pngchange.txt - changes for libpng version 0.2 added reader into png.h fixed small problems in stub file version 0.3 added pull reader split up pngwrite.c to several files added pnglib.txt added example.c cleaned up writer, adding a few new tranformations fixed some bugs in writer interfaced with zlib 0.5 added K&R support added check for 64 KB blocks for 16 bit machines version 0.4 cleaned up code and commented code simplified time handling into png_time created png_color_16 and png_color_8 to handle color needs cleaned up color type defines fixed various bugs made various names more consistant interfaced with zlib 0.71 cleaned up zTXt reader and writer (using zlib's Reset functions) split transformations into pngrtran.c and pngwtran.c version 0.5 interfaced with zlib 0.8 fixed many reading and writing bugs saved using 3 spaces instead of tabs version 0.6 added png_large_malloc() and png_large_free() added png_size_t cleaned up some compiler warnings added png_start_read_image() version 0.7 cleaned up lots of bugs finished dithering and other stuff added test program changed name from pnglib to libpng version 0.71 [June, 1995] changed pngtest.png for zlib 0.93 fixed error in libpng.txt and example.c version 0.8 cleaned up some bugs added png_set_filler() split up pngstub.c into pngmem.c, pngio.c, and pngerror.c added #define's to remove unwanted code moved png_info_init() to png.c added old_size into png_realloc() added functions to manually set filtering and compression info changed compression parameters based on image type optimized filter selection code added version info changed external functions passing floats to doubles (k&r problems?) put all the configurable stuff in pngconf.h enabled png_set_shift to work with paletted images on read added png_read_update_info() - updates info structure with transformations version 0.81 [August, 1995] incorporated Tim Wegner's medium model code (thanks, Tim) version 0.82 [September, 1995] [unspecified changes] version 0.85 [December, 1995] added more medium model code (almost everything's a far) added i/o, error, and memory callback functions fixed some bugs (16 bit, 4 bit interlaced, etc.) added first run progressive reader (barely tested) version 0.86 [January, 1996] fixed bugs improved documentation version 0.87 [January, 1996] fixed medium model bugs fixed other bugs introduced in 0.85 and 0.86 added some minor documentation version 0.88 [January, 1996] fixed progressive bugs replaced tabs with spaces cleaned up documentation added callbacks for read/write and warning/error functions version 0.89 [July, 1996] added new initialization API to make libpng work better with shared libs we now have png_create_read_struct(), png_create_write_struct(), png_create_info_struct(), png_destroy_read_struct(), and png_destroy_write_struct() instead of the separate calls to malloc and png_read_init(), png_info_init(), and png_write_init() changed warning/error callback functions to fix bug - this means you should use the new initialization API if you were using the old png_set_message_fn() calls, and that the old API no longer exists so that people are aware that they need to change their code changed filter selection API to allow selection of multiple filters since it didn't work in previous versions of libpng anyways optimized filter selection code fixed png_set_background() to allow using an arbitrary RGB color for paletted images fixed gamma and background correction for paletted images, so png_correct_palette is not needed unless you are correcting an external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED in pngconf.h) - if nobody uses this, it may disappear in the future. fixed bug with Borland 64K memory allocation (Alexander Lehmann) fixed bug in interlace handling (Smarasderagd, I think) added more error checking for writing and image to reduce invalid files separated read and write functions so that they won't both be linked into a binary when only reading or writing functionality is used new pngtest image also has interlacing and zTXt updated documentation to reflect new API version 0.90 [January, 1997] made CRC errors/warnings on critical and ancillary chunks configurable libpng will use the zlib CRC routines by (compile-time) default changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner) added external C++ wrapper statements to png.h (Gilles Dauphin) allow PNG file to be read when some or all of file signature has already been read from the beginning of the stream. ****This affects the size of info_struct and invalidates all programs that use a shared libpng**** fixed png_filler() declarations fixed? background color conversions fixed order of error function pointers to match documentation current chunk name is now available in png_struct to reduce the number of nearly identical error messages (will simplify multi-lingual support when available) try to get ready for unknown-chunk callback functions: - previously read critical chunks are flagged, so the chunk handling routines can determine if the chunk is in the right place - all chunk handling routines have the same prototypes, so we will be able to handle all chunks via a callback mechanism try to fix Linux "setjmp" buffer size problems version 0.95 [March, 1997] fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never fixed bug in PNG file signature compares when start != 0 changed parameter type of png_set_filler(...filler...) from png_byte to png_uint_32 added test for MACOS to ensure that both math.h and fp.h are not #included added macros for libpng to be compiled as a Windows DLL (Andreas Kupries) added "packswap" transformation, which changes the endianness of packed-pixel bytes (Kevin Bracey) added "strip_alpha" transformation, which removes the alpha channel of input images without using it (not neccesarily a good idea) added "swap_alpha" transformation, which puts the alpha channel in front of the color bytes instead of after removed all implicit variable tests which assume NULL == 0 (I think) changed several variables to "png_size_t" to show 16/32-bit limitations added new pCAL chunk read/write support added experimental filter selection weighting (Greg Roelofs) removed old png_set_rgbx() and png_set_xrgb() functions that have been obsolete for about 2 years now (use png_set_filler() instead) added macros to read 16- and 32-bit ints directly from buffer, to be used only on those systems that support it (namely PowerPC and 680x0) With some testing, this may become the default for MACOS/PPC systems. only calculate CRC on data if we are going to use it added macros for zTXt compression type PNG_zTXt_COMPRESSION_??? added macros for simple libpng debugging output selectable at compile time removed PNG_READ_END_MODE in progressive reader (Smarasderagd) more description of info_struct in libpng.txt and png.h more instructions in example.c more chunk types tested in pngtest.c renamed pngrcb.c to pngset.c, and all png_read_ functions to be png_set_. We now have corresponding png_get_ functions in pngget.c to get infomation in info_ptr. This isolates the application from the internal organization of png_info_struct (good for shared library implementations). version 0.96 [May, 1997] fixed serious bug with < 8bpp images introduced in 0.95 fixed 256-color transparency bug (Greg Roelofs) fixed up documentation (Greg Roelofs, Laszlo Nyul) fixed "error" in pngconf.h for Linux setjmp() behaviour fixed DOS medium model support (Tim Wegner) fixed png_check_keyword() for case with error in static string text added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul) added typecasts to quiet compiler errors added more debugging info version 0.97 [January, 1998] removed PNG_USE_OWN_CRC capability relocated png_set_crc_action from pngrutil.c to pngrtran.c fixed typecasts of "new_key", etc. (Andreas Dilger) added RFC 1152 [sic] date support fixed bug in gamma handling of 4-bit grayscale added 2-bit grayscale gamma handling (Glenn R-P) added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P) minor corrections in libpng.txt added simple sRGB support (Glenn R-P) easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED; all configurable options can be selected from command-line instead of having to edit pngconf.h (Glenn R-P) fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P) added more conditions for png_do_background, to avoid changing black pixels to background when a background is supplied and no pixels are transparent repaired PNG_NO_STDIO behaviour tested NODIV support and made it default behaviour (Greg Roelofs) added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler) regularized version numbering scheme and bumped shared-library major version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs) version 0.98 [January, 1998] cleaned up some typos in libpng.txt and in code documentation fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler) cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c changed recommendation about file_gamma for PC images to .51 from .45, in example.c and libpng.txt, added comments to distinguish between screen_gamma, viewing_gamma, and display_gamma. changed all references to RFC1152 to read RFC1123 and changed the PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent) changed srgb_intent from png_byte to int to avoid compiler bugs