[regression/8.0.99-ci.net8.24472.1] Invalidate Shadow Issue: VisualElement.Shadow property change no longer invalidates platform shadow

[Stedy59]

Description

Changes to a control's "shadow property" or changes to the shadow's properties directly no longer invalidate the platforms shadow.

Steps to Reproduce

No response

Link to public reproduction project repository

No response

Version with bug

8.0.90 SR9

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.70 SR7

Affected platforms

Android

Affected platform versions

Android - All

Did you find any workaround?

No response

Relevant log output

No response

[github-actions]

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[Stedy59]

Working in build 8.0.70-ci.net8.24321.1

screencapture.8.0.70-ci.net8.24321.1.mp4

No shadow invalidate in build 8.0.99-ci.net8.24472.1

NOTE - my custom handler for the dropdown receives the bound property change and modifies the AppCompatTextViews Shadow.

The only way to force the invalidate was to change the font on the views controls, or change the Shadow property to null, then provide a new shadow. ;(

screencapture.8.0.99-ci.net8.24472.1.mp4

[albyrock87]

I've tested this (on iOS) with b2c1d25 and also e0b3526 => it works fine:

	private void ChangeShadowClicked(object sender, EventArgs e)
	{
		var button = (View)TheButton.Parent;
		button.Shadow.Radius += 8;
	}

<Border
        HorizontalOptions="Center"
        BackgroundColor="LightBlue"
        Shadow="{Shadow Brush=Black, Offset='0,2', Radius=24, Opacity=0.2}"
        StrokeShape="{RoundRectangle CornerRadius=20}">
        <Button x:Name="TheButton" BackgroundColor="LightGreen" WidthRequest="200" HeightRequest="400" />
</Border>

[Stedy59]

I've tested this (on iOS) with b2c1d25 and also e0b3526 => it works fine:

	private void ChangeShadowClicked(object sender, EventArgs e)
	{
		var button = (View)TheButton.Parent;
		button.Shadow.Radius += 8;
	}

<Border
        HorizontalOptions="Center"
        BackgroundColor="LightBlue"
        Shadow="{Shadow Brush=Black, Offset='0,2', Radius=24, Opacity=0.2}"
        StrokeShape="{RoundRectangle CornerRadius=20}">
        <Button x:Name="TheButton" BackgroundColor="LightGreen" WidthRequest="200" HeightRequest="400" />
</Border>

Issue is with Android... Not IOS. Thanks.

[albyrock87]

@Stedy59 reading Affected platform versions / Android - All confused me, sorry :)

I've opened a PR to fix the issue :)

[albyrock87]

For reference this is very likely what broke it:
#24222

[albyrock87]

@rmarinho I suggest you to revert #24222 which broke:

• shadow changes
• clip changes

@jonathanpeppers setHasShadow and setHasClip are misleading names.. an invalidation is always expected there in order to update drawing upon changes.
I think we we could call invalidate instead of postInvalidate there considering MAUI will call those methods only from the main thread.

[jonathanpeppers]

@albyrock87 can you send a PR that just calls invalidate() instead? The slowdown was how postInvalidate() was queuing up so many callbacks. The sample was queuing up 100s of those.

[albyrock87]

@jonathanpeppers yes, I can create a simple PR just with that code.
Someone from the team will have to regenerate the .aar after it's merged though (for security reasons).

[albyrock87]

@jonathanpeppers @rmarinho #24990