AspectRatioLayout.cs

using System;
using System.ComponentModel;
using Microsoft.Maui.Controls;
using Microsoft.Maui.Layouts;
 
namespace NeuroAccessMaui.UI.Controls
{
 
    public class AspectRatioLayoutManager : LayoutManager
    {
        public AspectRatioLayoutManager(AspectRatioLayout layout) : base(layout)
        {
        }
 
        public new AspectRatioLayout Layout => (AspectRatioLayout)base.Layout;
 
        public override Size Measure(double widthConstraint, double heightConstraint)
        {
            double Aspect = this.Layout.AspectRatio;
            Thickness Padding = this.Layout.Padding;
            double AvailableWidth = Math.Max(0, widthConstraint - Padding.HorizontalThickness);
            double AvailableHeight = Math.Max(0, heightConstraint - Padding.VerticalThickness);
 
            double Width = AvailableWidth;
            double Height = Width / Aspect;
 
            if (AvailableHeight > 0 && Height > AvailableHeight)
            {
                Height = AvailableHeight;
                Width = Height * Aspect;
            }
 
            foreach (IView Child in this.Layout)
            {
                Child.Measure(Width, Height);
            }
 
            return new Size(Width + Padding.HorizontalThickness, Height + Padding.VerticalThickness);
        }
 
        public override Size ArrangeChildren(Rect bounds)
        {
            Thickness Padding = this.Layout.Padding;
            double ChildX = Padding.Left;
            double ChildY = Padding.Top;
            double ChildWidth = Math.Max(0, bounds.Width - Padding.HorizontalThickness);
            double ChildHeight = Math.Max(0, bounds.Height - Padding.VerticalThickness);
 
            foreach (IView Child in this.Layout)
            {
                Child.Arrange(new Rect(ChildX, ChildY, ChildWidth, ChildHeight));
            }
 
            return bounds.Size;
        }
    }
    public class AspectRatioLayout : Layout
    {
        public static readonly BindableProperty AspectRatioProperty =
            BindableProperty.Create(
                nameof(AspectRatio),
                typeof(double),
                typeof(AspectRatioLayout),
                1.0,
                propertyChanged: OnAspectRatioChanged);
 
        [TypeConverter(typeof(Converters.AspectRatioTypeConverter))]
        public double AspectRatio
        {
            get { return (double)this.GetValue(AspectRatioProperty); }
            set { this.SetValue(AspectRatioProperty, value); }
        }
 
        private static void OnAspectRatioChanged(BindableObject bindable, object oldValue, object newValue)
        {
            if (bindable is AspectRatioLayout AspectRatioView)
            {
                AspectRatioView.InvalidateMeasure();
            }
        }
 
        protected override ILayoutManager CreateLayoutManager()
        {
            return new AspectRatioLayoutManager(this);
        }
    }
}