com
version
com
-com Copyright (c) 1998-2012 Glenn Randers-Pehrson
+com Copyright (c) 2018-2023 Cosmin Truta
+com Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
com
com This code is released under the libpng license.
com For conditions of distribution and use, see the disclaimer
#
# 1) Create 'pngusr.h', enter the required private build information
# detailed below and #define PNG_NO_<option> for each option you
-# don't want in that file in that file. You can also turn on options
-# using PNG_<option>_SUPPORTED. When you have finished rerun
-# configure and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
+# don't want in that file. You can also turn on options using
+# PNG_<option>_SUPPORTED. When you have finished, rerun configure
+# and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
#
# make clean
# CPPFLAGS='-DPNG_USER_CONFIG' ./configure
logunsupported = 1
+# The following allows the output from configure to modify the contents of
+# pnglibconf.h
+
+@#ifdef HAVE_CONFIG_H
+@# include "config.h"
+@#endif
+
# PNG_USER_CONFIG has to be defined on the compiler command line
# to cause pngusr.h to be read while constructing pnglibconf.h
#
setting API_RULE default 0
-# This allows a prefix to be added to the front of every API functon name (and
+# This allows a prefix to be added to the front of every API function name (and
# therefore every symbol) by redefining all the function names with the prefix
# at the end of pnglibconf.h. It also turns on similar internal symbol renaming
# by causing a similar build-time only file, pngprefix.h, to be generated.
setting PREFIX
-# Default to using the read macros
-
-setting DEFAULT_READ_MACROS default 1
-
# Implementation specific control of the optimizations, enabled by those
# hardware or software options that need it (typically when run-time choices
# must be made by the user)
# ARM_NEON_API: (PNG_ARM_NEON == 1) allow the optimization to be switched on
# with png_set_option
# ARM_NEON_CHECK: (PNG_ARM_NEON == 1) compile a run-time check to see if Neon
-# extensions are supported, this is poorly supported and
-# deprectated - use the png_set_option API.
+# extensions are supported. This is poorly supported and
+# deprecated - use the png_set_option API.
setting ARM_NEON_OPT
option ARM_NEON_API disabled requires ALIGNED_MEMORY enables SET_OPTION,
sets ARM_NEON_OPT 1
option ARM_NEON_CHECK disabled requires ALIGNED_MEMORY,
sets ARM_NEON_OPT 1
+# These options are specific to the PowerPC VSX hardware optimizations.
+#
+# POWERPC_VSX_OPT: unset: check at compile time (__PPC64__,__ALTIVEC__,__VSX__
+# must be defined by the compiler, typically as a result
+# of specifying
+# "-mvsx -maltivec" compiler flags)
+# 0: disable (even if the CPU supports VSX.)
+# 1: check at run time (via POWERPC_VSX_{API,CHECK})
+# 2: switch on unconditionally (inadvisable - instead pass
+# -mvsx -maltivec to compiler options)
+# When building libpng avoid using any setting other than '0'; '1' is
+# set automatically when either 'API' or 'CHECK' are configured in,
+# '2' should not be necessary as "-mvsx -maltivec" will achieve the same
+# effect as well as applying VSX optimizations to the rest of the
+# libpng code.
+# POWERPC_VSX_API: (PNG_POWERPC_VSX == 1) allow the optimization to be switched on
+# with png_set_option
+# POWERPC_VSX_CHECK: (PNG_POWERPC_VSX == 1) compile a run-time check to see if VSX
+# extensions are supported. This is supported not for all OSes
+# (see contrib/powerpc/README)
+setting POWERPC_VSX_OPT
+option POWERPC_VSX_API disabled enables SET_OPTION,
+ sets POWERPC_VSX_OPT 1
+option POWERPC_VSX_CHECK disabled,
+ sets POWERPC_VSX_OPT 1
+
+
# These settings configure the default compression level (0-9) and 'strategy';
-# strategy is as defined by the implementors of zlib, it describes the input
+# strategy is as defined by the implementors of zlib. It describes the input
# data and modifies the zlib parameters in an attempt to optimize the balance
# between search and huffman encoding in the zlib algorithms. The defaults are
# the zlib.h defaults - the apparently recursive definition does not arise
# because the name of the setting is prefixed by PNG_
#
# The TEXT values are the defaults when writing compressed text (all forms)
-#
-# Include the zlib header too, so that the defaults below are known
+
+# Include the zlib header so that the defaults below are known
@# include <zlib.h>
# The '@' here means to substitute the value when pnglibconf.h is built
setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
+# TODO: why aren't these Z_RLE; zlib.h says that Z_RLE, specifically, is
+# appropriate for PNG images, maybe it doesn't exist in all versions?
