[devel]

Fixed point APIs are now supported throughout (no missing APIs).
  Internal fixed point arithmetic support exists for all internal floating
    point operations.
  sCAL validates the floating point strings it is passed.
  Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
  Two new APIs exist to get the number of passes without turning on the
    PNG_INTERLACE transform and to get the number of rows in the current
    pass.
  A new test program, pngvalid.c, validates the gamma code.
  Errors in the 16 bit gamma correction (overflows) have been corrected.
  cHRM chunk testing is done consistently (previously the floating point
    API bypassed it, because the test really didn't work on FP, now the test
    is performed on the actual values to be stored in the PNG file so it
    works in the FP case too.)
  Most floating point APIs now simply call the fixed point APIs after
    converting the values to the fixed point form used in the PNG file.
  The standard headers no longer include zlib.h, which is currently only
    required for pngstruct.h and can therefore be internal.
  (Patches by John Bowler)

scripts/pnglibconf.dfa

@@ -6,7 +6,7 @@
 #
 com pnglibconf.h - library build configuration
 com
-com libpng version PNGLIB_VERSION - last changed on July 24, 2010
+com libpng version PNGLIB_VERSION - last changed on July 29, 2010
 com
 com Copyright (c) 1998-2010 Glenn Randers-Pehrson
 com
@@ -134,6 +134,17 @@ logunsupported = 1
 @#  include "pngusr.h"
 @#endif
 
+# This is a special fixup for the Watcom C compiler on Windows, which has
+# multiple procedure call standards.  Unless PNG_API_RULE is set explicitly
+# (i.e. if it is not defined at this point) it will be forced to '2' here when
+# using Watcom.  This indicates to the other header files that Watcom behaviour
+# is required where appropriate.
+@#ifdef __WATCOMC__
+@#  ifndef PNG_API_RULE
+@#     define PNG_API_RULE 2 /* Use Watcom calling conventions */
+@#  endif
+@#endif
+
 # Note that PNG_USR_CONFIG only has an effect when building
 # pnglibconf.h
 setting USER_CONFIG requires USER_PRIVATEBUILD USER_DLLFNAME_POSTFIX
@@ -166,8 +177,14 @@ option WRITE_INT_FUNCTIONS disabled
 option WRITE enables WRITE_INT_FUNCTIONS
 
 # Generic options - affect both read and write.
+option WARNINGS
 option BENIGN_ERRORS
 option MNG_FEATURES
+
+# Arithmetic options, the first is the big switch that chooses between internal
+# floating and fixed point arithmetic implementations - it does not affect any
+# APIs.  The second two (the _POINT settings) switch off individual APIs.
+option FLOATING_ARITHMETIC
 option FLOATING_POINT enables ok_math
 option FIXED_POINT enables ok_math
 
@@ -287,8 +304,8 @@ option SEQUENTIAL_READ requires READ
 option READ_COMPOSITE_NODIV requires READ
 = NO_READ_COMPOSITE_NODIV PNG_NO_READ_COMPOSITED_NODIV
 
-# Inch conversions: not switched on by default
-option INCH_CONVERSIONS requires FLOATING_POINT
+# Inch conversions
+option INCH_CONVERSIONS
 = INCH_CONVERSIONS PNG_INCH_CONVERSIONS
 
 # IN DEVELOPMENT
@@ -319,6 +336,8 @@ option WRITE_USER_TRANSFORM requires WRITE_TRANSFORMS
 # trouble if left undefined
 option WRITE_INTERLACING requires WRITE
 
+# The following depends, internally, on WEIGHT_SHIFT and COST_SHIFT
+# where are set below.
 option WRITE_WEIGHTED_FILTER requires WRITE FLOATING_POINT
 
 option WRITE_FLUSH requires WRITE
@@ -349,6 +368,81 @@ option WRITE_ANCILLARY_CHUNKS requires WRITE
 option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
 option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
 
