-Installing libpng
+ Installing libpng
Contents
- I. Simple installation
- II. Rebuilding the configure scripts
- III. Using scripts/makefile*
- IV. Using cmake
- V. Directory structure
- VI. Building with project files
- VII. Building with makefiles
-VIII. Configuring libpng for 16-bit platforms
- IX. Configuring for DOS
- X. Configuring for Medium Model
- XI. Prepending a prefix to exported symbols
- XII. Configuring for compiler xxx:
-XIII. Removing unwanted object code
- XIV. Changes to the build and configuration of libpng in libpng-1.5.x
- XV. Setjmp/longjmp issues
- XVI. Other sources of information about libpng
+ I. Simple installation
+ II. Rebuilding the configure scripts
+ III. Using scripts/makefile*
+ IV. Using cmake
+ V. Directory structure
+ VI. Building with project files
+ VII. Building with makefiles
+ VIII. Configuring libpng for 16-bit platforms
+ IX. Configuring for DOS
+ X. Configuring for Medium Model
+ XI. Prepending a prefix to exported symbols
+ XII. Configuring for compiler xxx:
+ XIII. Removing unwanted object code
+ XIV. Enabling or disabling hardware optimizations
+ XV. Changes to the build and configuration of libpng in libpng-1.5.x
+ XVI. Setjmp/longjmp issues
+ XVII. Common linking failures
+ XVIII. Other sources of information about libpng
I. Simple installation
change configure.ac or Makefile.am, and you have a reasonably
up-to-date set of tools, running ./autogen.sh in a git clone before
running ./configure may fix the problem. To be really sure that you
-aren't using any of the included pre-built scripts, you can do this:
+aren't using any of the included pre-built scripts, especially if you
+are building from a tar distribution instead of a git distribution,
+do this:
./configure --enable-maintainer-mode
make maintainer-clean
Before installing libpng, you must first install zlib, if it
is not already on your system. zlib can usually be found
-wherever you got libpng; otherwise go to http://zlib.net. You can place
-zlib in in the same directory as libpng or in another directory.
+wherever you got libpng; otherwise go to https://zlib.net/. You can
+place zlib in the same directory as libpng or in another directory.
If your system already has a preinstalled zlib you will still need
to have access to the zlib.h and zconf.h include files that
and LD_LIBRARY_PATH in your environment before running "make test"
or "make distcheck":
-ZLIBLIB=/path/to/lib export ZLIBLIB
-ZLIBINC=/path/to/include export ZLIBINC
-CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
-LDFLAGS="-L$ZLIBLIB" export LDFLAGS
-LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+ ZLIBLIB=/path/to/lib export ZLIBLIB
+ ZLIBINC=/path/to/include export ZLIBINC
+ CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+ LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+ LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
-in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".
+in your environment and type
+
+ make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test
IV. Using cmake
If you want to use "cmake" (see www.cmake.org), type
- cmake . -DCMAKE_INSTALL_PREFIX=/path
- make
- make install
+ cmake . -DCMAKE_INSTALL_PREFIX=/path
+ make
+ make install
As when using the simple configure method described above, "/path" points to
the installation directory where you want to put the libpng "lib", "include",
Your directory structure should look like this:
- .. (the parent directory)
- libpng (this directory)
+ .. (the parent directory)
+ libpng (this directory)
INSTALL (this file)
README
*.h, *.c => libpng source files
CMakeLists.txt => "cmake" script
+ ci
+ ci_*.sh
configuration files:
configure.ac, configure, Makefile.am, Makefile.in,
autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
libpng-config.in, aclocal.m4, config.h.in, config.sub,
- depcomp, install-sh, mkinstalldirs, test-pngtest.sh
+ depcomp, install-sh, mkinstalldirs, test-pngtest.sh, etc.
contrib
arm-neon, conftest, examples, gregbook, libtests, pngminim,
pngminus, pngsuite, tools, visupng
projects
- cbuilder5, owatcom, visualc71, vstudio, xcode
+ owatcom, visualc71, vstudio
scripts
makefile.*
*.def (module definition files)
pngtest.png
etc.
zlib
- README, *.h, *.c contrib, etc.
