Build Skia as universal static libraries for OSX and iOS

skia.sh

readonly DEPOT_TOOLS_GIT='https://chromium.googlesource.com/chromium/tools/depot_tools.git'
readonly SKIA_GIT='https://skia.googlesource.com/skia.git'

readonly PROJECT_DIR="$(cd "$(dirname "$0")/../"; pwd)"
readonly BUILD_DIR="${PROJECT_DIR}/build"
readonly DEPOT_TOOLS_DIR="${BUILD_DIR}/depot_tools"
readonly SKIA_DIR="${BUILD_DIR}/skia"

download_depot_tools() {
  echo 'Downloading depot tools...'
  git clone "${DEPOT_TOOLS_GIT}" "${DEPOT_TOOLS_DIR}"
}

download_skia() {
  echo 'Downloading skia...'
  export PATH="${DEPOT_TOOLS_DIR}":"${PATH}"
  mkdir -p "${SKIA_DIR}/skia"
  pushd "${SKIA_DIR}/skia"
    gclient config --name . --unmanaged "${SKIA_GIT}"
    gclient sync
    git checkout master
  popd
}

build_skia() {
  pushd "${SKIA_DIR}/skia"
    export GYP_GENERATORS='ninja,xcode'

    echo 'Building for OS X...'
    GYP_DEFINES="skia_os='mac' skia_arch_width='32'" './gyp_skia'
    ninja -C 'out/Release' skia_lib tools
    copy_libraries_in_place "${SKIA_DIR}/skia/out/Release" 'osx' 'i386'
    GYP_DEFINES="skia_os='mac' skia_arch_width='64'" './gyp_skia'
    ninja -C 'out/Release' skia_lib tools
    copy_libraries_in_place "${SKIA_DIR}/skia/out/Release" 'osx' 'x86_64'

    echo 'Building for iOS...'
    GYP_DEFINES="skia_os='ios' skia_arch_type='arm' armv7='1' arm_neon='0'" './gyp_skia'
    ninja -C "out/Release-iphoneos" skia_lib tools
    copy_libraries_in_place "${SKIA_DIR}/skia/out/Release-iphoneos" 'ios' 'armv7'

    echo 'Building for iOS Simulator...'
    build_skia_for_ios_simulator 'i386' 'x86'
    copy_libraries_in_place "${SKIA_DIR}/skia/out/Release-iphonesimulator" 'ios' 'i386'
    build_skia_for_ios_simulator 'x86_64' 'x86_64'
    copy_libraries_in_place "${SKIA_DIR}/skia/out/Release-iphonesimulator" 'ios' 'x86_64'
  popd
}

build_skia_for_ios_simulator() {
  local arch=$1
  local arch_type=$2
  GYP_DEFINES="skia_os='ios' skia_arch_type='${arch_type}'" './gyp_skia'
  # Because gyp_skia doesn't generate ninja files for iPhone Simulator, we need
  # to replace the occurrences of the target architecture and the SDK directory
  # by hand.
  find 'out/Release-iphonesimulator' -type f -name '*.ninja' -exec \
      sed -i -e "s/armv7/${arch}/g" {} \;
  find 'out/Release-iphonesimulator' -type f -name '*.ninja' -exec \
      sed -i -e 's|iPhoneOS.platform|iPhoneSimulator.platform|g' {} \;
  find 'out/Release-iphonesimulator' -type f -name '*.ninja' -exec \
      sed -i -e 's|SDKs/iPhoneOS|SDKs/iPhoneSimulator|g' {} \;
  ninja -C 'out/Release-iphonesimulator' skia_lib tools
}

copy_libraries_in_place() {
  local dir=$1
  local platform=$2
  local arch=$3
  echo 'Copying libraries in place...'
  mkdir -p "${SKIA_DIR}/${platform}/${arch}"
  for file in $(find "${dir}" -name '*.a'); do
    cp -n "${file}" "${SKIA_DIR}/${platform}/${arch}"
  done
}

decompose_libraries() {
  echo 'Decomposing libraries to object files...'
  decompose_library 'osx' 'i386'
  decompose_library 'osx' 'x86_64'
  decompose_library 'ios' 'armv7'
  decompose_library 'ios' 'i386'
  decompose_library 'ios' 'x86_64'
}

decompose_library() {
  local platform=$1
  local arch=$2
  mkdir -p "${SKIA_DIR}/${platform}/${arch}/obj"
  for file in $(find "${SKIA_DIR}/${platform}/${arch}" -name '*.a'); do
    cd "${SKIA_DIR}/${platform}/${arch}/obj"; ar -x "${file}"
  done
}

create_universal_libraries() {
  echo 'Linking everything within architectures...'
  rm "${SKIA_DIR}"/osx/*/libskia.a
  rm "${SKIA_DIR}"/ios/*/libskia.a
  pushd "${SKIA_DIR}/osx/i386"; xcrun ar crus "libskia.a" obj/*.o; popd
  pushd "${SKIA_DIR}/osx/x86_64"; xcrun ar crus "libskia.a" obj/*.o; popd
  pushd "${SKIA_DIR}/ios/armv7"; xcrun ar crus "libskia.a" obj/*.o; popd
  pushd "${SKIA_DIR}/ios/i386"; xcrun ar crus "libskia.a" obj/*.o; popd
  pushd "${SKIA_DIR}/ios/x86_64"; xcrun ar crus "libskia.a" obj/*.o; popd

  echo 'Creating universal files...'
  rm "${SKIA_DIR}"/osx/libskia.a
  rm "${SKIA_DIR}"/ios/libskia.a
  xcrun lipo -create "${SKIA_DIR}"/osx/*/libskia.a -o "${SKIA_DIR}/osx/libskia.a"
  xcrun lipo -create "${SKIA_DIR}"/ios/*/libskia.a -o "${SKIA_DIR}/ios/libskia.a"
}

download_depot_tools
download_skia
build_skia
decompose_libraries
create_universal_libraries

This is a great script. I copied and tried to run the script today. Unfortunately there were lots of failing errors during the ios portion of the build:

duplicate symbol _main in: obj/tools/chrome_fuzz.chrome_fuzz.o obj/experimental/iOSSampleApp/Shared/chrome_fuzz.skia_ios.o ld: 1 duplicate symbol for architecture armv7 clang: error: linker command failed with exit code 1 (use -v to see invocation) [125/227] OBJCXX obj/experimental/SimpleiOSApp/test_image_decoder.SimpleApp.o ninja: build stopped: subcommand failed.

The last error was this:
fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: /Users/build/skia/ios/i386/libskia.a and /Users/build/skia/ios/x86_64/libskia.a have the same architectures (i386) and can't be in the same fat output file

Any help building this would be much appreciated.

Thanks again

Hi,

Actually i have created an assembly file, and included all the c++ header file in my objective c project. But i am not sure how to use the library to actually draw something and then show it.

any help is appreciated.