BUILDING.txt

*******************************************************************************
**     Building on Un*x Platforms (including Cygwin and OS X)
*******************************************************************************


==================
Build Requirements
==================

-- autoconf 2.56 or later
-- automake 1.7 or later
-- libtool 1.4 or later
   * If using Xcode 4.3 or later on OS X, autoconf and automake are no longer
     provided.  The easiest way to obtain them is from MacPorts
     (http://www.macports.org/).

-- NASM or YASM (if building x86 or x86-64 SIMD extensions)
   * NASM 0.98, or 2.01 or later is required for an x86 build (0.99 and 2.00 do
     not work properly with libjpeg-turbo's x86 SIMD code.)
   * NASM 2.00 or later is required for an x86-64 build.
   * NASM 2.07, or 2.11.09 or later is required for an x86-64 Mac build
     (2.11.08 does not work properly with libjpeg-turbo's x86-64 SIMD code when
     building macho64 objects.)  NASM or YASM can be obtained from MacPorts
     (http://www.macports.org/).

   The binary RPMs released by the NASM project do not work on older Linux
   systems, such as Red Hat Enterprise Linux 4.  On such systems, you can
   easily build and install NASM from a source RPM by downloading one of the
   SRPMs from

   http://www.nasm.us/pub/nasm/releasebuilds

   and executing the following as root:

     ARCH=`uname -m`
     rpmbuild --rebuild nasm-{version}.src.rpm
     rpm -Uvh /usr/src/redhat/RPMS/$ARCH/nasm-{version}.$ARCH.rpm

   NOTE: the NASM build will fail if texinfo is not installed.

-- GCC v4.1 or later recommended for best performance
   * Beginning with Xcode 4, Apple stopped distributing GCC and switched to
     the LLVM compiler.  Xcode v4.0 through v4.6 provides a GCC front end
     called LLVM-GCC.  Unfortunately, as of this writing, neither LLVM-GCC nor
     the LLVM (clang) compiler produces optimal performance with libjpeg-turbo.
     Building libjpeg-turbo with LLVM-GCC v4.2 results in a 10% performance
     degradation when compressing using 64-bit code, relative to building
     libjpeg-turbo with GCC v4.2.  Building libjpeg-turbo with LLVM (clang)
     results in a 20% performance degradation when compressing using 64-bit
     code, relative to building libjpeg-turbo with GCC v4.2.  If you are
     running Snow Leopard or earlier, it is suggested that you continue to use
     Xcode v3.2.6, which provides GCC v4.2.  If you are using Lion or later, it
     is suggested that you install Apple GCC v4.2 or GCC v5 through MacPorts.

-- If building the TurboJPEG Java wrapper, JDK or OpenJDK 1.5 or later is
   required.  Some systems, such as Solaris 10 and later and Red Hat Enterprise
   Linux 5 and later, have this pre-installed.  On OS X 10.5 and later, it will
   be necessary to install the Java Developer Package, which can be downloaded
   from http://developer.apple.com/downloads (Apple ID required.)  For systems
   that do not have a JDK installed, you can obtain the Oracle Java Development
   Kit from http://www.java.com.


==================
Out-of-Tree Builds
==================

Binary objects, libraries, and executables are generated in the same directory
from which configure was executed (the "binary directory"), and this directory
need not necessarily be the same as the libjpeg-turbo source directory.  You
can create multiple independent binary directories, in which different versions
of libjpeg-turbo can be built from the same source tree using different
compilers or settings.  In the sections below, {build_directory} refers to the
binary directory, whereas {source_directory} refers to the libjpeg-turbo source
directory.  For in-tree builds, these directories are the same.


