[Windows] Fix LineHeight values <1 having no effect by setting LineStackingStrategy to BlockLineHeight

[MartyIX]

Description of Change

This PR is cherry-picked #31219 with an added UI test to see the result.

The PR is structured to commits this way:

• The first commit adds a test
• The second commit implements a simple way to set the LineStackingStrategy=BlockLineHeight in code (I believe it adds performance overhead)
• The last commit implements the same change but by setting a default style in XAML to avoid setting LineStackingStrategy needlessly.

Comparison of screenshots on Windows

This is just for comparison reasons:

Currently	PR

Issues Fixed

Fixes #24520

[PureWeen]

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[PureWeen]

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[jsuarezruiz]

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[jfversluis]

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[MartyIX]

Tests seem to pass.

[MartyIX]

@bhavanesh2001 Could you please review/take a look?

[mattleibow]

How does this work with spans? Looking at the WPF docs: https://learn.microsoft.com/en-us/dotnet/api/system.windows.controls.textblock.linestackingstrategy?view=windowsdesktop-9.0

We do support line heights on the label AND the spans... Not sure how they play together, but this PR may be regardless of how it looks. I do think that a 0.5 light height should apply, even if it looks a bit silly since the user did explicitly set it. You may actually want weird things with weird fonts...

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <StackPanel>
    
    <!-- This TextBlock has a LineStackingStrategy set to "MaxHeight". -->
    <TextBlock LineStackingStrategy="MaxHeight" LineHeight="10" Width="500" TextWrapping="Wrap" 
     Background="Yellow">
      Use the <Span FontSize="30">LineStackingStrategy</Span> property to determine how a line box is
      created for each line. A value of <Span FontSize="20">MaxHeight</Span> specifies that the stack
      height is the smallest value that contains all the inline elements on that line when those
      elements are properly aligned. A value of <Span FontSize="20">BlockLineHeight</Span> specifies
      that the stack height is determined by the block element LineHeight property value.
    </TextBlock>

    <!-- Here is the same TextBlock but the LineStackingStrategy is set to "BlockLineHeight". -->
    <TextBlock LineStackingStrategy="BlockLineHeight" LineHeight="10" Width="500" TextWrapping="Wrap" 
     Background="Blue" Margin="0,40,0,0">
      Use the <Span FontSize="30">LineStackingStrategy</Span> property to determine how a line box is
      created for each line. A value of <Span FontSize="20">MaxHeight</Span> specifies that the stack
      height is the smallest value that contains all the inline elements on that line when those
      elements are properly aligned. A value of <Span FontSize="20">BlockLineHeight</Span> specifies
      that the stack height is determined by the block element LineHeight property value.
    </TextBlock>

  </StackPanel>
</Page>

[MartyIX]

How does this work with spans?

Honestly, I don't really know. I need to take a deeper look.

[jsuarezruiz]

Could we update the test to cover more cases? For example, using Spans.

Also, what happens with mixed fonts?

<Label>
    <Label.FormattedText>
        <FormattedString>
            <Span Text="Normal " FontFamily="Arial"/>
            <Span Text="Special" FontFamily="CustomFont"/>
        </FormattedString>
    </Label.FormattedText>
</Label>

With BlockLineHeight, if fonts have different block heights, this could cause inconsistent line spacing within the same label.

[jsuarezruiz]

Also, could we include some Labels inside containers with constrained height?

[MartyIX]

I tried to improve the test a bit:

However, it's not finished. I'm a bit out of time for a few days.

[MartyIX]

Improved version:

[PureWeen]

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[PureWeen]

src/Controls/tests/TestCases.HostApp/Issues/Issue24520.xaml(107,40): Error XC0009: No property, BindableProperty, or event found for "WordWrap", or mismatching type between value and property.

[MartyIX]

src/Controls/tests/TestCases.HostApp/Issues/Issue24520.xaml(107,40): Error XC0009: No property, BindableProperty, or event found for "WordWrap", or mismatching type between value and property.

Should be fixed

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[MartyIX]

See this comment: #24504 (comment)

changes made