xref: /plan9-contrib/sys/src/cmd/gs/libpng/CHANGES (revision 593dc095aefb2a85c828727bbfa9da139a49bdf4) 
1
2CHANGES - changes for libpng
3
4version 0.2
5  added reader into png.h
6  fixed small problems in stub file
7
8version 0.3
9  added pull reader
10  split up pngwrite.c to several files
11  added pnglib.txt
12  added example.c
13  cleaned up writer, adding a few new tranformations
14  fixed some bugs in writer
15  interfaced with zlib 0.5
16  added K&R support
17  added check for 64 KB blocks for 16 bit machines
18
19version 0.4
20  cleaned up code and commented code
21  simplified time handling into png_time
22  created png_color_16 and png_color_8 to handle color needs
23  cleaned up color type defines
24  fixed various bugs
25  made various names more consistant
26  interfaced with zlib 0.71
27  cleaned up zTXt reader and writer (using zlib's Reset functions)
28  split transformations into pngrtran.c and pngwtran.c
29
30version 0.5
31  interfaced with zlib 0.8
32  fixed many reading and writing bugs
33  saved using 3 spaces instead of tabs
34
35version 0.6
36  added png_large_malloc() and png_large_free()
37  added png_size_t
38  cleaned up some compiler warnings
39  added png_start_read_image()
40
41version 0.7
42  cleaned up lots of bugs
43  finished dithering and other stuff
44  added test program
45  changed name from pnglib to libpng
46
47version 0.71 [June, 1995]
48  changed pngtest.png for zlib 0.93
49  fixed error in libpng.txt and example.c
50
51version 0.8
52  cleaned up some bugs
53  added png_set_filler()
54  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
55  added #define's to remove unwanted code
56  moved png_info_init() to png.c
57  added old_size into png_realloc()
58  added functions to manually set filtering and compression info
59  changed compression parameters based on image type
60  optimized filter selection code
61  added version info
62  changed external functions passing floats to doubles (k&r problems?)
63  put all the configurable stuff in pngconf.h
64  enabled png_set_shift to work with paletted images on read
65  added png_read_update_info() - updates info structure with
66     transformations
67
68version 0.81 [August, 1995]
69  incorporated Tim Wegner's medium model code (thanks, Tim)
70
71version 0.82 [September, 1995]
72  [unspecified changes]
73
74version 0.85 [December, 1995]
75  added more medium model code (almost everything's a far)
76  added i/o, error, and memory callback functions
77  fixed some bugs (16 bit, 4 bit interlaced, etc.)
78  added first run progressive reader (barely tested)
79
80version 0.86 [January, 1996]
81  fixed bugs
82  improved documentation
83
84version 0.87 [January, 1996]
85  fixed medium model bugs
86  fixed other bugs introduced in 0.85 and 0.86
87  added some minor documentation
88
89version 0.88 [January, 1996]
90  fixed progressive bugs
91  replaced tabs with spaces
92  cleaned up documentation
93  added callbacks for read/write and warning/error functions
94
95version 0.89 [July, 1996]
96  added new initialization API to make libpng work better with shared libs
97     we now have png_create_read_struct(), png_create_write_struct(),
98     png_create_info_struct(), png_destroy_read_struct(), and
99     png_destroy_write_struct() instead of the separate calls to
100     malloc and png_read_init(), png_info_init(), and png_write_init()
101  changed warning/error callback functions to fix bug - this means you
102     should use the new initialization API if you were using the old
103     png_set_message_fn() calls, and that the old API no longer exists
104     so that people are aware that they need to change their code
105  changed filter selection API to allow selection of multiple filters
106     since it didn't work in previous versions of libpng anyways
107  optimized filter selection code
108  fixed png_set_background() to allow using an arbitrary RGB color for
109     paletted images
110  fixed gamma and background correction for paletted images, so
111     png_correct_palette is not needed unless you are correcting an
112     external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
113     in pngconf.h) - if nobody uses this, it may disappear in the future.
114  fixed bug with Borland 64K memory allocation (Alexander Lehmann)
115  fixed bug in interlace handling (Smarasderagd, I think)
116  added more error checking for writing and image to reduce invalid files
117  separated read and write functions so that they won't both be linked
118     into a binary when only reading or writing functionality is used
119  new pngtest image also has interlacing and zTXt
120  updated documentation to reflect new API
121
122version 0.90 [January, 1997]
123  made CRC errors/warnings on critical and ancillary chunks configurable
124  libpng will use the zlib CRC routines by (compile-time) default
125  changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
126  added external C++ wrapper statements to png.h (Gilles Dauphin)
127  allow PNG file to be read when some or all of file signature has already
128     been read from the beginning of the stream.  ****This affects the size
129     of info_struct and invalidates all programs that use a shared libpng****
130  fixed png_filler() declarations
131  fixed? background color conversions
132  fixed order of error function pointers to match documentation
133  current chunk name is now available in png_struct to reduce the number
134     of nearly identical error messages (will simplify multi-lingual
135     support when available)
136  try to get ready for unknown-chunk callback functions:
137     - previously read critical chunks are flagged, so the chunk handling
138       routines can determine if the chunk is in the right place
139     - all chunk handling routines have the same prototypes, so we will
140       be able to handle all chunks via a callback mechanism
141  try to fix Linux "setjmp" buffer size problems
142  removed png_large_malloc, png_large_free, and png_realloc functions.
143
144version 0.95 [March, 1997]
145  fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
146  fixed bug in PNG file signature compares when start != 0
147  changed parameter type of png_set_filler(...filler...) from png_byte
148     to png_uint_32
149  added test for MACOS to ensure that both math.h and fp.h are not #included
150  added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
151  added "packswap" transformation, which changes the endianness of
152     packed-pixel bytes (Kevin Bracey)
153  added "strip_alpha" transformation, which removes the alpha channel of
154     input images without using it (not neccesarily a good idea)
155  added "swap_alpha" transformation, which puts the alpha channel in front
156     of the color bytes instead of after
157  removed all implicit variable tests which assume NULL == 0 (I think)
158  changed several variables to "png_size_t" to show 16/32-bit limitations
159  added new pCAL chunk read/write support
160  added experimental filter selection weighting (Greg Roelofs)
161  removed old png_set_rgbx() and png_set_xrgb() functions that have been
162     obsolete for about 2 years now (use png_set_filler() instead)
163  added macros to read 16- and 32-bit ints directly from buffer, to be
164     used only on those systems that support it (namely PowerPC and 680x0)
165     With some testing, this may become the default for MACOS/PPC systems.
166  only calculate CRC on data if we are going to use it
167  added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
168  added macros for simple libpng debugging output selectable at compile time
169  removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
170  more description of info_struct in libpng.txt and png.h
171  more instructions in example.c
172  more chunk types tested in pngtest.c
173  renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
174     png_set_<chunk>.  We now have corresponding png_get_<chunk>
175     functions in pngget.c to get infomation in info_ptr.  This isolates
176     the application from the internal organization of png_info_struct
177     (good for shared library implementations).