======================
Building libjpeg-turbo
======================

The following procedure will build libjpeg-turbo on Linux, FreeBSD, Cygwin, and
Solaris/x86 systems (on Solaris, this generates a 32-bit library.  See below
for 64-bit build instructions.)

  cd {source_directory}
  cd {build_directory}
  sh {source_directory}/configure [additional configure flags]
  make

This will generate the following files under .libs/

  libjpeg.a
      Static link library for the libjpeg API

  libjpeg.so.{version} (Linux, Unix)
  libjpeg.{version}.dylib (OS X)
  cygjpeg-{version}.dll (Cygwin)
      Shared library for the libjpeg API

  By default, {version} is 62.1.0, 7.1.0, or 8.0.2, depending on whether
  libjpeg v6b (default), v7, or v8 emulation is enabled.  If using Cygwin,
  {version} is 62, 7, or 8.

  libjpeg.so (Linux, Unix)
  libjpeg.dylib (OS X)
      Development symlink for the libjpeg API

  libjpeg.dll.a (Cygwin)
      Import library for the libjpeg API

  libturbojpeg.a
      Static link library for the TurboJPEG API

  libturbojpeg.so.0.1.0 (Linux, Unix)
  libturbojpeg.0.1.0.dylib (OS X)
  cygturbojpeg-0.dll (Cygwin)
      Shared library for the TurboJPEG API

  libturbojpeg.so (Linux, Unix)
  libturbojpeg.dylib (OS X)
      Development symlink for the TurboJPEG API

  libturbojpeg.dll.a (Cygwin)
      Import library for the TurboJPEG API


libjpeg v7 or v8 API/ABI Emulation
----------------------------------

Add --with-jpeg7 to the configure command line to build a version of
libjpeg-turbo that is API/ABI-compatible with libjpeg v7.  Add --with-jpeg8 to
the configure command to build a version of libjpeg-turbo that is
API/ABI-compatible with libjpeg v8.  See README-turbo.txt for more information
on libjpeg v7 and v8 emulation.


In-Memory Source/Destination Managers
-------------------------------------

When using libjpeg v6b or v7 API/ABI emulation, add --without-mem-srcdst to the
configure command line to build a version of libjpeg-turbo that lacks the
jpeg_mem_src() and jpeg_mem_dest() functions.  These functions were not part of
the original libjpeg v6b and v7 APIs, so removing them ensures strict
conformance with those APIs.  See README-turbo.txt for more information.


Arithmetic Coding Support
-------------------------

Since the patent on arithmetic coding has expired, this functionality has been
included in this release of libjpeg-turbo.  libjpeg-turbo's implementation is
based on the implementation in libjpeg v8, but it works when emulating libjpeg
v7 or v6b as well.  The default is to enable both arithmetic encoding and
decoding, but those who have philosophical objections to arithmetic coding can
add --without-arith-enc or --without-arith-dec to the configure command line to
disable encoding or decoding (respectively.)


TurboJPEG Java Wrapper
----------------------
Add --with-java to the configure command line to incorporate an optional Java
Native Interface wrapper into the TurboJPEG shared library and build the Java
front-end classes to support it.  This allows the TurboJPEG shared library to
be used directly from Java applications.  See java/README for more details.

You can set the JAVAC, JAR, and JAVA configure variables to specify
alternate commands for javac, jar, and java (respectively.)  You can also
set the JAVACFLAGS configure variable to specify arguments that should be
passed to the Java compiler when building the front-end classes, and JNI_CFLAGS
to specify arguments that should be passed to the C compiler when building the
JNI wrapper.  Run 'configure --help' for more details.


========================
Installing libjpeg-turbo
========================

If you intend to install these libraries and the associated header files, then
replace 'make' in the instructions above with

  make install prefix={base dir} libdir={library directory}

For example,

  make install prefix=/usr/local libdir=/usr/local/lib64

will install the header files in /usr/local/include and the library files in
/usr/local/lib64.  If 'prefix' and 'libdir' are not specified, then the default
is to install the header files in /opt/libjpeg-turbo/include and the library
files in /opt/libjpeg-turbo/lib32 (32-bit) or /opt/libjpeg-turbo/lib64
(64-bit.)

NOTE: You can specify a prefix of /usr and a libdir of, for instance,
/usr/lib64 to overwrite the system's version of libjpeg.  If you do this,
however, then be sure to BACK UP YOUR SYSTEM'S INSTALLATION OF LIBJPEG before
overwriting it.  It is recommended that you instead install libjpeg-turbo into
a non-system directory and manipulate the LD_LIBRARY_PATH or create symlinks
to force applications to use libjpeg-turbo instead of libjpeg.  See
README-turbo.txt for more information.


=============
Build Recipes
=============


32-bit Build on 64-bit Linux
----------------------------

Add

  --host i686-pc-linux-gnu CFLAGS='-O3 -m32' LDFLAGS=-m32

to the configure command line.


