WPF 简单聊聊如何使用 DrawGlyphRun 绘制文本

        public MainWindow()
        {
            InitializeComponent();

            Loaded += MainWindow_Loaded;
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            var drawingVisual = new DrawingVisual();
            using (var drawingContext = drawingVisual.RenderOpen())
            {

            }
            Background = new VisualBrush(drawingVisual);
        }

using (var drawingContext = drawingVisual.RenderOpen())
{
    drawingContext.DrawRectangle(Brushes.Black, null, new Rect(0, 0, ActualWidth, ActualHeight));
}

var fontFamily = new FontFamily("微软雅黑");
Typeface typeface = fontFamily.GetTypefaces().First();

bool success = typeface.TryGetGlyphTypeface(out GlyphTypeface glyphTypeface);

var text = "林德熙abc123ATdVACC";

List<ushort> glyphIndices = new List<ushort>();

for (var i = 0; i < text.Length; i++)
{
    var c = text[i];
    var glyphIndex = glyphTypeface.CharacterToGlyphMap[c];
    glyphIndices.Add(glyphIndex);
}

List<double> advanceWidths = new List<double>();

for (var i = 0; i < text.Length; i++)
{
    var c = text[i];

    var width = glyphTypeface.AdvanceWidths[glyphIndex] * fontSize;
    advanceWidths.Add(width);
}

List<Point> glyphOffsets = new List<Point>();
var fontSize = 30;

for (var i = 0; i < text.Length; i++)
{
    var c = text[i];

    // 只是决定每个字的偏移量，记得加上 i 乘以哦。字符最好是叠加上 fontSize 的值，使用 fontSize 的倍数
    glyphOffsets.Add(new Point(fontSize * i, 0));
}

    var location = new Point(10, 100);

                XmlLanguage defaultXmlLanguage =
                    XmlLanguage.GetLanguage(CultureInfo.CurrentUICulture.IetfLanguageTag);

    var pixelsPerDip = (float) VisualTreeHelper.GetDpi(Application.Current.MainWindow).PixelsPerDip;

  var glyphRun = new GlyphRun
  (
      glyphTypeface,
      bidiLevel: 0,
      isSideways: false,
      renderingEmSize: fontSize,
      pixelsPerDip: pixelsPerDip,   // 只有在高版本的 .NET 才有此参数
      glyphIndices: glyphIndices,
      baselineOrigin: location,     // 设置文本的偏移量
      advanceWidths: advanceWidths, // 设置每个字符的字宽，也就是字号
      glyphOffsets: null,           // 设置每个字符的偏移量，可以为空
      characters: text.ToCharArray(),
      deviceFontName: null,
      clusterMap: null,
      caretStops: null,
      language: defaultXmlLanguage
  );

  drawingContext.DrawGlyphRun(Brushes.White, glyphRun);

var geometry = glyphRun.BuildGeometry();

  var computeInkBoundingBox = glyphRun.ComputeInkBoundingBox();
  var matrix = new Matrix();
  matrix.Translate(location.X, location.Y);
  computeInkBoundingBox.Transform(matrix);
  //相对于run.BuildGeometry().Bounds方法，run.ComputeInkBoundingBox()会多出一个厚度为1的框框，所以要减去
  if (computeInkBoundingBox.Width >= 2 && computeInkBoundingBox.Height >= 2)
  {
      computeInkBoundingBox.Inflate(-1, -1);
  }

     drawingContext.DrawRectangle(Brushes.Blue, null, computeInkBoundingBox);

    /// <summary>
    /// 用于回滚的字体对象<see cref="FontFamily"/>
    /// </summary>
    public class FallBackFontFamily
    {
        private const string FallBackFontFamilyName = "#GLOBAL USER INTERFACE";
        private FontFamily FallBack { get; } = new FontFamily(FallBackFontFamilyName);

        private FallBackFontFamily(CultureInfo culture)
        {
            FontFamilyItems = FallBack.FamilyMaps
                .Where(map => map.Language == null || map.Language.MatchCulture(culture))
                .Select(map => new FontFamilyMapItem(map)).ToList();
        }

        private IEnumerable<FontFamilyMapItem> FontFamilyItems { get; }

        /// <summary>
        /// 获取<see cref="FallBackFontFamily"/>对象的单例
        /// </summary>
        public static FallBackFontFamily Instance => FallBackFontFamilyLazy.Value;

        private static readonly Lazy<FallBackFontFamily> FallBackFontFamilyLazy =
            new Lazy<FallBackFontFamily>(() => new FallBackFontFamily(CultureInfo.CurrentCulture));

        /// <summary>
        /// 尝试获取fallback的字体名称
        /// </summary>
        /// <param name="unicodeChar"></param>
        /// <param name="familyName"></param>
        /// <returns></returns>
        public bool TryGetFallBackFontFamily(char unicodeChar, out string familyName)
        {
            var mapItem = FontFamilyItems.FirstOrDefault(item => item.InRange(unicodeChar));
            familyName = null;

            if (mapItem !=null)
            {
                familyName = mapItem.Target;
                return true;
            }
            return false;
        }
    }

        internal const string GlobalUI = "#GLOBAL USER INTERFACE";

        internal static FontFamily FontFamilyGlobalUI = new FontFamily(GlobalUI);

        public Typeface(
            FontFamily      fontFamily,
            FontStyle       style,
            FontWeight      weight,
            FontStretch     stretch
            )
            : this(
                fontFamily,
                style,
                weight,
                stretch,
                FontFamily.FontFamilyGlobalUI
                )
        {}

            if (typeface.TryGetGlyphTypeface(out var glyph))
            {
                // 忽略代码
            }
            else if (FallBackFontFamily.Instance.TryGetFallBackFontFamily(unicodeChar, out var familyName))
            {
            	// 上面代码的 unicodeChar 就是传入的文本的字符
            	// 通过上面代码可以拿到回滚的字体是否包含此字符的定义
            }
            else
            {
                // 没有可以支持此字符的字体，那就看业务逻辑的处理啦
            }

git init
git remote add origin https://gitee.com/lindexi/lindexi_gd.git
git pull origin 581ea123df0d1067ec1ed3527e8b85edb2fd082e

git remote remove origin
git remote add origin https://github.com/lindexi/lindexi_gd.git