X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/0272a10d2e6d5323422c4c8600fe47ccac0df182..930d20e710c36fead7f8251e068d72769cfb74f8:/src/png/libpng.3 diff --git a/src/png/libpng.3 b/src/png/libpng.3 index 62501a0af5..a34aea5331 100644 --- a/src/png/libpng.3 +++ b/src/png/libpng.3 @@ -1,404 +1,779 @@ -.TH LIBPNG 3 "September 8, 2007" +.TH LIBPNG 3 "September 23, 2010" .SH NAME -libpng \- Portable Network Graphics (PNG) Reference Library 1.2.20 +libpng \- Portable Network Graphics (PNG) Reference Library 1.4.4 .SH SYNOPSIS -\fB -#include \fP +\fI\fB + +\fB#include \fP + +\fI\fB \fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP -\fBint png_check_sig (png_bytep \fP\fIsig\fP\fB, int \fInum\fP\fB);\fP +\fI\fB + +\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fI\fB + +\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fI\fB \fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP +\fI\fB + \fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP +\fI\fB + \fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP +\fI\fB + \fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP +\fI\fB + \fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP +\fI\fB + \fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP +\fI\fB + \fBpng_structp png_create_read_struct_2(png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP -\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP +\fI\fB -\fBpng_structp png_create_write_struct_2(png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP +\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP -\fBint png_debug(int \fP\fIlevel\fP\fB, png_const_charp \fImessage\fP\fB);\fP +\fI\fB -\fBint png_debug1(int \fP\fIlevel\fP\fB, png_const_charp \fP\fImessage\fP\fB, \fIp1\fP\fB);\fP +\fBpng_structp png_create_write_struct_2(png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP -\fBint png_debug2(int \fP\fIlevel\fP\fB, png_const_charp \fP\fImessage\fP\fB, \fP\fIp1\fP\fB, \fIp2\fP\fB);\fP +\fI\fB \fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP +\fI\fB + \fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP +\fI\fB + \fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_free_default(png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP +\fI\fB + \fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_bit_depth (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_channels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP +\fI\fB + +\fBpng_uint_32 png_get_chunk_cache_max (png_structp \fIpng_ptr\fP\fB);\fP + +\fI\fB + \fBpng_byte png_get_color_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + +\fBpng_uint_32 png_get_compression_buffer_size (png_structp \fIpng_ptr\fP\fB);\fP + +\fI\fB + \fBpng_byte png_get_compression_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_copyright (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_voidp png_get_error_ptr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_filter_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_header_ver (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_header_version (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_charpp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_image_height (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_image_width (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP -\fB#if !defined(PNG_1_0_X) png_int_32 png_get_int_32 (png_bytep buf); \fI#endif +\fI\fB + +\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP + +\fI\fB \fBpng_byte png_get_interlace_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_byte png_get_libpng_ver (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + +\fBpng_alloc_size_t png_get_chunk_malloc_max (png_structp \fIpng_ptr\fP\fB);\fP + +\fI\fB + \fBpng_voidp png_get_mem_ptr(png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP +\fI\fB + \fBfloat png_get_pixel_aspect_ratio (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_voidp png_get_progressive_ptr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP -\fBpng_byte png_get_rgb_to_gray_status (png_structp png_ptr) png_uint_32 png_get_rowbytes (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + +\fBpng_byte png_get_rgb_to_gray_status (png_structp \fIpng_ptr) + +\fBpng_uint_32 png_get_rowbytes (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fI\fB \fBpng_bytepp png_get_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP +\fI\fB + \fBpng_bytep png_get_signature (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fI*intent\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP -\fBpng_uint_32 png_get_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_values\fP\fB);\fP +\fI\fB + +\fBpng_uint_32 png_get_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP -\fB#if !defined(PNG_1_0_X) png_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP +\fI\fB + +\fB/* This function is really an inline macro. \fI*/ + +\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP + +\fI\fB \fBpng_uint_32 png_get_uint_31 (png_bytep \fIbuf\fP\fB);\fP -\fBpng_uint_32 png_get_uint_32 (png_bytep buf); \fI#endif +\fI\fB + +\fB/* This function is really an inline macro. \fI*/ + +\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP + +\fI\fB \fBpng_uint_32 png_get_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP +\fI\fB + \fBpng_voidp png_get_user_chunk_ptr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_user_height_max( png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_voidp png_get_user_transform_ptr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_user_width_max (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_valid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP +\fI\fB + \fBpng_int_32 png_get_x_offset_microns (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_int_32 png_get_x_offset_pixels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_x_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_int_32 png_get_y_offset_microns (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_int_32 png_get_y_offset_pixels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_get_y_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP -\fBpng_uint_32 png_get_compression_buffer_size (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB \fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP +\fI\fB + \fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP -\fBDEPRECATED: void png_info_init (png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB -\fBDEPRECATED: void png_info_init_2 (png_infopp \fP\fIptr_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP +\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP -\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP +\fI\fB -\fBpng_voidp png_malloc_default(png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP +\fBpng_voidp png_malloc_default(png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP + +\fI\fB \fBvoidp png_memcpy (png_voidp \fP\fIs1\fP\fB, png_voidp \fP\fIs2\fP\fB, png_size_t \fIsize\fP\fB);\fP -\fBpng_voidp png_memcpy_check (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIs1\fP\fB, png_voidp \fP\fIs2\fP\fB, png_uint_32 \fIsize\fP\fB);\fP +\fI\fB \fBvoidp png_memset (png_voidp \fP\fIs1\fP\fB, int \fP\fIvalue\fP\fB, png_size_t \fIsize\fP\fB);\fP -\fBpng_voidp png_memset_check (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIs1\fP\fB, int \fP\fIvalue\fP\fB, png_uint_32 \fIsize\fP\fB);\fP - -\fBDEPRECATED: void png_permit_empty_plte (png_structp \fP\fIpng_ptr\fP\fB, int \fIempty_plte_permitted\fP\fB);\fP +\fI\fB \fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP +\fI\fB + \fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP -\fBvoid png_read_destroy (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_infop \fIend_info_ptr\fP\fB);\fP +\fI\fB \fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP -\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP +\fI\fB -\fBDEPRECATED: void png_read_init (png_structp \fIpng_ptr\fP\fB);\fP +\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP -\fBDEPRECATED: void png_read_init_2 (png_structpp \fP\fIptr_ptr\fP\fB, png_const_charp \fP\fIuser_png_ver\fP\fB, png_size_t \fP\fIpng_struct_size\fP\fB, png_size_t \fIpng_info_size\fP\fB);\fP +\fI\fB \fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP +\fI\fB + \fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP +\fI\fB + \fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP +\fI\fB + \fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP -\fB#if !defined(PNG_1_0_X) png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP +\fI\fB + +\fBpng_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP + +\fI\fB \fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP +\fI\fB + \fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP -\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int flags); \fI#endif +\fI\fB + +\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP + +\fI\fB \fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP +\fI\fB + \fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP +\fI\fB + \fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP +\fI\fB + \fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP +\fI\fB + +\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP + +\fI\fB + \fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP +\fI\fB + \fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP +\fI\fB + \fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP +\fI\fB + \fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP +\fI\fB + \fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP +\fI\fB + \fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP -\fBvoid png_set_dither (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_dither\fP\fB);\fP +\fI\fB \fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_expand_gray_1_2_4_to_8(png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP +\fI\fB + \fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP +\fI\fB + \fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP +\fI\fB + \fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP +\fI\fB + \fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP +\fI\fB + \fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP +\fI\fB + \fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP +\fI\fB + \fBvoid png_set_gray_1_2_4_to_8(png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP +\fI\fB + \fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_charp \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP +\fI\fB + \fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP +\fI\fB + \fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP +\fI\fB + \fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP +\fI\fB + +\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP + +\fI\fB + +\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP + +\fI\fB + \fBvoid png_set_mem_fn(png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP +\fI\fB + \fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_palette_to_rgb(png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP +\fI\fB + \fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP +\fI\fB + \fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP +\fI\fB + +\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP + +\fI\fB + \fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP +\fI\fB + \fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_fixed_point \fP\fIred\fP\fB, png_fixed_point \fIgreen\fP\fB);\fP +\fI\fB + \fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP +\fI\fB + \fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP +\fI\fB + \fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP +\fI\fB + \fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP +\fI\fB + \fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP +\fI\fB + \fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP +\fI\fB + \fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIintent\fP\fB);\fP +\fI\fB + \fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIintent\fP\fB);\fP +\fI\fB + \fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP +\fI\fB + \fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP -\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_values\fP\fB);\fP +\fI\fB + +\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP + +\fI\fB \fBvoid png_set_tRNS_to_alpha(png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP +\fI\fB + \fBvoid png_set_unknown_chunk_location(png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP +\fI\fB + \fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP +\fI\fB + \fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP +\fI\fB + \fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP +\fI\fB + \fBvoid png_set_compression_buffer_size(png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP +\fI\fB + \fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP +\fI\fB + \fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP +\fI\fB + \fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP +\fI\fB + \fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP +\fI\fB + \fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP -\fBvoid png_write_destroy (png_structp \fIpng_ptr\fP\fB);\fP +\fI\fB \fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP -\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP +\fI\fB -\fBDEPRECATED: void png_write_init (png_structp \fIpng_ptr\fP\fB);\fP +\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP -\fBDEPRECATED: void png_write_init_2 (png_structpp \fP\fIptr_ptr\fP\fB, png_const_charp \fP\fIuser_png_ver\fP\fB, png_size_t \fP\fIpng_struct_size\fP\fB, png_size_t \fIpng_info_size\fP\fB);\fP +\fI\fB \fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP +\fI\fB + \fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP +\fI\fB + \fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP +\fI\fB + \fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP +\fI\fB + +\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP + +\fI\fB + \fBvoidpf png_zalloc (voidpf \fP\fIpng_ptr\fP\fB, uInt \fP\fIitems\fP\fB, uInt \fIsize\fP\fB);\fP +\fI\fB + \fBvoid png_zfree (voidpf \fP\fIpng_ptr\fP\fB, voidpf \fIptr\fP\fB);\fP +\fI\fB + .SH DESCRIPTION The .I libpng @@ -410,14 +785,20 @@ Following is a copy of the libpng.txt file that accompanies libpng. .SH LIBPNG.TXT libpng.txt - A description on how to use and modify libpng - libpng version 1.2.20 - September 8, 2007 + libpng version 1.4.4 - September 23, 2010 Updated and distributed by Glenn Randers-Pehrson - Copyright (c) 1998-2007 Glenn Randers-Pehrson - For conditions of distribution and use, see copyright - notice in png.h. + Copyright (c) 1998-2010 Glenn Randers-Pehrson + + This document is released under the libpng license. + For conditions of distribution and use, see the disclaimer + and license in png.h + + Based on: - based on: + libpng versions 0.97, January 1998, through 1.4.4 - September 23, 2010 + Updated and distributed by Glenn Randers-Pehrson + Copyright (c) 1998-2010 Glenn Randers-Pehrson libpng 1.0 beta 6 version 0.96 May 28, 1997 Updated and distributed by Andreas Dilger @@ -444,8 +825,8 @@ will need. We assume that libpng is already installed; see the INSTALL file for instructions on how to install libpng. For examples of libpng usage, see the files "example.c", "pngtest.c", -and the files in the "contrib" directory, all of which are included in the -libpng distribution. +and the files in the "contrib" directory, all of which are included in +the libpng distribution. Libpng was written as a companion to the PNG specification, as a way of reducing the amount of time and effort it takes to support the PNG @@ -457,12 +838,14 @@ a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at The W3C and ISO documents have identical technical content. The PNG-1.2 specification is available at - +. It is technically equivalent +to the PNG specification (second edition) but has some additional material. The PNG-1.0 specification is available as RFC 2083 and as a -W3C Recommendation . Some -additional chunks are described in the special-purpose public chunks +W3C Recommendation . + +Some additional chunks are described in the special-purpose public chunks documents at . Other information @@ -545,9 +928,10 @@ so if it doesn't work, you don't have much to undo. Of course, you will also