a1fbbc6070
Summary: X-link: https://github.com/facebook/react-native/pull/37316 In Fabric, a ShadowNode may re-initialize YGConfig several times throughout the lifetime of a perpetually cloned Yoga Node. RN sets `pointScaleFactor` lazily, when laying out the rootview. So right now it initializes a config to `pointScaleFactor` of 1.0, sets it, sets a new `pointScaleFactor` on the config, then repeats. This cycles the config between two `pointScaleFactor` values and will excessively dirty the node now that `YGNodeSetConfig` dirties on config change (D45505089) This change makes it so that we retain previously used `pointScaleFactor` when cloning the Yoga nodes. Changelog: [Internal] Reviewed By: rozele Differential Revision: D45669878 fbshipit-source-id: bfd2e185d9264a1cda64e59132960060385e16f1
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 If the version is out of date, please create an issue or pull request on the vcpkg repository.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 installin thegentestdirectory to install dependencies of the test generator. - Run
ruby gentest.rbin thegentestdirectory.
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).