+ README, *.h, *.c, contrib, etc.
If the line endings in the files look funny, you may wish to get the other
distribution of libpng. It is available in both tar.gz (UNIX style line
VI. Building with project files
-If you are building libpng with MSVC, you can enter the
-libpng projects\visualc71 or vstudio directory and follow the instructions
-in README.txt.
+If you are building libpng with Microsoft Visual Studio, you can enter
+the directory projects\visualc71 or projects\vstudio and follow the
+instructions in README.txt.
-Otherwise enter the zlib directory and follow the instructions in zlib/README,
-then come back here and run "configure" or choose the appropriate
-makefile.sys in the scripts directory.
+Otherwise, enter the zlib directory and follow the instructions in
+zlib/README, then come back here and run "configure" or choose the
+appropriate makefile in the scripts directory.
VII. Building with makefiles
Copy the file (or files) that you need from the
scripts directory into this directory, for example
- MSDOS example: copy scripts\makefile.msc makefile
- copy scripts\pnglibconf.h.prebuilt pnglibconf.h
- UNIX example: cp scripts/makefile.std makefile
- cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+UNIX example:
+
+ cp scripts/makefile.std Makefile
+ make
+
+Windows example:
+
+ nmake -f scripts\makefile.vcwin32
Read the makefile to see if you need to change any source or
target directories to match your preferences.
Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
your output with the result shown in contrib/pngsuite/README.
-Most of the makefiles will allow you to run "make install" to
-put the library in its final resting place (if you want to
-do that, run "make install" in the zlib directory first if necessary).
-Some also allow you to run "make test-installed" after you have
-run "make install".
+Most of the makefiles used to allow you to run "make install" to put
+the library in its final resting place, but that feature is no longer
+supported. The only tested and supported manners to install libpng are
+the conventional build and install procedures driven by the configure
+script or by the CMake file.
-VIII. Configuring libpng for 16-bit platforms
+VIII. Configuring for DOS and other 16-bit platforms
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more than 64K at a time. Even if you can, the memory
-won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-IX. Configuring for DOS
+Officially, the support for 16-bit platforms has been removed.
For DOS users who only have access to the lower 640K, you will
have to limit zlib's memory usage via a png_set_compression_mem_level()
call. See zlib.h or zconf.h in the zlib library for more information.
-X. Configuring for Medium Model
+You may be or may not be in luck if you target the "large" memory model,
+but all the smaller models ("small", "compact" and "medium") are known
+to be unworkable. For DOS users who have access beyond the lower 640K,
+a "flat" 32-bit DOS model (such as DJGPP) is strongly recommended.
-Libpng's support for medium model has been tested on most of the popular
-compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set. Everything in the library (except for zlib's structure) is
-expecting far data. You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful). Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
+For DOS users who only have access to the lower 640K, you will have to
+limit zlib's memory usage via a png_set_compression_mem_level() call.
+You will also have to look into zconf.h to tell zlib (and thus libpng)
+that it cannot allocate more than 64K at a time. Even if you can, the
+memory won't be accessible. Therefore, you should limit zlib and libpng
+to 64K by defining MAXSEG_64K.
-XI. Prepending a prefix to exported symbols
+IX. Prepending a prefix to exported symbols
Starting with libpng-1.6.0, you can configure libpng (when using the
"configure" script) to prefix all exported symbols by means of the
transparent to applications; their function calls get transformed by
the macros to use the modified names.
-XII. Configuring for compiler xxx:
+X. Configuring for compiler xxx:
All includes for libpng are in pngconf.h. If you need to add, change
or delete an include, this is the place to do it.
files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
that previously appeared in the public headers.
-XIII. Removing unwanted object code
+XI. Removing unwanted object code
There are a bunch of #define's in pngconf.h that control what parts of
libpng are compiled. All the defines end in _SUPPORTED. If you are
never going to use a capability, you can change the #define to #undef
before recompiling libpng and save yourself code and data space, or
you can turn off individual capabilities with defines that begin with
-PNG_NO_.
