maui-linux/Xamarin.Forms.Platform.WP8/LabelRenderer.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Media;

namespace Xamarin.Forms.Platform.WinPhone
{
	public static class FormattedStringExtensions
	{
		public static IEnumerable<Inline> ToInlines(this FormattedString formattedString)
		{
			foreach (Span span in formattedString.Spans)
				yield return span.ToRun();
		}

		public static Run ToRun(this Span span)
		{
			var run = new Run { Text = span.Text };

			if (span.ForegroundColor != Color.Default)
				run.Foreground = span.ForegroundColor.ToBrush();

			if (!span.IsDefault())
#pragma warning disable 618
				run.ApplyFont(span.Font);
#pragma warning restore 618

			return run;
		}
	}

	public class LabelRenderer : ViewRenderer<Label, TextBlock>
	{
		bool _fontApplied;

		protected override System.Windows.Size ArrangeOverride(System.Windows.Size finalSize)
		{
			if (Element == null)
				return finalSize;
			double childHeight = Math.Max(0, Math.Min(Element.Height, Control.DesiredSize.Height));
			var rect = new Rect();

			switch (Element.VerticalTextAlignment)
			{
				case TextAlignment.Start:
					break;
				default:
				case TextAlignment.Center:
					rect.Y = (int)((finalSize.Height - childHeight) / 2);
					break;
				case TextAlignment.End:
					rect.Y = finalSize.Height - childHeight;
					break;
			}
			rect.Height = childHeight;
			rect.Width = finalSize.Width;
			Control.Arrange(rect);
			return finalSize;
		}

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

			var textBlock = new TextBlock { Foreground = (Brush)System.Windows.Application.Current.Resources["PhoneForegroundBrush"] };
			UpdateText(textBlock);
			UpdateColor(textBlock);
			UpdateAlign(textBlock);
			UpdateFont(textBlock);
			UpdateLineBreakMode(textBlock);
			SetNativeControl(textBlock);
		}

		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
		{
			if (e.PropertyName == Label.TextProperty.PropertyName || e.PropertyName == Label.FormattedTextProperty.PropertyName)
				UpdateText(Control);
			else if (e.PropertyName == Label.TextColorProperty.PropertyName)
				UpdateColor(Control);
			else if (e.PropertyName == Label.HorizontalTextAlignmentProperty.PropertyName || e.PropertyName == Label.VerticalTextAlignmentProperty.PropertyName)
				UpdateAlign(Control);
			else if (e.PropertyName == Label.FontProperty.PropertyName)
				UpdateFont(Control);
			else if (e.PropertyName == Label.LineBreakModeProperty.PropertyName)
				UpdateLineBreakMode(Control);
			base.OnElementPropertyChanged(sender, e);
		}

		void UpdateAlign(TextBlock textBlock)
		{
			if (textBlock == null)
				return;

			Label label = Element;
			if (label == null)
				return;

			textBlock.TextAlignment = label.HorizontalTextAlignment.ToNativeTextAlignment();
			textBlock.VerticalAlignment = label.VerticalTextAlignment.ToNativeVerticalAlignment();
		}

		void UpdateColor(TextBlock textBlock)
		{
			if (textBlock == null)
				return;

			Label label = Element;
			if (label != null && label.TextColor != Color.Default)
				textBlock.Foreground = label.TextColor.ToBrush();
			else
				textBlock.Foreground = (Brush)System.Windows.Application.Current.Resources["PhoneForegroundBrush"];
		}

		void UpdateFont(TextBlock textBlock)
		{
			if (textBlock == null)
				return;

			Label label = Element;
			if (label == null || (label.IsDefault() && !_fontApplied))
				return;

#pragma warning disable 618
			Font fontToApply = label.IsDefault() ? Font.SystemFontOfSize(NamedSize.Medium) : label.Font;
#pragma warning restore 618

			textBlock.ApplyFont(fontToApply);
			_fontApplied = true;
		}

		void UpdateLineBreakMode(TextBlock textBlock)
		{
			if (textBlock == null)
				return;

			switch (Element.LineBreakMode)
			{
				case LineBreakMode.NoWrap:
					textBlock.TextTrimming = TextTrimming.None;
					textBlock.TextWrapping = TextWrapping.NoWrap;
					break;
				case LineBreakMode.WordWrap:
					textBlock.TextTrimming = TextTrimming.None;
					textBlock.TextWrapping = TextWrapping.Wrap;
					break;
				case LineBreakMode.CharacterWrap:
					textBlock.TextTrimming = TextTrimming.WordEllipsis;
					textBlock.TextWrapping = TextWrapping.Wrap;
					break;
				case LineBreakMode.HeadTruncation:
					textBlock.TextTrimming = TextTrimming.WordEllipsis;
					textBlock.TextWrapping = TextWrapping.NoWrap;
					break;
				case LineBreakMode.TailTruncation:
					textBlock.TextTrimming = TextTrimming.WordEllipsis;
					textBlock.TextWrapping = TextWrapping.NoWrap;
					break;
				case LineBreakMode.MiddleTruncation:
					textBlock.TextTrimming = TextTrimming.WordEllipsis;
					textBlock.TextWrapping = TextWrapping.NoWrap;
					break;
				default:
					throw new ArgumentOutOfRangeException();
			}
		}

		void UpdateText(TextBlock textBlock)
		{
			if (textBlock == null)
				return;

			Label label = Element;
			if (label != null)
			{
				if (label.FormattedText == null)
					textBlock.Text = label.Text;
				else
				{
					FormattedString formattedText = label.FormattedText ?? label.Text;

					textBlock.Inlines.Clear();
					foreach (Inline inline in formattedText.ToInlines())
						textBlock.Inlines.Add(inline);
				}
			}
		}
	}
}