-.TH LIBPNG 3 "September 12, 2004"
+.TH LIBPNG 3 "September 8, 2007"
.SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.7
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.20
.SH SYNOPSIS
-\fI\fB
-
-\fB#include <png.h>\fP
-
-\fI\fB
+\fB
+#include <png.h>\fP
\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP
-\fI\fB
-
\fBint png_check_sig (png_bytep \fP\fIsig\fP\fB, int \fInum\fP\fB);\fP
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-
\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
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-
\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP
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-
\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP
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-
\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP
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-
\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
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-
\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
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-
\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
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-
\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
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-
\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
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-
\fBint png_debug2(int \fP\fIlevel\fP\fB, png_const_charp \fP\fImessage\fP\fB, \fP\fIp1\fP\fB, \fIp2\fP\fB);\fP
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-
\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP
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-
\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
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-
\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP
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\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
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-
\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
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-
\fBvoid png_free_default(png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
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\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP
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-
\fBpng_byte png_get_bit_depth (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
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\fBpng_byte png_get_channels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
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-
\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
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-
\fBpng_byte png_get_color_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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-
\fBpng_byte png_get_compression_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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-
\fBpng_byte png_get_copyright (png_structp \fIpng_ptr\fP\fB);\fP
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-
\fBpng_voidp png_get_error_ptr (png_structp \fIpng_ptr\fP\fB);\fP
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\fBpng_byte png_get_filter_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
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-
\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
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-
\fBpng_byte png_get_header_ver (png_structp \fIpng_ptr\fP\fB);\fP
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-
\fBpng_byte png_get_header_version (png_structp \fIpng_ptr\fP\fB);\fP
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-
\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
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\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
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\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
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\fBpng_uint_32 png_get_image_height (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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-
\fBpng_uint_32 png_get_image_width (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
-\fI\fB
+\fB#if !defined(PNG_1_0_X) png_int_32 png_get_int_32 (png_bytep buf); \fI#endif
\fBpng_byte png_get_interlace_type (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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-
\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP
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-
\fBpng_byte png_get_libpng_ver (png_structp \fIpng_ptr\fP\fB);\fP
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\fBpng_voidp png_get_mem_ptr(png_structp \fIpng_ptr\fP\fB);\fP
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\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
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\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
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\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
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\fBfloat png_get_pixel_aspect_ratio (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_uint_32 png_get_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_voidp png_get_progressive_ptr (png_structp \fIpng_ptr\fP\fB);\fP
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\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
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-\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_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
\fBpng_bytepp png_get_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
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\fBpng_bytep png_get_signature (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
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\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
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\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
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\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
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\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
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+\fB#if !defined(PNG_1_0_X) png_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP
-\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
+\fBpng_uint_32 png_get_uint_31 (png_bytep \fIbuf\fP\fB);\fP
-\fI\fB
+\fBpng_uint_32 png_get_uint_32 (png_bytep buf); \fI#endif
-\fBpng_voidp png_get_user_chunk_ptr (png_structp \fIpng_ptr\fP\fB);\fP
+\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
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+\fBpng_voidp png_get_user_chunk_ptr (png_structp \fIpng_ptr\fP\fB);\fP
\fBpng_uint_32 png_get_user_height_max( png_structp \fIpng_ptr\fP\fB);\fP
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\fBpng_voidp png_get_user_transform_ptr (png_structp \fIpng_ptr\fP\fB);\fP
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\fBpng_uint_32 png_get_user_width_max (png_structp \fIpng_ptr\fP\fB);\fP
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\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
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\fBpng_int_32 png_get_x_offset_microns (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_int_32 png_get_x_offset_pixels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_uint_32 png_get_x_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_int_32 png_get_y_offset_microns (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_int_32 png_get_y_offset_pixels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_uint_32 png_get_y_pixels_per_meter (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBpng_uint_32 png_get_compression_buffer_size (png_structp \fIpng_ptr\fP\fB);\fP
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\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP
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\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP
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\fBDEPRECATED: void png_info_init (png_infop \fIinfo_ptr\fP\fB);\fP
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\fBDEPRECATED: void png_info_init_2 (png_infopp \fP\fIptr_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP
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\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
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\fBpng_voidp png_malloc_default(png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP
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\fBvoidp png_memcpy (png_voidp \fP\fIs1\fP\fB, png_voidp \fP\fIs2\fP\fB, png_size_t \fIsize\fP\fB);\fP
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\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
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\fBvoidp png_memset (png_voidp \fP\fIs1\fP\fB, int \fP\fIvalue\fP\fB, png_size_t \fIsize\fP\fB);\fP
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\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
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\fBDEPRECATED: void png_permit_empty_plte (png_structp \fP\fIpng_ptr\fP\fB, int \fIempty_plte_permitted\fP\fB);\fP
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\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
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\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
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\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
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\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP
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\fBDEPRECATED: void png_read_init (png_structp \fIpng_ptr\fP\fB);\fP
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\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
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\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
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\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
-\fI\fB
+\fB#if !defined(PNG_1_0_X) png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP
-\fB#if \fI!defined(PNG_1_0_X)
+\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP
-\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP
+\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP
-\fI\fB#endif
-
-\fI\fB
+\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int flags); \fI#endif
\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_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
-\fI\fB
-
\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
\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
-
\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_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
-\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_values\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
-\fI\fB
-
\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
-\fI\fB
-
\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
-\fI\fB
-
\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
-
\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
.SH LIBPNG.TXT
libpng.txt - A description on how to use and modify libpng
- libpng version 1.2.7 - September 12, 2004
+ libpng version 1.2.20 - September 8, 2007
Updated and distributed by Glenn Randers-Pehrson
- <glennrp@users.sourceforge.net>
- Copyright (c) 1998-2004 Glenn Randers-Pehrson
+ <glennrp at users.sourceforge.net>
+ Copyright (c) 1998-2007 Glenn Randers-Pehrson
For conditions of distribution and use, see copyright
notice in png.h.
