changes

game engine, which is useful for everyone who is interested in it. I hope you can enjoy it.

    by default, for the benefit of DLL forward compatibility.  These will
    be re-enabled in version 1.2.0.
version 1.0.9rc2 [January 22, 2001]
  Revised cygwin support.

version 1.0.9 [January 31, 2001]
  Added check of cygwin's ALL_STATIC in pngconf.h
  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
version 1.0.10beta1 [March 14, 2001]
  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
  Reformatted libpng.3 to eliminate bad line breaks.
  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
  Added prototype for png_mmx_support() near the top of pnggccrd.c
  Moved some error checking from png_handle_IHDR to png_set_IHDR.
  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
  Revised png_mmx_support() function in pnggccrd.c
  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
  Fixed memory leak in contrib/visupng/PngFile.c
  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
  Added warnings when retrieving or setting gamma=0.
  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
version 1.0.10rc1 [March 23, 2001]
  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
    and png_strlen.
  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).

version 1.0.10 [March 30, 2001]
  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
  Added beos project files (Chris Herborth)
version 1.0.11beta1 [April 3, 2001]
  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
  Removed a no-longer needed AIX work-around from pngconf.h
  Changed several "//" single-line comments to C-style in pnggccrd.c
version 1.0.11beta2 [April 11, 2001]
  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
  Updated scripts/pngos2.def
version 1.0.11beta3 [April 14, 2001]
  Added checking the results of many instances of png_malloc() for NULL
version 1.0.11beta4 [April 20, 2001]
  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
    from user's malloc_fn().
  Removed some useless type casts of the NULL pointer.
  Added makefile.netbsd

version 1.0.11 [April 27, 2001]
  Revised makefile.netbsd
version 1.0.12beta1 [May 14, 2001]
  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
  Eliminated the png_error about apps using png_read|write_init().  Instead,
    libpng will reallocate the png_struct and info_struct if they are too small.
    This retains future binary compatibility for old applications written for
    libpng-0.88 and earlier.
version 1.2.0beta1 [May 6, 2001]
  Bumped DLLNUM to 2.
  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
    by default.
  Added runtime selection of MMX features.
  Added png_set_strip_error_numbers function and related macros.
version 1.2.0beta2 [May 7, 2001]
  Finished merging 1.2.0beta1 with version 1.0.11
  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
version 1.2.0beta3 [May 17, 2001]
  Enabled user memory function by default.
  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
  Increased png_mng_features flag from png_byte to png_uint_32.
  Bumped shared-library (so-number) and dll-number to 3.
version 1.2.0beta4 [June 23, 2001]
  Check for missing profile length field in iCCP chunk and free chunk_data
     in case of truncated iCCP chunk.
  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
  Bumped dll-number from 2 to 3 in makefile.cygwin
  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
     if user attempts to run it on an 8-bit display.
  Updated contrib/gregbook
  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
  Updated makefile.ibmc
  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
     of png_write_oFFS width and height from png_uint_32 to png_int_32.
  Updated example.c
  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
version 1.2.0beta5 [August 8, 2001]
  Revised contrib/gregbook
  Revised makefile.gcmmx
  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
     when PNG_THREAD_UNSAFE_OK is defined.
  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
     value exceeding 2^bit_depth-1
  Revised makefile.sgi and makefile.sggcc
  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
  Removed restriction that do_invert_mono only operate on 1-bit opaque files

version 1.2.0 [September 1, 2001]
  Changed a png_warning() to png_debug() in pnggccrd.c
  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
version 1.2.1beta1 [October 19, 2001]
  Revised makefile.std in contrib/pngminus
  Include background_1 in png_struct regardless of gamma support.
  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
  Revised example.c to provide more details about using row_callback().
version 1.2.1beta2 [October 25, 2001]
  Added type cast to each NULL appearing in a function call, except for
    WINCE functions.
  Added makefile.so9.
version 1.2.1beta3 [October 27, 2001]
  Removed type casts from all NULLs.
  Simplified png_create_struct_2().
version 1.2.1beta4 [November 7, 2001]
  Revised png_create_info_struct() and png_creat_struct_2().
  Added error message if png_write_info() was omitted.
  Type cast NULLs appearing in function calls when _NO_PROTO or
    PNG_TYPECAST_NULL is defined.
version 1.2.1rc1 [November 24, 2001]
  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
    is defined.
  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
    the user malloc_fn, to agree with the prototype in png.h
  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
  Updated makefile.sgi to recognize LIBPATH and INCPATH.
  Updated various makefiles so "make clean" does not remove previous major
    version of the shared library.
version 1.2.1rc2 [December 4, 2001]
  Always allocate 256-entry internal palette, hist, and trans arrays, to
    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
  Added a check for prefix_length > data_length in iCCP chunk handler.