64-bit Build on 64-bit OS X
---------------------------

Add

  --host x86_64-apple-darwin NASM=/opt/local/bin/nasm

to the configure command line.  NASM 2.07 or later from MacPorts must be
installed.


32-bit Build on 64-bit OS X
---------------------------

Add

  --host i686-apple-darwin CFLAGS='-O3 -m32' LDFLAGS=-m32

to the configure command line.


64-bit Backward-Compatible Build on 64-bit OS X
-----------------------------------------------

Add

  --host x86_64-apple-darwin NASM=/opt/local/bin/nasm \
  CFLAGS='-isysroot /Developer/SDKs/MacOSX10.5.sdk \
    -mmacosx-version-min=10.5 -O3' \
    LDFLAGS='-isysroot /Developer/SDKs/MacOSX10.5.sdk \
    -mmacosx-version-min=10.5'

to the configure command line.  The OS X 10.5 SDK, and NASM 2.07 or later from
MacPorts, must be installed.


32-bit Backward-Compatible Build on OS X
----------------------------------------

Add

  --host i686-apple-darwin \
    CFLAGS='-isysroot /Developer/SDKs/MacOSX10.5.sdk \
    -mmacosx-version-min=10.5 -O3 -m32' \
    LDFLAGS='-isysroot /Developer/SDKs/MacOSX10.5.sdk \
    -mmacosx-version-min=10.5 -m32'

to the configure command line.  The OS X 10.5 SDK must be installed.


64-bit Library Build on 64-bit Solaris
--------------------------------------

Add

  --host x86_64-pc-solaris CFLAGS='-O3 -m64' LDFLAGS=-m64

to the configure command line.


32-bit Build on 64-bit FreeBSD
------------------------------

Add

  --host i386-unknown-freebsd CC='gcc -B /usr/lib32' CFLAGS='-O3 -m32' \
    LDFLAGS='-B/usr/lib32'

to the configure command line.  NASM 2.07 or later from FreeBSD ports must be
installed.


Oracle Solaris Studio
---------------------

Add

  CC=cc

to the configure command line.  libjpeg-turbo will automatically be built with
the maximum optimization level (-xO5) unless you override CFLAGS.

To build a 64-bit version of libjpeg-turbo using Oracle Solaris Studio, add

  --host x86_64-pc-solaris CC=cc CFLAGS='-xO5 -m64' LDFLAGS=-m64

to the configure command line.


MinGW Build on Cygwin
---------------------

Use CMake (see recipes below)


===========
ARM Support
===========

This release of libjpeg-turbo can use ARM NEON SIMD instructions to accelerate
JPEG compression/decompression by approximately 2-4x on ARMv7 and later
platforms.  If libjpeg-turbo is configured on an ARM Linux platform, then the
build system will automatically include the NEON SIMD routines, if they are
supported.  Build instructions for other ARM-based platforms follow.


Building libjpeg-turbo for iOS
------------------------------

iOS platforms, such as the iPhone and iPad, use ARM processors, some of which
support NEON instructions.  Additional steps are required in order to build
libjpeg-turbo for these platforms.

Additional build requirements:

  gas-preprocessor.pl
  (https://raw.githubusercontent.com/libjpeg-turbo/gas-preprocessor/master/gas-preprocessor.pl)
  should be installed in your PATH.


ARM 32-bit Build (Xcode 4.6.x and earlier, LLVM-GCC):

Set the following shell variables for simplicity:

  Xcode 4.2 and earlier:
  IOS_PLATFORMDIR=/Developer/Platforms/iPhoneOS.platform
  Xcode 4.3 and later:
  IOS_PLATFORMDIR=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform

  IOS_SYSROOT=$IOS_PLATFORMDIR/Developer/SDKs/iPhoneOS*.sdk
  IOS_GCC=$IOS_PLATFORMDIR/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2

  ARMv6 (code will run on all iOS devices, not SIMD-accelerated):
  [NOTE: Requires Xcode 4.4.x or earlier]
  IOS_CFLAGS="-march=armv6 -mcpu=arm1176jzf-s -mfpu=vfp"