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.
+
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
file format in application programs.
instances of the structures. Each thread should have its own
png_struct and png_info instances, and thus its own image.
Libpng does not protect itself against two threads using the
-same instance of a structure. Note: thread safety may be defeated
-by use of some of the MMX assembler code in pnggccrd.c, which is only
-compiled when the user defines PNG_THREAD_UNSAFE_OK.
+same instance of a structure.
.SH II. Structures
png_read_png(png_ptr, info_ptr, png_transforms, NULL)
-where png_transforms is an integer containing the logical OR of
+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().
is called to insert filler bytes, either before or after each RGB triplet.
16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
byte of the color value first, unless png_set_strip_16() is called to
-transform it to regular RGB RGB triplets, or png_set_filler|add alpha()
-is called to insert filler bytes, either before or after each RRGGBB
-triplet. Similarly, 8-bit or 16-bit grayscale data can be modified with
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert filler bytes, either before or
+after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
+be modified with
png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
The following code transforms grayscale images of less than 8 to 8 bits,
png_set_palette_to_rgb(png_ptr);
if (color_type == PNG_COLOR_TYPE_GRAY &&
- bit_depth < 8) png_set_gray_1_2_4_to_8(png_ptr);
+ bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
if (png_get_valid(png_ptr, info_ptr,
PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
readability. In some future version they may actually do different
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.
+
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.
png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
where "filler" contains the alpha value to assign to each pixel.
-This function became available in libpng-1.2.7.
+This function was added in libpng-1.2.7.
If you are reading an image with an alpha channel, and you need the
data as ARGB instead of the normal PNG format RGBA:
The default values approximate those recommended in the Charles
Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
-Copyright (c) 1998-01-04 Charles Poynton poynton@inforamp.net
+Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
.SS Finishing a sequential read
-After you are finished reading the image through either the high- or
-low-level interfaces, you can finish reading the file. If you are
+After you are finished reading the image through the
+low-level interface, you can finish reading the file. If you are
interested in comments or time, which may be stored either before or
after the image data, you should pass the separate png_info struct if
you want to keep the comments from before and after the image
png_free_data(png_ptr, info_ptr, mask, seq)
mask - identifies data to be freed, a mask
- containing the logical OR of one or
+ containing the bitwise OR of one or
more of
PNG_FREE_PLTE, PNG_FREE_TRNS,
PNG_FREE_HIST, PNG_FREE_ICCP,
png_set_invalid(png_ptr, info_ptr, mask);
mask - identifies the chunks to be made invalid,
- containing the logical OR of one or
+ containing the bitwise OR of one or
more of
PNG_INFO_gAMA, PNG_INFO_sBIT,
PNG_INFO_cHRM, PNG_INFO_PLTE,
png_init_io(png_ptr, fp);
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+ png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
.SS Write callbacks
At this point, you can set up a callback function that will be
/* turn on or off filtering, and/or choose
specific filters. You can use either a single
- PNG_FILTER_VALUE_NAME or the logical OR of one
+ PNG_FILTER_VALUE_NAME or the bitwise OR of one
or more PNG_FILTER_NAME masks. */
png_set_filter(png_ptr, 0,
PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
png_write_png(png_ptr, info_ptr, png_transforms, NULL)
-where png_transforms is an integer containing the logical OR of some set of
+where png_transforms is an integer containing the bitwise OR of some set of
transformation flags. This call is equivalent to png_write_info(),
followed the set of transformations indicated by the transform mask,
then png_write_image(), and finally png_write_end().
