Fix scroll progress negative in reverse directions

[mattgperry]

Summary

• Fixes scroll progress returning negative values when using containers with flex-direction: column-reverse, flex-direction: row-reverse, or writing-mode: vertical-rl
• Root cause: browsers report negative scrollLeft/scrollTop for reverse-direction containers, but the progress calculation assumed non-negative values
• Fix: apply Math.abs() to the raw scroll position in updateAxisInfo so progress is always in the 0–1 range

Test plan

• Added unit test for negative scrollTop (y-axis, simulating column-reverse)
• Added unit test for negative scrollLeft (x-axis, simulating row-reverse / vertical-rl)
• All existing scroll tests still pass
• Full build passes

Fixes #3340

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

Clean fix for scroll progress returning negative values in reverse-direction containers (flex-direction: column-reverse/row-reverse, writing-mode: vertical-rl). The single-line change applies Math.abs() to scroll positions before calculation, ensuring progress stays in 0-1 range.

• Applied Math.abs() to scrollTop/scrollLeft in updateAxisInfo (info.ts:49)
• Added two comprehensive unit tests covering negative y-axis and x-axis scroll values
• Fix is minimal, focused, and well-tested
• Velocity calculation remains consistent since it operates on the already-normalized axis.current values
• All existing tests pass

Confidence Score: 5/5

• Safe to merge with no concerns
• One-line implementation fix with comprehensive test coverage that directly addresses the reported issue. The change is minimal, well-contained, and all existing tests pass. No edge cases or side effects identified.
• No files require special attention

Important Files Changed

Filename	Overview
packages/framer-motion/src/render/dom/scroll/info.ts	Applied Math.abs() to scroll position on line 49 to handle negative values from reverse-direction containers, ensuring progress calculation stays in 0-1 range
packages/framer-motion/src/render/dom/scroll/tests/index.test.ts	Added comprehensive tests for negative scrollTop (y-axis) and negative scrollLeft (x-axis) to verify the fix handles reverse-direction containers correctly

_{Last reviewed commit: abaf16e}