Xamarin.Forms.Platform.iOS/Renderers/BoxRenderer.cs


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using System.ComponentModel;
using UIKit;
using RectangleF = CoreGraphics.CGRect;
using SizeF = CoreGraphics.CGSize;

namespace Xamarin.Forms.Platform.iOS
{
	public class BoxRenderer : VisualElementRenderer<BoxView>
	{
		UIColor _colorToRenderer;
		SizeF _previousSize;

		public override void Draw(RectangleF rect)
		{
			using (var context = UIGraphics.GetCurrentContext())
			{
				_colorToRenderer.SetFill();
				context.FillRect(rect);
			}
			base.Draw(rect);

			_previousSize = Bounds.Size;
		}

		public override void LayoutSubviews()
		{
			if (_previousSize != Bounds.Size)
				SetNeedsDisplay();
		}

		protected override void OnElementChanged(ElementChangedEventArgs<BoxView> e)
		{
			base.OnElementChanged(e);

			if (Element != null)
				SetBackgroundColor(Element.BackgroundColor);
		}

		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged(sender, e);
			if (e.PropertyName == BoxView.ColorProperty.PropertyName)
				SetBackgroundColor(Element.BackgroundColor);
			else if (e.PropertyName == VisualElement.IsVisibleProperty.PropertyName && Element.IsVisible)
				SetNeedsDisplay();
		}

		protected override void SetBackgroundColor(Color color)
		{
			if (Element == null)
				return;

			var elementColor = Element.Color;
			if (!elementColor.IsDefault)
				_colorToRenderer = elementColor.ToUIColor();
			else
				_colorToRenderer = color.ToUIColor();

			SetNeedsDisplay();
		}
	}
}