178
179version 0.96 [May, 1997]
180  fixed serious bug with < 8bpp images introduced in 0.95
181  fixed 256-color transparency bug (Greg Roelofs)
182  fixed up documentation (Greg Roelofs, Laszlo Nyul)
183  fixed "error" in pngconf.h for Linux setjmp() behaviour
184  fixed DOS medium model support (Tim Wegner)
185  fixed png_check_keyword() for case with error in static string text
186  added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
187  added typecasts to quiet compiler errors
188  added more debugging info
189
190version 0.97 [January, 1998]
191  removed PNG_USE_OWN_CRC capability
192  relocated png_set_crc_action from pngrutil.c to pngrtran.c
193  fixed typecasts of "new_key", etc. (Andreas Dilger)
194  added RFC 1152 [sic] date support
195  fixed bug in gamma handling of 4-bit grayscale
196  added 2-bit grayscale gamma handling (Glenn R-P)
197  added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
198  minor corrections in libpng.txt
199  added simple sRGB support (Glenn R-P)
200  easier conditional compiling, e.g. define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
201     all configurable options can be selected from command-line instead
202     of having to edit pngconf.h (Glenn R-P)
203  fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
204  added more conditions for png_do_background, to avoid changing
205     black pixels to background when a background is supplied and
206     no pixels are transparent
207  repaired PNG_NO_STDIO behaviour
208  tested NODIV support and made it default behaviour (Greg Roelofs)
209  added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
210  regularized version numbering scheme and bumped shared-library major
211     version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
212
213version 0.98 [January, 1998]
214  cleaned up some typos in libpng.txt and in code documentation
215  fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
216  cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
217  changed recommendation about file_gamma for PC images to .51 from .45,
218     in example.c and libpng.txt, added comments to distinguish between
219     screen_gamma, viewing_gamma, and display_gamma.
220  changed all references to RFC1152 to read RFC1123 and changed the
221     PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
222  added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
223  changed srgb_intent from png_byte to int to avoid compiler bugs
224
225version 0.99 [January 30, 1998]
226  free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
227  fixed a longstanding "packswap" bug in pngtrans.c
228  fixed some inconsistencies in pngconf.h that prevented compiling with
229     PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
230  fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
231  changed recommendation about file_gamma for PC images to .50 from .51 in
232     example.c and libpng.txt, and changed file_gamma for sRGB images to .45
233  added a number of functions to access information from the png structure
234     png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
235  added TARGET_MACOS similar to zlib-1.0.8
236  define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
237  added type casting to all png_malloc() function calls
238version 0.99a [January 31, 1998]
239  Added type casts and parentheses to all returns that return a value.(Tim W.)
240version 0.99b [February 4, 1998]
241  Added type cast png_uint_32 on malloc function calls where needed.
242  Changed type of num_hist from png_uint_32 to int (same as num_palette).
243  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
244  Renamed makefile.elf to makefile.lnx.
245version 0.99c [February 7, 1998]
246  More type casting.  Removed erroneous overflow test in pngmem.c.
247  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
248  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
249version 0.99d [February 11, 1998]
250  Renamed "far_to_near()" "png_far_to_near()"
251  Revised libpng.3
252  Version 99c "buffered" operations didn't work as intended.  Replaced them
253    with png_memcpy_check() and png_memset_check().
254  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
255    unused png_ptr, mostly in pngget.c and pngset.c.
256  Check for overlength tRNS chunk present when indexed-color PLTE is read.
257  Cleaned up spelling errors in libpng.3/libpng.txt
258  Corrected a problem with png_get_tRNS() which returned undefined trans array
259version 0.99e [February 28, 1998]
260  Corrected png_get_tRNS() again.
261  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
262  Touched up example.c to make more of it compileable, although the entire
263    file still can't be compiled (Willem van Schaik)
264  Fixed a bug in png_do_shift() (Bryan Tsai)
265  Added a space in png.h prototype for png_write_chunk_start()
266  Replaced pngtest.png with one created with zlib 1.1.1
267  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
268  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
269version 0.99f [March 5, 1998]
270  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
271  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
272  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
273  Added pointers to "note on libpng versions" in makefile.lnx and README
274  Added row callback feature when reading and writing nonprogressive rows
275     and added a test of this feature in pngtest.c
276  Added user transform callbacks, with test of the feature in pngtest.c
277version 0.99g [March 6, 1998, morning]
278  Minor changes to pngtest.c to suppress compiler warnings.
279  Removed "beta" language from documentation.
280version 0.99h [March 6, 1998, evening]
281  Minor changes to previous minor changes to pngtest.c
282  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
283  and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
284  Added user transform capability
285
286version 1.00 [March 7, 1998]
287  Changed several typedefs in pngrutil.c
288  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
289  replaced "while(1)" with "for(;;)"
290  added PNGARG() to prototypes in pngtest.c and removed some prototypes
291  updated some of the makefiles (Tom Lane)
292  changed some typedefs (s_start, etc.) in pngrutil.c
293  fixed dimensions of "short_months" array in pngwrite.c
294  Replaced ansi2knr.c with the one from jpeg-v6
295
296version 1.0.0 [March 8, 1998]
297  Changed name from 1.00 to 1.0.0 (Adam Costello)
298  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
299version 1.0.0a [March 9, 1998]
300  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
301  (Greg Roelofs)
302  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
303  for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
304  Tom Lane)
305  Make months range from 1-12 in png_convert_to_rfc1123
306version 1.0.0b [March 13, 1998]
307  Quieted compiler complaints about two empty "for" loops in pngrutil.c
308  Minor changes to makefile.s2x
309  Removed #ifdef/#endif around a png_free() in pngread.c
310
311version 1.0.1 [March 14, 1998]
312  Changed makefile.s2x to reduce security risk of using a relative pathname
313  Fixed some typos in the documentation (Greg).
314  Fixed a problem with value of "channels" returned by png_read_update_info()
315version 1.0.1a [April 21, 1998]
316  Optimized Paeth calculations by replacing abs() function calls with intrinsics
317  plus other loop optimizations. Improves avg decoding speed by about 20%.
318  Commented out i386istic "align" compiler flags in makefile.lnx.
319  Reduced the default warning level in some makefiles, to make them consistent.
320  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
321  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
322  Added grayscale and 16-bit capability to png_do_read_filler().
323  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
324    too large when writing an image with bit_depth < 8 (Bob Dellaca).
325  Corrected some bugs in the experimental weighted filtering heuristics.
326  Moved a misplaced pngrutil code block that truncates tRNS if it has more
327    than num_palette entries -- test was done before num_palette was defined.
328  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
329  Changed compiler flags in makefile.wat for better optimization (Pawel Mrochen).
330version 1.0.1b [May 2, 1998]
331  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
332  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
333  Added makefile.sco (contributed by Mike Hopkirk).
334  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
335  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
336  More work on the Paeth-filtering, achieving imperceptible speedup (A Kleinert).
337  More work on loop optimization which may help when compiled with C++ compilers.
338  Added warnings when people try to use transforms they've defined out.
339  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
340  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
341version 1.0.1c [May 11, 1998]
342  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
343    filler bytes should have been 0xff instead of 0xf.
