Font AutoScalingEnabled

[PureWeen]

Description of Change

Implements #1683

For Android/WinUI the default behavior here doesn't change.

This now means that fonts on iOS will auto scale based on the dynamic font sizing settings on the device

Additions made

• Adds Font.AutoScalingEnabled

• Adds Button.FontAutoScalingEnabled

• Adds DatePicker.FontAutoScalingEnabled

• Adds Editor.FontAutoScalingEnabled

• Adds Entry.FontAutoScalingEnabled

• Adds FontElement.FontAutoScalingEnabled

• Adds Label.FontAutoScalingEnabled

• Adds Picker.FontAutoScalingEnabled

• Adds RadioButton.FontAutoScalingEnabled

• Adds SearchBar.FontAutoScalingEnabled

• Adds Span.FontAutoScalingEnabled

• Adds TimePicker.FontAutoScalingEnabled

• Adds FontImageSource.FontAutoScalingEnabled

• (Android) Adds

	public struct FontSize
	{
		public FontSize(float value, ComplexUnitType unit)
		{
			Value = value;
			Unit = unit;
		}

		public float Value { get; set; }
		public ComplexUnitType Unit { get; set; }
	}

• (Android) Changes float IFontManager.GetSize => FontSize IFontManager.GetSize

Removed

• Button.Font (to make Button consistent with all the other controls)
• (iOS) IFontManager.GetSize Nothing outside of FontManager is currently using this so I just removed it for now

[arevellfraedom]

Great change 👍
I can't quite tell what the defaults are for font scaling now on ios vs android? Because Android would have been on, iOS off before this change.

Also, in practice we found it necessary to limit how large fonts grow on iOS because it was impractical to design all the way up to AX5.

Our approach was to do this:

using var maxSizedFont = UIFontMetrics.DefaultMetrics.GetScaledFont(font, UITraitCollection.Create(UIContentSizeCategory.ExtraExtraExtraLarge));

var maxSize = maxSizedFont.PointSize;
return UIFontMetrics.DefaultMetrics.GetScaledFont(font, maxSize);

[rachelkang]

@arevellfraedom font scaling will automatically be enabled across all the platforms including iOS now!

[arevellfraedom]

@arevellfraedom font scaling will automatically be enabled across all the platforms including iOS now!

This is great! But also a little scary! (lots of app layouts will break until people fix them)
You might want to have a way of turning this off globally to give people a chance to fix things up - it can be non-trivial to work out what to do.

[rachelkang]

@arevellfraedom yes definitely! so this PR does both of those things! It both:

1. Ensures font scaling will automatically be enabled across all the platforms including iOS
2. Introduces a FontAutoScalingEnabled boolean property that can be set to false if so desired

[heybuddiescode]

Hej - I'm a bit late to the game, however I'm really missing a way to turn this off globally. The FontAutoScalingEnabled for some reason is not respected when applied as a Xaml Styling, therefore breaking our whole app.

Eg. this style in a separate file, every other attribute is respected, except for the FontAutoScalingEnabled.
<Style x:Key="TextSmall" TargetType="Label"> <Setter Property="TextColor" Value="{StaticResource PrimaryColor}" /> <Setter Property="FontFamily" Value="SourceSansPro-Regular" /> <Setter Property="FontSize" Value="Small" /> <Setter Property="FontAutoScalingEnabled" Value="False"/> </Style>

[mattleibow]

@heybuddiescode can you open a new issue for this?