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Diffstat (limited to 'libpng/scripts/pnglibconf.dfa')
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diff --git a/libpng/scripts/pnglibconf.dfa b/libpng/scripts/pnglibconf.dfa new file mode 100644 index 00000000..52c0c742 --- /dev/null +++ b/libpng/scripts/pnglibconf.dfa @@ -0,0 +1,919 @@ +# scripts/pnglibconf.dfa - library build configuration control +# +@/*- pnglibconf.dfn intermediate file +@ * generated from scripts/pnglibconf.dfa +@ */ +# +com pnglibconf.h - library build configuration +com +version +com +com Copyright (c) 1998-2017 Glenn Randers-Pehrson +com +com This code is released under the libpng license. +com For conditions of distribution and use, see the disclaimer +com and license in png.h +com + +file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H + +# This file is preprocessed by scripts/options.awk and the +# C compiler to generate 'pnglibconf.h' - a list of all the +# configuration options. The file lists the various options +# that can *only* be specified during the libpng build; +# pnglibconf.h freezes the definitions selected for the specific +# build. +# +# The syntax is detailed in scripts/options.awk; this is a summary +# only: +# +# setting <name> [requires ...] [default] +# #define PNG_<name> <value> /* value comes from current setting */ +# option <name> [requires ...] [if ...] [enables ...] [disabled] +# #define PNG_<name>_SUPPORTED if the requirements are met and +# enable the other options listed +# chunk <name> [requires ...] [enables ...] [disabled] +# Enable chunk processing for the given ancillary chunk; any +# 'requires something' expands to READ_something for read and +# WRITE_something for write, but the enables list members are +# used as given (e.g. enables GAMMA just expands to that on the +# correspond READ_name and WRITE_name lines.) +# +# "," may be used to separate options on an 'option' line and is ignored; it +# doesn't change the meaning of the line. (NOT setting, where "," becomes +# part of the setting!) A comma at the end of an option line causes a +# continuation (the next line is included in the option too.) +# +# Note that the 'on' and 'off' keywords, while valid on both option +# and chunk, should not be used in this file because they force the +# relevant options on or off. + +#---------------------------------------------------------------------- + +# The following setting, option and chunk values can all be changed +# while building libpng: +# +# setting: change 'setting' lines to fine tune library performance; +# changes to the settings don't affect the libpng API functionally +# +# option: change 'option' lines to remove or add capabilities from +# or to the library; options change the library API +# +# chunk: change 'chunk' lines to remove capabilities to process +# optional ('ancillary') chunks. This does not prevent PNG +# decoding but does change the libpng API because some chunks +# will be ignored. +# +# There are three ways of disabling features, in no particular order: +# +# 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: +# +# make clean +# CPPFLAGS='-DPNG_USER_CONFIG' ./configure +# make pnglibconf.h +# +# pngusr.h is only used during the creation of pnglibconf.h, but it +# is safer to ensure that -DPNG_USER_CONFIG is specified throughout +# the build by changing the CPPFLAGS passed to the initial ./configure +# +# 2) Add definitions of the settings you want to change to +# CPPFLAGS; for example: +# +# -DPNG_DEFAULT_READ_MACROS=0 +# +# (This would change the default to *not* use read macros.) Be +# very careful to change only settings that don't alter the API +# because this approach bypasses the private build checking. You +# can also change settings from pngpriv.h (read pngpriv.h) safely +# without API changes. Do that in the same way. +# +# 3) Write a new '.dfa' file (say 'pngusr.dfa') and in this file +# provide override values for setting entries and turn option or +# chunk values explicitly 'on' or 'off': +# +# setting FOO default VALUE +# option BAR [on|off] +# +# Then add this file to the options.awk command line (the *first* +# one) after this file. The