[Danyalo]

Summary

Fixes #3090.

On Android, VirtualView.saveAndSetupCanvas built an element's CTM as mMatrix × ctm (mCTM.preConcat(ctm)). With Android's Matrix, that applies the parent's CTM to a point first and the element's own transform second, so under nested transforms, or a transform under a scaled viewBox, the order is reversed.

Drawing was unaffected, because the canvas is concatenated separately, and so were touches, because hit-testing walks each element's inverse matrix. Everything that reads mCTM was wrong:

• vectorEffect="non-scaling-stroke" paths, which draw with mCTM after canvas.setMatrix(null)
• getScreenCTM() and getCTM()
• element client rects, which set the element views' bounds (used for onLayout and accessibility)

iOS reads the CTM from the drawing context (CGContextGetCTM), so it was already correct.

Changes

• VirtualView.saveAndSetupCanvas: mCTM.preConcat(ctm) → mCTM.postConcat(ctm), i.e. ctm × mMatrix.
• RNSVGRenderableManager.getCTM: ctm.preConcat(invViewBoxMatrix) → ctm.postConcat(invViewBoxMatrix). The old order compensated for the reversed CTM and was only right for a single level of transform. With the CTM fixed it has to undo the viewBox from the left.

The VirtualView line is the same change that was part of #2802 and was reverted with it in #2832, which was about #2802's performance cost (#2831). This PR contains only the matrix order, plus the getCTM change #2802 didn't include.

Behaviour change

getScreenCTM() now returns the correct matrix for any element with a transform under a scaled viewBox, and both getScreenCTM() and getCTM() are correct for nested transforms. Code that worked around the old values on Android will see different numbers. getCTM() for a single transform level is unchanged.

Test Plan

What's required for testing (prerequisites)?

Android emulator or device. I used a Pixel 9 emulator (API 36, pixel ratio 2.625, which the Android E2E references use) with apps/fabric-example.

What are the steps to reproduce (after prerequisites)?

1. Test example Test3090

1. In apps/common/index.tsx import ./test, and in apps/common/test/index.tsx render <Test3090 />.
2. Run apps/fabric-example on Android.
3. The blue non-scaling-stroke triangle should lie on the red reference, and the printed matrices should match the expected values.

	main	This PR
non-scaling-stroke path	offset up and left of the reference	on the reference
getScreenCTM()	a=1.5 d=1.5 e=25 f=10	a=1.5 d=1.5 e=90.06 f=45.03
getCTM()	a=0.5 d=0.5 e=25 f=10	a=0.5 d=0.5 e=30 f=15
Screenshot

(The .06/.03 come from the 300 dp <Svg> being 787.5 px wide at this density, which rounds to 788. The a and d values are off by the same factor on main too.)

2. E2E case e2e/cases/5.svg

non-scaling-stroke outline on a square, under two nested <g transform> and a viewBox scaled ×2. References generated with yarn generateE2eReferences. I committed only the new 5.png files, not the regenerated existing ones.

yarn e2e   # Android, fabric-example, E2E tab

• main: 5.svg fails, 7448 differing pixels (limit 525). The other cases are unchanged.
• This PR: all 5 cases pass.

3. Touch events still work

Example app → TouchEvents, with this PR:

• "Bind touch events callback on Group element with viewBox" (<G scale="1.4"> under a scaled viewBox, <Circle scale="1.2"> inside it): pressing the green circle and the yellow rect gives "Pressed on G", pressing "H" gives "Pressed on Text", and pressing empty space gives nothing.
• First example: pressing the red circle gives "Press on Circle".

4. Checks

yarn lint and yarn tsc pass (after building lib/).

Compatibility

OS	Implemented
iOS	n/a (unchanged)
MacOS	n/a (unchanged)
Android	✅
Web	n/a (unchanged)

Not run locally: iOS E2E (the new ios/5.png reference is generated at pixel ratio 3 like the others) and the old architecture (Paper). The change is in Java code shared by both architectures.

Checklist

• I have tested this on a device and a simulator (Android emulator only)
• I added documentation in README.md (not needed)
• I updated the typed files (typescript) (no API change)
• I added a test for the API in the __tests__ folder (added apps/common/test/Test3090.tsx and E2E case 5.svg instead)