📄 png.h
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png_uint_32 flush_rows; /* number of rows written since last flush */
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
int gamma_shift; /* number of "insignificant" bits 16-bit gamma */
#ifdef PNG_FLOATING_POINT_SUPPORTED
float gamma; /* file gamma value */
float screen_gamma; /* screen gamma value (display_exponent) */
#endif
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
png_bytep gamma_table; /* gamma table for 8-bit depth files */
png_bytep gamma_from_1; /* converts from 1.0 to screen */
png_bytep gamma_to_1; /* converts from file to 1.0 */
png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
#endif
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
png_color_8 sig_bit; /* significant bits in each available channel */
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
png_color_8 shift; /* shift for significant bit tranformation */
#endif
#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
|| defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
png_bytep trans; /* transparency values for paletted files */
png_color_16 trans_values; /* transparency values for non-paletted files */
#endif
png_read_status_ptr read_row_fn; /* called after each row is decoded */
png_write_status_ptr write_row_fn; /* called after each row is encoded */
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
png_progressive_info_ptr info_fn; /* called after header data fully read */
png_progressive_row_ptr row_fn; /* called after each prog. row is decoded */
png_progressive_end_ptr end_fn; /* called after image is complete */
png_bytep save_buffer_ptr; /* current location in save_buffer */
png_bytep save_buffer; /* buffer for previously read data */
png_bytep current_buffer_ptr; /* current location in current_buffer */
png_bytep current_buffer; /* buffer for recently used data */
png_uint_32 push_length; /* size of current input chunk */
png_uint_32 skip_length; /* bytes to skip in input data */
png_size_t save_buffer_size; /* amount of data now in save_buffer */
png_size_t save_buffer_max; /* total size of save_buffer */
png_size_t buffer_size; /* total amount of available input data */
png_size_t current_buffer_size; /* amount of data now in current_buffer */
int process_mode; /* what push library is currently doing */
int cur_palette; /* current push library palette index */
# if defined(PNG_TEXT_SUPPORTED)
png_size_t current_text_size; /* current size of text input data */
png_size_t current_text_left; /* how much text left to read in input */
png_charp current_text; /* current text chunk buffer */
png_charp current_text_ptr; /* current location in current_text */
# endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
/* for the Borland special 64K segment handler */
png_bytepp offset_table_ptr;
png_bytep offset_table;
png_uint_16 offset_table_number;
png_uint_16 offset_table_count;
png_uint_16 offset_table_count_free;
#endif
#if defined(PNG_READ_DITHER_SUPPORTED)
png_bytep palette_lookup; /* lookup table for dithering */
png_bytep dither_index; /* index translation for palette files */
#endif
#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
png_uint_16p hist; /* histogram */
#endif
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
png_byte heuristic_method; /* heuristic for row filter selection */
png_byte num_prev_filters; /* number of weights for previous rows */
png_bytep prev_filters; /* filter type(s) of previous row(s) */
png_uint_16p filter_weights; /* weight(s) for previous line(s) */
png_uint_16p inv_filter_weights; /* 1/weight(s) for previous line(s) */
png_uint_16p filter_costs; /* relative filter calculation cost */
png_uint_16p inv_filter_costs; /* 1/relative filter calculation cost */
#endif
#if defined(PNG_TIME_RFC1123_SUPPORTED)
png_charp time_buffer; /* String to hold RFC 1123 time text */
#endif
/* New members added in libpng-1.0.6 */
#ifdef PNG_FREE_ME_SUPPORTED
png_uint_32 free_me; /* flags items libpng is responsible for freeing */
#endif
#if defined(PNG_USER_CHUNKS_SUPPORTED)
png_voidp user_chunk_ptr;
png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
#endif
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
int num_chunk_list;
png_bytep chunk_list;
#endif
/* New members added in libpng-1.0.3 */
#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
png_byte rgb_to_gray_status;
/* These were changed from png_byte in libpng-1.0.6 */
png_uint_16 rgb_to_gray_red_coeff;
png_uint_16 rgb_to_gray_green_coeff;
png_uint_16 rgb_to_gray_blue_coeff;
#endif
/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
#if defined(PNG_MNG_FEATURES_SUPPORTED) || \
defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
/* changed from png_byte to png_uint_32 at version 1.2.0 */
#ifdef PNG_1_0_X
png_byte mng_features_permitted;
#else
png_uint_32 mng_features_permitted;
#endif /* PNG_1_0_X */
#endif
/* New member added in libpng-1.0.7 */
#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
png_fixed_point int_gamma;
#endif
/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
#if defined(PNG_MNG_FEATURES_SUPPORTED)
png_byte filter_type;
#endif
#if defined(PNG_1_0_X) || (defined(PNG_DEBUG) && defined(PNG_USE_PNGGCCRD))
/* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */
png_uint_32 row_buf_size;
#endif
/* New members added in libpng-1.2.0 */
#if !defined(PNG_1_0_X) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
png_byte mmx_bitdepth_threshold;
png_uint_32 mmx_rowbytes_threshold;
png_uint_32 asm_flags;
#endif
/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
#ifdef PNG_USER_MEM_SUPPORTED
png_voidp mem_ptr; /* user supplied struct for mem functions */
png_malloc_ptr malloc_fn; /* function for allocating memory */
png_free_ptr free_fn; /* function for freeing memory */
#endif
/* New member added in libpng-1.0.13 and 1.2.0 */
png_bytep big_row_buf; /* buffer to save current (unfiltered) row */
#if defined(PNG_READ_DITHER_SUPPORTED)
/* The following three members were added at version 1.0.14 and 1.2.4 */
png_bytep dither_sort; /* working sort array */
png_bytep index_to_palette; /* where the original index currently is */
/* in the palette */
png_bytep palette_to_index; /* which original index points to this */
/* palette color */
#endif
/* New members added in libpng-1.0.16 and 1.2.6 */
png_byte compression_type;
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
png_uint_32 user_width_max;
png_uint_32 user_height_max;
#endif
};
/* This triggers a compiler error in png.c, if png.c and png.h
* do not agree upon the version number.
*/
typedef png_structp version_1_2_8;
typedef png_struct FAR * FAR * png_structpp;
/* Here are the function definitions most commonly used. This is not
* the place to find out how to use libpng. See libpng.txt for the
* full explanation, see example.c for the summary. This just provides
* a simple one line description of the use of each function.
*/
/* Returns the version number of the library */
extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));
/* Tell lib we have already handled the first <num_bytes> magic bytes.
* Handling more than 8 bytes from the beginning of the file is an error.
*/
extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
int num_bytes));
/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
* PNG file. Returns zero if the supplied bytes match the 8-byte PNG
* signature, and non-zero otherwise. Having num_to_check == 0 or
* start > 7 will always fail (ie return non-zero).
*/
extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
png_size_t num_to_check));
/* Simple signature checking function. This is the same as calling
* png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
*/
extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num));
/* Allocate and initialize png_ptr struct for reading, and any other memory. */
extern PNG_EXPORT(png_structp,png_create_read_struct)
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn));
/* Allocate and initialize png_ptr struct for writing, and any other memory */
extern PNG_EXPORT(png_structp,png_create_write_struct)
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn));
#ifdef PNG_WRITE_SUPPORTED
extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
PNGARG((png_structp png_ptr));
#endif
#ifdef PNG_WRITE_SUPPORTED
extern PNG_EXPORT(void,png_set_compression_buffer_size)
PNGARG((png_structp png_ptr, png_uint_32 size));
#endif
/* Reset the compression stream */
extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));
/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
#ifdef PNG_USER_MEM_SUPPORTED
extern PNG_EXPORT(png_structp,png_create_read_struct_2)
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
png_malloc_ptr malloc_fn, png_free_ptr free_fn));
extern PNG_EXPORT(png_structp,png_create_write_struct_2)
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
png_malloc_ptr malloc_fn, png_free_ptr free_fn));
#endif
/* Write a PNG chunk - size, type, (optional) data, CRC. */
extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
png_bytep chunk_name, png_bytep data, png_size_t length));
/* Write the start of a PNG chunk - length and chunk name. */
extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
png_bytep chunk_name, png_uint_32 length));
/* Write the data of a PNG chunk started with png_write_chunk_start(). */
extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
png_bytep data, png_size_t length));
/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
/* Allocate and initialize the info structure */
extern PNG_EXPORT(png_infop,png_create_info_struct)
PNGARG((png_structp png_ptr));
/* Initialize the info structure (old interface - DEPRECATED) */
extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr));
#undef png_info_init
#define png_info_init(info_ptr) png_info_init_3(&info_ptr,\
png_sizeof(png_info));
extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
png_size_t png_info_struct_size));
/* Writes all the PNG information before the image. */
extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
png_infop info_ptr));
extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
png_infop info_ptr));
#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
/* read the information before the actual image data. */
extern PNG_EXPORT(void,png_read_info) PNGARG((png_struct
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