make macro DFA_XTRA is provided to make +# this easier (set it like CPPFLAGS prior to running ./configure). +# Look at the builds below contrib/pngminim for some extreme examples +# of how this can be used. +# +# Don't edit this file unless you are contributing a patch to +# libpng and need new or modified options/settings. +#---------------------------------------------------------------------- + +# The following causes commented out #undef lines to be written to +# pnglibconf.h; this can be stopped by logunsupported=0 in a later +# file or on the command line (after pnglibconf.dfa) + +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 +# +# If you create a private DLL you need to define the following +# macros in the file 'pngusr.h' and set -DPNG_USER_CONFIG for +# compilation (i.e. in CPPFLAGS.) +# #define PNG_USER_PRIVATEBUILD \ +# <Describes by whom and why this version of the DLL was built> +# e.g. #define PNG_USER_PRIVATEBUILD "Build by MyCompany for xyz reasons." +# #define PNG_USER_DLLFNAME_POSTFIX <two-letter postfix that serve to +# distinguish your DLL from those of the official release. These +# correspond to the trailing letters that come after the version +# number and must match your private DLL name> +# e.g. // private DLL "libpng13gx.dll" +# #define PNG_USER_DLLFNAME_POSTFIX "gx" +# +# The following macros are also at your disposal if you want to complete the +# DLL VERSIONINFO structure. +# - PNG_USER_VERSIONINFO_COMMENTS +# - PNG_USER_VERSIONINFO_COMPANYNAME +# - PNG_USER_VERSIONINFO_LEGALTRADEMARKS + +# It is necessary to include configures definitions here so that AC_DEFINE +# in configure.ac works in a comprehensible way +@#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H) +@# include "config.h" +@#endif + +@#ifdef PNG_USER_CONFIG +@# 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 + +# IN DEVELOPMENT +# These are currently experimental features; define them if you want (NOTE: +# experimental options must be disabled before they are defined in this file!) + +# NONE + +# Note that PNG_USER_CONFIG only has an effect when building +# pnglibconf.h + +setting USER_CONFIG +setting USER_PRIVATEBUILD +setting USER_DLLFNAME_POSTFIX +setting USER_VERSIONINFO_COMMENTS +setting USER_VERSIONINFO_COMPANYNAME +setting USER_VERSIONINFO_LEGALTRADEMARKS + +# Record the 'API rule' used to select calling conventions on +# those systems that support such things (see all the comments in +# pngconf.h) +# Changing this setting has a fundamental affect on the PNG ABI, +# do not release shared libraries with this changed. + +setting API_RULE default 0 + +# This allows a prefix to be added to the front of every API functon 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 + +# 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) +option SET_OPTION disabled + +# These options are specific to the ARM NEON hardware optimizations. At present +# these optimizations depend on GCC specific pre-processing of an assembler (.S) +# file so they probably won't work with other compilers. +# +# ARM_NEON_OPT: unset: check at compile time (__ARM_NEON__ must be defined by +# the compiler, typically as a result of specifying +# CC="gcc -mfpu=neon".) +# 0: disable (even if the CPU has a NEON FPU.) +# 1: check at run time (via ARM_NEON_{API,CHECK}) +# 2: switch on unconditionally (inadvisable - instead pass +# -mfpu=neon to GCC in CC) +# 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 -mfpu=neon will achieve the same +# effect as well as applying NEON optimizations to the rest of the +# libpng code. +# NOTE: any setting other than '0' requires ALIGNED_MEMORY +# 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 +# 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 +# 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 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 +# USE_READ_MACROS option on (see pngconf.h) + +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 a 'disabled', not a 'requires'. +# If these are needed, they are enabled in the 'WRITE options' section +# below. + +option WRITE_INT_FUNCTIONS disabled + +# Error controls +# +# WARNINGS: normally on, if off no warnings