Content scaler for Unity Noesis GUI

ContentScaler.cs

#if UNITY_5_3_OR_NEWER
    #define NOESIS
    using Noesis;
#else
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Media;
#endif

namespace NoesisGUI.Extensions.Scaling
{
    using System;

    public enum ContentMatchMode
    {
        MatchWidthOrHeight,
        Expand,
        Shrink
    }
    
    [TemplatePart(Name = "ContentPresenter", Type = typeof(ContentPresenter))]
    public class ContentScaler : ContentControl
    {
        private const float LogBase = 2;
        
        public static readonly DependencyProperty ReferenceWidthProperty = DependencyProperty.Register(nameof(ReferenceWidth),
            typeof(float), typeof(ContentScaler), new FrameworkPropertyMetadata(1920.0f, FrameworkPropertyMetadataOptions.AffectsMeasure));
        public static readonly DependencyProperty ReferenceHeightProperty = DependencyProperty.Register(nameof(ReferenceHeight),
            typeof(float), typeof(ContentScaler), new FrameworkPropertyMetadata(1080.0f, FrameworkPropertyMetadataOptions.AffectsMeasure));
        
        public static readonly DependencyProperty ContentMatchModeProperty = DependencyProperty.Register(nameof(ContentMatchMode),
            typeof(ContentMatchMode), typeof(ContentScaler), new FrameworkPropertyMetadata(ContentMatchMode.MatchWidthOrHeight, FrameworkPropertyMetadataOptions.AffectsMeasure));
        public static readonly  DependencyProperty MatchWidthOrHeightProperty = DependencyProperty.Register(nameof(MatchWidthOrHeight),
            typeof(float), typeof(ContentScaler), new FrameworkPropertyMetadata(0.0f, FrameworkPropertyMetadataOptions.AffectsMeasure));
        
        private ContentPresenter m_ContentPresenter;
        private ScaleTransform m_ScaleTransform;

        public float ReferenceWidth
        {
            get => (float) GetValue(ReferenceWidthProperty);
            set => SetValue(ReferenceWidthProperty, value);
        }

        public float ReferenceHeight
        {
            get => (float) GetValue(ReferenceHeightProperty);
            set => SetValue(ReferenceHeightProperty, value);
        }

        public ContentMatchMode ContentMatchMode
        {
            get => (ContentMatchMode) GetValue(ContentMatchModeProperty);
            set => SetValue(ContentMatchModeProperty, value);
        }

        public float MatchWidthOrHeight
        {
            get => (float) GetValue(MatchWidthOrHeightProperty);
            set => SetValue(MatchWidthOrHeightProperty, value);
        }

        static ContentScaler()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(ContentScaler), new FrameworkPropertyMetadata(typeof(ContentScaler)));
        }

        public override void OnApplyTemplate()
        {
            var templateRoot = VisualTreeHelper.GetChild(this, 0) as FrameworkElement;
            if(templateRoot == null)
                return;
                
            m_ContentPresenter = (ContentPresenter)templateRoot.FindName("ContentPresenter");
            m_ScaleTransform = new ScaleTransform(1f, 1f);
            m_ContentPresenter.LayoutTransform = m_ScaleTransform;

            m_ContentPresenter.Loaded += (sender, args) =>
            {
                InvalidateMeasure();
            };
        }

        protected override Size MeasureOverride(Size availableSize)
        {
            if(double.IsPositiveInfinity(availableSize.Width))
                availableSize = new Size(ReferenceWidth, availableSize.Height);
            if(double.IsPositiveInfinity(availableSize.Height))
                availableSize = new Size(availableSize.Width, ReferenceHeight);

            var scale = CalculateScale(availableSize);

            m_ScaleTransform.ScaleX = scale;
            m_ScaleTransform.ScaleY = scale;
            
            return availableSize;
        }

        private float CalculateScale(Size availableSize)
        {
            switch (ContentMatchMode)
            {
                case ContentMatchMode.MatchWidthOrHeight:
                {
                    var logWidth = (float) Math.Log(availableSize.Width / ReferenceWidth, LogBase);
                    var logHeight = (float) Math.Log(availableSize.Height / ReferenceHeight, LogBase);
                    var logWeightedAverage = logWidth + (logHeight - logWidth) * MatchWidthOrHeight;
                    
                    return (float)Math.Pow(LogBase, logWeightedAverage);
                }
                case ContentMatchMode.Expand:
                    return (float)Math.Min(availableSize.Width / ReferenceWidth, availableSize.Height / ReferenceHeight);
                case ContentMatchMode.Shrink:
                    return (float)Math.Max(availableSize.Width / ReferenceWidth, availableSize.Height / ReferenceHeight);
                default:
                    return 1.0f;
            }
        }
    }
}

ContentScalerStyle.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:scaling="clr-namespace:NoesisGUI.Extensions.Scaling">
    
    <Style TargetType="{x:Type scaling:ContentScaler}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type scaling:ContentScaler}">
                    <Border>
                        <ContentPresenter x:Name="ContentPresenter"/>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

How to use:

<UserControl x:Class="Testing.TestScreen"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:scaling="clr-namespace:NoesisGUI.Extensions.Scaling">
    <scaling:ContentScaler ReferenceWidth="1920" ReferenceHeight="1080" ContentMatchMode="MatchWidthOrHeight" MatchWidthOrHeight="0">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="64"/>
                <RowDefinition Height="64"/>
            </Grid.RowDefinitions>

        </Grid>
    </scaling:ContentScaler>
</UserControl>