Xamarin.Forms Android & iOS: LabelTextKerningEffect

Droid.LabelTextKerningEffect.cs

using System.Linq;
using System.Text;
using Android.Text;
using Android.Text.Style;
using Android.Widget;
using MyNamespace.Effects;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using static Android.Widget.TextView;

[assembly: ResolutionGroupName("MyNamespace.Effects")]
[assembly: ExportEffect(typeof(MyNamespace.Droid.Effects.LabelTextKerningEffect), nameof(LabelTextKerningEffect))]
namespace MyNamespace.Droid.Effects
{
    public class LabelTextKerningEffect : PlatformEffect
    {
        protected override void OnAttached()
        {
            var effect = (MyNamespace.Effects.LabelTextKerningEffect)Element.Effects.FirstOrDefault(e => e is MyNamespace.Effects.LabelTextKerningEffect);
            ApplySpacing(effect.Kerning);
        }

        protected override void OnDetached() { }

        void ApplySpacing(float letterSpacing)
        {
            var lbl = Control as TextView;
            if (lbl == null || string.IsNullOrEmpty(lbl.Text)) return;
            
            if (Build.VERSION.SdkInt >= BuildVersionCodes.Lollipop)
            {
                lbl.LetterSpacing = letterSpacing;
            }
            else
            {
                var originalText = lbl.Text;
                var builder = new StringBuilder();
                for (int i = 0; i < originalText.Length; i++)
                {
                    builder.Append(originalText[i]);
                    if (i + 1 < originalText.Length)
                        builder.Append("\u00A0"); // 'NO-BREAK SPACE'
                }

                var finalText = new SpannableString(builder.ToString());
                if (builder.ToString().Length > 1)
                {
                    for (int i = 1; i < builder.ToString().Length; i += 2)
                        finalText.SetSpan(new ScaleXSpan(letterSpacing * 4), i, i + 1, SpanTypes.ExclusiveExclusive);
                }
                lbl.SetText(finalText, BufferType.Spannable);
            }
        }
    }
}

iOS.LabelTextKerningEffect.cs

using System.Linq;
using MyNamespace.Effects;
using Foundation;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ResolutionGroupName("MyNamespace.Effects")]
[assembly: ExportEffect(typeof(MyNamespace.iOS.Effects.LabelTextKerningEffect), nameof(LabelTextKerningEffect))]
namespace MyNamespace.iOS.Effects
{
    public class LabelTextKerningEffect : PlatformEffect
    {
        protected override void OnAttached()
        {
            var effect = (MyNamespace.Effects.LabelTextKerningEffect)Element.Effects.FirstOrDefault(e => e is MyNamespace.Effects.LabelTextKerningEffect);
            ApplySpacing(effect.Kerning);
        }

        protected override void OnDetached() { }

        void ApplySpacing(float letterSpacing)
        {
            var lbl = Control as UILabel;
            if (lbl == null || string.IsNullOrEmpty(lbl.Text)) return;
            lbl.AttributedText = new NSAttributedString(lbl.Text, kerning: letterSpacing);
        }
    }
}

MainPage.xaml

<?xml version="1.0" encoding="utf-8"?>
<ContentPage
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:XFLetterSpacing"
    xmlns:effects="clr-namespace:XFLetterSpacing.Effects"
    x:Class="XFLetterSpacing.MainPage">
    <StackLayout>
        <!-- Place new controls here -->
        <Label Text="Welcome!" HorizontalOptions="Center" VerticalOptions="CenterAndExpand">
            <Label.Effects>
                <effects:LabelTextLetterSpacingEffect Kerning="5" />
            </Label.Effects>
        </Label>
    </StackLayout>
</ContentPage>

Shared.LabelTextKerningEffect.cs

public class LabelTextKerningEffect : RoutingEffect
{
    public float Kerning { get; set; }
    public LabelTextKerningEffect() : base($"MyNamespace.Effects.{nameof(LabelTextKerningEffect)}") { }
}