Download & Compile Libpng for iOS (all architectures)

libpng.sh

# Builds a Libpng framework for the iPhone and the iPhone Simulator.
# Creates a set of universal libraries that can be used on an iPhone and in the
# iPhone simulator. Then creates a pseudo-framework to make using libpng in Xcode
# less painful.
#
# To configure the script, define:
#    IPHONE_SDKVERSION: iPhone SDK version (e.g. 8.1)
#
# Then go get the source tar.bz of the libpng you want to build, shove it in the
# same directory as this script, and run "./libpng.sh". Grab a cuppa. And voila.
#===============================================================================

: ${LIB_VERSION:=1.4.14}

# Current iPhone SDK
: ${IPHONE_SDKVERSION:=`xcodebuild -showsdks | grep iphoneos | egrep "[[:digit:]]+\.[[:digit:]]+" -o | tail -1`}
# Specific iPhone SDK
# : ${IPHONE_SDKVERSION:=8.1}

: ${XCODE_ROOT:=`xcode-select -print-path`}

: ${TARBALLDIR:=`pwd`}
: ${SRCDIR:=`pwd`/src}
: ${IOSBUILDDIR:=`pwd`/ios/build}
: ${OSXBUILDDIR:=`pwd`/osx/build}
: ${PREFIXDIR:=`pwd`/ios/prefix}
: ${IOSFRAMEWORKDIR:=`pwd`/ios/framework}
: ${OSXFRAMEWORKDIR:=`pwd`/osx/framework}

LIB_TARBALL=$TARBALLDIR/libpng-$LIB_VERSION.tar.gz
LIB_SRC=$SRCDIR/libpng-${LIB_VERSION}

#===============================================================================
ARM_DEV_CMD="xcrun --sdk iphoneos"
SIM_DEV_CMD="xcrun --sdk iphonesimulator"

#===============================================================================
# Functions
#===============================================================================

abort()
{
    echo
    echo "Aborted: $@"
    exit 1
}

doneSection()
{
    echo
    echo "================================================================="
    echo "Done"
    echo
}

#===============================================================================

cleanEverythingReadyToStart()
{
    echo Cleaning everything before we start to build...

    rm -rf iphone-build iphonesim-build
    rm -rf $IOSBUILDDIR
    rm -rf $PREFIXDIR
    rm -rf $IOSFRAMEWORKDIR/$FRAMEWORK_NAME.framework

    doneSection
}

#===============================================================================

downloadLibpng()
{
    if [ ! -s $LIB_TARBALL ]; then
        echo "Downloading libpng ${LIB_VERSION}"
        curl -L -o $LIB_TARBALL http://sourceforge.net/projects/libpng/files/libpng14/${LIB_VERSION}/libpng-${LIB_VERSION}.tar.gz
    fi

    doneSection
}

#===============================================================================

unpackLibpng()
{
    [ -f "$LIB_TARBALL" ] || abort "Source tarball missing."

    echo Unpacking libpng into $SRCDIR...

    [ -d $SRCDIR ]    || mkdir -p $SRCDIR
    [ -d $LIB_SRC ] || ( cd $SRCDIR; tar xfj $LIB_TARBALL )
    [ -d $LIB_SRC ] && echo "    ...unpacked as $LIB_SRC"

    doneSection
}

#===============================================================================

buildLibpngForIPhoneOS()
{
    export CC=$XCODE_ROOT/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
    export CC_BASENAME=clang

    export CXX=$XCODE_ROOT/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++
    export CXX_BASENAME=clang++