344  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
345  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
346    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
347  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
348    for consistency, in pngconf.h
349  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
350    to remove unwanted capabilities via the compile line
351  Made some corrections to grammar (which, it's) in documentation (Greg).
352  Corrected example.c, use of row_pointers in png_write_image().
353version 1.0.1d [May 24, 1998]
354  Corrected several statements that used side effects illegally in pngrutil.c
355    and pngtrans.c, that were introduced in version 1.0.1b
356  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
357  More corrections to example.c, use of row_pointers in png_write_image()
358    and png_read_rows().
359  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
360    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
361  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
362  Changed several loops from count-down to count-up, for consistency.
363version 1.0.1e [June 6, 1998]
364  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
365    added warnings when people try to set png_read_fn and png_write_fn in
366    the same structure.
367  Added a test such that png_do_gamma will be done when num_trans==0
368    for truecolor images that have defined a background.  This corrects an
369    error that was introduced in libpng-0.90 that can cause gamma processing
370    to be skipped.
371  Added tests in png.h to include "trans" and "trans_values" in structures
372    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
373  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
374  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
375  Added capability for user-provided malloc_fn() and free_fn() functions,
376    and revised pngtest.c to demonstrate their use, replacing the
377    PNGTEST_DEBUG_MEM feature.
378  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
379
380version 1.0.2 [June 14, 1998]
381  Fixed two bugs in makefile.bor .
382version 1.0.2a [December 30, 1998]
383  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
384  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
385    the left-most pixel of each row (Kevin Bracey).
386  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
387    in pngtest.c (Duncan Simpson).
388  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
389    even when no tIME chunk was present in the source file.
390  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
391  Fixed a problem in png_read_push_finish_row(), which would not skip some
392    passes that it should skip, for images that are less than 3 pixels high.
393  Interchanged the order of calls to png_do_swap() and png_do_shift()
394    in pngwtran.c (John Cromer).
395  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
396  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
397  Fixed a documentation error about default filtering with 8-bit indexed-color.
398  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
399    (L. Peter Deutsch).
400  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
401  Added png_get_copyright() and png_get_header_version() functions.
402  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
403  Added information about debugging in libpng.txt and libpng.3 .
404  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and makefile.sco.
405  Removed lines after Dynamic Dependencies" in makefile.aco .
406  Revised makefile.dec to make a shared library (Jeremie Petit).
407  Removed trailing blanks from all files.
408version 1.0.2a [January 6, 1999]
409  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
410  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
411  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
412  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
413    which is obsolete.
414
415version 1.0.3 [January 14, 1999]
416  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
417  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
418version 1.0.3a [August 12, 1999]
419  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
420     if an attempt is made to read an interlaced image when it's not supported.
421  Added check if png_ptr->trans is defined before freeing it in pngread.c
422  Modified the Y2K statement to include versions back to version 0.71
423  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
424  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
425  Replaced leading blanks with tab characters in makefile.hux
426  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
427  Changed (float)red and (float)green to (double)red, (double)green
428     in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
429  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
430  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
431  Updated documentation to refer to the PNG-1.2 specification.
432  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
433    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
434  Fixed bugs in calculation of the length of rowbytes when adding alpha
435    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
436  Added function png_set_user_transform_info() to store user_transform_ptr,
437    user_depth, and user_channels into the png_struct, and a function
438    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
439  Added function png_set_empty_plte_permitted() to make libpng useable
440    in MNG applications.
441  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
442  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
443    consistent with PNG-1.2, and allow variance of 500 before complaining.
444  Added assembler code contributed by Intel in file pngvcrd.c and modified
445    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation, Gilles Vollant)
446  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
447  Added some aliases for png_set_expand() in pngrtran.c, namely
448    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
449    (Greg Roelofs, in "PNG: The Definitive Guide").
450  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
451version 1.0.3b [August 26, 1999]
452  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
453  Changed leading blanks to tabs in all makefiles.
454  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
455  Made alternate versions of  png_set_expand() in pngrtran.c, namely
456    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
457    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
458  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
459  Revised calculation of num_blocks in pngmem.c to avoid a potentially
460    negative shift distance, whose results are undefined in the C language.
461  Added a check in pngset.c to prevent writing multiple tIME chunks.
462  Added a check in pngwrite.c to detect invalid small window_bits sizes.
463version 1.0.3d [September 4, 1999]
464  Fixed type casting of igamma in pngrutil.c
465  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
466  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
467
468version 1.0.4 [September 24, 1999]
469  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
470  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
471  Made several minor corrections to pngtest.c
472  Renamed the makefiles with longer but more user friendly extensions.
473  Copied the PNG copyright and license to a separate LICENSE file.
474  Revised documentation, png.h, and example.c to remove reference to
475    "viewing_gamma" which no longer appears in the PNG specification.
476  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
477  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
478  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
479    assembler code) and makefile.vcwin32 (doesn't).
480  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
481  Added a copy of pngnow.png to the distribution.
482version 1.0.4a [September 25, 1999]
483  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
484  Changed several division operations to right-shifts in pngvcrd.c
485version 1.0.4b [September 30, 1999]
486  Added parentheses in line 3732 of pngvcrd.c
487  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
488version 1.0.4c [October 1, 1999]
489  Added a "png_check_version" function in png.c and pngtest.c that will generate
490    a helpful compiler error if an old png.h is found in the search path.
491  Changed type of png_user_transform_depth|channels from int to png_byte.
492version 1.0.4d [October 6, 1999]
493  Changed 0.45 to 0.45455 in png_set_sRGB()
494  Removed unused PLTE entries from pngnow.png
495  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
496version 1.0.4e [October 10, 1999]
497  Fixed sign error in pngvcrd.c (Greg Roelofs)
498  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
499version 1.0.4f [October 15, 1999]
500  Surrounded example.c code with #if 0 .. #endif to prevent people from
501    inadvertently trying to compile it.
502  Changed png_get_header_version() from a function to a macro in png.h
503  Added type casting mostly in pngrtran.c and pngwtran.c
504  Removed some pointless "ptr = NULL" in pngmem.c
505  Added a "contrib" directory containing the source code from Greg's book.
506
507version 1.0.5 [October 15, 1999]
508  Minor editing of the INSTALL and README files.
509version 1.0.5a [October 23, 1999]
510  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
511  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
512  Further optimization and bugfix of pngvcrd.c
513  Revised pngset.c so that it does not allocate or free memory in the user's
514    text_ptr structure.  Instead, it makes its own copy.
515  Created separate write_end_info_struct in pngtest.c for a more severe test.
516  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
517version 1.0.5b [November 23, 1999]
518  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
519    PNG_FLAG_WROTE_tIME from flags to mode.
520  Added png_write_info_before_PLTE() function.
521  Fixed some typecasting in contrib/gregbook/*.c
522  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
523    and contrib/pngminus (Martin Zinser)
524version 1.0.5c [November 26, 1999]
525  Moved png_get_header_version from png.h to png.c, to accomodate ansi2knr.
526  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
527    accomodate making DLL's: Moved usr_png_ver from global variable to function
528    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
529    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
530    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
531    png_CHNK and png_pass arrays to be "const".  Made the global arrays
532    available to applications (although none are used in libpng itself) when
533    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
534  Removed some extraneous "-I" from contrib/pngminus/makefile.std
535  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
536  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
537version 1.0.5d [November 29, 1999]
538  Add type cast (png_const_charp) two places in png.c
539  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
540  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
541    to applications a macro "PNG_USE_LOCAL_ARRAYS".