+"PNG_NO_".
In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
The size of the library itself should not be an issue, because only
those sections that are actually used will be loaded into memory.
-XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+XII. Enabling or disabling hardware optimizations
+
+Certain hardware capabilities, such as the Intel SSE instructions,
+are normally detected at run time. Enable them with configure options
+such as one of
+
+ --enable-arm-neon=yes
+ --enable-mips-msa=yes
+ --enable-intel-sse=yes
+ --enable-powerpc-vsx=yes
+
+or enable them all at once with
+
+ --enable-hardware-optimizations=yes
+
+or, if you are not using "configure", you can use one
+or more of
+
+ CPPFLAGS += "-DPNG_ARM_NEON"
+ CPPFLAGS += "-DPNG_MIPS_MSA"
+ CPPFLAGS += "-DPNG_INTEL_SSE"
+ CPPFLAGS += "-DPNG_POWERPC_VSX"
+
+See for example scripts/makefile.linux-opt
+
+If you wish to avoid using them,
+you can disable them via the configure option
+
+ --disable-hardware-optimizations
+
+to disable them all, or
+
+ --enable-intel-sse=no
+
+to disable a particular one,
+or via compiler-command options such as
+
+ CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
+ -DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
+
+If you are using cmake, hardware optimizations are "on"
+by default. To disable them, use
+
+ cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
+ -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
+
+or disable them all at once with
+
+ cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
+
+XIII. Changes to the build and configuration of libpng in libpng-1.5.x
Details of internal changes to the library code can be found in the CHANGES
file and in the GIT repository logs. These will be of no concern to the vast
approach is documented in pngconf.h
Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
+calling standard on those platforms tested so far ("__cdecl" on Microsoft
Windows). This is because the support requirements for alternative
calling conventions seem to no longer exist. Developers who find it
necessary to set PNG_API_RULE to 1 should advise the mailing list
libpng, because than the settings would not accurately reflect the settings
that were used to build libpng.
-XV. Setjmp/longjmp issues
+XIV. Setjmp/longjmp issues
Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp()
is known to be not thread-safe on some platforms and we don't know of
configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
-DPNG_NO_SETJMP on your compile line, or with
- #undef PNG_SETJMP_SUPPORTED
+ #undef PNG_SETJMP_SUPPORTED
in your pnglibconf.h or pngusr.h.
with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
-XVI. Other sources of information about libpng:
+XV. Common linking failures
-Further information can be found in the README and libpng-manual.txt
-files, in the individual makefiles, in png.h, and the manual pages
-libpng.3 and png.5.
+If your application fails to find libpng or zlib entries while linking:
-Using the ./configure script -- 16 December 2002.
-=================================================
+ Be sure "-lz" appears after "-lpng" on your linking command.
-The ./configure script should work compatibly with what scripts/makefile.*
-did, however there are some options you might need to add to configure
-explicitly, which previously was done semi-automatically (if you didn't edit
-scripts/makefile.* yourself, that is)
+ Be sure you have built libpng, zlib, and your application for the
+ same platform (e.g., 32-bit or 64-bit).
-CFLAGS="-Wall -O -funroll-loops \
--malign-loops=2 -malign-functions=2" ./configure --prefix=/usr/include \
---with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include
+ If you are using the vstudio project, observe the WARNING in
+ project/vstudio/README.txt.
-You can alternatively specify --includedir=/usr/include, /usr/local/include,
-/usr/include/libpng16, or whatever.
+XVI. Other sources of information about libpng:
-If you find that the configure script is out-of-date or is not supporting
-your platform properly, try running autogen.sh to regenerate "configure",
-"Makefile.in", and the other configuration files. Then try configure again.
+Further information can be found in the README and libpng-manual.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.
+Copyright (c) 2022 Cosmin Truta
+Copyright (c) 1998-2002,2006-2016 Glenn Randers-Pehrson
+This document is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h.
projects / platform / upstream / libpng.git / blobdiff