are generated +# ERROR_TEXT: normally on, if off errors happen but there is no message +# ERROR_NUMBERS: unimplemented feature, therefore disabled +# BENIGN_ERRORS: support for just issuing warnings for recoverable errors +# +# BENIGN_READ_ERRORS: +# By default recoverable errors on read should just generate warnings, +# generally safe but PNG files that don't conform to the specification will +# be accepted if a meaningful result can be produced. +# +# BENIGN_WRITE_ERRORS: +# 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 +# ignored. + +option WARNINGS +option ERROR_TEXT +option ERROR_NUMBERS disabled + +option BENIGN_ERRORS +option BENIGN_WRITE_ERRORS requires BENIGN_ERRORS disabled +option BENIGN_READ_ERRORS requires BENIGN_ERRORS + + +# Generic options - affect both read and write. + +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. +# +# Prior to libpng 1.6.8 one of the API (_POINT) variants had to be selected. At +# 1.6.8 this restriction has been removed; the simplified API can be used +# without enabling any of the low level fixed/floating APIs. + +option FLOATING_ARITHMETIC +option FLOATING_POINT +option FIXED_POINT + +# This protects us against compilers that run on a windowing system +# and thus don't have or would rather us not use the stdio types: +# stdin, stdout, and stderr. The only one currently used is stderr +# in png_error() and png_warning(). #defining PNG_NO_CONSOLE_IO will +# prevent these from being compiled and used. #defining PNG_NO_STDIO +# will also prevent these, plus will prevent the entire set of stdio +# macros and functions (FILE *, printf, etc.) from being compiled and used, +# unless (PNG_DEBUG > 0) has been #defined. + +option STDIO +option CONSOLE_IO requires STDIO + +# Note: prior to 1.5.0 this option could not be disabled if STDIO +# was enabled. Prior to 1.5.3 this option required STDIO + +option TIME_RFC1123 + +# PNG_SETJMP_NOT_SUPPORTED is an old equivalent for NO_SETJMP + +option SETJMP += NO_SETJMP SETJMP_NOT_SUPPORTED + +# If this is disabled it is not possible for apps to get the +# values from the 'info' structure, this effectively removes +# quite a lot of the READ API. + +option EASY_ACCESS + +# Added at libpng-1.2.0 + +option USER_MEM + +# Added at libpng-1.4.0 + +option IO_STATE + +# Libpng limits: limit the size of images and data on read. +# +# If this option is disabled all the limit checking code will be disabled: + +option USER_LIMITS requires READ + +# The default settings given below for the limits mean that libpng will +# limit the size of images or the size of data in ancilliary 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 + +# Use 0x7fffffff for unlimited +setting USER_WIDTH_MAX default 1000000 +setting USER_HEIGHT_MAX default 1000000 + +# 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 + +# 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 +# conformant, however the library that results is still non-standard. +# See the comments above about how to change options and settings. + +# READ options +# +# WARNING: in libpng 1.5 maintained configuration compatibility with earlier +# versions. In some cases turning off an option turned off other options, in +# others it was ineffective unless dependent options were also turned off. +# Libpng 1.6 changes this: in general if you turn off an option that affects +# APIs it stays off and simply disables APIs that depend on it. +# +# As a result if you simply port the libpng 1.5 configuration to libpng 1.6 you +# will probably see build failures due to missing APIs. Fixing these failures +# requires some, perhaps considerable, knowledge of what your libpng using +# applications are doing, fortunately there is no great reason for you to move +# to libpng 1.6; the new interfaces in 1.6 will take several years to become +# popular. + +option READ enables READ_INTERLACING SET_OPTION + +# Disabling READ_16BIT does not disable reading 16-bit PNG files, but it +# forces them to be chopped down to 8-bit, and disables any 16-bit +# processing after that has happened. You need to be sure to enable +# READ_SCALE_16_TO_8 or READ_STRIP_16_TO_8 when you disable READ_16BIT for +# this