version 1.2.1 [December 7, 2001]
  None.
version 1.2.2beta1 [February 22, 2002]
  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
  Revised makefile.darwin to remove "-undefined suppress" option.
  Added checks for gamma and chromaticity values over 21474.83, which exceed
    the limit for PNG unsigned 32-bit integers when encoded.
  Revised calls to png_create_read_struct() and png_create_write_struct()
    for simpler debugging.
  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
version 1.2.2beta2 [February 23, 2002]
  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
  Check for invalid image dimensions in png_get_IHDR.
  Added missing "fi;" in the install target of the SGI makefiles.
  Added install-static to all makefiles that make shared libraries.
  Always do gamma compensation when image is partially transparent.
version 1.2.2beta3 [March 7, 2002]
  Compute background.gray and background_1.gray even when color_type is RGB
    in case image gets reduced to gray later.
  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
  Removed unused png_write_destroy_info prototype from png.h
  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
  Added install-shared target to all makefiles that make shared libraries.
  Stopped a double free of palette, hist, and trans when not using free_me.
  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
version 1.2.2beta4 [March 8, 2002]
  Compute background.gray and background_1.gray even when color_type is RGB
    in case image gets reduced to gray later (Jason Summers).
  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
version 1.2.2beta5 [March 26, 2002]
  Added missing PNGAPI to several function definitions.
  Check for invalid bit_depth or color_type in png_get_IHDR(), and
    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
  Revised iTXt support to accept NULL for lang and lang_key.
  Compute gamma for color components of background even when color_type is gray.
  Changed "()" to "{}" in scripts/libpng.pc.in.
  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
version 1.2.2beta6 [March 31, 2002]
version 1.0.13beta1 [March 31, 2002]
  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
  Ensure that the right function (user or default) is used to free the
    png_struct after an error in png_create_read_struct_2().
version 1.2.2rc1 [April 7, 2002]
version 1.0.13rc1 [April 7, 2002]
  Save the ebx register in pnggccrd.c (Sami Farin)
  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
  Updated makefiles to put headers in include/libpng and remove old include/*.h.

version 1.2.2 [April 15, 2002]
version 1.0.13 [April 15, 2002]
  Revised description of png_set_filter() in libpng.3/libpng.txt.
  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
version 1.0.13patch01 [April 17, 2002]
version 1.2.2patch01 [April 17, 2002]
  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and makefile.sggcc
  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to install
  Added install: target to makefile.32sunu and makefile.64sunu
version 1.0.13patch03 [April 18, 2002]
version 1.2.2patch03 [April 18, 2002]
  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
  subdirectory to libpngNN subdirectory without the full pathname.
  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
version 1.2.3rc1 [April 28, 2002]
  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
  Revised makefile.darwin to make relative links without full pathname.
  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
    to put one in their application.
  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
    removed them from module definition files.
version 1.2.3rc2 [May 1, 2002]
  Fixed bug in reporting number of channels in pngget.c and pngset.c,
    that was introduced in version 1.2.2beta5.
  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
    png_default_flush(), and png_push_fill_buffer() and included them in
    module definition files.
  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
version 1.2.3rc3 [May 1, 2002]
  Revised prototype for png_default_flush()
  Remove old libpng.pc and libpngNN.pc before installing new ones.
version 1.2.3rc4 [May 2, 2002]
  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
  Added libpng-config and libpngNN-config and modified makefiles to install them.
  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
version 1.2.3rc5 [May 11, 2002]
  Changed "error" and "message" in prototypes to "error_message" and
    "warning_message" to avoid namespace conflict.
  Revised 15 mak