[macOS/iOS] Border clipping incorrect when Content is scaled (or has any other Transform applied?)

[jknaudt21]

Description

Mac counterpart of #17523

Screen.Recording.2023-09-20.at.4.25.10.PM.mov

Steps to Reproduce

Use the sample app "Border resize content" page

Link to public reproduction project repository

No response

Version with bug

8.0.0-rc.1.9171

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS, macOS

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

No response

[ghost]

We've added this issue to our backlog, and we will work to address it as time and resources allow. If you have any additional information or questions about this issue, please leave a comment. For additional info about issue management, please read our Triage Process.

[jknaudt21]

Upon investigating a bit further, this seems to be a problem with the Scale calculations. Both Image and Label have the same issues the moment their scale is changed.

[jstedfast]

@jknaudt21 yes, it's the same on Android - it's related to the Scale transform (and likely other transforms will also have issues)

[jknaudt21]

Dropping this issue as my work is being redirected outside of Maui. From what I started to investigate, this issue stems from the fact that the ContentView is:

• Not adjusting the image's center correctly. Right now the mask is shifting around with the transform's applied to the mask. A bandaid fix is to force it to be centered based on the Frame. Something like adjustedMaskPosition = new(content.Frame.GetMidX(), content.Frame.GetMidY()
• The mask is also resizing based on the transforms the image received. It shouldn't do that and instead transform to what the border was received. A bandaid fix is to do _contentMask.Transform = _contentMask.Transform.Concat(scaleTransform.Invert()), where the scaleTransform is just the M11, M22, and M33 positions of the transform matrix.

[XamlTest]

Verified this on VS 17.10.0 Preview 2.0(8.0.7). Repro on iOS 17.2 and MacCatalyst with below Project:
BorderResizeContent.zip