    # avoid the `LDFLAGS` env to include the homebrew Cellar
    export LDFLAGS=""
    
    cd $LIB_SRC

    echo Building Libpng for iPhoneSimulator
    export CFLAGS="-O3 -arch i386 -arch x86_64 -isysroot $XCODE_ROOT/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator${IPHONE_SDKVERSION}.sdk -mios-simulator-version-min=${IPHONE_SDKVERSION} -Wno-error-implicit-function-declaration"
    make distclean
    ./configure --prefix=$PREFIXDIR/iphonesim-build --disable-dependency-tracking --enable-static=yes --enable-shared=no
    make
    make install
    doneSection

    echo Building Libpng for iPhone
    export CFLAGS="-O3 -arch armv7 -arch armv7s -arch arm64 -isysroot $XCODE_ROOT/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS${IPHONE_SDKVERSION}.sdk -mios-version-min=${IPHONE_SDKVERSION}"
    make distclean
    ./configure --host=arm-apple-darwin --prefix=$PREFIXDIR/iphone-build --disable-dependency-tracking --enable-static=yes --enable-shared=no
    make
    make install
    doneSection
}

#===============================================================================

scrunchAllLibsTogetherInOneLibPerPlatform()
{
    cd $PREFIXDIR

    # iOS Device
    mkdir -p $IOSBUILDDIR/armv7
    mkdir -p $IOSBUILDDIR/armv7s
    mkdir -p $IOSBUILDDIR/arm64

    # iOS Simulator
    mkdir -p $IOSBUILDDIR/i386
    mkdir -p $IOSBUILDDIR/x86_64

    ALL_LIBS=""

    echo Splitting all existing fat binaries...

    $ARM_DEV_CMD lipo "iphone-build/lib/libpng.a" -thin armv7 -o $IOSBUILDDIR/armv7/libpng.a
    $ARM_DEV_CMD lipo "iphone-build/lib/libpng.a" -thin armv7s -o $IOSBUILDDIR/armv7s/libpng.a
    $ARM_DEV_CMD lipo "iphone-build/lib/libpng.a" -thin arm64 -o $IOSBUILDDIR/arm64/libpng.a

    $SIM_DEV_CMD lipo "iphonesim-build/lib/libpng.a" -thin i386 -o $IOSBUILDDIR/i386/libpng.a
    $SIM_DEV_CMD lipo "iphonesim-build/lib/libpng.a" -thin x86_64 -o $IOSBUILDDIR/x86_64/libpng.a

    echo Build an universal library
}

#===============================================================================
buildFramework()
{
    : ${1:?}
    FRAMEWORKDIR=$1
    BUILDDIR=$2

    VERSION_TYPE=Alpha
    FRAMEWORK_NAME=libpng
    FRAMEWORK_VERSION=A

    FRAMEWORK_CURRENT_VERSION=$LIB_VERSION
    FRAMEWORK_COMPATIBILITY_VERSION=$LIB_VERSION

    FRAMEWORK_BUNDLE=$FRAMEWORKDIR/$FRAMEWORK_NAME.framework
    echo "Framework: Building $FRAMEWORK_BUNDLE from $BUILDDIR..."

    rm -rf $FRAMEWORK_BUNDLE

    echo "Framework: Setting up directories..."
    mkdir -p $FRAMEWORK_BUNDLE
    mkdir -p $FRAMEWORK_BUNDLE/Versions
    mkdir -p $FRAMEWORK_BUNDLE/Versions/$FRAMEWORK_VERSION
    mkdir -p $FRAMEWORK_BUNDLE/Versions/$FRAMEWORK_VERSION/Resources
    mkdir -p $FRAMEWORK_BUNDLE/Versions/$FRAMEWORK_VERSION/Headers
    mkdir -p $FRAMEWORK_BUNDLE/Versions/$FRAMEWORK_VERSION/Documentation

    echo "Framework: Creating symlinks..."
    ln -s $FRAMEWORK_VERSION               $FRAMEWORK_BUNDLE/Versions/Current
    ln -s Versions/Current/Headers         $FRAMEWORK_BUNDLE/Headers
    ln -s Versions/Current/Resources       $FRAMEWORK_BUNDLE/Resources
    ln -s Versions/Current/Documentation   $FRAMEWORK_BUNDLE/Documentation
    ln -s Versions/Current/$FRAMEWORK_NAME $FRAMEWORK_BUNDLE/$FRAMEWORK_NAME

