How to build Skia
Make sure you have first followed the instructions to download Skia.
Skia uses GN to configure its builds.
A few build configurations remain unported to GN, so you may see some
files laying around left over from when we used GYP. Don’t bother looking at
Run GN to generate your build files.
bin/gn gen out/Static --args='is_official_build=true' bin/gn gen out/Shared --args='is_official_build=true is_component_build=true'
If you find you don’t have
bin/gn, make sure you’ve run
GN allows fine-grained settings for developers and special situations.
bin/gn gen out/Debug bin/gn gen out/Release --args='is_debug=false' bin/gn gen out/Clang --args='cc="clang" cxx="clang++"' bin/gn gen out/Cached --args='cc_wrapper="ccache"' bin/gn gen out/RTTI --args='extra_cflags_cc=["-frtti"]'
To see all the arguments available, you can run
bin/gn args out/Debug --list
Having generated your build files, run Ninja to compile and link Skia.
ninja -C out/Static ninja -C out/Shared ninja -C out/Debug ninja -C out/Release ninja -C out/Clang ninja -C out/Cached ninja -C out/RTTI
To build Skia for Android you need an Android NDK.
If you do not have an NDK and have access to CIPD, you can use one of these commands to fetch the NDK our bots use:
python infra/bots/assets/android_ndk_linux/download.py -t /tmp/ndk python infra/bots/assets/android_ndk_darwin/download.py -t /tmp/ndk python infra/bots/assets/android_ndk_windows/download.py -t C:/ndk
When generating your GN build files, pass the path to your
ndk and your
bin/gn gen out/arm --args='ndk="/tmp/ndk" target_cpu="arm"' bin/gn gen out/arm64 --args='ndk="/tmp/ndk" target_cpu="arm64"' bin/gn gen out/mips64el --args='ndk="/tmp/ndk" target_cpu="mips64el"' bin/gn gen out/mipsel --args='ndk="/tmp/ndk" target_cpu="mipsel"' bin/gn gen out/x64 --args='ndk="/tmp/ndk" target_cpu="x64"' bin/gn gen out/x86 --args='ndk="/tmp/ndk" target_cpu="x86"'
Other arguments like
is_component_build continue to work.
ndk_api gives you access to newer Android features like Vulkan.
To test on an Android device, push the binary and
and run it as normal. You may find
ninja -C out/arm64 adb push out/arm64/dm /data/local/tmp adb push resources /data/local/tmp adb shell "cd /data/local/tmp; ./dm --src gm --config gpu"
Mac users may want to pass
bin/gn gen to generate an Xcode project.
Skia can build on Windows with Visual Studio 2015 Update 3. No older or newer version is supported. The bots use a packaged toolchain, which you may be able to download like this:
python infra/bots/assets/win_toolchain/download.py -t C:/toolchain
If you pass that downloaded path to GN via
windk, you can build using that
toolchain instead of your own from Visual Studio. This toolchain is the only
way we support 32-bit builds, by also setting
Visual Studio Solutions
If you use Visual Studio, you may want to pass
bin/gn gen to
all.sln. That solution will exist within the GN directory for the
specific configuration, and will only build/run that configuration.
If you want a Visual Studio Solution that supports multiple GN configurations,
there is a helper script. It requires that all of your GN directories be inside
out directory. First, create all of your GN configurations as usual.
--ide=vs when running
bin/gn gen for each one. Then:
This creates a new dedicated output directory and solution file
out/sln/skia.sln. It has one solution configuration for each GN configuration,
and supports building and running any of them. It also adjusts syntax highlighting
of inactive code blocks based on preprocessor definitions from the selected
We have added a GN-to-CMake translator mainly for use with IDEs that like CMake project descriptions. This is not meant for any purpose beyond development.
bin/gn gen out/config --ide=json --json-ide-script=../../gn/gn_to_cmake.py
Skia offers several features that make use of third-party libraries, like
libpng, libwebp, or libjpeg-turbo to decode images, or ICU and sftnly to subset
fonts. All these third-party dependencies are optional, and can be controlled
by a GN argument that looks something like
skia_use_foo for appropriate
Most of these third-party dependencies can also be satisfied by pre-built
system libraries. If
skia_use_foo is enabled, turn on
to build and link Skia against the headers and libaries found on the system
paths. You can use
extra_ldflags to add include or
library paths if needed.
By default Skia will build and embed its own copies of these third-party libraries. This configuration is for development only. We do not recommend shipping Skia this way. However, this is the only configuration of Skia that receives significant testing.