png_free_data(png_ptr, info_ptr, mask, seq)
mask - identifies data to be freed, a mask
- containing the logical OR of one or
+ containing the bitwise OR of one or
more of
PNG_FREE_PLTE, PNG_FREE_TRNS,
PNG_FREE_HIST, PNG_FREE_ICCP,
.SH V. Modifying/Customizing libpng:
-There are three issues here. The first is changing how libpng does
+There are two issues here. The first is changing how libpng does
standard things like memory allocation, input/output, and error handling.
The second deals with more complicated things like adding new chunks,
adding new transformations, and generally changing how libpng works.
Both of those are compile-time issues; that is, they are generally
determined at the time the code is written, and there is rarely a need
-to provide the user with a means of changing them. The third is a
-run-time issue: choosing between and/or tuning one or more alternate
-versions of computationally intensive routines; specifically, optimized
-assembly-language (and therefore compiler- and platform-dependent)
-versions.
+to provide the user with a means of changing them.
Memory allocation, input/output, and error handling
If you need to read or write custom chunks, you may need to get deeper
into the libpng code. The library now has mechanisms for storing
and writing chunks of unknown type; you can even declare callbacks
-for custom chunks. Hoewver, this may not be good enough if the
+for custom chunks. However, this may not be good enough if the
library code itself needs to know about interactions between your
chunk and existing `intrinsic' chunks.
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 VI. Runtime optimization
-
-A new feature in libpng 1.2.0 is the ability to dynamically switch between
-standard and optimized versions of some routines. Currently these are
-limited to three computationally intensive tasks when reading PNG files:
-decoding row filters, expanding interlacing, and combining interlaced or
-transparent row data with previous row data. Currently the optimized
-versions are available only for x86 (Intel, AMD, etc.) platforms with
-MMX support, though this may change in future versions. (For example,
-the non-MMX assembler optimizations for zlib might become similarly
-runtime-selectable in future releases, in which case libpng could be
-extended to support them. Alternatively, the compile-time choice of
-floating-point versus integer routines for gamma correction might become
-runtime-selectable.)
-
-Because such optimizations tend to be very platform- and compiler-dependent,
-both in how they are written and in how they perform, the new runtime code
-in libpng has been written to allow programs to query, enable, and disable
-either specific optimizations or all such optimizations. For example, to
-enable all possible optimizations (bearing in mind that some "optimizations"
-may actually run more slowly in rare cases):
-
- #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
- png_uint_32 mask, flags;
-
- flags = png_get_asm_flags(png_ptr);
- mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
- png_set_asm_flags(png_ptr, flags | mask);
- #endif
-
-To enable only optimizations relevant to reading PNGs, use PNG_SELECT_READ
-by itself when calling png_get_asm_flagmask(); similarly for optimizing
-only writing. To disable all optimizations:
-
- #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
- flags = png_get_asm_flags(png_ptr);
- mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
- png_set_asm_flags(png_ptr, flags & ~mask);
- #endif
-
-To enable or disable only MMX-related features, use png_get_mmx_flagmask()
-in place of png_get_asm_flagmask(). The mmx version takes one additional
-parameter:
-
- #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
- int selection = PNG_SELECT_READ | PNG_SELECT_WRITE;
- int compilerID;
-
- mask = png_get_mmx_flagmask(selection, &compilerID);
- #endif
-
-On return, compilerID will indicate which version of the MMX assembler
-optimizations was compiled. Currently two flavors exist: Microsoft
-Visual C++ (compilerID == 1) and GNU C (a.k.a. gcc/gas, compilerID == 2).
-On non-x86 platforms or on systems compiled without MMX optimizations, a
-value of -1 is used.
-
-Note that both png_get_asm_flagmask() and png_get_mmx_flagmask() return
-all valid, settable optimization bits for the version of the library that's
-currently in use. In the case of shared (dynamically linked) libraries,
-this may include optimizations that did not exist at the time the code was
-written and compiled. It is also possible, of course, to enable only known,
-specific optimizations; for example:
-
- #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
- flags = 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_set_asm_flags(png_ptr, flags);
- #endif
-
-This method would enable only the MMX read-optimizations available at the
-time of libpng 1.2.0's release, regardless of whether a later version of
-the DLL were actually being used. (Also note that these functions did not
-exist in versions older than 1.2.0, so any attempt to run a dynamically
-linked app on such an older version would fail.)
