Flame chart - jumpTo called before scroll position offsets have new size
- Dominant language
- Dart
- Stars
- 1.7k
- Forks
- 404
- Avg merge
- 6d 17h
- Merged PRs (30d)
- 18
Description
In flame_chart.dart, we call
```
linkedHorizontalScrollControllerGroup.jumpTo(newScrollOffset);
```
to update the scroll offset as we zoom. We call this inside of an animation controller listener `zoomController.addListener(() { ... })`. At times when we call this, `scrollController.position.maxScrollOffset` is not updated for the new zoom level and layout size, causing `jumpTo` to fire BallisticScrollActivities to bounce the scroll offset back to what it thinks is the `maxScrollOffset`.
We need to have a way to call `jumpTo` when we can guarantee that the min / max scroll offsets are updated for the new zoom value.
I attempted to set these offsets manually using `scrollController.position.applyContentDimensions(minScrollOffset, maxScrollOffset)` but this results in an error regarding gesture detectors: `The replaceGestureRecognizers() method can only be called during the layout phase.`
Contributor guide
Research direction
Start in flame_chart.dart at the zoomController listener and the linkedHorizontalScrollControllerGroup.jumpTo(newScrollOffset) call. Reproduce zooming near a scroll boundary, then verify that jumpTo runs only after the new min/max scroll offsets are available, without triggering ballistic bounce or the gesture-detector layout error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- dart, flutter
- Domain
- data-visualization, frontend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100