to work properly. You should disable the other option if you need to +# ensure a particular conversion (otherwise the app can chose.) + +option READ_16BIT requires READ enables 16BIT + +option READ_QUANTIZE requires READ + +option READ_TRANSFORMS requires READ += NO_READ_TRANSFORMS READ_TRANSFORMS_NOT_SUPPORTED + +# Read gamma handling. Gamma processing is a core part of libpng and many of +# the capabilities are dependent on libpng performing gamma correction. +# +# In libpng 1.6 disabling gamma processing (setting PNG_NO_READ_GAMMA) +# consistently disables those parts of the API that depend on it. Prior to +# 1.6.0 this was not true; the results were unpredictable and varied between +# releases. +# +# If you disable gamma processing and your program no longer compiles you need +# to ask whether you really need the APIs that are missing. If you do then you +# almost certainly need the gamma processing. +# +# If you handle gamma issues outside libpng then you do not need the libpng +# gamma processing; and it is an enormous waste of space. You just need to +# remove the use of libpng APIs that depend on it. +option READ_GAMMA requires READ_TRANSFORMS, READ_gAMA, READ_sRGB + +option READ_ALPHA_MODE requires READ_TRANSFORMS, READ_GAMMA +option READ_BACKGROUND requires READ_TRANSFORMS, READ_STRIP_ALPHA, READ_GAMMA +option READ_BGR requires READ_TRANSFORMS +option READ_EXPAND_16 requires READ_TRANSFORMS, READ_16BIT, READ_EXPAND +option READ_EXPAND requires READ_TRANSFORMS +option READ_FILLER requires READ_TRANSFORMS +option READ_GRAY_TO_RGB requires READ_TRANSFORMS +option READ_INVERT_ALPHA requires READ_TRANSFORMS +option READ_INVERT requires READ_TRANSFORMS +option READ_PACK requires READ_TRANSFORMS +option READ_PACKSWAP requires READ_TRANSFORMS +option READ_RGB_TO_GRAY requires READ_TRANSFORMS, READ_GAMMA enables COLORSPACE +option READ_SCALE_16_TO_8 requires READ_TRANSFORMS +option READ_SHIFT requires READ_TRANSFORMS +option READ_STRIP_16_TO_8 requires READ_TRANSFORMS +option READ_STRIP_ALPHA requires READ_TRANSFORMS +option READ_SWAP_ALPHA requires READ_TRANSFORMS +option READ_SWAP requires READ_TRANSFORMS, READ_16BIT +option READ_USER_TRANSFORM requires READ_TRANSFORMS + +option PROGRESSIVE_READ requires READ +option SEQUENTIAL_READ requires READ + +# You can define PNG_NO_PROGRESSIVE_READ if you don't do progressive reading. +# This is not talking about interlacing capability! You'll still have +# interlacing unless you turn off the following which is required +# for PNG-compliant decoders. (In other words, do not do this - in +# fact it can't be disabled from the command line!) +#option READ_INTERLACING requires READ + +option READ_COMPOSITE_NODIV requires READ += NO_READ_COMPOSITE_NODIV NO_READ_COMPOSITED_NODIV + +# Inch conversions + +option INCH_CONVERSIONS += INCH_CONVERSIONS INCH_CONVERSIONS + +# API to build a grayscale palette +# NOTE: this is not used internally by libpng at present. + +option BUILD_GRAYSCALE_PALETTE + +# WRITE options + +option WRITE enables WRITE_INT_FUNCTIONS + +# Disabling WRITE_16BIT prevents 16-bit PNG files from being +# generated. +option WRITE_16BIT requires WRITE enables 16BIT + +option WRITE_TRANSFORMS requires WRITE += NO_WRITE_TRANSFORMS WRITE_TRANSFORMS_NOT_SUPPORTED + +option WRITE_SHIFT requires WRITE_TRANSFORMS +option WRITE_PACK requires WRITE_TRANSFORMS +option WRITE_BGR requires WRITE_TRANSFORMS +option WRITE_SWAP requires WRITE_TRANSFORMS, WRITE_16BIT +option WRITE_PACKSWAP requires WRITE_TRANSFORMS +option WRITE_INVERT requires WRITE_TRANSFORMS +option WRITE_FILLER requires WRITE_TRANSFORMS +option WRITE_SWAP_ALPHA requires WRITE_TRANSFORMS +option WRITE_INVERT_ALPHA requires WRITE_TRANSFORMS +option WRITE_USER_TRANSFORM requires WRITE_TRANSFORMS + +# This is not required for PNG-compliant encoders, but can cause +# trouble if left undefined + +option WRITE_INTERLACING requires WRITE + +# Deprecated, will be removed. +option WRITE_WEIGHTED_FILTER requires WRITE + +option WRITE_FLUSH requires WRITE + +# Note: these can be turned off explicitly if not required by the +# apps implementing the user transforms +option USER_TRANSFORM_PTR