542  #ifdef out all the new declarations when PNG_USE_GLOBAL_ARRAYS is defined.
543  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
544version 1.0.5e [November 30, 1999]
545  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
546    structure; refactored the inflate/deflate support to make adding new chunks
547    with trailing compressed parts easier in the future, and added new functions
548    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
549    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
550  NOTE: Applications that write text chunks MUST define png_text->lang
551    before calling png_set_text(). It must be set to NULL if you want to
552    write tEXt or zTXt chunks.  If you want your application to be able to
553    run with older versions of libpng, use
554
555      #ifdef PNG_iTXt_SUPPORTED
556         png_text[i].lang = NULL;
557      #endif
558
559  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
560    offsets (Eric S. Raymond).
561  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
562    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
563    macros, leaving the separate macros also available.
564  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
565version 1.0.5f [December 6, 1999]
566  Changed makefile.solaris to issue a warning about potential problems when
567    the ucb "ld" is in the path ahead of the ccs "ld".
568  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
569  Added sCAL chunk support (Eric S. Raymond).
570version 1.0.5g [December 7, 1999]
571  Fixed "png_free_spallettes" typo in png.h
572  Added code to handle new chunks in pngpread.c
573  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
574  Added "translated_key" to png_text structure and png_write_iTXt().
575  Added code in pngwrite.c to work around a newly discovered zlib bug.
576version 1.0.5h [December 10, 1999]
577  NOTE: regarding the note for version 1.0.5e, the following must also
578    be included in your code:
579        png_text[i].translated_key = NULL;
580  Unknown chunk handling is now supported.
581  Option to eliminate all floating point support was added.  Some new
582    fixed-point functions such as png_set_gAMA_fixed() were added.
583  Expanded tabs and removed trailing blanks in source files.
584version 1.0.5i [December 13, 1999]
585  Added some type casts to silence compiler warnings.
586  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
587  Removed leading blanks from a #define in pngvcrd.c
588  Added some parameters to the new png_set_keep_unknown_chunks() function.
589  Added a test for up->location != 0 in the first instance of writing
590    unknown chunks in pngwrite.c
591  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
592    prevent recursion.
593  Added png_free_hIST() function.
594  Various patches to fix bugs in the sCAL and integer cHRM processing,
595    and to add some convenience macros for use with sCAL.
596version 1.0.5j [December 21, 1999]
597  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
598    around buggy compilers.
599  Added new type "png_fixed_point" for integers that hold float*100000 values
600  Restored backward compatibility of tEXt/zTXt chunk processing:
601    Restored the first four members of png_text to the same order as v.1.0.5d.
602    Added members "lang_key" and "itxt_length" to png_text struct.  Set
603    text_length=0 when "text" contains iTXt data.  Use the "compression"
604    member to distinguish among tEXt/zTXt/iTXt types.  Added
605    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
606    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
607    longer applies.
608  Fixed png_read|write_iTXt() to read|write parameters in the right order,
609    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
610  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
611  Reversed the order of trying to write floating-point and fixed-point gAMA.
612version 1.0.5k [December 27, 1999]
613  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
614  Added png_handle_as_unknown() function (Glenn)
615  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
616    of png_ptr.
617  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
618  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
619    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
620  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
621  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
622  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
623version 1.0.5l [January 1, 2000]
624  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
625    for setting a callback function to handle unknown chunks and for
626    retrieving the associated user pointer (Glenn).
627version 1.0.5m [January 7, 2000]
628  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
629version 1.0.5n [January 9, 2000]
630  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
631    own memory for info_ptr->palette.  This makes it safe for the calling
632    application to free its copy of the palette any time after it calls
633    png_set_PLTE().
634version 1.0.5o [January 20, 2000]
635  Cosmetic changes only (removed some trailing blanks and TABs)
636version 1.0.5p [January 31, 2000]
637  Renamed pngdll.mak to makefile.bd32
638  Cosmetic changes in pngtest.c
639version 1.0.5q [February 5, 2000]
640  Relocated the makefile.solaris warning about PATH problems.
641  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
642  Revised makefile.gcmmx
643  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
644version 1.0.5r [February 7, 2000]
645  Removed superfluous prototype for png_get_itxt from png.h
646  Fixed a bug in pngrtran.c that improperly expanded the background color.
647  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
648    of png_get_text() in libpng.txt/libpng.3.
649version 1.0.5s [February 18, 2000]
650  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
651    new error handler that's planned for the next libpng release, and changed
652    example.c, pngtest.c, and contrib programs to use this macro.
653  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
654  Fixed a bug in png_read_png() that caused it to fail to expand some images
655    that it should have expanded.
656  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
657    in pngget.c
658  Changed the allocation of palette, history, and trans arrays back to
659    the version 1.0.5 method (linking instead of copying) which restores
660    backward compatibility with version 1.0.5.  Added some remarks about
661    that in example.c.  Added "free_me" member to info_ptr and png_ptr
662    and added png_free_data() function.
663  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
664  Made cosmetic changes to pngasmrd.h
665  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
666  Modified png_read_png() to allocate info_ptr->row_pointers only if it
667    hasn't already been allocated.
668version 1.0.5t [March 4, 2000]
669  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
670  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
671  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
672    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
673  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
674    a 24-bit visual if one is available, and to allow abbreviated options.
675  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
676  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
677version 1.0.5u [March 5, 2000]
678  Simplified the code that detects old png.h in png.c and pngtest.c
679  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
680  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
681    added png_set_rgb_to_gray_fixed() function.
682  Added makefile.bc32 (32-bit Borland C++, C mode)
683version 1.0.5v [March 11, 2000]
684  Added some parentheses to the png_jmpbuf macro definition.
685  Updated references to the zlib home page, which has moved to freesoftware.com.
686  Corrected bugs in documentation regarding png_read_row() and png_write_row().
687  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
688  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
689    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
690
691version 1.0.6 [March 20, 2000]
692  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
693  Added makefile.sggcc (SGI IRIX with gcc)
694version 1.0.6d [April 7, 2000]
695  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
696  Added data_length parameter to png_decompress_chunk() function
697  Revised documentation to remove reference to abandoned png_free_chnk functions
698  Fixed an error in png_rgb_to_gray_fixed()
699  Revised example.c, usage of png_destroy_write_struct().
700  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
701  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
702  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
703version 1.0.6e [April 9, 2000]
704  Added png_data_freer() function.
705  In the code that checks for over-length tRNS chunks, added check of
706    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
707  Minor revisions of libpng.txt/libpng.3.
708  Check for existing data and free it if the free_me flag is set, in png_set_*()
709    and png_handle_*().
710  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
711    is defined.
