[BUG] DrawingView with large LineWidth

[MFinkBK]

Is there an existing issue for this?

• I have searched the existing issues

Did you read the "Reporting a bug" section on Contributing file?

• I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

Current Behavior

When using a larger value for the DrawingView property LineWidth, e.g. 50, the resulting image looks strange, most probably because a wrong LineCap value is used. See the attached screenshot from the sample app:

Expected Behavior

The resulting image uses the proper line cap type.

Steps To Reproduce

1. Modify the LineWidth value of the DrawingView of the DrawingViewPage.xaml file in the sample app.
2. Run the Sample app
3. Go to the Drawing View
4. Draw something in the "Draw & GO" area
5. Observe the gray area below.

Link to public reproduction project repository

https://github.com/CommunityToolkit/Maui

Environment

- .NET MAUI CommunityToolkit: 14.1.1
- OS: Windows 11 25H2
- .NET MAUI: 10.0.60

Anything else?

No response

[MFinkBK]

I checked the DrawingView code a bit and it seems that the code for Android, MacIos and Tizen uses round stroke cap values for painting, only on Windows it isn't set anywhere.

[VladislavAntonyuk]

@MFinkBK do you see the issue only on windows? Do other platforms look correct?

[MFinkBK]

I now also tested Android and iOS it works correctly there. I think it's Windows only.

[MFinkBK]

After playing around a bit with the sample app and DrawingViewService.windows.cs I think I have a fix. First, I tried out adding properties to InkDrawingAttributes, but it didn't work:

Maui/src/CommunityToolkit.Maui.Core/Views/DrawingView/Service/DrawingViewService.windows.cs

Line 93 in 0fe8edc

var inkDrawingAttributes = new InkDrawingAttributes

I think they are never used, since in the DrawInk() method, only DrawLine is used, which probably ignores ink drawing properties:

Maui/src/CommunityToolkit.Maui.Core/Views/DrawingView/Service/DrawingViewService.windows.cs

Line 167 in 0fe8edc

session.DrawLine(

I could fix it by passing a CanvasStrokeStyle object to the DrawLine call. I can prepare a PR if you like.