if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM +option USER_TRANSFORM_INFO if READ_USER_TRANSFORM, WRITE_USER_TRANSFORM + +# This enables API to set compression parameters for compressing +# 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, +# tEXt, zTXt, tRNS, pCAL). Others will just save time and make png_info +# a bit smaller. + +# The size of the png_text structure changed in libpng-1.0.6 when +# iTXt support was added. iTXt support was turned off by default through +# libpng-1.2.x, to support old apps that malloc the png_text structure +# instead of calling png_set_text() and letting libpng malloc it. It +# was turned on by default in libpng-1.4.0. + +option READ_ANCILLARY_CHUNKS requires READ +# PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated. += NO_READ_ANCILLARY_CHUNKS READ_ANCILLARY_CHUNKS_NOT_SUPPORTED + +option WRITE_ANCILLARY_CHUNKS requires WRITE +# PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED is deprecated. += NO_WRITE_ANCILLARY_CHUNKS WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED + +# 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 + +# 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. + +# Colorspace support (enabled as required); just the support for colorant +# information. Gamma support, likewise, is just support for the gamma +# information, READ_GAMMA is required for gamma transformations (so it +# is possible to read PNG gamma without enabling all the libpng transform +# code - do this for applications that do their own gamma processing) +# +# As of 1.6.0 COLORSPACE is only useful if the application processes the +# information; this is because the library does not do any colorspace +# processing, it just validates the data in the PNG file. + +option GAMMA disabled +option COLORSPACE enables GAMMA disabled + +# When an ICC profile is read, or png_set, it will be checked for a match +# against known sRGB profiles if the sRGB handling is enabled. The +# PNG_sRGB_PROFILE_CHECKS setting controls how much work is done during the +# check: +# +# -1: Don't do any sRGB profile checking. +# +# 0: Just validate the profile MD5 signature if present, otherwise use +# the checks in option 1. +# +# 1: Additionally check the length, intent and adler32 checksum of the +# actual data. If enabled this will reject known profiles that have +# had the rendering intent in the header changed as well as other edits +# done without updating the checksum. See the discussion below. +# +# 2: Additionally checksum all the data using the ethernet CRC32 algorithm. +# This makes it more difficult to fake profiles and makes it less likely +# to get a false positive on profiles with no signature, but is probably +# just a waste of time since all currently approved ICC sRGB profiles have +# a secure MD5 signature. +# +# The rendering intent. An ICC profile stores an intended rendering intent, +# but does not include the value in the signature. The intent is documented +# as the intent that should be used when combining two profiles. The sRGB +# profile is intended, however, to be used with any of the four defined intents. +# For this reason the sRGB chunk includes an 'intent' to be used when displaying +# the image (intent is really a property of the image not the profile.) +# +# Unfortunately the iCCP chunk does not. It may therefore be that some +# applications modify the intent in profiles (including sRGB profiles) to work +# round this problem. Selecting an option other than option '0' will cause such +# modified profiles to be rejected. +# +# Security. The use of Adler32 and CRC32 checksums does not help significantly +# with any security issues. It is relatively easy to produce arbitrary profiles +# with the required checksums on current computer systems. Nevertheless +# security does not seem to be an issue because the only consequence of a false +# positive is a false assertion that the profile is an sRGB profile. This might +# be used to hide data from libpng using applications, but it doesn't seem +# possible to damage them. + +setting sRGB_PROFILE_CHECKS default 2 + +# 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 ALIGNED_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 