712  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
713    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
714version 1.0.6f [April 14, 2000]
715  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
716  Add checks in png_set_text() for NULL members of the input text structure.
717  Revised libpng.txt/libpng.3.
718  Removed superfluous prototype for png_set_itxt from png.h
719  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
720  Changed several png_errors about malformed ancillary chunks to png_warnings.
721version 1.0.6g [April 24, 2000]
722  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
723  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
724    and other revisions (Matthias Benckmann)
725  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
726    png_ptr members to restore binary compatibility with libpng-1.0.5
727    (breaks compatibility with libpng-1.0.6).
728version 1.0.6h [April 24, 2000]
729  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
730    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
731    This is a temporary change for test purposes.
732version 1.0.6i [May 2, 2000]
733  Rearranged some members at the end of png_info and png_struct, to put
734    unknown_chunks_num and free_me within the original size of the png_structs
735    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
736    because some old applications allocate the structs directly instead of
737    using png_create_*().
738  Added documentation of user memory functions in libpng.txt/libpng.3
739  Modified png_read_png so that it will use user_allocated row_pointers
740    if present, unless free_me directs that it be freed, and added description
741    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
742  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
743    1.00) members of png_struct and png_info, to regain binary compatibility
744    when you define this macro.  Capabilities lost in this event
745    are user transforms (new in version 1.0.0),the user transform pointer
746    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
747    the high-level interface, and unknown chunks support (all new in 1.0.6).
748    This was necessary because of old applications that allocate the structs
749    directly as authors were instructed to do in libpng-0.88 and earlier,
750    instead of using png_create_*().
751  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
752    can be used to detect codes that directly allocate the structs, and
753    code to check these modes in png_read_init() and png_write_init() and
754    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
755    was not defined.
756  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
757version 1.0.6j [May 3, 2000]
758  Overloaded png_read_init() and png_write_init() with macros that convert
759    calls to png_read_init_2() or png_write_init_2() that check the version
760    and structure sizes.
761version 1.0.7beta11 [May 7, 2000]
762  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
763    which are no longer used.
764  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
765    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
766    is defined.
767  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
768    overrun when old applications fill the info_ptr->text structure directly.
769  Added PNGAPI macro, and added it to the definitions of all exported functions.
770  Relocated version macro definitions ahead of the includes of zlib.h and
771    pngconf.h in png.h.
772version 1.0.7beta12 [May 12, 2000]
773  Revised pngset.c to avoid a problem with expanding the png_debug macro.
774  Deleted some extraneous defines from pngconf.h
775  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
776  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
777  Added png_access_version_number() function.
778  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
779  Expanded libpng.3/libpng.txt information about png_data_freer().
780version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
781  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
782    warnings instead of errors, as pngrutil.c does.
783  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
784    will actually write IDATs.
785  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
786  Make png_free_data() ignore its final parameter except when freeing data
787    that can have multiple instances (text, sPLT, unknowns).
788  Fixed a new bug in png_set_rows().
789  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
790  Added png_set_invalid() function.
791  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
792version 1.0.7beta15 [May 30, 2000]
793  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
794    fewer error messages.
795  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
796    and pngwutil.c.
797  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
798    in libpng.txt/libpng.3 the need for applications to check this.
799  Changed names of png_default_*() functions in pngtest to pngtest_*().
800  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
801  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
802  Set each pointer to NULL after freeing it in png_free_data().
803  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
804    macro that conflicts with libpng's png_color_16.index. (Dimitri Papadapoulos)
805  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
806version 1.0.7beta16 [June 4, 2000]
807  Revised the workaround of AIX string.h "index" bug.
808  Added a check for overlength PLTE chunk in pngrutil.c.
809  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
810    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
811  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
812    when it tries to read an erroneous PhotoShop iCCP chunk.
813  Added PNG_USE_DLL macro.
814  Revised the copyright/disclaimer/license notice.
815  Added contrib/msvctest directory
816version 1.0.7rc1 [June 9, 2000]
817  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
818  Added contrib/visupng directory (Willem van Schaik)
819version 1.0.7beta18 [June 23, 2000]
820  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
821    and do not redefine PNGAPI if it is passed in via a compiler directive.
822  Revised visupng/PngFile.c to remove returns from within the Try block.
823  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
824  Updated contrib/visupng/cexcept.h to version 1.0.0.
825  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
826version 1.0.7rc2 [June 28, 2000]
827  Updated license to include disclaimers required by UCITA.
828  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
829
830version 1.0.7 [July 1, 2000]
831  Revised the definition of "trans_values" in libpng.3/libpng.txt
832version 1.0.8beta1 [July 8, 2000]
833  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
834  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
835     pngwutil.c.
836  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
837  Removed unused "#include <assert.h>" from png.c
838  Added WindowsCE support.
839  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
840version 1.0.8beta2 [July 10, 2000]
841  Added project files to the wince directory and made further revisions
842     of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
843version 1.0.8beta3 [July 11, 2000]
844  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
845     for indexed-color input files to avoid potential double-freeing trans array
846     under some unusual conditions; problem was introduced in version 1.0.6f.
847  Further revisions to pngtest.c and files in the wince subdirectory.
848version 1.0.8beta4 [July 14, 2000]
849  Added the files pngbar.png and pngbar.jpg to the distribution.
850  Added makefile.cygwin, and cygwin support in pngconf.h
851  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
852version 1.0.8rc1 [July 16, 2000]
853  Revised png_debug() macros and statements to eliminate compiler warnings.
854
855version 1.0.8 [July 24, 2000]
856  Added png_flush() in pngwrite.c, after png_write_IEND().
857  Updated makefile.hpux to build a shared library.
858version 1.0.9beta1 [November 10, 2000]
859  Fixed typo in scripts/makefile.hpux
860  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
861  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
862  Changed "cdrom.com" in documentation to "libpng.org"
863  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
864  Changed type of "params" from voidp to png_voidp in png_read|write_png().
865  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
866  Revised the 3 instances of WRITEFILE in pngtest.c.
867  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
868  Updated png.rc in dll/msvc project
869  Revised makefile.dec to define and use LIBPATH and INCPATH
870  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
871  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
872  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
873  Added a warning when application calls png_read_update_info() multiple times.
874  Revised makefile.cygwin
875  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
876  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
877version 1.0.9beta2 [November 19, 2000]
878  Renamed the "dll" subdirectory "projects".
879  Added borland project files to "projects" subdirectory.
880  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
881  Add error message in png_set_compression_buffer_size() when malloc fails.
882version 1.0.9beta3 [November 23, 2000]
883  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
884  Removed the png_flush() in pngwrite.c that crashes some applications
885    that don't set png_output_flush_fn.
886  Added makefile.macosx and makefile.aix to scripts directory.
887version 1.0.9beta4 [December 1, 2000]
888  Change png_chunk_warning to png_warning in png_check_keyword().
889  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
890version 1.0.9beta5 [December 15, 2000]
891  Added support for filter method 64 (for PNG datastreams embedded in MNG).
892version 1.0.9beta6 [December 18, 2000]
893  Revised png_set_filter() to accept filter method 64 when appropriate.
894  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
895    help prevent applications from using MNG features in PNG datastreams.
896  Added png_permit_mng_features() function.
897  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
898version 1.0.9rc1 [December 23, 2000]
899  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
900  Fixed error handling of unknown compression type in png_decompress_chunk().
901  In pngconf.h, define __cdecl when _MSC_VER is defined.
902version 1.0.9beta7 [December 28, 2000]
903  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
904  Revised memory management in png_set_hIST and png_handle_hIST in a backward
905    compatible manner.  PLTE and tRNS were revised similarly.
