mapbox / mapbox/mapbox-maps-flutter

Round polygon has too few vertices with certain zoom settings

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Dominant language
Dart
Stars
380
Forks
204
PR merge metrics
No merged PRs in 30d

Description

Since plugin's API does not provide an easy way to create a circle with a given radius in meters, I used a circular polygon for that, as suggested [here](https://github.com/mapbox/mapbox-maps-flutter/issues/62).

If I create a circular polygon with 64 vertices, most of the times it looks good, smooth, but sometimes, when I play with the zoom, the polygon gets rendered with less vertices than it should (usually 16 or 8), which is noticeable. Seems like it's some kind of a Mapbox rendering optimization. Can this be turned off or fixed somehow?

Increasing vertices count does not help. I also tried drawing a line (polyline) around the circle, but it has the same issue.

Video:

https://github.com/mapbox/mapbox-maps-flutter/assets/55327556/96b27fee-d4ac-4329-94f3-e94e7a532c22

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the circular polygon and polyline behavior while changing zoom settings, using the linked video as the expected symptom. Investigate the Mapbox rendering path involved in zoom-dependent vertex reduction; done means the shape remains visibly smooth at the reported zoom levels or the limitation and workaround are clearly established.

Written by the indexing model from the issue text.

Assessment

Tech stack
dart, flutter
Domain
mobile-dev
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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