malloc, DeePNG_free);
// set read_chunk_callback
png_set_read_user_chunk_fn(png_ptr,
reinterpret_cast<void*>(this),
PNG_read_chunk_callback);
png_set_keep_unknown_chunks(png_ptr, 2, NULL, 0);
// keep only if safe-to-copy chunks, for all unknown chunks
// create png_info
info_ptr = png_create_info_struct(png_ptr);
// create end_info
end_info = png_create_info_struct(png_ptr);
// set stream input functions
png_set_read_fn(png_ptr, (voidp)Stream, DeePNG_read_data);
// set read_row_callback
png_set_read_status_fn(png_ptr, DeePNG_read_row_callback);
// call png_read_info
png_read_info(png_ptr, info_ptr);
// retrieve IHDR
png_uint_32 width, height;
int bit_depth, color_type, interlace_type, compression_type, filter_type;
png_get_IHDR(png_ptr,info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, &compression_type, &filter_type);
// expand palletted image which has transparent color, to 32bpp
if (png_get_valid(png_ptr, info_ptr,PNG_INFO_tRNS))
{
png_set_expand(png_ptr);
color_type=PNG_COLOR_TYPE_RGB_ALPHA;
}
// analyse IHDR ( color_type )
switch(color_type)
{
case PNG_COLOR_TYPE_GRAY_ALPHA:
PixelFormat=pf32bit;
break;
case PNG_COLOR_TYPE_GRAY:
// w/b
SetGrayscalePalette(this,bit_depth);
break;
case PNG_COLOR_TYPE_PALETTE:
SetColorDepth(this,bit_depth);
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
PixelFormat=pf32bit;
break;
case PNG_COLOR_TYPE_RGB:
PixelFormat=pf24bit;
break;
default:
throw EDeePNG("EDeePNG : Non-supported color type.");
}
// retrieve offset information
png_int_32 offset_x, offset_y;
int offset_unit_type;
if(png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y, &offset_unit_type))
{
ofs_x = offset_x;
ofs_y = offset_y;
ofs_unit = offset_unit_type;
ofs_set = true;
}
else
{
ofs_set = false;
}
// check size
if(width>=65536 || height>=65536)
{
throw EDeePNG("EDeePNG : Too large image size.");
}
// retrieve palette
if(color_type == PNG_COLOR_TYPE_PALETTE)
{
int num_palette;
png_color *palette = NULL;
png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette);
int i;
#pragma pack(push, 1)
struct
{
WORD palVersion;
WORD palNumEntries;
PALETTEENTRY entry[256];
} pal;
#pragma pack(pop)
pal.palVersion = 0x300;
pal.palNumEntries = num_palette;
for(i = 0; i < num_palette; i++)
{
pal.entry[i].peRed = palette[i].red;
pal.entry[i].peGreen = palette[i].green;
pal.entry[i].peBlue = palette[i].blue;
pal.entry[i].peFlags = 0;
}
Palette = CreatePalette((const LOGPALETTE*)&pal);
}
// collapse 16bit precision data to 8bit
if(bit_depth == 16) png_set_strip_16(png_ptr);
// change color component order
if (color_type == PNG_COLOR_TYPE_RGB ||
color_type == PNG_COLOR_TYPE_RGB_ALPHA)
png_set_bgr(png_ptr);
// call png_read_update_info ...
png_read_update_info(png_ptr, info_ptr);
// set size
Width=width, Height=height;
// allocate memory for row_pointers
row_pointers = new png_bytep[height];
png_uint_32 rowbytes = png_get_rowbytes(png_ptr, info_ptr);
image = new BYTE[rowbytes*height];
for(i = 0;i < height; i++)
{
row_pointers[i] = image + i*rowbytes;
}
// load image
png_read_image(png_ptr, row_pointers);
// finish loading image
png_read_end(png_ptr, info_ptr);
// set image to ScanLines
BYTE *imageptr = image;
if(color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
// IA IA IA ....
for(i = 0; i < height; i++)
{
BYTE *scanptr = (BYTE*)ScanLine[i];
png_uint_32 j;
for(j = 0; j < width; j++)
{
BYTE i = *(imageptr++);
scanptr[0] = i;
scanptr[1] = i;
scanptr[2] = i;
scanptr[3] = *(imageptr++);
scanptr += 4;
}
}
}
else
{
// intact copy
for(i = 0; i < height; i++)
{
BYTE *scanptr = (BYTE*)ScanLine[i];
memcpy(scanptr, imageptr, rowbytes);
imageptr += rowbytes;
}
}
}
catch(...)