than 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 + +# 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 + +# 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 +# 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 +# timepng) can be achieved by very large increases (to 32kbyte) on regular data, +# but highly compressible data shows only around 2% improvement. The size is +# chosen to minimize the effects of DoS attacks based on using very large +# amounts of highly compressible data. + +setting INFLATE_BUF_SIZE default 1024 + +# This is the maximum amount of IDAT data that the sequential reader will +# process at one time. The setting does not affect the size of IDAT chunks +# read, just the amount read at once. Neither does it affect the progressive +# reader, which processes just the amount of data the application gives it. +# The sequential reader is currently unable to process more than one IDAT at +# once - it has to read and process each one in turn. There is no point setting +# this to a value larger than the IDAT chunks typically encountered (it would +# just waste memory) but there may be some point in reducing it below the value +# of ZBUF_SIZE (the size of IDAT chunks written by libpng.) + +setting IDAT_READ_SIZE default PNG_ZBUF_SIZE + +# Ancillary chunks +chunk bKGD +chunk cHRM enables COLORSPACE +chunk eXIf +chunk gAMA enables GAMMA +chunk hIST +chunk iCCP enables COLORSPACE, GAMMA +chunk iTXt enables TEXT +chunk oFFs +chunk pCAL +chunk pHYs +chunk sBIT +chunk sCAL +chunk sPLT +chunk sRGB enables COLORSPACE, GAMMA, SET_OPTION +chunk tEXt requires TEXT +chunk tIME +chunk tRNS +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 +# of the regular chunk reading too. + +option READ_OPT_PLTE requires READ_ANCILLARY_CHUNKS + +# Unknown chunk handling +# +# 'UNKNOWN_CHUNKS' is a global option to disable all unknown chunk handling on +# read or write; everything else below requires it (directly or indirectly). +option UNKNOWN_CHUNKS + +# There are three main options to control the ability to read and write unknown +# chunks. If either read option is turned on then unknown chunks will be read, +# otherwise they are skipped. If the write option is turned on unknown chunks +# set by png_set_unknown_chunks will be written otherwise it is an error to call +# that API on a write struct. +option WRITE_UNKNOWN_CHUNKS requires WRITE requires UNKNOWN_CHUNKS +option WRITE_UNKNOWN_CHUNKS enables STORE_UNKNOWN_CHUNKS + +# The first way to read user chunks is to have libpng save them for a later call +# to png_get_unknown_chunks, the application must call +# png_set_keep_unknown_chunks to cause this to actually happen (see png.h) +option SAVE_UNKNOWN_CHUNKS requires READ requires SET_UNKNOWN_CHUNKS +option SAVE_UNKNOWN_CHUNKS enables READ_UNKNOWN_CHUNKS, STORE_UNKNOWN_CHUNKS + +# The second approach is to use an application provided callback to process the +# chunks, the callback can either handle the chunk entirely itself or request +# that libpng store the chunk for later retrieval via png_get_unknown_chunks. +# +# NOTE: If STORE_UNKNOWN_CHUNKS is not enabled (which is the default if +# both SAVE_UNKNOWN_CHUNKS and WRITE_UNKNOWN_CHUNKS are disabled) then a +# 0 result from the callback will be ignored because no support for saving +# unknown chunks has been compiled in. The normal symptom is that your app +# fails to compile because png_get_unknown_chunks is no longer defined in png.h. +# If you encounter this issue simply enable STORE_UNKNOWN_CHUNKS in your build. +# +# Note that there is no 'WRITE_USER_CHUNKS' so the USER_CHUNKS option is always +# the same as READ_USER_CHUNKS at present +option READ_USER_CHUNKS requires READ, UNKNOWN_CHUNKS +option READ_USER_CHUNKS enables READ_UNKNOWN_CHUNKS, USER_CHUNKS + +# Two further options are provided to allow detailed control of the handling. +# The first enables png_set_keep_unknown_chunks; this allows the default to be +# changed from discarding unknown chunks and allows per-chunk control. This is +# required to use the SAVE_UNKNOWN_CHUNKS option. If enabled this option also +# applies to write (see png.h), otherwise