[iOS] Implement VerticalTextAlignment property in Label

[jsuarezruiz]

Description of Change

Implement VerticalTextAlignment property in iOS Label.

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

Does this PR touch anything that might affect accessibility?

• No

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[rmarinho]

   D:\agent\1\s\src\Core\src\Platform\iOS\MauiLabel.cs(37,64): error CS0246: The type or namespace name 'nfloat' could not be found (are you missing a using directive or an assembly reference?) [D:\agent\1\s\src\Core\src\Core-net6.csproj]

We hve to move to new code of nfloat

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[Redth]

@jsuarezruiz i'm seeing a crash on catalyst / ios can you please investigate?

[jsuarezruiz]

Updated fixing the issue and checked that is working as expected:

[rachelkang]

I see VerticalTextAlignment.End (blue) is working, but it doesn't seem like VerticalTextAlignment.Start (pink) and VerticalTextalignment.Center (yellow) are

                <Label 
                    BackgroundColor="Pink"
                    VerticalTextAlignment="Start"
                    Text="This should be at the top"
                    HeightRequest="100"/>
                <Label 
                    BackgroundColor="Yellow"
                    VerticalTextAlignment="Center"
                    Text="This should be at the middle"
                    HeightRequest="100"/>
                <Label 
                    BackgroundColor="Blue"
                    VerticalTextAlignment="End"
                    Text="This should be at the bottom"
                    HeightRequest="100"/>

[jsuarezruiz]

Updated:

[Redth]

Still freezing on Catalyst... not sure why...

[PureWeen]

I fixed the infinite loop and VTA if you're not using a background on the label.

When you use a background on a Label it places the UILabel inside a WrapperView. The WrapperView resets the Frame every time a layout occurs.

I didn't find an obvious way to account for this so I think we should just merge this and log a bug for the WrapperView variation.

The original PR had kind of the opposite problem. It worked in some cases with the WrapperView because that's how the original code from XF worked where everything was wrapped. I don't think setting your own Frame inside LayoutSubviews is a good way to go. In Forms this was fine because the UILabel was a SubView of the VisualElementRenderer so the order of things made sense.

I changed the code so it sets the Frame from Handler.Arrange which is going to occur right before LayoutSubviews. The previous solution probably worked for wrapped views because the Frame was being updated inside LayoutSubviews but I think it would be better to get everyone's size figured out before the platform reaches LayoutSubviews. We probably want to add some code so the WrappedView can call Arrange or something on its child instead of just replacing the `Frame``

[rachelkang]

Doesn't appear to be working for me on catalyst :/

[PureWeen]

Doesn't appear to be working for me on catalyst :/

#3714 (comment)

#5575

[rachelkang]

Doesn't appear to be working for me on catalyst :/

#3714 (comment)

#5575

confirming it works without the background color!