  ARMv7 (code will run on iPhone 3GS-4S/iPad 1st-3rd Generation and newer):
  IOS_CFLAGS="-march=armv7 -mcpu=cortex-a8 -mtune=cortex-a8 -mfpu=neon"

  ARMv7s (code will run on iPhone 5/iPad 4th Generation and newer):
  [NOTE: Requires Xcode 4.5 or later]
  IOS_CFLAGS="-march=armv7s -mcpu=swift -mtune=swift -mfpu=neon"

Follow the procedure under "Building libjpeg-turbo" above, adding

  --host arm-apple-darwin10 \
    CC="$IOS_GCC" LD="$IOS_GCC" \
    CFLAGS="-mfloat-abi=softfp -isysroot $IOS_SYSROOT -O3 $IOS_CFLAGS" \
    LDFLAGS="-mfloat-abi=softfp -isysroot $IOS_SYSROOT $IOS_CFLAGS"

to the configure command line.


ARM 32-bit Build (Xcode 5.0.x and later, Clang):

Set the following shell variables for simplicity:

  IOS_PLATFORMDIR=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform
  IOS_SYSROOT=$IOS_PLATFORMDIR/Developer/SDKs/iPhoneOS*.sdk
  IOS_GCC=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang

  ARMv7 (code will run on iPhone 3GS-4S/iPad 1st-3rd Generation and newer):
  IOS_CFLAGS="-arch armv7"

  ARMv7s (code will run on iPhone 5/iPad 4th Generation and newer):
  IOS_CFLAGS="-arch armv7s"

Follow the procedure under "Building libjpeg-turbo" above, adding

  --host arm-apple-darwin10 \
    CC="$IOS_GCC" LD="$IOS_GCC" \
    CFLAGS="-mfloat-abi=softfp -isysroot $IOS_SYSROOT -O3 $IOS_CFLAGS" \
    LDFLAGS="-mfloat-abi=softfp -isysroot $IOS_SYSROOT $IOS_CFLAGS" \
    CCASFLAGS="-no-integrated-as $IOS_CFLAGS"

to the configure command line.


ARMv8 64-bit Build (Xcode 5.0.x and later, Clang):

Code will run on iPhone 5S/iPad Mini 2/iPad Air and newer.

Set the following shell variables for simplicity:

  IOS_PLATFORMDIR=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform
  IOS_SYSROOT=$IOS_PLATFORMDIR/Developer/SDKs/iPhoneOS*.sdk
  IOS_GCC=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
  IOS_CFLAGS="-arch arm64"

Follow the procedure under "Building libjpeg-turbo" above, adding

  --host aarch64-apple-darwin \
    CC="$IOS_GCC" LD="$IOS_GCC" \
    CFLAGS="-isysroot $IOS_SYSROOT -O3 $IOS_CFLAGS" \
    LDFLAGS="-isysroot $IOS_SYSROOT $IOS_CFLAGS"

to the configure command line.


NOTE:  You can also add -miphoneos-version-min={version} to $IOS_CFLAGS above
in order to support older versions of iOS than the default version supported by
the SDK.

Once built, lipo can be used to combine the ARMv6, v7, v7s, and/or v8 variants
into a universal library.


Building libjpeg-turbo for Android
----------------------------------

Building libjpeg-turbo for Android platforms requires the Android NDK
(https://developer.android.com/tools/sdk/ndk) and autotools.  The following is
a general recipe script that can be modified for your specific needs.

  # Set these variables to suit your needs
  NDK_PATH={full path to the "ndk" directory-- for example, /opt/android/ndk}
  BUILD_PLATFORM={the platform name for the NDK package you installed--
    for example, "windows-x86" or "linux-x86_64"}
  TOOLCHAIN_VERSION={"4.6", "4.8", etc.  This corresponds to a toolchain
    directory under ${NDK_PATH}/toolchains/.}
  ANDROID_VERSION={The minimum version of Android to support-- for example,
    "9", "19", etc.}

