Summary: YogaKit integrates Yoga with UIKit as a higher level framework. It does not expose config setting to users. We set YGErrataClassic for now to prioritize compatibility instead of conformance (YogaKit is relatively used in fbsource as well). I'm also tempted to remove the usage of ExperimentalWebFlexBasis since last I heard rozelle thought it was generally broken, but I am a bit afraid to if it has been enabled so long, and is used in many cases in Meta. Differential Revision: https://internalfb.com/D45298803 fbshipit-source-id: 37a097b06edc5043416303ca0d7b51ed70925797
Yoga

Yoga is an embeddable and performant flexbox layout engine with bindings for multiple languages.
Building
Yoga's main implementation targets C++ 14 with accompanying build logic in CMake. A wrapper is provided to build the main library and run unit tests.
./unit_tests <Debug|Release>
While not required, this script will use ninja if it is installed for faster builds.
Yoga is additionally part of the vcpkg collection of ports maintained by Microsoft and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.
Adding Tests
Many of Yoga's tests are automatically generated, using HTML fixtures describing node structure. These are rendered in Chrome to generate an expected layout result for the tree. New fixtures can be added to gentest/fixtures
.
<div id="my_test" style="width: 100px; height: 100px; align-items: center;">
<div style="width: 50px; height: 50px;"></div>
</div>
To generate new tests from added fixtures:
- Run
bundle install
in thegentest
directory to install dependencies of the test generator. - Run
ruby gentest.rb
in thegentest
directory.
Debugging
Yoga provides a VSCode "launch.json" configuration which allows debugging unit tests. Simply add your breakpoints, and run "Debug C++ Unit tests (lldb)" (or "Debug C++ Unit tests (vsdbg)" on Windows).