dotnet 读 WPF 源代码笔记 GlyphRun 的 DeviceFontName 的功能是什么

    public class GlyphRun : DUCE.IResource, ISupportInitialize
    {
        /// <summary>
        /// Identifies a specific device font for which the GlyphRun has been optimized. When a GlyphRun is
        /// being rendered on a device that has built-in support for this named font, then the GlyphRun should be rendered using a
        /// possibly device specific mechanism for selecting that font, and by sending the Unicode codepoints rather than the
        /// glyph indices. When rendering onto a device that does not include built-in support for the named font,
        /// this property should be ignored.
        /// </summary>
        public string DeviceFontName
        {
            get
            {
                CheckInitialized();
                return _deviceFontName;
            }
            set
            {
                CheckInitializing(); // This can only be set during initialization.
                _deviceFontName = value;
            }
        }

        private string              _deviceFontName;

        ...// 忽略其他代码
    }

namespace System.Windows.Xps.Serialization
{
    internal class VisualSerializer: IMetroDrawingContext
    {
        private static GlyphRun FilterXmlInvalidChar(GlyphRun glyphRun)
        {
            ...// 忽略其他代码

                GlyphRun filtered = new GlyphRun(
                    glyphRun.GlyphTypeface,
                    glyphRun.BidiLevel,
                    glyphRun.IsSideways,
                    glyphRun.FontRenderingEmSize,
                    glyphRun.PixelsPerDip,
                    glyphRun.GlyphIndices,
                    glyphRun.BaselineOrigin,
                    glyphRun.AdvanceWidths,
                    glyphRun.GlyphOffsets,
                    filteredCharacters,
                    glyphRun.DeviceFontName,
                    glyphRun.ClusterMap,
                    glyphRun.CaretStops,
                    glyphRun.Language
                    );

                return filtered;
        }
        ...// 忽略其他代码
    }
}