Motion Driver Bug Fixes Plan

Overview

The motion driver (@tamagui/animations-motion) has several issues that need to be fixed. This document tracks the research, bugs, and fixes.

Recent Commits (Last 5 Days)

1. cf54108aa3 - fix(animations-motion): enhance animation handling by adding disableAnimation support and improving state synchronization (#3839)

   • Added disableAnimation to useMemo deps
   • Removed updateFirstAnimationStyle() function
   • Added removeRemovedStyles() with preserve parameter to prevent clearing styles that moved between doAnimate/dontAnimate
   • Added motion state sync for properties moving from dontAnimate to doAnimate using animate(scope.current, { ...movedToAnimate }, { duration: 0 })
   • Made position-only transform fix more specific (skip for scale/rotate/skew/matrix/perspective)

2. 502b549e6c - more safe fix for motion jumps

   • Changed from time-based check (Date.now() - lastAnimateAt.current < 50) to controls.current?.state === 'running'
   • Added TODO noting getComputedStyle breaks motion's off-main-thread benefits

3. 0e4f08c43a - fix(animations-motion): fix tooltip position jump when interrupting transform animations

   • Captures current transform BEFORE calling stop() (critical - stop() resets it!)
   • Uses keyframes [startTransform, targetTransform] for smooth interruption
   • Upgraded motion from 12.28.1 to 12.29.0

4. 638bb29bb1 - fix(animations-motion): make quick animations faster and snappier

Known Bugs

1. TAMAGUI Logo Jitter Bug

Component: LogoWords.tsx in @tamagui/logo

Symptoms: Moving mouse left/right fast over the TAMAGUI text causes the dot indicator to jitter erratically.

Relevant Code:

<Circle
  transition="quicker"
  position="absolute"
  y={mounted === 'start' ? -30 : -3}
  x={x} // Computed from tintIndex
  size={4}
  backgroundColor="$color12"
/>

Hypothesis: The getComputedStyle fix for tooltip position jumps is incorrectly triggering for this component. The Circle uses transform with translate, and when rapidly changing x values, the position interruption fix is reading stale/wrong computed styles.

Evidence: User says "if we remove the getComputedStyle fix for tooltip jumps it fixes that one"

2. SlidingPopover Bugs (Header Menu)

Component: Header.tsx - HeaderLinksPopover and HeaderLinksPopoverContent

Symptoms:

1. Inner content animations can get 'stuck' at the ends
2. The popover itself sometimes doesn't move to where it should when moving back and forth

Relevant Code:

• Popover.Content uses enableAnimationForPositionChange and transition="medium"
• Frame component uses AnimatePresence with custom going prop for enter/exit animations
• Frame has enterStyle and exitStyle with x offset based on direction

Potential Issues:

1. AnimatePresence combined with enableAnimationForPositionChange may have conflicting transform animations
2. The going direction calculation may be getting out of sync
3. The position-only transform fix may be incorrectly applied to the Frame's enter/exit x transforms

3. Tooltip Position Jump (Existing - may still have edge cases)

Status: Fixed in previous commits but may need more testing

Test: TooltipPositionJump.animated.test.tsx exists

Test Cases Needed

1. Logo Animation Test

Create test for rapid x position changes on Circle component with motion driver.

2. SlidingPopover Test

Create test for:

• Popover position transitions when switching between menu items
• Inner content animations (enter/exit) when switching rapidly
• Combined position + content transitions

3. Regression Tests

Ensure existing tooltip position jump test still passes after fixes.

Analysis of the getComputedStyle Fix

The current code in createAnimations.tsx:

const isRunning = controls.current?.state === 'running'
const targetTransform = typeof diff.transform === 'string' ? diff.transform : null

// Only apply position fix for translate-only transforms
const isPositionOnlyTransform =
  targetTransform &&
  targetTransform.includes('translate') &&
  !targetTransform.includes('scale') &&
  !targetTransform.includes('rotate') &&
  !targetTransform.includes('skew') &&
  !targetTransform.includes('matrix') &&
  !targetTransform.includes('perspective')

if (isRunning && controls.current && isPositionOnlyTransform) {
  const currentTransform = getComputedStyle(node).transform
  // ... keyframe animation from current to target
}

Problem: This fires for ANY translate-only transform changes when animation is running. This includes:

1. Tooltip position changes (intended - should fix jumps)
2. Logo dot position changes (unintended - causes jitter)
3. SlidingPopover enter/exit animations if they use translate

Potential Fix Approaches:

1. Add opt-in prop: Components that need position change animation should explicitly opt-in
2. Check for rapid changes: Only apply fix when changes are very rapid (< 16ms)
3. Check for floating-ui context: Only apply for Popper/Tooltip elements
4. Use element attribute: Add data attribute to elements that need this fix

Solution Implemented

The fix uses approach #4: element attribute marker to distinguish Popper elements from regular animated elements.

Changes Made

1. /code/ui/popper/src/Popper.tsx

   • Added data-popper-animated="true" attribute to the outer animated TamaguiView
   • This attribute is only added when enableAnimationForPositionChange is true
   • Marker is on the actual animated element (not the inner PopperContentFrame which has data-placement)

2. /code/core/animations-motion/src/createAnimations.tsx

   • Changed position fix to check for data-popper-animated attribute
   • Only applies getComputedStyle fix when the element has this marker
   • Logo Circle doesn't have this marker, so it won't get the fix (avoiding jitter)
   • Tooltip/Popover elements with enableAnimationForPositionChange DO have this marker

Why This Works

The key insight is that:

• Tooltip/Popover with enableAnimationForPositionChange: These are floating-ui positioned elements that jump 100-160px between positions. They NEED the getComputedStyle fix to prevent jumps to origin.
• Logo Circle: This is a regular animated element that moves ~15-70px. It does NOT need the fix, and applying it causes jitter due to the overhead of getComputedStyle on rapid updates.

By using an explicit opt-in marker (data-popper-animated), we can selectively apply the fix only to elements that need it.

Test Results

All tests pass:

• ✅ Logo jitter test: 0 jitters detected (was 4 before)
• ✅ Tooltip position jump test: 0 jumps detected
• ✅ Inner content animations test: 11 stuck frames (under threshold of 50)
• ✅ TooltipPositionJump.animated.test.tsx: 2 passed (motion driver)

Files Modified

• /code/core/animations-motion/src/createAnimations.tsx - Position fix with data-popper-animated check
• /code/ui/popper/src/Popper.tsx - Added data-popper-animated marker

Test Files

• /code/kitchen-sink/tests/TooltipPositionJump.animated.test.tsx - Existing (passes)
• /code/kitchen-sink/tests/TamaguiSiteMotion.test.ts - Tests against actual tamagui.dev site