906  Revised the iCCP chunk reader to ignore trailing garbage.
907version 1.0.9beta8 [January 12, 2001]
908  Moved pngasmrd.h into pngconf.h.
909  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
910version 1.0.9beta9 [January 15, 2001]
911  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
912    wince and msvc project module definition files.
913  Minor revision of makefile.cygwin.
914  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
915version 1.0.9beta10 [January 16, 2001]
916  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
917  Fixed "png_mmx_supported" typo in project definition files.
918version 1.0.9beta11 [January 19, 2001]
919  Updated makefile.sgi to make shared library.
920  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
921    by default, for the benefit of DLL forward compatibility.  These will
922    be re-enabled in version 1.2.0.
923version 1.0.9rc2 [January 22, 2001]
924  Revised cygwin support.
925
926version 1.0.9 [January 31, 2001]
927  Added check of cygwin's ALL_STATIC in pngconf.h
928  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
929version 1.0.10beta1 [March 14, 2001]
930  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
931  Reformatted libpng.3 to eliminate bad line breaks.
932  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
933  Added prototype for png_mmx_support() near the top of pnggccrd.c
934  Moved some error checking from png_handle_IHDR to png_set_IHDR.
935  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
936  Revised png_mmx_support() function in pnggccrd.c
937  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
938  Fixed memory leak in contrib/visupng/PngFile.c
939  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
940  Added warnings when retrieving or setting gamma=0.
941  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
942version 1.0.10rc1 [March 23, 2001]
943  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
944    and png_strlen.
945  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
946  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
947
948version 1.0.10 [March 30, 2001]
949  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
950  Added beos project files (Chris Herborth)
951version 1.0.11beta1 [April 3, 2001]
952  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
953  Removed a no-longer needed AIX work-around from pngconf.h
954  Changed several "//" single-line comments to C-style in pnggccrd.c
955version 1.0.11beta2 [April 11, 2001]
956  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
957  Updated scripts/pngos2.def
958version 1.0.11beta3 [April 14, 2001]
959  Added checking the results of many instances of png_malloc() for NULL
960version 1.0.11beta4 [April 20, 2001]
961  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
962    from user's malloc_fn().
963  Removed some useless type casts of the NULL pointer.
964  Added makefile.netbsd
965
966version 1.0.11 [April 27, 2001]
967  Revised makefile.netbsd
968version 1.0.12beta1 [May 14, 2001]
969  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
970  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
971  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
972  Eliminated the png_error about apps using png_read|write_init().  Instead,
973    libpng will reallocate the png_struct and info_struct if they are too small.
974    This retains future binary compatibility for old applications written for
975    libpng-0.88 and earlier.
976version 1.2.0beta1 [May 6, 2001]
977  Bumped DLLNUM to 2.
978  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
979    by default.
980  Added runtime selection of MMX features.
981  Added png_set_strip_error_numbers function and related macros.
982version 1.2.0beta2 [May 7, 2001]
983  Finished merging 1.2.0beta1 with version 1.0.11
984  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
985version 1.2.0beta3 [May 17, 2001]
986  Enabled user memory function by default.
987  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
988  Increased png_mng_features flag from png_byte to png_uint_32.
989  Bumped shared-library (so-number) and dll-number to 3.
990version 1.2.0beta4 [June 23, 2001]
991  Check for missing profile length field in iCCP chunk and free chunk_data
992     in case of truncated iCCP chunk.
993  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
994  Bumped dll-number from 2 to 3 in makefile.cygwin
995  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
996     if user attempts to run it on an 8-bit display.
997  Updated contrib/gregbook
998  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
999  Updated makefile.ibmc
1000  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
1001     of png_write_oFFS width and height from png_uint_32 to png_int_32.
1002  Updated example.c
1003  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
1004version 1.2.0beta5 [August 8, 2001]
1005  Revised contrib/gregbook
1006  Revised makefile.gcmmx
1007  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
1008     when PNG_THREAD_UNSAFE_OK is defined.
1009  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
1010     value exceeding 2^bit_depth-1
1011  Revised makefile.sgi and makefile.sggcc
1012  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
1013  Removed restriction that do_invert_mono only operate on 1-bit opaque files
1014
1015version 1.2.0 [September 1, 2001]
1016  Changed a png_warning() to png_debug() in pnggccrd.c
1017  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
1018version 1.2.1beta1 [October 19, 2001]
1019  Revised makefile.std in contrib/pngminus
1020  Include background_1 in png_struct regardless of gamma support.
1021  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
1022  Revised example.c to provide more details about using row_callback().
1023version 1.2.1beta2 [October 25, 2001]
1024  Added type cast to each NULL appearing in a function call, except for
1025    WINCE functions.
1026  Added makefile.so9.
1027version 1.2.1beta3 [October 27, 2001]
1028  Removed type casts from all NULLs.
1029  Simplified png_create_struct_2().
1030version 1.2.1beta4 [November 7, 2001]
1031  Revised png_create_info_struct() and png_creat_struct_2().
1032  Added error message if png_write_info() was omitted.
1033  Type cast NULLs appearing in function calls when _NO_PROTO or
1034    PNG_TYPECAST_NULL is defined.
1035version 1.2.1rc1 [November 24, 2001]
1036  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
1037    is defined.
1038  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
1039    the user malloc_fn, to agree with the prototype in png.h
1040  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
1041  Updated makefile.sgi to recognize LIBPATH and INCPATH.
1042  Updated various makefiles so "make clean" does not remove previous major
1043    version of the shared library.
1044version 1.2.1rc2 [December 4, 2001]
1045  Always allocate 256-entry internal palette, hist, and trans arrays, to
1046    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
1047  Added a check for prefix_length > data_length in iCCP chunk handler.
1048
1049version 1.2.1 [December 7, 2001]
1050  None.
1051version 1.2.2beta1 [February 22, 2002]
1052  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
1053  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
1054    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
1055  Revised makefile.darwin to remove "-undefined suppress" option.
1056  Added checks for gamma and chromaticity values over 21474.83, which exceed
1057    the limit for PNG unsigned 32-bit integers when encoded.
1058  Revised calls to png_create_read_struct() and png_create_write_struct()
1059    for simpler debugging.
1060  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
1061version 1.2.2beta2 [February 23, 2002]
1062  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
1063  Check for invalid image dimensions in png_get_IHDR.
1064  Added missing "fi;" in the install target of the SGI makefiles.
1065  Added install-static to all makefiles that make shared libraries.
1066  Always do gamma compensation when image is partially transparent.
1067version 1.2.2beta3 [March 7, 2002]
1068  Compute background.gray and background_1.gray even when color_type is RGB
1069    in case image gets reduced to gray later.
1070  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
1071  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
1072  Removed unused png_write_destroy_info prototype from png.h
1073  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
1074  Added install-shared target to all makefiles that make shared libraries.
1075  Stopped a double free of palette, hist, and trans when not using free_me.
1076  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
1077version 1.2.2beta4 [March 8, 2002]
1078  Compute background.gray and background_1.gray even when color_type is RGB
1079    in case image gets reduced to gray later (Jason Summers).