want to insure that you are, in fact, dealing with a PNG file. Libpng provides a simple check to see if a file is a PNG file. To use it, pass in the first 1 to 8 bytes of the file to the function -png_sig_cmp(), and it will return 0 if the bytes match the corresponding -bytes of the PNG signature, or nonzero otherwise. Of course, the more bytes -you pass in, the greater the accuracy of the prediction. +png_sig_cmp(), and it will return 0 (false) if the bytes match the +corresponding bytes of the PNG signature, or nonzero (true) otherwise. +Of course, the more bytes you pass in, the greater the accuracy of the +prediction. If you are intending to keep the file pointer open for use in libpng, you must ensure you don't read more than 8 bytes from the beginning @@ -642,9 +1026,13 @@ free any memory. } If you would rather avoid the complexity of setjmp/longjmp issues, -you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case +you can compile libpng with PNG_NO_SETJMP, in which case errors will result in a call to PNG_ABORT() which defaults to abort(). +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + Now you need to set up the input code. The default for libpng is to use the C function fread(). If you use this, you will need to pass a valid FILE * in the function png_init_io(). Be sure that the file is @@ -661,6 +1049,15 @@ libpng know that there are some bytes missing from the start of the file. png_set_sig_bytes(png_ptr, number); +You can change the zlib compression buffer size to be used while +reading compressed data with + + png_set_compression_buffer_size(png_ptr, buffer_size); + +where the default size is 8192 bytes. Note that the buffer size +is changed immediately and the buffer is reallocated immediately, +instead of setting a flag to be acted upon later. + .SS Setting up callback code You can set up a callback function to handle any unknown chunks in the @@ -670,15 +1067,19 @@ input stream. You must supply the function png_unknown_chunkp chunk); { /* The unknown chunk structure contains your - chunk data: */ + chunk data, along with similar data for any other + unknown chunks: */ + png_byte name[5]; png_byte *data; png_size_t size; + /* Note that libpng has already taken care of the CRC handling */ - /* put your code here. Return one of the - following: */ + /* put your code here. Search for your chunk in the + unknown chunk structure, process it, and return one + of the following: */ return (-n); /* chunk had an error */ return (0); /* did not recognize */ @@ -698,6 +1099,11 @@ you can retrieve with png_get_user_chunk_ptr(png_ptr); +If you call the png_set_read_user_chunk_fn() function, then all unknown +chunks will be saved when read, in case your callback function will need +one or more of them. This behavior can be changed with the +png_set_keep_unknown_chunks() function, described below. + At this point, you can set up a callback function that will be called after each row has been read, which you can use to control a progress meter or the like. It's demonstrated in pngtest.c. @@ -715,40 +1121,19 @@ To inform libpng about your function, use png_set_read_status_fn(png_ptr, read_row_callback); -.SS Width and height limits - -The PNG specification allows the width and height of an image to be as -large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns. -Since very few applications really need to process such large images, -we have imposed an arbitrary 1-million limit on rows and columns. -Larger images will be rejected immediately with a png_error() call. If -you wish to override this limit, you can use - - png_set_user_limits(png_ptr, width_max, height_max); - -to set your own limits, or use width_max = height_max = 0x7fffffffL -to allow all valid dimensions (libpng may reject some very large images -anyway because of potential buffer overflow conditions). - -You should put this statement after you create the PNG structure and -before calling png_read_info(), png_read_png(), or png_process_data(). -If you need to retrieve the limits that are being applied, use - - width_max = png_get_user_width_max(png_ptr); - height_max = png_get_user_height_max(png_ptr); - .SS Unknown-chunk handling Now you get to set the way the library processes unknown chunks in the input PNG stream. Both known and unknown chunks will be read. Normal behavior is that known chunks will be parsed into information in -various info_ptr members; unknown chunks will be discarded. To change -this, you can call: +various info_ptr members while unknown chunks will be discarded. This +behavior can be wasteful if your application will never use some known +chunk types. To change this, you can call: png_set_keep_unknown_chunks(png_ptr, keep, chunk_list, num_chunks); - keep - 0: do not handle as unknown - 1: do not keep + keep - 0: default unknown chunk handling + 1: ignore; do not keep 2: keep only if safe-to-copy 3: keep even if unsafe-to-copy You can use these definitions: @@ -771,6 +1156,83 @@ instances of png_set_keep_unknown_chunks(), the final instance will take precedence. The IHDR and IEND chunks should not be named in chunk_list; if they are, libpng will process them normally anyway. +Here is an example of the usage of png_set_keep_unknown_chunks(), +where the private "vpAg" chunk will later be processed by a user chunk +callback function: + + png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'}; + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + png_byte unused_chunks[]= + { + 104, 73, 83, 84, (png_byte) '\0', /* hIST */ + 105, 84, 88, 116, (png_byte) '\0', /* iTXt */ + 112, 67, 65, 76, (png_byte) '\0', /* pCAL */ + 115, 67, 65, 76, (png_byte) '\0', /* sCAL */ + 115, 80, 76, 84, (png_byte) '\0', /* sPLT */ + 116, 73, 77, 69, (png_byte) '\0', /* tIME */ + }; + #endif + + ... + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + /* ignore all unknown chunks: */ + png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0); + /* except for vpAg: */ + png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1); + /* also ignore unused known chunks: */ + png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks, + (int)sizeof(unused_chunks)/5); + #endif + +.SS User limits + +The PNG specification allows the width and height of an image to be as +large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns. +Since very few applications really need to process such large images, +we have imposed an arbitrary 1-million limit on rows and columns. +Larger images will be rejected immediately with a png_error() call. If +you wish to override this limit, you can use + + png_set_user_limits(png_ptr, width_max, height_max); + +to set your own limits, or use width_max = height_max = 0x7fffffffL +to allow all valid dimensions (libpng may reject some very large images +anyway because of potential buffer overflow conditions). + +You should put this statement after you create the PNG structure and +before calling png_read_info(), png_read_png(), or png_process_data(). +If you need to retrieve the limits that are being applied, use + + width_max = png_get_user_width_max(png_ptr); + height_max = png_get_user_height_max(png_ptr); + +The PNG specification sets no limit on the number of ancillary chunks +allowed in a PNG datastream. You can impose a limit on the total number +of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with + + png_set_chunk_cache_max(png_ptr, user_chunk_cache_max); + +where 0x7fffffffL means unlimited. You can retrieve this limit with + + chunk_cache_max = png_get_chunk_cache_max(png_ptr); + +This limit also applies to the number of buffers that can be allocated +by png_decompress_chunk() while decompressing iTXt, zTXt, and iCCP chunks. + +You can also set a limit on the amount of memory that a compressed chunk +other than IDAT can occupy, with + + png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max); + +and you can retrieve the limit with + + chunk_malloc_max = png_get_chunk_malloc_max(png_ptr); + +Any chunks that would cause either of these limits to be exceeded will +be ignored. + .SS The high-level read interface At this point there are two ways to proceed; through the high-level @@ -798,14 +1260,16 @@ you want to do are limited