setting Z_DEFAULT_STRATEGY default @Z_FILTERED
setting Z_DEFAULT_NOFILTER_STRATEGY default @Z_DEFAULT_STRATEGY
setting ZLIB_VERNUM default @ZLIB_VERNUM
+# Linkage of:
+#
+# API: libpng API functions
+# CALLBACK: internal non-file-local callbacks
+# FUNCTION: internal non-file-local functions
+# DATA: internal non-file-local (const) data
+setting LINKAGE_API default extern
+setting LINKAGE_CALLBACK default extern
+setting LINKAGE_FUNCTION default extern
+setting LINKAGE_DATA default extern
+
setting TEXT_Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION
setting TEXT_Z_DEFAULT_STRATEGY default @Z_DEFAULT_STRATEGY
+# Default to using the read macros
+
+setting DEFAULT_READ_MACROS default 1
+
# The alternative is to call functions to read PNG values, if
# the functions are turned *off* the read macros must always
# be enabled, so turning this off will actually force the
option READ_INT_FUNCTIONS requires READ
-# The same for write, but these can only be switched off if
-# no writing is required at all - hence the use of an 'enables'
-# not a 'requires' below:
+# The same for write but these can only be switched off if no writing
+# is required at all - hence the use of a 'disabled', not a 'requires'.
+# If these are needed, they are enabled in the 'WRITE options' section
+# below.
option WRITE_INT_FUNCTIONS disabled
-option WRITE enables WRITE_INT_FUNCTIONS
# Error controls
#
# By default recoverable errors on write should just generate warnings,
# not generally safe because this allows the application to write invalid
# PNG files. Applications should enable this themselves; it's useful
-# because it means that a failure to write an ancilliary chunk can often be
+# because it means that a failure to write an ancillary chunk can often be
# ignored.
-option WARNINGS
+option WARNINGS disabled
option ERROR_TEXT
option ERROR_NUMBERS disabled
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 an
+# floating and fixed point arithmetic implementations - it does not affect any
# APIs. The second two (the _POINT settings) switch off individual APIs.
#
# Prior to libpng 1.6.8 one of the API (_POINT) variants had to be selected. At
option IO_STATE
-# This is only for PowerPC big-endian and 680x0 systems
-# some testing, not enabled by default.
-# NO LONGER USED
-
-#option READ_BIG_ENDIAN disabled
+# Libpng limits: limit the size of images and data on read.
+#
+# If this option is disabled all the limit checking code will be disabled:
-# Allow users to control limits on what the READ code will
-# read:
+option USER_LIMITS requires READ
-# Added at libpng-1.2.43; adds limit fields to png_struct,
-# allows some usages of these fields
+# The default settings given below for the limits mean that libpng will
+# limit the size of images or the size of data in ancillary chunks to less
+# than the specification or implementation limits. Settings have the
+# following interpretations:
+#
+# USER_WIDTH_MAX: maximum width of an image that will be read
+# USER_HEIGHT_MAX: maximum height
+# USER_CHUNK_MALLOC_MAX: maximum in-memory (decompressed) size of a single chunk
+# USER_CHUNK_CACHE_MAX: maximum number of chunks to be cached
+#
+# Only chunks that are variable in number are counted towards the
-option USER_LIMITS
+# Use 0x7fffffff for unlimited
+setting USER_WIDTH_MAX default 1000000
+setting USER_HEIGHT_MAX default 1000000
-# Added at libpng-1.2.6; adds setting APIs, allows additional
-# usage of this field (UTSL)
+# Use 0 for unlimited
+setting USER_CHUNK_CACHE_MAX default 1000
+setting USER_CHUNK_MALLOC_MAX default 8000000
+# If this option is enabled APIs to set the above limits at run time are added;
+# without this the hardwired (compile time) limits will be used.
option SET_USER_LIMITS requires USER_LIMITS
-# Feature added at libpng-1.4.0, this flag added at 1.4.1
-option SET_USER_LIMITS enables SET_CHUNK_CACHE_LIMIT
-# Feature added at libpng-1.4.1, this flag added at 1.4.1
-
-option SET_USER_LIMITS enables SET_CHUNK_MALLOC_LIMIT
-
-# Libpng limits.
-#
-# If these settings are *not* set libpng will not limit the size of
-# images or the size of data in ancilliary chunks. This does lead to
-# security issues if PNG files come from untrusted sources.