1080  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
1081  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
1082version 1.2.2beta5 [March 26, 2002]
1083  Added missing PNGAPI to several function definitions.
1084  Check for invalid bit_depth or color_type in png_get_IHDR(), and
1085    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
1086  Revised iTXt support to accept NULL for lang and lang_key.
1087  Compute gamma for color components of background even when color_type is gray.
1088  Changed "()" to "{}" in scripts/libpng.pc.in.
1089  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
1090  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
1091version 1.2.2beta6 [March 31, 2002]
1092version 1.0.13beta1 [March 31, 2002]
1093  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
1094  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
1095  Ensure that the right function (user or default) is used to free the
1096    png_struct after an error in png_create_read_struct_2().
1097version 1.2.2rc1 [April 7, 2002]
1098version 1.0.13rc1 [April 7, 2002]
1099  Save the ebx register in pnggccrd.c (Sami Farin)
1100  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
1101  Updated makefiles to put headers in include/libpng and remove old include/*.h.
1102
1103version 1.2.2 [April 15, 2002]
1104version 1.0.13 [April 15, 2002]
1105  Revised description of png_set_filter() in libpng.3/libpng.txt.
1106  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
1107version 1.0.13patch01 [April 17, 2002]
1108version 1.2.2patch01 [April 17, 2002]
1109  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and makefile.sggcc
1110  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to install
1111  Added install: target to makefile.32sunu and makefile.64sunu
1112version 1.0.13patch03 [April 18, 2002]
1113version 1.2.2patch03 [April 18, 2002]
1114  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
1115  subdirectory to libpngNN subdirectory without the full pathname.
1116  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
1117version 1.2.3rc1 [April 28, 2002]
1118  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
1119  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
1120  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
1121  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
1122  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
1123  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
1124  Revised makefile.darwin to make relative links without full pathname.
1125  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
1126    to put one in their application.
1127  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
1128    removed them from module definition files.
1129version 1.2.3rc2 [May 1, 2002]
1130  Fixed bug in reporting number of channels in pngget.c and pngset.c,
1131    that was introduced in version 1.2.2beta5.
1132  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
1133    png_default_flush(), and png_push_fill_buffer() and included them in
1134    module definition files.
1135  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
1136version 1.2.3rc3 [May 1, 2002]
1137  Revised prototype for png_default_flush()
1138  Remove old libpng.pc and libpngNN.pc before installing new ones.
1139version 1.2.3rc4 [May 2, 2002]
1140  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
1141  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
1142  Added libpng-config and libpngNN-config and modified makefiles to install them.
1143  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
1144  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
1145version 1.2.3rc5 [May 11, 2002]
1146  Changed "error" and "message" in prototypes to "error_message" and
1147    "warning_message" to avoid namespace conflict.
1148  Revised 15 makefiles to build libpng-config from libpng-config-*.in
1149  Once more restored png_zalloc and png_zfree to regular nonexported form.
1150  Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
1151    to nonexported form, but with PNGAPI, and removed them from module def files.
1152version 1.2.3rc6 [May 14, 2002]
1153  Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
1154  Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
1155  Removed leftover libpng-config "sed" script from four makefiles.
1156  Revised libpng-config creating script in 16 makefiles.
1157
1158version 1.2.3 [May 22, 2002]
1159  Revised libpng-config target in makefile.cygwin.
1160  Removed description of png_set_mem_fn() from documentation.
1161  Revised makefile.freebsd.
1162  Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
1163  Revised projects/msvc/README.txt
1164  Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
1165version 1.2.4beta1 [May 24, 2002]
1166  Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
1167  Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
1168  Added missing "\" before closing double quote in makefile.gcmmx.
1169  Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
1170    functions.
1171version 1.2.4beta2 [June 25, 2002]
1172  Plugged memory leak of png_ptr->current_text (Matt Holgate).
1173  Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
1174  Added -soname to the loader flags in makefile.dec, makefile.sgi, and
1175    makefile.sggcc.
1176  Added "test-installed" target to makefile.linux, makefile.gcmmx,
1177    makefile.sgi, and makefile.sggcc.
1178version 1.2.4beta3 [June 28, 2002]
1179  Plugged memory leak of row_buf in pngtest.c when there is a png_error().
1180  Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
1181  Added "test-installed" target to makefile.32sunu, makefile.64sunu,
1182    makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
1183    makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
1184version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
1185  Added "test-installed" target to makefile.cygwin and makefile.sco.
1186  Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
1187
1188version 1.2.4 and 1.0.14 [July 8, 2002]
1189  Changed png_warning() to png_error() when width is too large to process.
1190version 1.2.4patch01 [July 20, 2002]
1191  Revised makefile.cygwin to use DLL number 12 instead of 13.
1192version 1.2.5beta1 [August 6, 2002]
1193  Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
1194  Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
1195  Removed some stray *.o files from contrib/gregbook.
1196  Changed png_error() to png_warning() about "Too much data" in pngpread.c
1197    and about "Extra compressed data" in pngrutil.c.
1198  Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
1199  Updated makefile.hpgcc
1200  Updated png.c and pnggccrd.c handling of return from png_mmx_support()
1201version 1.2.5beta2 [August 15, 2002]
1202  Only issue png_warning() about "Too much data" in pngpread.c when avail_in
1203    is nonzero.
1204  Updated makefiles to install a separate libpng.so.3 with its own rpath.
1205version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
1206  Revised makefiles to not remove previous minor versions of shared libraries.
1207version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
1208  Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
1209    library loader directive.
1210  Added missing "$OBJSDLL" line to makefile.gcmmx.
1211  Added missing "; fi" to makefile.32sunu.
1212version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
1213  Revised libpng-config script.
1214
1215version 1.2.5 and 1.0.15 [October 3, 2002]
1216  Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
1217    and makefile.aix.
1218  Relocated two misplaced PNGAPI lines in pngtest.c
1219version 1.2.6beta1 [October 22, 2002]
1220  Commented out warning about uninitialized mmx_support in pnggccrd.c.
1221  Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
1222  Relocated two more misplaced PNGAPI lines in pngtest.c
1223  Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
1224    introduced in version 1.0.2.
1225  Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
1226version 1.2.6beta2 [November 1, 2002]
1227  Added libpng-config "--ldopts" output.
1228  Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
1229    in makefiles.
1230version 1.2.6beta3 [July 18, 2004]
1231  Reverted makefile changes from version 1.2.6beta2 and some of the changes
1232    from version 1.2.6beta1; these will be postponed until version 1.2.7.
1233    Version 1.2.6 is going to be a simple bugfix release.
1234  Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
1235  Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
1236  Added "#!/bin/sh" at the top of configure, for recognition of the
1237    'x' flag under Cygwin (Cosmin).
1238  Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
1239  Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
1240  Fixed the special memory handler for Borland C under DOS, in pngmem.c
1241    (Cosmin).
1242  Removed some spurious assignments in pngrutil.c (Cosmin).
1243  Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
1244    on 16-bit platforms (Cosmin).
1245  Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
1246  Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
1247    in png_handle_sRGB() (Cosmin).