  HOST=arm-linux-androideabi
  TOOLCHAIN=${NDK_PATH}/toolchains/${HOST}-${TOOLCHAIN_VERSION}/prebuilt/${BUILD_PLATFORM}
  SYSROOT=${NDK_PATH}/platforms/android-${ANDROID_VERSION}/arch-arm
  ANDROID_INCLUDES="-I${SYSROOT}/usr/include -I${TOOLCHAIN}/include"
  ANDROID_CFLAGS="-march=armv7-a -mfloat-abi=softfp -fprefetch-loop-arrays \
    -fstrict-aliasing --sysroot=${SYSROOT}"
  export CPP=${TOOLCHAIN}/bin/${HOST}-cpp
  export AR=${TOOLCHAIN}/bin/${HOST}-ar
  export AS=${TOOLCHAIN}/bin/${HOST}-as
  export NM=${TOOLCHAIN}/bin/${HOST}-nm
  export CC=${TOOLCHAIN}/bin/${HOST}-gcc
  export LD=${TOOLCHAIN}/bin/${HOST}-ld
  export RANLIB=${TOOLCHAIN}/bin/${HOST}-ranlib
  export OBJDUMP=${TOOLCHAIN}/bin/${HOST}-objdump
  export STRIP=${TOOLCHAIN}/bin/${HOST}-strip
  cd {build_directory}
  sh {source_directory}/configure --host=${HOST} \
    CFLAGS="${ANDROID_INCLUDES} ${ANDROID_CFLAGS} -O3" \
    CPPFLAGS="${ANDROID_INCLUDES} ${ANDROID_CFLAGS}" \
    LDFLAGS="${ANDROID_CFLAGS}" --with-simd ${1+"$@"}
  make


*******************************************************************************
**     Building on Windows (Visual C++ or MinGW)
*******************************************************************************


==================
Build Requirements
==================

-- CMake (http://www.cmake.org) v2.8.8 or later

-- Microsoft Visual C++ 2005 or later

   If you don't already have Visual C++, then the easiest way to get it is by
   installing the Windows SDK:

   http://msdn.microsoft.com/en-us/windows/bb980924.aspx

   The Windows SDK includes both 32-bit and 64-bit Visual C++ compilers and
   everything necessary to build libjpeg-turbo.

   * You can also use Microsoft Visual Studio Express Edition, which is a free
     download.  (NOTE: versions prior to 2012 can only be used to build 32-bit
     code.)
   * If you intend to build libjpeg-turbo from the command line, then add the
     appropriate compiler and SDK directories to the INCLUDE, LIB, and PATH
     environment variables.  This is generally accomplished by executing
     vcvars32.bat or vcvars64.bat and SetEnv.cmd.  vcvars32.bat and
     vcvars64.bat are part of Visual C++ and are located in the same directory
     as the compiler.  SetEnv.cmd is part of the Windows SDK.  You can pass
     optional arguments to SetEnv.cmd to specify a 32-bit or 64-bit build
     environment.

... OR ...

-- MinGW

   MinGW-builds (http://sourceforge.net/projects/mingwbuilds/) or
   tdm-gcc (http://tdm-gcc.tdragon.net/) recommended if building on a Windows
   machine.  Both distributions install a Start Menu link that can be used to
   launch a command prompt with the appropriate compiler paths automatically
   set.

-- NASM (http://www.nasm.us/) 0.98 or later (NASM 2.05 or later is required for
   a 64-bit build)

-- If building the TurboJPEG Java wrapper, JDK 1.5 or later is required.  This
   can be downloaded from http://www.java.com.


==================
Out-of-Tree Builds
==================

Binary objects, libraries, and executables are generated in the same directory
from which cmake was executed (the "binary directory"), and this directory need
not necessarily be the same as the libjpeg-turbo source directory.  You can
create multiple independent binary directories, in which different versions of
libjpeg-turbo can be built from the same source tree using different compilers
or settings.  In the sections below, {build_directory} refers to the binary
directory, whereas {source_directory} refers to the libjpeg-turbo source
directory.  For in-tree builds, these directories are the same.


======================
Building libjpeg-turbo
======================


Visual C++ (Command Line)
-------------------------

  cd {build_directory}
  cmake -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release {source_directory}
  nmake

This will build either a 32-bit or a 64-bit version of libjpeg-turbo, depending
on which version of cl.exe is in the PATH.