+# Moved to pnglibconf.h at libpng-1.5.0
+# Feature support: in 1.4 this was in pngconf.h, but the following
+# features have no affect on the libpng API.  Add library
+# only features to the end of this list.  Add features that
+# affect the API above.  (Note: the list of chunks follows
+# the library-only settings.)
+#
+# BUILD TIME ONLY OPTIONS
+#   These options do not affect the API but rather alter how the
+#   API is implemented, they get recorded in pnglibconf.h, but
+#   can't be changed by the application.
+
+# Check the correctness of cHRM chunks
+option CHECK_cHRM requires cHRM
+#
+# Artificially align memory - the code typically aligns to 8 byte
+# boundaries if this is switched on, it's a small waste of space
+# but can help (in theory) on some architectures.  Only affects
+# internal structures.  Added at libpng 1.4.0
+option ALIGN_MEMORY
+
+# Buggy compilers (e.g., gcc 2.7.2.2) need PNG_NO_POINTER_INDEXING
+# See png[wr]util.c, normally this should always be *on*
+option POINTER_INDEXING
+
+# Other defines for things like memory and the like can go here.
+
+# BUILD TIME SETTINGS
+# Like build time options these do not affect the API, but they
+# may be useful to applications because they record details of
+# how the API will behave particularly with regard to overall
+# accuracy.
+
+# This controls how fine the quantizing gets.  As this allocates
+# a largish chunk of memory (32K), those who are not as concerned
+# with quantizing quality can decrease some or all of these.
+setting QUANTIZE_RED_BITS default 5
+setting QUANTIZE_GREEN_BITS default 5
+setting QUANTIZE_BLUE_BITS default 5
+
+# This controls how fine the gamma correction becomes when you
+# are only interested in 8 bits anyway.  Increasing this value
+# results in more memory being used, and more pow() functions
+# being called to fill in the gamma tables.  Don't set this value
+# less then 8, and even that may not work (I haven't tested it).
+setting MAX_GAMMA_8 default 11
+
+# This controls how much a difference in gamma we can tolerate before
+# we actually start doing gamma conversion, it's a fixed point value,
+# so the default below is 0.05, meaning libpng ignores corrections in
+# the range 0.95 to 1.05
+setting GAMMA_THRESHOLD_FIXED default 5000
+
+# Scaling factor for filter heuristic weighting calculations
+setting WEIGHT_SHIFT default 8
+setting COST_SHIFT default 3
+
+# Precision to use when converting a floating point value to a PNG
+# extension format string in an sCAL chunk (only relevant if the
+# floating point API is enabled)
+setting sCAL_PRECISION default 5
+
+# This is the size of the compression buffer, and thus the size of
+# an IDAT chunk.  Make this whatever size you feel is best for your
+# machine.  One of these will be allocated per png_struct.  When this
+# is full, it writes the data to the disk, and does some other
+# calculations.  Making this an extremely small size may slow
+# the library down, but you may want to experiment to determine
+# where it becomes significant, if you are concerned with memory
+# usage.  Note that zlib allocates at least 32Kb also.  For readers,
+# this describes the size of the buffer available to read the data in.
+# Unless this gets smaller than the size of a row (compressed),
+# it should not make much difference how big this is.
+setting ZBUF_SIZE default 8192
+
 # Ancillary chunks
 chunk bKGD
 chunk cHRM
@@ -389,13 +483,8 @@ option WRITE_UNKNOWN_CHUNKS requires WRITE
 
 option HANDLE_AS_UNKNOWN
 
-option GET_INT_32 requires READ
-# png_get_int_32 is required by the ancillary chunks oFFs and pCAL
-option READ_oFFs enables GET_INT_32
-option READ_pCAL enables GET_INT_32
-
 option SAVE_INT_32 requires WRITE
-# Likewise for png_save_int_32
+# png_save_int_32 is required by the ancillary chunks oFFs and pCAL
 option WRITE_oFFs enables SAVE_INT_32
 option WRITE_pCAL enables SAVE_INT_32