the write API simply writes all the +# chunks it is given. +# +# The second option extends the unknown handling to allow known chunks to be +# handled as though they were unknown. This option doesn't change any APIs, it +# merely turns on the code to check known as well as unknown chunks. +# +# This option no longer affects the write code. It can be safely disabled and +# will prevent applications stopping libpng reading known chunks. +option SET_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS +option HANDLE_AS_UNKNOWN requires SET_UNKNOWN_CHUNKS + +# The following options are derived from the above and should not be turned on +# explicitly. +option READ_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled +option STORE_UNKNOWN_CHUNKS requires UNKNOWN_CHUNKS disabled + +option CONVERT_tIME requires WRITE_ANCILLARY_CHUNKS +# The "tm" structure is not supported on WindowsCE + +@#ifdef _WIN32_WCE +@# define PNG_NO_CONVERT_tIME +@#endif + +option WRITE_FILTER requires WRITE + +option SAVE_INT_32 disabled +# png_save_int_32 is required internally for writing the ancillary chunks oFFs +# and pCAL and for both reading and writing iCCP (for the generation/checking of +# the corresponding cHRM/gAMA chunks) if full ICC is supported. + +# added at libpng-1.5.4 + +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 WRITE_oFFs enables SAVE_INT_32 +option WRITE_pCAL enables SAVE_INT_32 +option WRITE_cHRM enables SAVE_INT_32 + +option WRITE_COMPRESSED_TEXT disabled +option WRITE_iCCP enables WRITE_COMPRESSED_TEXT +option WRITE_iTXt enables WRITE_COMPRESSED_TEXT +option WRITE_zTXt enables WRITE_COMPRESSED_TEXT + +# Turn this off to disable png_read_png() and png_write_png() and +# leave the row_pointers member out of the info structure. + +option INFO_IMAGE + +# added at libpng-1.5.10 +# Turn this off to disable warning about invalid palette index and +# leave the num_palette_max member out of the png structure. + +option CHECK_FOR_INVALID_INDEX enables READ_CHECK_FOR_INVALID_INDEX +option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX +option READ_CHECK_FOR_INVALID_INDEX requires READ, CHECK_FOR_INVALID_INDEX +option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE, CHECK_FOR_INVALID_INDEX + +# added at libpng-1.5.15 +option GET_PALETTE_MAX enables READ_GET_PALETTE_MAX WRITE_GET_PALETTE_MAX +option READ_GET_PALETTE_MAX requires READ_CHECK_FOR_INVALID_INDEX disabled +option WRITE_GET_PALETTE_MAX requires WRITE_CHECK_FOR_INVALID_INDEX disabled + +# Simplified API options (added at libpng-1.6.0) +# In libpng 1.6.8 the handling of these options was changed to used 'requires' +# throughout, so that disabling some of the low level support always disables +# the base simplified read/write API. This much simplifies the handling and +# makes 'everything = off' work in a more intuitive way. It eliminates a +# previously reported feature that APIs previously enabled by the simplified +# API couldn't be turned off without explicitly turning off the simplified +# APIs. +# +# Read: +option SIMPLIFIED_READ, + requires SEQUENTIAL_READ, READ_TRANSFORMS, SETJMP, BENIGN_ERRORS, + READ_EXPAND, READ_16BIT, READ_EXPAND_16, READ_SCALE_16_TO_8, + READ_RGB_TO_GRAY, READ_ALPHA_MODE, READ_BACKGROUND, READ_STRIP_ALPHA, + READ_FILLER, READ_SWAP, READ_PACK, READ_GRAY_TO_RGB, READ_GAMMA, + READ_tRNS, READ_bKGD, READ_gAMA, READ_cHRM, READ_sRGB, READ_sBIT + +# AFIRST and BGR read options: +# Prior to libpng 1.6.8 these were disabled but switched on if the low level +# libpng routines that do the swaps were enabled. This worked but was +# confusing. In libpng 1.6.8 the options were changed to simple 'requires' +# and are enabled by default. This should work the same way in practice. +option SIMPLIFIED_READ_AFIRST enables FORMAT_AFIRST, + requires SIMPLIFIED_READ READ_SWAP_ALPHA + +option SIMPLIFIED_READ_BGR enables FORMAT_BGR, + requires SIMPLIFIED_READ READ_BGR + +# Write: +option SIMPLIFIED_WRITE, + 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 + +option SIMPLIFIED_WRITE_BGR enables FORMAT_BGR, + requires SIMPLIFIED_WRITE WRITE_BGR + +# Formats: +option FORMAT_AFIRST disabled +option FORMAT_BGR disabled |