The following files will be generated under {build_directory}:

  jpeg-static.lib
      Static link library for the libjpeg API
  sharedlib/jpeg{version}.dll
      DLL for the libjpeg API
  sharedlib/jpeg.lib
      Import library for the libjpeg API
  turbojpeg-static.lib
      Static link library for the TurboJPEG API
  turbojpeg.dll
      DLL for the TurboJPEG API
  turbojpeg.lib
      Import library for the TurboJPEG API

{version} is 62, 7, or 8, depending on whether libjpeg v6b (default), v7, or
v8 emulation is enabled.


Visual C++ (IDE)
----------------

Choose the appropriate CMake generator option for your version of Visual Studio
(run "cmake" with no arguments for a list of available generators.)  For
instance:

  cd {build_directory}
  cmake -G "Visual Studio 10" {source_directory}

NOTE:  Add "Win64" to the generator name (for example, "Visual Studio 10
Win64") to build a 64-bit version of libjpeg-turbo.  Recent versions of CMake
no longer document that.  A separate build directory must be used for 32-bit
and 64-bit builds.

You can then open ALL_BUILD.vcproj in Visual Studio and build one of the
configurations in that project ("Debug", "Release", etc.) to generate a full
build of libjpeg-turbo.

This will generate the following files under {build_directory}:

  {configuration}/jpeg-static.lib
      Static link library for the libjpeg API
  sharedlib/{configuration}/jpeg{version}.dll
      DLL for the libjpeg API
  sharedlib/{configuration}/jpeg.lib
      Import library for the libjpeg API
  {configuration}/turbojpeg-static.lib
      Static link library for the TurboJPEG API
  {configuration}/turbojpeg.dll
      DLL for the TurboJPEG API
  {configuration}/turbojpeg.lib
      Import library for the TurboJPEG API

{configuration} is Debug, Release, RelWithDebInfo, or MinSizeRel, depending on
the configuration you built in the IDE, and {version} is 62, 7, or 8,
depending on whether libjpeg v6b (default), v7, or v8 emulation is enabled.


MinGW
-----

NOTE: This assumes that you are building on a Windows machine.  If you are
cross-compiling on a Linux/Unix machine, then see "Build Recipes" below.

  cd {build_directory}
  cmake -G "MinGW Makefiles" {source_directory}
  mingw32-make

This will generate the following files under {build_directory}

  libjpeg.a
      Static link library for the libjpeg API
  sharedlib/libjpeg-{version}.dll
      DLL for the libjpeg API
  sharedlib/libjpeg.dll.a
      Import library for the libjpeg API
  libturbojpeg.a
      Static link library for the TurboJPEG API
  libturbojpeg.dll
      DLL for the TurboJPEG API
  libturbojpeg.dll.a
      Import library for the TurboJPEG API

{version} is 62, 7, or 8, depending on whether libjpeg v6b (default), v7, or
v8 emulation is enabled.


Debug Build
-----------

Add "-DCMAKE_BUILD_TYPE=Debug" to the cmake command line.  Or, if building with
NMake, remove "-DCMAKE_BUILD_TYPE=Release" (Debug builds are the default with
NMake.)


libjpeg v7 or v8 API/ABI Emulation
-----------------------------------

Add "-DWITH_JPEG7=1" to the cmake command line to build a version of
libjpeg-turbo that is API/ABI-compatible with libjpeg v7.  Add "-DWITH_JPEG8=1"
to the cmake command to build a version of libjpeg-turbo that is
API/ABI-compatible with libjpeg v8.  See README-turbo.txt for more information
on libjpeg v7 and v8 emulation.


In-Memory Source/Destination Managers
-------------------------------------

When using libjpeg v6b or v7 API/ABI emulation, add -DWITH_MEM_SRCDST=0 to the
CMake command line to build a version of libjpeg-turbo that lacks the
jpeg_mem_src() and jpeg_mem_dest() functions.  These functions were not part of
the original libjpeg v6b and v7 APIs, so removing them ensures strict
conformance with those APIs.  See README-turbo.txt for more information.


Arithmetic Coding Support
-------------------------

Since the patent on arithmetic coding has expired, this functionality has been
included in this release of libjpeg-turbo.  libjpeg-turbo's implementation is
based on the implementation in libjpeg v8, but it works when emulating libjpeg
v7 or v6b as well.  The default is to enable both arithmetic encoding and
decoding, but those who have philosophical objections to arithmetic coding can
add "-DWITH_ARITH_ENC=0" or "-DWITH_ARITH_DEC=0" to the cmake command line to
disable encoding or decoding (respectively.)