{
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
if(row_pointers) delete [] row_pointers;
if(image) delete [] image;
throw;
}
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
if(row_pointers) delete [] row_pointers;
if(image) delete [] image;
}
static uint8_t png_read( png_structp readPtr, png_image * image, uint32_t flags )
{
// png_set_error_fn( readPtr, NULL, png_user_error, NULL );
png_infop infoPtr = png_create_info_struct( readPtr );
if (!infoPtr)
{
pngio_error( "Couldn't initialize PNG info struct." );
png_destroy_read_struct( & readPtr, NULL, NULL );
return 0;
}
if (setjmp( png_jmpbuf( readPtr ) ))
{
pngio_error( "An error occured while reading the PNG file." );
png_destroy_read_struct( & readPtr, & infoPtr, NULL );
png_image_free( image );
return 0;
}
png_set_sig_bytes( readPtr, 8 );
#ifdef PNG_APPLE_MODE_SUPPORTED
if (png_get_apple_mode())
{
png_set_keep_unknown_chunks( readPtr, PNG_HANDLE_CHUNK_ALWAYS, NULL, 0 );
png_set_read_user_chunk_fn( readPtr, NULL, png_read_user_chunk );
}
#endif
png_read_info( readPtr, infoPtr );
png_uint_32 w = png_get_image_width( readPtr, infoPtr );
png_uint_32 h = png_get_image_height( readPtr, infoPtr );
png_uint_32 bitDepth = png_get_bit_depth( readPtr, infoPtr );
png_uint_32 channels = png_get_channels( readPtr, infoPtr );
png_uint_32 interlaceType = png_get_interlace_type( readPtr, infoPtr );
png_uint_32 colorType = png_get_color_type( readPtr, infoPtr );
switch (colorType)
{
case PNG_COLOR_TYPE_PALETTE:
png_set_palette_to_rgb( readPtr );
channels = 3;
break;
case PNG_COLOR_TYPE_GRAY:
if (bitDepth < 8)
{
png_set_expand_gray_1_2_4_to_8( readPtr );
bitDepth = 8;
}
png_set_gray_to_rgb( readPtr );
break;
}
if (png_get_valid( readPtr, infoPtr, PNG_INFO_tRNS ))
{
png_set_tRNS_to_alpha( readPtr );
channels += 1;
}
else if (!(colorType & PNG_COLOR_MASK_ALPHA))
{
png_set_add_alpha( readPtr, 0xff, PNG_FILLER_AFTER );
}
if (bitDepth == 16)
{
png_set_strip_16( readPtr );
}
#ifdef PNG_APPLE_MODE_SUPPORTED
if (png_get_apple_mode())
{
if (flags & PNG_IMAGE_PREMULTIPLY_ALPHA)
{
png_set_read_user_transform_fn( readPtr, png_read_swap_transform );
}
else
{
png_set_read_user_transform_fn( readPtr, png_read_swap_and_unpremultiply_transform );
}
png_set_user_transform_info( readPtr, NULL, bitDepth, channels );
png_read_update_info( readPtr, infoPtr );
}
else
#endif
{
if (flags & PNG_IMAGE_PREMULTIPLY_ALPHA)
{
png_set_read_user_transform_fn( readPtr, png_read_premultiply_transform );
}
}
png_image_alloc( image, w, h );
png_bytep p = image->data;
const size_t passCount = interlaceType == PNG_INTERLACE_NONE ? 1 : png_set_interlace_handling( readPtr );
const size_t bytesPerRow = w * 4;
if (flags & PNG_IMAGE_FLIP_VERTICAL)
{
for (size_t pass = 0; pass < passCount; pass++)
{
for (size_t i = 0; i < h; i++)
{
png_read_row( readPtr, p + (bytesPerRow * (h - i - 1)), NULL );
}
}
}
else
{
// png_bytep rp[h];
// for (size_t i = 0; i < h; i++)
// {
// rp[i] = p + (bytesPerRow * i);
// }
// png_read_image( readPtr, rp );
for (size_t pass = 0; pass < passCount; pass++)
{
for (size_t i = 0; i < h; i++)
{
png_read_row( readPtr, p + (bytesPerRow * i), NULL );
}
}
}
png_destroy_read_struct( & readPtr, & infoPtr, NULL );
return 1;
}
