Polygons not properly rendered with Impeller

[zhoujun951236]

What is the bug?

This is the first time I found out the problem using the three-way library：youmtinetflutterpacks/power_geojson#1

Eventually I found out it's a transparency issue, as long as the Opacity of the color isn't 1 and 0, I don't have the streaking problem.

How can we reproduce it?

This repository has the test code, just need to comment out a few lines.
youmtinetflutterpacks/power_geojson#1

Do you have a potential solution?

No response

[JaffaKetchup]

Hey, thanks for filing a report.
I'm a little confused? Is the issue with FM? If it is, please provide a minimal reproducible example with no external dependencies.

[zhoujun951236]

Thanks for your reply.
The link below is my demo
https://github.com/zhoujun951236/flutter_map_test

.example/lib/polygons/asset.dart
It is the key code

[zhoujun951236]

Add .withOpacity(0.5) and it's fine

[zhoujun951236]

I tested flutter_map 7.0.2 and 8.0.1 both have exceptions

[ibrierley]

I think you need to create a minimal example as mentioned. Just the minimal lines and code to reproduce the problem. Remove everything else except for flutter_map and just include the polyline points.

[zhoujun951236]

Thanks for your reply, I prepared a very simple demo.
https://github.com/zhoujun951236/simple_map_test

[ibrierley]

No problems for me with that example on Web or Android, is it possible you are using a specific device that's affected ?

[zhoujun951236]

This one looks like a problem

Color(0xFFA29A0A).withValues(alpha: 0.5) This works without problems

[ibrierley]

Actually, I did manage to replicate on an Android Tablet, but not on Web.

[ibrierley]

I think this is an Impeller problem..if you try flutter run --no-enable-impeller then I think the problem may vanish, but it would be good for someone else to reverify.

[zhoujun951236]

For the above example, I've been using an iPhone 11 (system version 15.1) and the Android emulator.
I tried flutter run --no-enable-impeller and it did work fine.

[mootw]

This looks like some impeller rendering issues that i saw as well. #1965 though i have not noticed this regression recently. I am running on flutter 3.29.0, which version of flutter are you using?

[ibrierley]

I was on 3.27, but have just updated to 3.29, and its the same (fine without impeller, long line when its not disabled.