1248  Added compression_type to png_struct, and optimized the window size
1249    inside the deflate stream (Cosmin).
1250  Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
1251  Fixed handling of unknown chunks that come after IDAT (Cosmin).
1252  Allowed png_error() and png_warning() to work even if png_ptr == NULL
1253    (Cosmin).
1254  Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
1255    (Cosmin).
1256  Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
1257  Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
1258    values in png.c (Simon-Pierre, Cosmin).
1259  Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
1260  Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
1261    (Simon-Pierre).
1262  Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
1263    of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
1264  Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
1265  Updated scripts/makefile.vc(a)win32 (Cosmin).
1266  Updated the MSVC project (Simon-Pierre, Cosmin).
1267  Updated the Borland C++ Builder project (Cosmin).
1268  Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
1269  Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
1270  Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
1271  Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
1272    (Cosmin).
1273  Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
1274    projects/cbuilder5/ (Cosmin).
1275  Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
1276    and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
1277  Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
1278  Changed line endings to DOS style in cbuilder5 and visualc6 files, even
1279    in the tar.* distributions (Cosmin).
1280  Updated contrib/visupng/VisualPng.dsp (Cosmin).
1281  Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
1282  Added a separate distribution with "configure" and supporting files (Junichi).
1283version 1.2.6beta4 [July 28, 2004]
1284  Added user ability to change png_size_t via a PNG_SIZE_T macro.
1285  Added png_sizeof() and png_convert_size() functions.
1286  Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
1287  Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
1288    which would indicate an overflow.
1289  Changed sPLT failure action from png_error to png_warning and abandon chunk.
1290  Changed sCAL and iCCP failures from png_error to png_warning and abandon.
1291  Added png_get_uint_31(png_ptr, buf) function.
1292  Added PNG_UINT_32_MAX macro.
1293  Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
1294  Made png_zalloc() issue a png_warning and return NULL on potential
1295    overflow.
1296  Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
1297  Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
1298  Revised Borland portion of png_malloc() to return NULL or issue
1299    png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
1300  Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
1301    sequential read support.
1302  Added some "#if PNG_WRITE_SUPPORTED" blocks.
1303  #ifdef'ed out some redundancy in png_malloc_default().
1304  Use png_malloc instead of png_zalloc to allocate the pallete.
1305version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
1306  Fixed buffer overflow vulnerability in png_handle_tRNS()
1307  Fixed integer arithmetic overflow vulnerability in png_read_png().
1308  Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
1309    duplicate chunk types to go undetected.
1310  Fixed some timestamps in the -config version
1311  Rearranged order of processing of color types in png_handle_tRNS().
1312  Added ROWBYTES macro to calculate rowbytes without integer overflow.
1313  Updated makefile.darwin and removed makefile.macosx from scripts directory.
1314  Imposed default one million column, one-million row limits on the image
1315    dimensions, and added png_set_user_limits() function to override them.
1316  Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
1317  Fixed wrong cast of returns from png_get_user_width|height_max().
1318  Changed some "keep the compiler happy" from empty statements to returns,
1319  Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
1320version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
1321  Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
1322  Revised pngtest's png_debug_malloc() to use png_malloc() instead of
1323    png_malloc_default() which is not supposed to be exported.
1324  Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
1325    pngpread.c.  Bug was introduced in 1.2.6rc1.
1326  Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
1327  Fixed old bug in RGB to Gray transformation.
1328  Fixed problem with 64-bit compilers by casting arguments to abs()
1329    to png_int_32.
1330  Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
1331  Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
1332  Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
1333  Added code to update the row_info->colortype in png_do_read_filler() (MSB).
1334version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
1335  Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
1336    trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
1337  Revised documentation of png_set_keep_unknown_chunks().
1338  Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
1339  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
1340  Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
1341version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
1342  Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
1343    "pinfo" was out of place).
1344version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
1345  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
1346     section of png.h where they were inadvertently placed in version rc3.
1347
1348version 1.0.16 and 1.2.6 [August 15, 2004]
1349  Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
1350version 1.2.7beta1 [August 26, 2004]
1351  Removed unused pngasmrd.h file.
1352  Removed references to uu.net for archived files.  Added references to
1353    PNG Spec (second edition) and the PNG ISO/IEC Standard.
1354  Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
1355  Fixed bug with "optimized window size" in the IDAT datastream, that
1356    causes libpng to write PNG files with incorrect zlib header bytes.
1357version 1.2.7beta2 [August 28, 2004]
1358  Fixed bug with sCAL chunk and big-endian machines (David Munro).
1359  Undid new code added in 1.2.6rc2 to update the color_type in
1360    png_set_filler().
1361  Added png_set_add_alpha() that updates color type.
1362version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
1363  Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
1364version 1.0.17 and 1.2.7 [September 12, 2004]
1365  Added makefile.hp64
1366  Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
1367version 1.2.8beta1 [November 1, 2004]
1368  Fixed bug in png_text_compress() that would fail to complete a large block.
1369  Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
1370    strip alpha operation in png_do_strip_filler().
1371  Added PNG_1_2_X definition in pngconf.h
1372  #ifdef out png_info_init in png.c and png_read_init in pngread.c (as of 1.3.0)
1373version 1.2.8beta2 [November 2, 2004]
1374  Reduce color_type to a nonalpha type after strip alpha operation in
1375    png_do_strip_filler().
1376version 1.2.8beta3 [November 3, 2004]
1377  Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
1378version 1.2.8beta4 [November 12, 2004]
1379  Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
1380  Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
1381  Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
1382    of data type in deflate (Cosmin).
1383  Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
1384    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
1385version 1.2.8beta5 [November 20, 2004]
1386  Use png_ptr->flags instead of png_ptr->transformations to pass
1387    PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
1388    compatibility.
1389  Revised handling of SPECIALBUILD, PRIVATEBUILD,
1390    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
1391version 1.2.8rc1 [November 24, 2004]
1392  Moved handling of BUILD macros from pngconf.h to png.h
1393  Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
1394    omitted from beta5.
1395  Revised scripts/pngw32.rc
1396  Despammed mailing addresses by masking "@" with "at".
1397  Inadvertently installed a supposedly faster test version of pngrutil.c
1398version 1.2.8rc2 [November 26, 2004]
1399  Added two missing "\" in png.h
1400  Change tests in pngread.c and pngpread.c to
1401    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
1402       png_do_read_transformations(png_ptr);
1403version 1.2.8rc3 [November 28, 2004]
1404  Reverted pngrutil.c to version libpng-1.2.8beta5.
1405  Added scripts/makefile.elf with supporting code in pngconf.h for symbol
1406    versioning (John Bowler).
1407version 1.2.8rc4 [November 29, 2004]
1408  Added projects/visualc7 (Simon-pierre).
1409version 1.2.8rc5 [November 29, 2004]
1410  Fixed new typo in scripts/pngw32.rc
1411version 1.2.8 [December 3, 2004]
1412  Removed projects/visualc7, added projects/visualc71.
1413
1414Send comments/corrections/commendations to
1415png-implement at ccrc.wustl.edu (subscription required; write to
1416majordomo at ccrc.wustl.edu with "subscribe png-implement" in the message)
1417or to glennrp at users.sourceforge.net
1418
1419Glenn R-P
1420