@remotion/web-renderer: Preserve transforms for precomposited filters

[JonnyBurger]

Summary

• add a minimal rotated drop-shadow() reproduction for Skills2Gesture does not client-side render well #9901
• preserve the original 2D affine transform when drawing a precomposited filter layer instead of stretching it into an axis-aligned bounding box
• keep the existing WebGL path for 3D precomposition unchanged

Testing

• bun run build
• bun run stylecheck
• bun run testwebrenderer (240 test files passed; 672 tests passed and 21 skipped)
• focused issue Skills2Gesture does not client-side render well #9901, issue web-renderer: Filter drop shadow not working as expected with transform scale #7199, and 3D precomposition tests in Chromium, Firefox, and WebKit
• red/green verified by disconnecting and restoring the affine blit

Closes #9901

[vercel]

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Project	Deployment	Actions	Updated (UTC)
bugs	Ready	Preview	Jul 30, 2026 8:18am
remotion	Ready	Preview	Jul 30, 2026 8:18am

[pullfrog]

✅ No new issues found.

Reviewed changes — a reproduction test for issue #9901 (rotated drop-shadow() not preserving rotation during client-side precomposition), consisting of a new fixture, test, and Root.tsx registration.

• Fixture — A minimal 800x500 composition with a #edf7ff pill rotated 30deg and carrying a drop-shadow() filter. No React import, consistent with nearby zero-import fixtures like inside-3d-transform.tsx.
• Test — Renders the fixture via renderStillOnWeb, draws the PNG blob onto an OffscreenCanvas, and asserts a single pixel (200, 80) equals the pill background color [237, 247, 255, 255]. That coordinate lies inside the correctly-rotated pill but outside its axis-aligned bounding box, so this fails on all browsers until the precomposition bug is fixed.
• Root.tsx registration — Placed beside the related issue7199ScaleAndDropShadow composition.

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[pullfrog]

✅ No new issues found.

Reviewed changes (delta since 293a98c) — the core fix in process-node.ts that preserves 2D affine transforms when drawing precomposited filter layers.

• process-node.ts — When the precomposited layer is 2D (not needing WebGL), applies totalMatrix via setTransform on the canvas instead of resetting to identity. Uses precomposeRect as the draw destination (since the canvas transform handles positioning) and sets parentOffsetScale to 1 (since setTransform already incorporates scale). The 3D path keeps the existing behavior unchanged.
• The issue-7199 regression test (scale + drop-shadow) should remain unaffected — for pure scale, the canvas transform + precomposeRect produces the same screen-space result as the old identity transform + rectAfterTransforms.

  ^{｜ View workflow run ｜ Using DeepSeek Pro (free via Pullfrog for OSS) (Claude Opus not used — the program covers this model; add its provider key to run your pick) ｜ 𝕏}