[iOS][Windows] Fix Label background not clipped when Clip property is set

[Shalini-Ashokan]

Note

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Issue Details

Label.Clip did not clip the background on iOS and Windows when Background was also set. The background rendered outside the clipping geometry.

Root Cause

When a Label has a non-null Background, LabelHandler.NeedsContainer returns true, wrapping the label in a WrapperView.

iOS: MapBackground called handler.ToPlatform(), which returns the WrapperView when a container is present. The background was applied to the wrapper, but WrapperView.SetClip() only masks sublayers named MauiBackgroundLayer — solid colors set via BackgroundColor are not sublayers, so they were never masked.

Windows: MapClip clipped only the child TextBlock's composition visual. The WrapperView's own Panel.Background visual was not subject to the child's clip.

Description of Change

iOS: Changed MapBackground to use handler.PlatformView?.UpdateBackground(label) (routes to MauiLabel) instead of handler.ToPlatform() (routes to WrapperView). The WrapperView clip then correctly clips the label and its background together.

Windows: Added a MapClip override for LabelHandler that also applies a CompositionGeometricClip to the WrapperView's own element visual via a new ClipSelf property, ensuring the wrapper background is clipped in sync with the child.

Validated the behavior in the following platforms

• Android
• Windows
• iOS
• Mac

Issues Fixed

Fixes #34114

Output ScreenShot

Before	After
34114-Before.mov	34114-After.mov

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 34276

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 34276"

[dotnet-policy-service]

Hey there @@Shalini-Ashokan! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.