-setting USER_WIDTH_MAX
-setting USER_HEIGHT_MAX
-setting USER_CHUNK_CACHE_MAX
-setting USER_CHUNK_MALLOC_MAX
-
-# To default all these settings to values that are large but probably
-# safe turn the SAFE_LIMITS option on; this will cause the value in
-# pngpriv.h to be used. Individual values can also be set, simply set
-# them in pngusr.dfa with '@#define PNG_setting value' lines.
-option SAFE_LIMITS enables USER_LIMITS disabled
-= SAFE_LIMITS SAFE_LIMITS
-
# All of the following options relate to code capabilities for
# processing image data before creating a PNG or after reading one.
# You can remove these capabilities safely and still be PNG
# WRITE options
-option WRITE
+option WRITE enables WRITE_INT_FUNCTIONS
# Disabling WRITE_16BIT prevents 16-bit PNG files from being
# generated.
option WRITE_INTERLACING requires WRITE
-# The following depends, internally, on WEIGHT_SHIFT and COST_SHIFT
-# where are set below.
-
+# Deprecated, will be removed.
option WRITE_WEIGHTED_FILTER requires WRITE
option WRITE_FLUSH requires WRITE
# non-IDAT chunks (zTXt, iTXt, iCCP, and unknown chunks). This feature
# was added at libpng-1.5.3.
option WRITE_CUSTOMIZE_ZTXT_COMPRESSION requires WRITE
+option WRITE_CUSTOMIZE_COMPRESSION requires WRITE
# Any chunks you are not interested in, you can undef here. The
-# ones that allocate memory may be expecially important (hIST,
+# ones that allocate memory may be especially important (hIST,
# tEXt, zTXt, tRNS, pCAL). Others will just save time and make png_info
# a bit smaller.
# These options disable *all* the text chunks if turned off
+option TEXT disabled
option READ_TEXT requires READ_ANCILLARY_CHUNKS enables TEXT
option WRITE_TEXT requires WRITE_ANCILLARY_CHUNKS enables TEXT
# 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).
+# less than 8, and even that may not work (I haven't tested it).
setting MAX_GAMMA_8 default 11
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 ZBUF_SIZE default 8192
# This is the size of the decompression buffer used when counting or checking
-# the decompressed size of an LZ stream from a compressed ancilliary chunk; the
+# the decompressed size of an LZ stream from a compressed ancillary chunk; the
# decompressed data is never used so a different size may be optimal. This size
# was determined using contrib/libtests/timepng.c with compressed zTXt data
# around 11MByte in size. Slight speed improvements (up to about 14% in
# Ancillary chunks
chunk bKGD
chunk cHRM enables COLORSPACE
+chunk eXIf
chunk gAMA enables GAMMA
chunk hIST
chunk iCCP enables COLORSPACE, GAMMA
-chunk iTXt
+chunk iTXt enables TEXT
chunk oFFs
chunk pCAL
chunk pHYs
chunk tEXt requires TEXT
chunk tIME
chunk tRNS
-chunk zTXt
+chunk zTXt enables TEXT
# This only affects support of the optional PLTE chunk in RGB and RGBA
# images. Notice that READ_ANCILLARY_CHUNKS therefore disables part
option WRITE_OPTIMIZE_CMF requires WRITE
option READ_COMPRESSED_TEXT disabled
+option READ_iCCP enables READ_COMPRESSED_TEXT
option READ_iTXt enables READ_COMPRESSED_TEXT
option READ_zTXt enables READ_COMPRESSED_TEXT
-option READ_COMPRESSED_TEXT enables READ_TEXT
option WRITE_oFFs enables SAVE_INT_32
option WRITE_pCAL enables SAVE_INT_32
option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
-option WRITE_COMPRESSED_TEXT enables WRITE_TEXT
# Turn this off to disable png_read_png() and png_write_png() and
# leave the row_pointers member out of the info structure.
# Write:
option SIMPLIFIED_WRITE,
- requires WRITE STDIO, SETJMP, WRITE_SWAP, WRITE_PACK,
+ requires WRITE, SETJMP, WRITE_SWAP, WRITE_PACK,
WRITE_tRNS, WRITE_gAMA, WRITE_sRGB, WRITE_cHRM
+# 1.6.22: allow simplified write without stdio support:
+option SIMPLIFIED_WRITE_STDIO requires SIMPLIFIED_WRITE STDIO
+
option SIMPLIFIED_WRITE_AFIRST enables FORMAT_AFIRST,
requires SIMPLIFIED_WRITE WRITE_SWAP_ALPHA
projects / platform / upstream / libpng.git / blobdiff