[ZainnQureshii]

Summary

parseTransform expands CSS matrix(a, b, c, d, tx, ty) into the 16-value native matrix, but it put tx and ty at indices 8 and 9 (packages/react-strict-dom/src/native/css/parseTransform.js). React Native reads that array column-major with translation at indices 12 and 13 (the translate case in ReactCommon/react/renderer/graphics/Transform.cpp sets matrix[12] and matrix[13]), and the CSS Transforms spec maps matrix(a, b, c, d, e, f) to matrix3d(a, b, 0, 0, c, d, 0, 0, 0, 0, 1, 0, e, f, 0, 1). So on native any translation inside a 2D matrix() was dropped.

For matrix(1, 0, 0, 1, 12, -34) the output goes from [1, 0, 0, 0, 0, 1, 0, 0, 12, -34, 1, 0, 0, 0, 0, 1] to [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 12, -34, 0, 1].

The existing matrix parser expectation is updated, and there are two new regression tests: one on the parser and one through css.create() on an html.div.

Test plan

npm run jest -w react-strict-dom -- --runInBand --runTestsByPath src/native/css/__tests__/parseTransform-test.js tests/css/css-create-test.native.js

With the fix reverted and the tests kept: 3 failed, 108 passed. With the fix: 111 passed.

npm run jest -w react-strict-dom

19 suites, 899 tests passed. Prettier and ESLint are clean on the changed files. Not run: device rendering and Flow.

Prepared with AI assistance (Claude Code) and reviewed with GitHub Copilot.

🤖 Generated with Claude Code