TurboJPEG Java Wrapper
----------------------
Add "-DWITH_JAVA=1" to the cmake command line to incorporate an optional Java
Native Interface wrapper into the TurboJPEG shared library and build the Java
front-end classes to support it.  This allows the TurboJPEG shared library to
be used directly from Java applications.  See java/README for more details.

If you are using CMake 2.8, you can set the Java_JAVAC_EXECUTABLE,
Java_JAVA_EXECUTABLE, and Java_JAR_EXECUTABLE CMake variables to specify
alternate commands or locations for javac, jar, and java (respectively.)  If
you are using CMake 2.6, set JAVA_COMPILE, JAVA_RUNTIME, and JAVA_ARCHIVE
instead.  You can also set the JAVACFLAGS CMake variable to specify arguments
that should be passed to the Java compiler when building the front-end classes.


========================
Installing libjpeg-turbo
========================

You can use the build system to install libjpeg-turbo into a directory of your
choosing (as opposed to creating an installer.)  To do this, add:

  -DCMAKE_INSTALL_PREFIX={install_directory}

to the cmake command line.

For example,

  cmake -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX=c:\libjpeg-turbo {source_directory}
  nmake install

will install the header files in c:\libjpeg-turbo\include, the library files
in c:\libjpeg-turbo\lib, the DLL's in c:\libjpeg-turbo\bin, and the
documentation in c:\libjpeg-turbo\doc.


=============
Build Recipes
=============


64-bit MinGW Build on Cygwin
----------------------------

  cd {build_directory}
  CC=/usr/bin/x86_64-w64-mingw32-gcc \
    cmake -G "Unix Makefiles" -DCMAKE_SYSTEM_NAME=Windows \
    -DCMAKE_RC_COMPILER=/usr/bin/x86_64-w64-mingw32-windres.exe \
    {source_directory}
  make

This produces a 64-bit build of libjpeg-turbo that does not depend on
cygwin1.dll or other Cygwin DLL's.  The mingw64-x86_64-gcc-core and
mingw64-x86_64-gcc-g++ packages (and their dependencies) must be installed.


32-bit MinGW Build on Cygwin
----------------------------

  cd {build_directory}
  CC=/usr/bin/i686-w64-mingw32-gcc \
    cmake -G "Unix Makefiles" -DCMAKE_SYSTEM_NAME=Windows \
    -DCMAKE_RC_COMPILER=/usr/bin/i686-w64-mingw32-windres.exe \
    {source_directory}
  make

This produces a 32-bit build of libjpeg-turbo that does not depend on
cygwin1.dll or other Cygwin DLL's.  The mingw64-i686-gcc-core and
mingw64-i686-gcc-g++ packages (and their dependencies) must be installed.


MinGW Build on Linux
--------------------

  cd {build_directory}
  CC={mingw_binary_path}/i386-mingw32-gcc \
    cmake -G "Unix Makefiles" -DCMAKE_SYSTEM_NAME=Windows \
    -DCMAKE_AR={mingw_binary_path}/i386-mingw32-ar \
    -DCMAKE_RANLIB={mingw_binary_path}/i386-mingw32-ranlib \
    {source_directory}
  make


*******************************************************************************
**     Creating Release Packages
*******************************************************************************

The following commands can be used to create various types of release packages:


Unix/Linux
----------

make rpm

  Create Red Hat-style binary RPM package.  Requires RPM v4 or later.

make srpm

  This runs 'make dist' to create a pristine source tarball, then creates a
  Red Hat-style source RPM package from the tarball.  Requires RPM v4 or later.

make deb

  Create Debian-style binary package.  Requires dpkg.

make dmg

  Create Macintosh package/disk image.  This requires pkgbuild and
  productbuild, which are installed by default on OS X 10.7 and later and which
  can be obtained by installing Xcode 3.2.6 (with the "Unix Development"
  option) on OS X 10.6.  Packages built in this manner can be installed on OS X
  10.5 and later, but they must be built on OS X 10.6 or later.

make udmg [BUILDDIR32={32-bit build directory}]

