-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. Configuring libpng for multiprocessing
- 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
where you want to install the libpng "lib", "include", and "bin"
subdirectories.
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
II. Rebuilding the configure scripts
If configure does not work on your system, or if you have a need to
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
+ *.h, *.c => libpng source files
CMakeLists.txt => "cmake" script
configuration files:
configure.ac, configure, Makefile.am, Makefile.in,
libpng-config.in, aclocal.m4, config.h.in, config.sub,
depcomp, install-sh, mkinstalldirs, test-pngtest.sh
contrib
- gregbook
- libtests
- pngminim
- pngminus
- pngsuite
- visupng
+ arm-neon, conftest, examples, gregbook, libtests, pngminim,
+ pngminus, pngsuite, tools, visupng
projects
- visualc71
- vstudio
+ cbuilder5, owatcom, visualc71, vstudio, xcode
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\visualc6 or visualc71 directory and follow the instructions
+libpng projects\visualc71 or vstudio directory and follow the instructions
in README.txt.
Otherwise enter the zlib directory and follow the instructions in zlib/README,
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
+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
Read the makefile to see if you need to change any source or
target directories to match your preferences.
VIII. Configuring libpng for 16-bit platforms
You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more then 64K at a time. Even if you can, the memory
+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
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
+XIV. 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
+
+XV. 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
after the build of pnglibconf.h and it is never included in an application
build.
-The rarely used alternative of adding a list of feature macros to the
+The formerly used alternative of adding a list of feature macros to the
CPPFLAGS setting in the build also still works; however, the macros will be
copied to pnglibconf.h and this may produce macro redefinition warnings
when the individual C files are compiled.
Configuration options are now documented in scripts/pnglibconf.dfa. This
file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off dependent features are
-also removed. As a recommended alternative to using feature macros in
+consistent; that is, if a feature is switched off, dependent features are
+also switched off. As a recommended alternative to using feature macros in
pngusr.h a system builder may also define equivalent options in pngusr.dfa
(or, indeed, any file) and add that to the configuration by setting
DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate
-how to do this, and illustrate a case where pngusr.h is still required.
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory). Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
-XV. Configuring libpng for multiprocessing
+XVI. 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.
-XVI. Other sources of information about libpng:
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
-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.
+XVII. Common linking failures
+
+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/libpng%NN%, or whatever.
+XVIII. 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) 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