-
-To determine whether the processor supports MMX instructions at all, use
-the png_mmx_support() function:
-
- #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
- mmxsupport = png_mmx_support();
- #endif
-
-It returns -1 if MMX support is not compiled into libpng, 0 if MMX code
-is compiled but MMX is not supported by the processor, or 1 if MMX support
-is fully available. Note that png_mmx_support(), png_get_mmx_flagmask(),
-and png_get_asm_flagmask() all may be called without allocating and ini-
-tializing any PNG structures (for example, as part of a usage screen or
-"about" box).
-
-The following code can be used to prevent an application from using the
-thread_unsafe features, even if libpng was built with PNG_THREAD_UNSAFE_OK
-defined:
-
-#if defined(PNG_USE_PNGGCCRD) && defined(PNG_ASSEMBLER_CODE_SUPPORTED) \
- && defined(PNG_THREAD_UNSAFE_OK)
- /* Disable thread-unsafe features of pnggccrd */
- if (png_access_version() >= 10200)
- {
- png_uint_32 mmx_disable_mask = 0;
- png_uint_32 asm_flags;
-
- mmx_disable_mask |= ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW \
- | PNG_ASM_FLAG_MMX_READ_FILTER_SUB \
- | PNG_ASM_FLAG_MMX_READ_FILTER_AVG \
- | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH );
- asm_flags = png_get_asm_flags(png_ptr);
- png_set_asm_flags(png_ptr, asm_flags & ~mmx_disable_mask);
- }
-#endif
-
-For more extensive examples of runtime querying, enabling and disabling
-of optimized features, see contrib/gregbook/readpng2.c in the libpng
-source-code distribution.
-
.SH VII. MNG support
The MNG specification (available at http://www.libpng.org/pub/mng) allows
png_permit_mng_features() function:
feature_set = png_permit_mng_features(png_ptr, mask)
- mask is a png_uint_32 containing the logical OR of the
+ mask is a png_uint_32 containing the bitwise OR of the
features you want to enable. These include
PNG_FLAG_MNG_EMPTY_PLTE
PNG_FLAG_MNG_FILTER_64
PNG_ALL_MNG_FEATURES
- feature_set is a png_uint_32 that is the logical AND of
+ feature_set is a png_uint_32 that is the bitwise AND of
your mask with the set of MNG features that is
supported by the version of libpng that you are using.
.SH IX. Y2K Compliance in libpng
-September 12, 2004
+September 8, 2007
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 1.2.7 are Y2K compliant. It is my belief that earlier
+upward through 1.2.20 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
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 12.so.0.1.0.17rc1
+ 1.0.17rc1 10 10017 10.so.0.1.0.17rc1
1.2.7rc1 13 10207 12.so.0.1.2.7rc1
- 1.0.17 10 10017 12.so.0.1.0.17
+ 1.0.17 10 10017 10.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
+ 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
+ 1.0.18 10 10018 10.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]
+ 1.2.10 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]
+ 1.2.11 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]
+ 1.2.13 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]
Henceforth the source version will match the shared-library minor
and patch numbers; the shared-library major version number will be
release number plus "betaNN" or "rcN".
.SH "SEE ALSO"
-libpngpf(3), png(5)
+.IR libpngpf(3) ", " png(5)
.LP
.IR libpng :
.IP
.SH AUTHORS
This man page: Glenn Randers-Pehrson
-<glennrp@users.sourceforge.net>
+<glennrp at users.sourceforge.net>
The contributing authors would like to thank all those who helped
with testing, bug fixes, and patience. This wouldn't have been
Thanks to Frank J. T. Wojcik for helping with the documentation.
-Libpng version 1.2.7 - September 12, 2004:
+Libpng version 1.2.20 - September 8, 2007:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
-Currently maintained by Glenn Randers-Pehrson (glennrp@users.sourceforge.net).
+Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
Supported by the PNG development group
.br
-png-implement@ccrc.wustl.edu (subscription required; write to
-majordomo@ccrc.wustl.edu with "subscribe png-implement" in the message).
+png-mng-implement at lists.sf.net
+(subscription required; visit
+png-mng-implement at lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe).
.SH COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
If you modify libpng you may insert additional notices immediately following
this sentence.
-libpng version 1.2.6, September 12, 2004, is
-Copyright (c) 2004 Glenn Randers-Pehrson, and is
+libpng versions 1.2.6, August 15, 2004, through 1.2.20, September 8, 2007, 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
certification mark of the Open Source Initiative.
Glenn Randers-Pehrson
-glennrp@users.sourceforge.net
-September 12, 2004
+glennrp at users.sourceforge.net
+September 8, 2007
.\" end of man page
projects / wxWidgets.git / blobdiff