    FRAMEWORK_INSTALL_NAME=$FRAMEWORK_BUNDLE/Versions/$FRAMEWORK_VERSION/$FRAMEWORK_NAME

    echo "Lipoing library into $FRAMEWORK_INSTALL_NAME..."
    $ARM_DEV_CMD lipo -create $BUILDDIR/*/libpng.a -o "$FRAMEWORK_INSTALL_NAME" || abort "Lipo $1 failed"

    echo "Framework: Copying includes..."
    cp -r $PREFIXDIR/iphone-build/include/*  $FRAMEWORK_BUNDLE/Headers/

    echo "Framework: Creating plist..."
    cat > $FRAMEWORK_BUNDLE/Resources/Info.plist <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>CFBundleDevelopmentRegion</key>
<string>English</string>
<key>CFBundleExecutable</key>
<string>${FRAMEWORK_NAME}</string>
<key>CFBundleIdentifier</key>
<string>org.libpng</string>
<key>CFBundleInfoDictionaryVersion</key>
<string>6.0</string>
<key>CFBundlePackageType</key>
<string>FMWK</string>
<key>CFBundleSignature</key>
<string>????</string>
<key>CFBundleVersion</key>
<string>${FRAMEWORK_CURRENT_VERSION}</string>
</dict>
</plist>
EOF

    doneSection
}

#===============================================================================
# Execution starts here
#===============================================================================

mkdir -p $IOSBUILDDIR

# cleanEverythingReadyToStart #may want to comment if repeatedly running during dev

echo "LIB_VERSION:       $LIB_VERSION"
echo "LIB_SRC:           $LIB_SRC"
echo "IOSBUILDDIR:       $IOSBUILDDIR"
echo "PREFIXDIR:         $PREFIXDIR"
echo "IOSFRAMEWORKDIR:   $IOSFRAMEWORKDIR"
echo "IPHONE_SDKVERSION: $IPHONE_SDKVERSION"
echo "XCODE_ROOT:        $XCODE_ROOT"
echo

downloadLibpng
unpackLibpng
buildLibpngForIPhoneOS
scrunchAllLibsTogetherInOneLibPerPlatform
buildFramework $IOSFRAMEWORKDIR $IOSBUILDDIR

echo "Completed successfully"

#===============================================================================

Hi thanks for this script, though when i download to my desktop and type

./libpngsh

Framework: Building /Users/$myusername/Desktop/ios/framework/libpng.framework from /Users/iansharp/Desktop/ios/build...
Framework: Setting up directories...
Framework: Creating symlinks...
Lipoing library into /Users/$myusername/Desktop/ios/framework/libpng.framework/Versions/A/libpng...
fatal error: /Applications/Xcode 6.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: can't open input file: /Users/$myusername/Desktop/ios/build/*/libpng.a (No such file or directory)

@khanhankkhan, I got the same error. If you scroll up in the output, you will see that it does not unpack the libpng source correctly. Just update the script to a later version of libpng (like 1.6.20) and it goes much further. At the moment I'm stuck with the zlib dependency though - the compiler is not finding zlib.h. The same author has posted a similar gist for zlib which works for me, so there's probably just a little work incorporating zlib.

@dulaccc Thanks for sharing your script!

Actually, leave the version at 1.4.14. Change the curl line in downloadLibpng() to this:
curl -L -o $LIB_TARBALL http://sourceforge.net/projects/libpng/files/libpng14/older-releases/${LIB_VERSION}/libpng-${LIB_VERSION}.tar.gz

The URL just needed "/older-releases" in the path. Now it works great. :)

When I tried to run the archive was unrecognized by tar (OSX). I changed up the script to 1.6.24 (extension is now xz). Seems to have built fine and loaded into XCode (IOS 9.3), haven't tested it out yet though. Thank you for making this great script dulaccc!

I was able to compile 1.6.27 but in order to get around zlib errors I removed

# Include the zlib header so that the defaults below are known
@#  include <zlib.h>

from:
scripts/pnglibconf.dfa