to the following set: PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity to transparency PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples + PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples + to RGB (or GA to RGBA) (This excludes setting a background color, doing gamma transformation, -dithering, and setting filler.) If this is the case, simply do this: +quantizing, and setting filler.) If this is the case, simply do this: png_read_png(png_ptr, info_ptr, png_transforms, NULL) -where png_transforms is an integer containing the bitwise OR of -some set of transformation flags. This call is equivalent to png_read_info(), +where png_transforms is an integer containing the bitwise OR of some +set of transformation flags. This call is equivalent to png_read_info(), followed the set of transformations indicated by the transform mask, then png_read_image(), and finally png_read_end(). @@ -835,6 +1299,8 @@ row_pointers prior to calling png_read_png() with "Image is too wide to process in memory"); row_pointers = png_malloc(png_ptr, height*png_sizeof(png_bytep)); + for (int i=0; i) and png_get_(png_ptr, info_ptr, ...) functions return non-zero if the data has been read, or zero if it is missing. The parameters to the -png_get_ are set directly if they are simple data types, or a pointer -into the info_ptr is returned for any complex types. +png_get_ are set directly if they are simple data types, or a +pointer into the info_ptr is returned for any complex types. png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette); @@ -987,11 +1459,11 @@ into the info_ptr is returned for any complex types. whichever are appropriate for the given color type (png_color_16) - png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, - &trans_values); - trans - array of transparent entries for - palette (PNG_INFO_tRNS) - trans_values - graylevel or color sample values of + png_get_tRNS(png_ptr, info_ptr, &trans_alpha, + &num_trans, &trans_color); + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + trans_color - graylevel or color sample values of the single transparent color for non-paletted images (PNG_INFO_tRNS) num_trans - number of transparent entries @@ -1033,6 +1505,10 @@ into the info_ptr is returned for any complex types. string for unknown). text_ptr[i].lang_key - keyword in UTF-8 (empty string for unknown). + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist + when the library is built with iTXt chunk support. + num_text - number of comments (same as num_comments; you can put NULL here to avoid the duplication) @@ -1211,8 +1687,43 @@ things. As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was added. It expands the sample depth without changing tRNS to alpha. -At the same time, png_set_gray_1_2_4_to_8() was deprecated, and it -will be removed from a future version. + +As of libpng version 1.4.4, not all possible expansions are supported. + +In the following table, the 01 means grayscale with depth<8, 31 means +indexed with depth<8, other numerals represent the color type, "T" means +the tRNS chunk is present, A means an alpha channel is present, and O +means tRNS or alpha is present but all pixels in the image are opaque. + + FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O + TO + 01 - + 31 - + 0 1 - + 0T - + 0O - + 2 GX - + 2T - + 2O - + 3 1 - + 3T - + 3O - + 4A T - + 4O - + 6A GX TX TX - + 6O GX TX - + +Within the matrix, + "-" means the transformation is not supported. + "X" means the transformation is obtained by png_set_expand(). + "1" means the transformation is obtained by + png_set_expand_gray_1_2_4_to_8 + "G" means the transformation is obtained by + png_set_gray_to_rgb(). + "P" means the transformation is obtained by + png_set_expand_palette_to_rgb(). + "T" means the transformation is obtained by + png_set_tRNS_to_alpha(). PNG can have files with 16 bits per channel. If you only can handle 8 bits per channel, this will strip the pixels down to 8 bit. @@ -1247,10 +1758,10 @@ values of the pixels: PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels stored in a PNG image have been "scaled" or "shifted" up to the next -higher possible bit depth (e.g. from 5 bits/sample in the range [0,31] to -8 bits/sample in the range [0, 255]). However, it is also possible to -convert the PNG pixel data back to the original bit depth of the image. -This call reduces the pixels back down to the original bit depth: +higher possible bit depth (e.g. from 5 bits/sample in the range [0,31] +to 8 bits/sample in the range [0, 255]). However, it is also possible +to convert the PNG pixel data back to the original bit depth of the +image. This call reduces the pixels back down to the original bit depth: png_color_8p sig_bit; @@ -1438,7 +1949,7 @@ recommended that PNG viewers support gamma correction. png_set_gamma(png_ptr, screen_gamma, 0.45455); If you need to reduce an RGB file to a paletted file, or if a paletted -file has more entries then will fit on your screen, png_set_dither() +file has more entries then will fit on your screen, png_set_quantize() will do that. Note that this is a simple match dither that merely finds the closest color available. This should work fairly well with optimized palettes, and fairly badly with linear color cubes. If you @@ -1457,7 +1968,7 @@ histogram, it may not do as good a job. png_get_hIST(png_ptr, info_ptr, &histogram); - png_set_dither(png_ptr, palette, num_palette, + png_set_quantize(png_ptr, palette, num_palette, max_screen_colors, histogram, 1); } else @@ -1465,7 +1976,7 @@ histogram, it may not do as good a job. png_color std_color_cube[MAX_SCREEN_COLORS] = { ... colors ... }; - png_set_dither(png_ptr, std_color_cube, + png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS, MAX_SCREEN_COLORS, NULL,0); } @@ -1697,12 +2208,11 @@ point to libpng-allocated storage with the following function: This function may be safely called when the relevant storage has already been freed, or has not yet been allocated, or was allocated -by the user and not by libpng, and will in those -cases do nothing. The "seq" parameter is ignored if only one item -of the selected data type, such as PLTE, is allowed. If "seq" is not --1, and multiple items are allowed for the data type identified in -the mask, such as text or sPLT, only the n'th item in the structure -is freed, where n is "seq". +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not -1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". The default behavior is only to free data that was allocated internally by libpng. This can be changed, so that libpng will not free the data, @@ -1741,8 +2251,8 @@ if you transfer responsibility for free'ing text_ptr from libpng to your application, your application must not separately free those members. The png_free_data() function will turn off the "valid" flag for anything -it frees. If you need to turn the flag off for a chunk that was freed by your -application instead of by libpng, you can use +it frees. If you need to turn the flag off for a chunk that was freed by +your application instead of by libpng, you can use png_set_invalid(png_ptr, info_ptr, mask); mask - identifies the chunks to be made invalid, @@ -2001,9 +2511,13 @@ section below for more information on the libpng error handling. return; If you would rather avoid the complexity of setjmp/longjmp issues, -you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case +you can compile libpng with PNG_NO_SETJMP, in which case errors will result in a call to PNG_ABORT() which defaults to abort(). +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + Now you need to set up the output code. The default for libpng is to use the C function fwrite(). If you use this, you will need to pass a valid FILE * in the function png_init_io(). Be sure that the file is @@ -2052,8 +2566,8 @@ the filter method, for which the only valid values are 0 (as of the July 1999 PNG specification, version 1.2) or 64 (if you are writing a PNG datastream that is to be embedded in a MNG datastream). The third parameter is a flag that indicates which filter type(s) are to be tested -for each scanline. See the PNG specification for details on the specific filter -types. +for