mchSamples-MAUI/ch02_DesigningViews/ex_OutlineText/Views/LabelOutline.xaml.cs

using System.Diagnostics;
using SkiaSharp;
using SkiaSharp.Views.Maui;

namespace ex_OutlineText.Views;

public partial class LabelOutline : ContentView
{
	public LabelOutline()
	{
		InitializeComponent();
	}

	public static readonly BindableProperty TextProperty 
        = BindableProperty.Create(nameof(Text), 
                                  typeof(string),
                                  typeof(LabelOutline),
                                  "something");

    public string Text
    {
        get { return (string)GetValue(TextProperty); }
        set { SetValue(TextProperty, value); }
	}

	public static readonly BindableProperty FillProperty 
        = BindableProperty.Create(nameof(Fill), 
                                  typeof(Color),
                                  typeof(LabelOutline),
                                  Colors.DarkSalmon);

    public Color Fill
    {
        get { return (Color)GetValue(FillProperty); }
        set { SetValue(FillProperty, value); }
	}

	public static readonly BindableProperty StrokeProperty 
        = BindableProperty.Create(nameof(Stroke), 
                                  typeof(Color),
                                  typeof(LabelOutline),
                                  Colors.DarkSalmon);

    public Color Stroke
    {
        get { return (Color)GetValue(StrokeProperty); }
        set { SetValue(StrokeProperty, value); }
	}

	public static readonly BindableProperty StrokeWidthProperty 
        = BindableProperty.Create(nameof(StrokeWidth), 
                                  typeof(float),
                                  typeof(LabelOutline),
                                  1.0f);

    public float StrokeWidth
    {
        get { return (float)GetValue(StrokeWidthProperty); }
        set { SetValue(StrokeWidthProperty, value); }
	}

	public static readonly BindableProperty FontFamilyProperty 
        = BindableProperty.Create(nameof(FontFamily), 
                                  typeof(string),
                                  typeof(LabelOutline),
                                  "something");

    public string FontFamily
    {
        get { return (string)GetValue(FontFamilyProperty); }
        set { SetValue(FontFamilyProperty, value); }
	}

	public static readonly BindableProperty TextSizeProperty 
        = BindableProperty.Create(nameof(TextSize), 
                                  typeof(float),
                                  typeof(LabelOutline),
                                  24.0f);

    public float TextSize
    {
        get { return (float)GetValue(TextSizeProperty); }
        set { SetValue(TextSizeProperty, value); }
	}

	public static readonly BindableProperty AspectProperty 
        = BindableProperty.Create(nameof(Aspect), 
                                  typeof(Aspect),
                                  typeof(LabelOutline),
                                  Aspect.Center);

	public Aspect Aspect
    {
        get { return (Aspect)GetValue(AspectProperty); }
        set { SetValue(AspectProperty, value); }
	}

	public static readonly BindableProperty RatioProperty 
        = BindableProperty.Create(nameof(Ratio), 
                                  typeof(float),
                                  typeof(LabelOutline),
                                  0.95f);

    public float Ratio
    {
        get { return (float)GetValue(RatioProperty); }
        set { SetValue(RatioProperty, value); }
	}

	private void OnPainting(object sender, SKPaintSurfaceEventArgs args)
	{
		SKImageInfo info = args.Info;
		SKSurface surface = args.Surface;
		SKCanvas canvas = surface.Canvas;

		canvas.Clear();

		string text = Text;

		// Create an SKPaint object to display the text
		SKPaint textPaint = new SKPaint
		{
			Style = SKPaintStyle.Fill,
			StrokeWidth = StrokeWidth,
			FakeBoldText = true,
			Typeface = SKTypeface.FromFamilyName(FontFamily),
			Color = Fill.ToSKColor(),
			TextSize = TextSize
		};

		switch(Aspect)
		{
			case Aspect.AspectFit:
				float textHeight = Ratio * info.Height;
				float textWidth2 = textPaint.MeasureText(text);
				textWidth2 = Ratio * info.Width * textPaint.TextSize / textWidth2;
				textPaint.TextSize = Math.Min(textHeight, textWidth2);
				Console.WriteLine($"info.Width: {info.Width} ; info.Height: {info.Height} ; textPaint.TextSize: {textPaint.TextSize} ; textHeight: {textHeight} ; textWidth: {textWidth2}");
				break;
			case Aspect.AspectFill:
			case Aspect.Fill:
				float textWidth = textPaint.MeasureText(text);
				textPaint.TextSize = Ratio * info.Width * textPaint.TextSize / textWidth;
				Console.WriteLine($"info.Width: {info.Width} ; info.Height: {info.Height} ; textPaint.TextSize: {textPaint.TextSize}");
				break;
			case Aspect.Center:
			default:
				break;
		}
		// Adjust TextSize property so text is 95% of screen width
		// float textWidth = textPaint.MeasureText(text);
		// textPaint.TextSize = 0.95f * info.Width * textPaint.TextSize / textWidth;

		// Find the text bounds
		SKRect textBounds = new SKRect();
		textPaint.MeasureText(text, ref textBounds);

		// Calculate offsets to center the text on the screen
		float xText = info.Width / 2 - textBounds.MidX;
		float yText = info.Height / 2 - textBounds.MidY;

		// And draw the text
		canvas.DrawText(text, xText, yText, textPaint);

		textPaint.Style = SKPaintStyle.Stroke;
		textPaint.Color = Stroke.ToSKColor();

		canvas.DrawText(text, xText, yText, textPaint);
	}
}