  On 64-bit OS X systems, this creates a Macintosh package and disk image that
  contains universal i386/x86-64 binaries.  You should first configure a 32-bit
  out-of-tree build of libjpeg-turbo, then configure a 64-bit out-of-tree
  build, then run 'make udmg' from the 64-bit build directory.  The build
  system will look for the 32-bit build under {source_directory}/osxx86 by
  default, but you can override this by setting the BUILDDIR32 variable on the
  make command line as shown above.

make iosdmg [BUILDDIR32={32-bit build directory}] \
  [BUILDDIRARMV6={ARMv6 build directory}] \
  [BUILDDIRARMV7={ARMv7 build directory}] \
  [BUILDDIRARMV7S={ARMv7s build directory}] \
  [BUILDDIRARMV8={ARMv8 build directory}]

  On OS X systems, this creates a Macintosh package and disk image in which the
  libjpeg-turbo static libraries contain ARM architectures necessary to build
  iOS applications.  If building on an x86-64 system, the binaries will also
  contain the i386 architecture, as with 'make udmg' above.  You should first
  configure ARMv6, ARMv7, ARMv7s, and/or ARMv8 out-of-tree builds of
  libjpeg-turbo (see "Building libjpeg-turbo for iOS" above.)  If you are
  building an x86-64 version of libjpeg-turbo, you should configure a 32-bit
  out-of-tree build as well.  Next, build libjpeg-turbo as you would normally,
  using an out-of-tree build.  When it is built, run 'make iosdmg' from the
  build directory.  The build system will look for the ARMv6 build under
  {source_directory}/iosarmv6 by default, the ARMv7 build under
  {source_directory}/iosarmv7 by default, the ARMv7s build under
  {source_directory}/iosarmv7s by default, the ARMv8 build under
  {source_directory}/iosarmv8 by default, and (if applicable) the 32-bit build
  under {source_directory}/osxx86 by default, but you can override this by
  setting the BUILDDIR32, BUILDDIRARMV6, BUILDDIRARMV7, BUILDDIRARMV7S, and/or
  BUILDDIRARMV8 variables on the make command line as shown above.

  NOTE: If including an ARMv8 build in the package, then you may need to use
  Xcode's version of lipo instead of the operating system's.  To do this, pass
  an argument of LIPO="xcrun lipo" on the make command line.

make cygwinpkg

  Build a Cygwin binary package.


Windows
-------

If using NMake:

  cd {build_directory}
  nmake installer

If using MinGW:

  cd {build_directory}
  make installer

If using the Visual Studio IDE, build the "installer" project.

The installer package (libjpeg-turbo[-gcc][64].exe) will be located under
{build_directory}.  If building using the Visual Studio IDE, then the installer
package will be located in a subdirectory with the same name as the
configuration you built (such as {build_directory}\Debug\ or
{build_directory}\Release\).

Building a Windows installer requires the Nullsoft Install System
(http://nsis.sourceforge.net/.)  makensis.exe should be in your PATH.


*******************************************************************************
**     Regression testing
*******************************************************************************

The most common way to test libjpeg-turbo is by invoking 'make test' on
Unix/Linux platforms or 'ctest' on Windows platforms, once the build has
completed.  This runs a series of tests to ensure that mathematical
compatibility has been maintained between libjpeg-turbo and libjpeg v6b.  This
also invokes the TurboJPEG unit tests, which ensure that the colorspace
extensions, YUV encoding, decompression scaling, and other features of the
TurboJPEG C and Java APIs are working properly (and, by extension, that the
equivalent features of the underlying libjpeg API are also working.)

Invoking 'make testclean' or 'nmake testclean' (if using NMake) or building
the 'testclean' target (if using the Visual Studio IDE) will clean up the
output images generated by 'make test'.

On Unix/Linux platforms, more extensive tests of the TurboJPEG C and Java
wrappers can be run by invoking 'make tjtest'.  These extended TurboJPEG tests
essentially iterate through all of the available features of the TurboJPEG APIs
that are not covered by the TurboJPEG unit tests (this includes the lossless
transform options) and compare the images generated by each feature to images
generated using the equivalent feature in the libjpeg API.  The extended
TurboJPEG tests are meant to test for regressions in the TurboJPEG wrappers,
not in the underlying libjpeg API library.