each scanline. See the PNG specification for details on the specific +filter types. /* turn on or off filtering, and/or choose @@ -2064,7 +2578,7 @@ types. PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE | PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB | PNG_FILTER_UP | PNG_FILTER_VALUE_UP | - PNG_FILTER_AVE | PNG_FILTER_VALUE_AVE | + PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG | PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH| PNG_ALL_FILTERS); @@ -2153,6 +2667,15 @@ Some of the more important parts of the png_info are: can also be PNG_INTRAPIXEL_DIFFERENCING) +If you call png_set_IHDR(), the call must appear before any of the +other png_set_*() functions, because they might require access to some of +the IHDR settings. The remaining png_set_*() functions can be called +in any order. + +If you wish, you can reset the compression_type, interlace_type, or +filter_method later by calling png_set_IHDR() again; if you do this, the +width, height, bit_depth, and color_type must be the same in each call. + png_set_PLTE(png_ptr, info_ptr, palette, num_palette); palette - the palette for the file @@ -2210,12 +2733,13 @@ Some of the more important parts of the png_info are: appropriate for the given color type (png_color_16) - png_set_tRNS(png_ptr, info_ptr, trans, num_trans, - trans_values); - trans - array of transparent entries for - palette (PNG_INFO_tRNS) - trans_values - graylevel or color sample values of - the single transparent color for + png_set_tRNS(png_ptr, info_ptr, trans_alpha, + num_trans, trans_color); + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + trans_color - graylevel or color sample values + (in order red, green, blue) of the + single transparent color for non-paletted images (PNG_INFO_tRNS) num_trans - number of transparent entries (PNG_INFO_tRNS) @@ -2252,6 +2776,10 @@ Some of the more important parts of the png_info are: empty for unknown). text_ptr[i].translated_keyword - keyword in UTF-8 (NULL or empty for unknown). + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist + when the library is built with iTXt chunk support. + num_text - number of comments png_set_sPLT(png_ptr, info_ptr, &palette_ptr, @@ -2424,7 +2952,12 @@ transformations are permitted, enabled by the following masks. PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity to transparency PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples - PNG_TRANSFORM_STRIP_FILLER Strip out filler bytes. + PNG_TRANSFORM_STRIP_FILLER Strip out filler + bytes (deprecated). + PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading + filler bytes + PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing + filler bytes If you have valid image data in the info structure (you can use png_set_rows() to put image data in the info structure), simply do this: @@ -2452,10 +2985,10 @@ this with a call to png_write_info(). Note that there is one transformation you may need to do before png_write_info(). In PNG files, the alpha channel in an image is the -level of opacity. If your data is supplied as a level of -transparency, you can invert the alpha channel before you write it, so -that 0 is fully transparent and 255 (in 8-bit or paletted images) or -65535 (in 16-bit images) is fully opaque, with +level of opacity. If your data is supplied as a level of transparency, +you can invert the alpha channel before you write it, so that 0 is +fully transparent and 255 (in 8-bit or paletted images) or 65535 +(in 16-bit images) is fully opaque, with png_set_invert_alpha(png_ptr); @@ -2642,14 +3175,13 @@ a single row_pointer instead of an array of row_pointers: png_write_row(png_ptr, row_pointer); -When the file is interlaced, things can get a good deal more -complicated. The only currently (as of the PNG Specification -version 1.2, dated July 1999) defined interlacing scheme for PNG files -is the "Adam7" interlace scheme, that breaks down an -image into seven smaller images of varying size. libpng will build -these images for you, or you can do them yourself. If you want to -build them yourself, see the PNG specification for details of which -pixels to write when. +When the file is interlaced, things can get a good deal more complicated. +The only currently (as of the PNG Specification version 1.2, dated July +1999) defined interlacing scheme for PNG files is the "Adam7" interlace +scheme, that breaks down an image into seven smaller images of varying +size. libpng will build these images for you, or you can do them +yourself. If you want to build them yourself, see the PNG specification +for details of which pixels to write when. If you don't want libpng to handle the interlacing details, just use png_set_interlace_handling() and call png_write_rows() the @@ -2661,17 +3193,17 @@ writing any rows: number_of_passes = png_set_interlace_handling(png_ptr); -This will return the number of passes needed. Currently, this -is seven, but may change if another interlace type is added. +This will return the number of passes needed. Currently, this is seven, +but may change if another interlace type is added. Then write the complete image number_of_passes times. png_write_rows(png_ptr, row_pointers, number_of_rows); -As some of these rows are not used, and thus return immediately, -you may want to read about interlacing in the PNG specification, -and only update the rows that are actually used. +As some of these rows are not used, and thus return immediately, you may +want to read about interlacing in the PNG specification, and only update +the rows that are actually used. .SS Finishing a sequential write @@ -2704,15 +3236,14 @@ point to libpng-allocated storage with the following function: This function may be safely called when the relevant storage has already been freed, or has not yet been allocated, or was allocated -by the user and not by libpng, and will in those -cases do nothing. The "seq" parameter is ignored if only one item -of the selected data type, such as PLTE, is allowed. If "seq" is not --1, and multiple items are allowed for the data type identified in -the mask, such as text or sPLT, only the n'th item in the structure -is freed, where n is "seq". - -If you allocated data such as a palette that you passed -in to libpng with png_set_*, you must not free it until just before the call to +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not -1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". + +If you allocated data such as a palette that you passed in to libpng +with png_set_*, you must not free it until just before the call to png_destroy_write_struct(). The default behavior is only to free data that was allocated internally @@ -2778,29 +3309,34 @@ goes through callbacks that are user-settable. The default routines are in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change these functions, call the appropriate png_set_*_fn() function. -Memory allocation is done through the functions png_malloc() -and png_free(). These currently just call the standard C functions. If -your pointers can't access more then 64K at a time, you will want to set -MAXSEG_64K in zlib.h. Since it is unlikely that the method of handling -memory allocation on a platform will change between applications, these -functions must be modified in the library at compile time. If you prefer -to use a different method of allocating and freeing data, you can use -png_create_read_struct_2() or png_create_write_struct_2() to register -your own functions as described above. -These functions also provide a void pointer that can be retrieved via +Memory allocation is done through the functions png_malloc(), png_calloc(), +and png_free(). These currently just call the standard C functions. +png_calloc() calls png_malloc() and then png_memset() to clear the newly +allocated memory to zero. If your pointers can't access more then 64K +at a time, you will want to set MAXSEG_64K in zlib.h. Since it is +unlikely that the method of handling memory allocation on a platform +will change between applications, these functions must be modified in +the library at compile time. If you prefer to use a different method +of allocating and freeing data, you can use