iOS

These instructions are historical and not explictly supported. There is currently no explictly supported way to build Skia for iOS.

The following has been tested on MacOS Yosemite with Xcode version 6.3.

Quickstart

First, install XCode.

# Install depot tools.
git clone 'https://chromium.googlesource.com/chromium/tools/depot_tools.git'
export PATH="${PWD}/depot_tools:${PATH}"

# Get Skia.
git clone 'https://skia.googlesource.com/skia'
cd skia

# Create the project files.
GYP_DEFINES="skia_os='ios' skia_arch_type='arm' armv7=1 arm_neon=0" python bin/sync-and-gyp
# Build and run SampleApp.
xed out/gyp/SampleApp.xcodeproj # opens the SampleApp project in Xcode

Prerequisites

Make sure the following have been installed:

Check out the source code

See the instructions here.

Generate XCode projects

We use the open-source gyp tool to generate XCode projects (and analogous build scripts on other platforms) from our multiplatform “gyp” files.

Before building, make sure that gyp knows to create an XCode project or ninja build files. If you leave GYP_GENERATORS undefined it will assume the following default:

GYP_GENERATORS="ninja,xcode"

Or you can set it to xcode alone, if you like.

You can then generate the Xcode projects by running:

GYP_DEFINES="skia_os='ios' skia_arch_type='arm' armv7=1 arm_neon=0" python bin/sync-and-gyp

Alternatively, you can do:

export GYP_DEFINES="skia_os='ios' skia_arch_type='arm' armv7=1 arm_neon=0"
python bin/sync-and-gyp

Build and run tests

The ‘dm’ test program is wrapped in an app called iOSShell. The project for iOSShell is at out/gyp/iOSShell.xcodeproj. Running this app with the flag ‘–dm’ will run unit tests and golden master images. Other arguments to the standard ‘dm’ test program can also be passed in.

To launch the iOS app on a device from the command line you can use a tool such as ios-deploy:

xcodebuild -project out/gyp/iOSShell.xcodeproj -configuration Debug
ios-deploy --bundle xcodebuild/Debug-iphoneos/iOSShell.app -I -d --args "--dm <dm_args>"

The usual mode you want for testing is Debug mode (SK_DEBUG is defined, and debug symbols are included in the binary). If you would like to build the Release version instead:

xcodebuild -project out/gyp/iOSShell.xcodeproj -configuration Release
ios-deploy --bundle xcodebuild/Release-iphoneos/iOSShell.app -I -d --args "--dm <dm_args>"

Build and run nanobench (performance tests)

The ‘nanobench’ test program is also wrapped in iOSShell.app. Passing in the flag ‘–nanobench’ will run these tests.

Here’s an example of running nanobench from the command line. We will build with the “Release” configuration, since we are running performance tests.

xcodebuild --project out/gyp/iOSShell.xcodeproj -configuration Release
ios-deploy --bundle xcodebuild/Release-iphoneos/iOSShell.app -I -d --args "--nanobench <nanobench_args>"

Build and run SampleApp in the XCode IDE

  • Run sync-and-gyp as described above.
  • In the Finder, navigate to $SKIA_INSTALLDIR/trunk/out/gyp
  • Double-click SampleApp.xcodeproj ; this will launch XCode and open the SampleApp project
  • Make sure the SampleApp target is selected, and choose an iOS device to run on
  • Click the “Build and Run” button in the top toolbar
  • Once the build is complete, launching the app will display a window with lots of shaded text examples. On the upper left there is a drop down menu that allows you to cycle through different test pages. On the upper right there is a dialog with a set of options, including different rendering methods for each test page.

Provisioning

To run the Skia apps on an iOS device rather than using the simulator, you will need a developer account and a provisioning profile. See Launching Your App on Devices for more information.

Managing App Data

By default, the iOS apps will look for resource files in the Documents/resources folder of the app and write any output files to Documents/. To upload resources so that the app can read them you can use a tool such as ios-deploy. For example:

ios-deploy --bundle_id 'com.google.SkiaSampleApp' --upload resources/baby_tux.png --to Documents/resources/baby_tux.png

You can use the same tool to download log files and golden master (GM) images:

ios-deploy --bundle_id 'com.google.iOSShell' --download=/Documents --to ./my_download_location

Alternatively, you can put resources and other files in the bundle of the application. In this case, you’ll need to run the app with the option ‘–resourcePath .’