png_create_read_struct_2() or +png_create_write_struct_2() to register your own functions as described +above. These functions also provide a void pointer that can be retrieved +via mem_ptr=png_get_mem_ptr(png_ptr); Your replacement memory functions must have prototypes as follows: png_voidp malloc_fn(png_structp png_ptr, - png_size_t size); + png_alloc_size_t size); void free_fn(png_structp png_ptr, png_voidp ptr); Your malloc_fn() must return NULL in case of failure. The png_malloc() function will normally call png_error() if it receives a NULL from the system memory allocator or from your replacement malloc_fn(). +Your free_fn() will never be called with a NULL ptr, since libpng's +png_free() checks for NULL before calling free_fn(). + Input/Output in libpng is done through png_read() and png_write(), which currently just call fread() and fwrite(). The FILE * is stored in png_struct and is initialized via png_init_io(). If you wish to change @@ -2828,16 +3364,23 @@ The replacement I/O functions must have prototypes as follows: png_bytep data, png_size_t length); void user_flush_data(png_structp png_ptr); +The user_read_data() function is responsible for detecting and +handling end-of-data errors. + Supplying NULL for the read, write, or flush functions sets them back -to using the default C stream functions. It is an error to read from -a write stream, and vice versa. +to using the default C stream functions, which expect the io_ptr to +point to a standard *FILE structure. It is probably a mistake +to use NULL for one of write_data_fn and output_flush_fn but not both +of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined. +It is an error to read from a write stream, and vice versa. Error handling in libpng is done through png_error() and png_warning(). Errors handled through png_error() are fatal, meaning that png_error() should never return to its caller. Currently, this is handled via setjmp() and longjmp() (unless you have compiled libpng with -PNG_SETJMP_NOT_SUPPORTED, in which case it is handled via PNG_ABORT()), -but you could change this to do things like exit() if you should wish. +PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()), +but you could change this to do things like exit() if you should wish, +as long as your function does not return. On non-fatal errors, png_warning() is called to print a warning message, and then control returns to the calling code. @@ -2870,10 +3413,10 @@ The motivation behind using setjmp() and longjmp() is the C++ throw and catch exception handling methods. This makes the code much easier to write, as there is no need to check every return code of every function call. However, there are some uncertainties about the status of local variables -after a longjmp, so the user may want to be careful about doing anything after -setjmp returns non-zero besides returning itself. Consult your compiler -documentation for more details. For an alternative approach, you may wish -to use the "cexcept" facility (see http://cexcept.sourceforge.net). +after a longjmp, so the user may want to be careful about doing anything +after setjmp returns non-zero besides returning itself. Consult your +compiler documentation for more details. For an alternative approach, you +may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net). .SS Custom chunks @@ -2885,15 +3428,14 @@ library code itself needs to know about interactions between your chunk and existing `intrinsic' chunks. If you need to write a new intrinsic chunk, first read the PNG -specification. Acquire a first level of -understanding of how it works. Pay particular attention to the -sections that describe chunk names, and look at how other chunks were -designed, so you can do things similarly. Second, check out the -sections of libpng that read and write chunks. Try to find a chunk -that is similar to yours and use it as a template. More details can -be found in the comments inside the code. It is best to handle unknown -chunks in a generic method, via callback functions, instead of by -modifying libpng functions. +specification. Acquire a first level of understanding of how it works. +Pay particular attention to the sections that describe chunk names, +and look at how other chunks were designed, so you can do things +similarly. Second, check out the sections of libpng that read and +write chunks. Try to find a chunk that is similar to yours and use +it as a template. More details can be found in the comments inside +the code. It is best to handle unknown chunks in a generic method, +via callback functions, instead of by modifying libpng functions. If you wish to write your own transformation for the data, look through the part of the code that does the transformations, and check out some of @@ -2935,11 +3477,12 @@ you may also have to change the memory allocators (png_malloc, etc.). .SS Configuring for compiler xxx: -All includes for libpng are in pngconf.h. If you need to add/change/delete -an include, this is the place to do it. The includes that are not -needed outside libpng are protected by the PNG_INTERNAL definition, -which is only defined for those routines inside libpng itself. The -files in libpng proper only include png.h, which includes pngconf.h. +All includes for libpng are in pngconf.h. If you need to add, change +or delete an include, this is the place to do it. +The includes that are not needed outside libpng are placed in pngpriv.h, +which is only used by the routines inside libpng itself. +The files in libpng proper only include pngpriv.h and png.h, which +in turn includes pngconf.h. .SS Configuring zlib: @@ -3008,7 +3551,7 @@ currently does not allocate the filter buffers until png_write_row() is called for the first time.) filters = PNG_FILTER_NONE | PNG_FILTER_SUB - PNG_FILTER_UP | PNG_FILTER_AVE | + PNG_FILTER_UP | PNG_FILTER_AVG | PNG_FILTER_PAETH | PNG_ALL_FILTERS; png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, @@ -3069,14 +3612,14 @@ off en masse with compiler directives that define PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS, or all four, along with directives to turn on any of the capabilities that you do -want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable -the extra transformations but still leave the library fully capable of reading -and writing PNG files with all known public chunks -Use of the PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive -produces a library that is incapable of reading or writing ancillary chunks. -If you are not using the progressive reading capability, you can -turn that off with PNG_NO_PROGRESSIVE_READ (don't confuse -this with the INTERLACING capability, which you'll still have). +want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the extra +transformations but still leave the library fully capable of reading +and writing PNG files with all known public chunks. Use of the +PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library +that is incapable of reading or writing ancillary chunks. If you are +not using the progressive reading capability, you can turn that off +with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING +capability, which you'll still have). All the reading and writing specific code are in separate files, so the linker should only grab the files it needs. However, if you want to @@ -3130,7 +3673,7 @@ When PNG_DEBUG = 1, the macros are defined, but only png_debug statements having level = 0 will be printed. There aren't any such statements in this version of libpng, but if you insert some they will be printed. -.SH VII. MNG support +.SH VI. MNG support The MNG specification (available at http://www.libpng.org/pub/mng) allows certain extensions to PNG for PNG images that are embedded in MNG datastreams. @@ -3155,7 +3698,7 @@ or any other MNG chunks; your application must provide its own support for them. You may wish to consider using libmng (available at http://www.libmng.com) instead. -.SH VIII. Changes to Libpng from version 0.88 +.SH VII. Changes to Libpng from version 0.88 It should be noted that versions of libpng later than 0.96 are not distributed by the original libpng author, Guy Schalnat, nor by @@ -3204,15 +3747,348 @@ application: png_uint_32 application_vn = PNG_LIBPNG_VER; -.SH IX. Y2K Compliance in libpng +.SH VIII. Changes to Libpng from version 1.0.x to 1.2.x + +Support for user memory management was enabled by default. To +accomplish this, the functions png_create_read_struct_2(), +png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(), +png_malloc_default(), and png_free_default() were added. + +Support for the iTXt chunk has been enabled by default as of +version 1.2.41. + +Support for certain MNG features was enabled. + +Support for numbered error messages was added. However, we never got +around to actually numbering the error messages. The function +png_set_strip_error_numbers() was added (Note: the prototype for this +function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE +builds of libpng-1.2.15. It was restored in libpng-1.2.36). + +The png_malloc_warn() function was added at libpng-1.2.3. This issues +a png_warning and returns NULL instead of aborting when it fails to +acquire the requested memory allocation. + +Support for setting user limits on image width and height was enabled +by default. The functions png_set_user_limits(), png_get_user_width_max(), +and png_get_user_height_max() were added at libpng-1.2.6. + +The png_set_add_alpha() function was added at libpng-1.2.7. + +The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9. +Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the +tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is +deprecated. + +A number of macro definitions in support of runtime selection of +assembler code features (especially Intel MMX code support) were +added at libpng-1.2.0: + + PNG_ASM_FLAG_MMX_SUPPORT_COMPILED + PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU + PNG_ASM_FLAG_MMX_READ_COMBINE_ROW + PNG_ASM_FLAG_MMX_READ_INTERLACE + PNG_ASM_FLAG_MMX_READ_FILTER_SUB + PNG_ASM_FLAG_MMX_READ_FILTER_UP + PNG_ASM_FLAG_MMX_READ_FILTER_AVG + PNG_ASM_FLAG_MMX_READ_FILTER_PAETH + PNG_ASM_FLAGS_INITIALIZED + PNG_MMX_READ_FLAGS + PNG_MMX_FLAGS + PNG_MMX_WRITE_FLAGS + PNG_MMX_FLAGS + +We added the following functions in support of runtime +selection of assembler code features: + + png_get_mmx_flagmask() + png_set_mmx_thresholds() + png_get_asm_flags() + png_get_mmx_bitdepth_threshold() + png_get_mmx_rowbytes_threshold() + png_set_asm_flags() + +We replaced all of these functions with simple stubs in libpng-1.2.20, +when the Intel assembler code was removed due to a licensing issue. + +These macros are deprecated: + + PNG_READ_TRANSFORMS_NOT_SUPPORTED + PNG_PROGRESSIVE_READ_NOT_SUPPORTED + PNG_NO_SEQUENTIAL_READ_SUPPORTED + PNG_WRITE_TRANSFORMS_NOT_SUPPORTED + PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED + PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED + +They have been replaced, respectively, by: + + PNG_NO_READ_TRANSFORMS + PNG_NO_PROGRESSIVE_READ + PNG_NO_SEQUENTIAL_READ + PNG_NO_WRITE_TRANSFORMS + PNG_NO_READ_ANCILLARY_CHUNKS + PNG_NO_WRITE_ANCILLARY_CHUNKS + +PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been +deprecated since libpng-1.0.16 and libpng-1.2.6. + +The function + png_check_sig(sig, num) +was replaced with + !png_sig_cmp(sig, 0, num) +It has been deprecated since libpng-0.90. + +The function + png_set_gray_1_2_4_to_8() +which also expands tRNS to alpha was replaced with + png_set_expand_gray_1_2_4_to_8() +which does not. It has been deprecated since libpng-1.0.18 and 1.2.9. + +.SH IX. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x + +Private libpng prototypes and macro definitions were moved from +png.h and pngconf.h into a new pngpriv.h header file. + +Functions png_set_benign_errors(), png_benign_error(), and +png_chunk_benign_error() were added. + +Support for setting the maximum amount of memory that the application +will allocate for reading chunks was added, as a security measure. +The functions png_set_chunk_cache_max() and png_get_chunk_cache_max() +were added to the library. + +We implemented support for I/O states by adding png_ptr member io_state +and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c + +We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level +input transforms. + +Checking for and reporting of errors in the IHDR chunk is more thorough. + +Support for global arrays was removed, to improve thread safety. + +Some obsolete/deprecated macros and functions have been removed. + +Typecasted NULL definitions such as + #define png_voidp_NULL (png_voidp)NULL +were eliminated. If you used these in your application, just use +NULL instead. + +The png_struct and info_struct members "trans" and "trans_values" were +changed to "trans_alpha" and "trans_color", respectively. + +The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles +were removed. + +The PNG_1_0_X and PNG_1_2_X macros were eliminated. + +The PNG_LEGACY_SUPPORTED macro was eliminated. + +Many WIN32_WCE #ifdefs were removed. + +The functions png_read_init(info_ptr), png_write_init(info_ptr), +png_info_init(info_ptr), png_read_destroy(), and png_write_destroy() +have been removed. They have been deprecated since libpng-0.95. + +The png_permit_empty_plte() was removed. It has been deprecated +since libpng-1.0.9. Use png_permit_mng_features() instead. + +We removed the obsolete stub functions png_get_mmx_flagmask(), +png_set_mmx_thresholds(), png_get_asm_flags(), +png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(), +png_set_asm_flags(), and png_mmx_supported() + +We removed the obsolete png_check_sig(), png_memcpy_check(), and +png_memset_check() functions. Instead use !png_sig_cmp(), png_memcpy(), +and png_memset(), respectively. + +The function png_set_gray_1_2_4_to_8() was removed. It has been +deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with +png_set_expand_gray_1_2_4_to_8() because the former function also +expanded palette images. + +We changed the prototype for png_malloc() from + png_malloc(png_structp png_ptr, png_uint_32 size) +to + png_malloc(png_structp png_ptr, png_alloc_size_t size) + +This also applies to the prototype for the user replacement malloc_fn(). + +The png_calloc() function was added and is used in place of +of "png_malloc(); png_memset();" except in the case in png_read_png() +where the array consists of pointers; in this case a "for" loop is used +after the png_malloc() to set the pointers to NULL, to give robust. +behavior in case the application runs out of memory part-way through +the process. + +We changed the prototypes of png_get_compression_buffer_size() and +png_set_compression_buffer_size() to work with png_size_t instead of +png_uint_32. + +Support for numbered error messages was removed by default, since we +never got around to actually numbering the error messages. The function +png_set_strip_error_numbers() was removed from the library by default. + +The png_zalloc() and png_zfree() functions are no longer exported. +The png_zalloc() function no longer zeroes out the memory that it +allocates. + +Support for dithering was disabled by default in libpng-1.4.0, because +been well tested and doesn't actually "dither". The code was not +removed, however, and could be enabled by building libpng with +PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support +was reenabled, but the function was renamed png_set_quantize() to +reflect more accurately what it actually does. At the same time, +the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to +PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS. + +We removed the trailing '.' from the warning and error messages. -September 8, 2007 +.SH X. Detecting libpng + +The png_get_io_ptr() function has been present since libpng-0.88, has never +changed, and is unaffected by conditional compilation macros. It is the +best choice for use in configure scripts for detecting the presence of any +libpng version since 0.88. In an autoconf "configure.in" you could use + + AC_CHECK_LIB(png, png_get_io_ptr, ... + +.SH XI. Source code repository + +Since about February 2009, version 1.2.34, libpng has been under "git" source +control. The git repository was built from old libpng-x.y.z.tar.gz files +going back to version 0.70. You can access the git repository (read only) +at + + git://libpng.git.sourceforge.net/gitroot/libpng + +or you can browse it via "gitweb" at + + http://libpng.git.sourceforge.net/git/gitweb.cgi?p=libpng + +Patches can be sent to glennrp at users.sourceforge.net or to +png-mng-implement at lists.sourceforge.net or you can upload them to +the libpng bug tracker at + + http://libpng.sourceforge.net + +.SH XII. Coding style + +Our coding style is similar to the "Allman" style, with curly +braces on separate lines: + + if (condition) + { + action; + } + + else if (another condition) + { + another action; + } + +The braces can be omitted from simple one-line actions: + + if (condition) + return (0); + +We use 3-space indentation, except for continued statements which +are usually indented the same as the first line of the statement +plus four more spaces. + +For macro definitions we use 2-space indentation, always leaving the "#" +in the first column. + + #ifndef PNG_NO_FEATURE + # ifndef PNG_FEATURE_SUPPORTED + # define PNG_FEATURE_SUPPORTED + # endif + #endif + +Comments appear with the leading "/*" at the same indentation as +the statement that follows the comment: + + /* Single-line comment */ + statement; + + /* This is a multiple-line + * comment. + */ + statement; + +Very short comments can be placed after the end of the statement +to which they pertain: + + statement; /* comment */ + +We don't use C++ style ("//") comments. We have, however, +used them in the past in some now-abandoned MMX assembler +code. + +Functions and their curly braces are not indented, and +exported functions are marked with PNGAPI: + + /* This is a public function that is visible to + * application programers. It does thus-and-so. + */ + void PNGAPI + png_exported_function(png_ptr, png_info, foo) + { + body; + } + +The prototypes for all exported functions appear in png.h, +above the comment that says + + /* Maintainer: Put new public prototypes here ... */ + +We mark all non-exported functions with "/* PRIVATE */"": + + void /* PRIVATE */ + png_non_exported_function(png_ptr, png_info, foo) + { + body; + } + +The prototypes for non-exported functions (except for those in +pngtest) appear in +pngpriv.h +above the comment that says + + /* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */ + +The names of all exported functions and variables begin +with "png_", and all publicly visible C preprocessor +macros begin with "PNG_". + +We put a space after each comma and after each semicolon +in "for" statments, and we put spaces before and after each +C binary operator and after "for" or "while", and before +"?". We don't put a space between a typecast and the expression +being cast, nor do we put one between a function name and the +left parenthesis that follows it: + + for (i = 2; i > 0; --i) + y[i] = a(x) + (int)b; + +We prefer #ifdef and #ifndef to #if defined() and if !defined() +when there is only one macro being tested. + +We do not use the TAB character for indentation in the C sources. + +Lines do not exceed 80 characters. + +Other rules can be inferred by inspecting the libpng source. + +.SH XIII. Y2K Compliance in libpng + +September 23, 2010 Since the PNG Development group is an ad-hoc body, we can't make an official declaration. This is your unofficial assurance that libpng from version 0.71 and -upward through 1.2.20 are Y2K compliant. It is my belief that earlier +upward through 1.4.4 are Y2K compliant. It is my belief that earlier versions were also Y2K compliant. Libpng only has three year fields. One is a 2-byte unsigned integer that @@ -3356,61 +4232,48 @@ the first widely used release: 1.0.16 10 10016 10.so.0.1.0.16 1.2.6 13 10206 12.so.0.1.2.6 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2 - 1.0.17rc1 10 10017 10.so.0.1.0.17rc1 + 1.0.17rc1 10 10017 12.so.0.1.0.17rc1 1.2.7rc1 13 10207 12.so.0.1.2.7rc1 - 1.0.17 10 10017 10.so.0.1.0.17 + 1.0.17 10 10017 12.so.0.1.0.17 1.2.7 13 10207 12.so.0.1.2.7 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5 - 1.0.18rc1-5 10 10018 10.so.0.1.0.18rc1-5 + 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5 - 1.0.18 10 10018 10.so.0.1.0.18 + 1.0.18 10 10018 12.so.0.1.0.18 1.2.8 13 10208 12.so.0.1.2.8 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3 1.2.9beta4-11 13 10209 12.so.0.9[.0] 1.2.9rc1 13 10209 12.so.0.9[.0] 1.2.9 13 10209 12.so.0.9[.0] - 1.2.10beta1-8 13 10210 12.so.0.10[.0] - 1.2.10rc1-3 13 10210 12.so.0.10[.0] + 1.2.10beta1-7 13 10210 12.so.0.10[.0] + 1.2.10rc1-2 13 10210 12.so.0.10[.0] 1.2.10 13 10210 12.so.0.10[.0] - 1.2.11beta1-4 13 10211 12.so.0.11[.0] - 1.0.19rc1-5 10 10019 10.so.0.19[.0] - 1.2.11rc1-5 13 10211 12.so.0.11[.0] - 1.0.19 10 10019 10.so.0.19[.0] + 1.4.0beta1-6 14 10400 14.so.0.0[.0] + 1.2.11beta1-4 13 10210 12.so.0.11[.0] + 1.4.0beta7-8 14 10400 14.so.0.0[.0] 1.2.11 13 10211 12.so.0.11[.0] - 1.0.20 10 10020 10.so.0.20[.0] 1.2.12 13 10212 12.so.0.12[.0] - 1.2.13beta1 13 10213 12.so.0.13[.0] - 1.0.21 10 10021 10.so.0.21[.0] + 1.4.0beta9-14 14 10400 14.so.0.0[.0] 1.2.13 13 10213 12.so.0.13[.0] - 1.2.14beta1-2 13 10214 12.so.0.14[.0] - 1.0.22rc1 10 10022 10.so.0.22[.0] - 1.2.14rc1 13 10214 12.so.0.14[.0] - 1.2.15beta1-6 13 10215 12.so.0.15[.0] - 1.0.23rc1-5 10 10023 10.so.0.23[.0] - 1.2.15rc1-5 13 10215 12.so.0.15[.0] - 1.0.23 10 10023 10.so.0.23[.0] - 1.2.15 13 10215 12.so.0.15[.0] - 1.2.16beta1-2 13 10216 12.so.0.16[.0] - 1.2.16rc1 13 10216 12.so.0.16[.0] - 1.0.24 10 10024 10.so.0.24[.0] - 1.2.16 13 10216 12.so.0.16[.0] - 1.2.17beta1-2 13 10217 12.so.0.17[.0] - 1.0.25rc1 10 10025 10.so.0.25[.0] - 1.2.17rc1-3 13 10217 12.so.0.17[.0] - 1.0.25 10 10025 10.so.0.25[.0] - 1.2.17 13 10217 12.so.0.17[.0] - 1.0.26 10 10026 10.so.0.26[.0] - 1.2.18 13 10218 12.so.0.18[.0] - 1.2.19beta1-31 13 10219 12.so.0.19[.0] - 1.0.27rc1-6 10 10027 10.so.0.27[.0] - 1.2.19rc1-6 13 10219 12.so.0.19[.0] - 1.0.27 10 10027 10.so.0.27[.0] - 1.2.19 13 10219 12.so.0.19[.0] - 1.2.20beta01-04 13 10220 12.so.0.20[.0] - 1.0.28rc1-6 10 10028 10.so.0.28[.0] - 1.2.20rc1-6 13 10220 12.so.0.20[.0] - 1.0.28 10 10028 10.so.0.28[.0] - 1.2.20 13 10220 12.so.0.20[.0] + 1.4.0beta15-36 14 10400 14.so.0.0[.0] + 1.4.0beta37-87 14 10400 14.so.14.0[.0] + 1.4.0rc01 14 10400 14.so.14.0[.0] + 1.4.0beta88-109 14 10400 14.so.14.0[.0] + 1.4.0rc02-08 14 10400 14.so.14.0[.0] + 1.4.0 14 10400 14.so.14.0[.0] + 1.4.1beta01-03 14 10401 14.so.14.1[.0] + 1.4.1rc01 14 10401 14.so.14.1[.0] + 1.4.1beta04-12 14 10401 14.so.14.1[.0] + 1.4.1rc02-04 14 10401 14.so.14.1[.0] + 1.4.1 14 10401 14.so.14.1[.0] + 1.4.2beta01 14 10402 14.so.14.2[.0] + 1.4.2rc02-06 14 10402 14.so.14.2[.0] + 1.4.2 14 10402 14.so.14.2[.0] + 1.4.3beta01-05 14 10403 14.so.14.3[.0] + 1.4.3rc01-03 14 10403 14.so.14.3[.0] + 1.4.3 14 10403 14.so.14.3[.0] + 1.4.4beta01-08 14 10404 14.so.14.4[.0] + 1.4.4rc01-06 14 10404 14.so.14.4[.0] Henceforth the source version will match the shared-library minor and patch numbers; the shared-library major version number will be @@ -3423,7 +4286,7 @@ version 1.0.6j; from then on they were given the upcoming public release number plus "betaNN" or "rcN". .SH "SEE ALSO" -.IR libpngpf(3) ", " png(5) +.BR "png"(5), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5) .LP .IR libpng : .IP @@ -3466,7 +4329,7 @@ possible without all of you. Thanks to Frank J. T. Wojcik for helping with the documentation. -Libpng version 1.2.20 - September 8, 2007: +Libpng version 1.4.4 - September 23, 2010: Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). @@ -3487,7 +4350,9 @@ included in the libpng distribution, the latter shall prevail.) If you modify libpng you may insert additional notices immediately following this sentence. -libpng versions 1.2.6, August 15, 2004, through 1.2.20, September 8, 2007, are +This code is released under the libpng license. + +libpng versions 1.2.6, August 15, 2004, through 1.4.4, September 23, 2010, are Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are distributed according to the same disclaimer and license as libpng-1.2.5 with the following individual added to the list of Contributing Authors @@ -3586,7 +4451,7 @@ certification mark of the Open Source Initiative. Glenn Randers-Pehrson glennrp at users.sourceforge.net -September 8, 2007 +September 23, 2010 .\" end of man page