public static string GenerateRtf (TextDocument doc, Mono.TextEditor.Highlighting.ISyntaxMode mode, Mono.TextEditor.Highlighting.ColorScheme style, ITextEditorOptions options)
		{
			var rtfText = new StringBuilder ();
			var colorList = new List<Cairo.Color> ();

			var selection = new TextSegment (0, doc.TextLength);
			int startLineNumber = doc.OffsetToLineNumber (selection.Offset);
			int endLineNumber = doc.OffsetToLineNumber (selection.EndOffset);
			
			bool isItalic = false;
			bool isBold = false;
			int curColor = -1;
			foreach (var line in doc.GetLinesBetween (startLineNumber, endLineNumber)) {
				bool appendSpace = false;
				if (mode == null) {
					AppendRtfText (rtfText, doc, System.Math.Max (selection.Offset, line.Offset), System.Math.Min (line.EndOffset, selection.EndOffset), ref appendSpace);
					continue;
				}
				foreach (var chunk in mode.GetChunks (style, line, line.Offset, line.Length)) {
					int start = System.Math.Max (selection.Offset, chunk.Offset);
					int end = System.Math.Min (chunk.EndOffset, selection.EndOffset);
					var chunkStyle = style.GetChunkStyle (chunk);
					if (start < end) {
						if (isBold != (chunkStyle.FontWeight == Xwt.Drawing.FontWeight.Bold)) {
							isBold = chunkStyle.FontWeight == Xwt.Drawing.FontWeight.Bold;
							rtfText.Append (isBold ? @"\b" : @"\b0");
							appendSpace = true;
						}
						if (isItalic != (chunkStyle.FontStyle == Xwt.Drawing.FontStyle.Italic)) {
							isItalic = chunkStyle.FontStyle == Xwt.Drawing.FontStyle.Italic;
							rtfText.Append (isItalic ? @"\i" : @"\i0");
							appendSpace = true;
						}
						var foreground = style.GetForeground (chunkStyle);
						if (!colorList.Contains (foreground)) 
							colorList.Add (foreground);
						int color = colorList.IndexOf (foreground);
						if (curColor != color) {
							curColor = color;
							rtfText.Append (@"\cf" + (curColor + 1));
							appendSpace = true;
						}
						AppendRtfText (rtfText, doc, start, end, ref appendSpace);
					}
				}
				rtfText.Append (@"\par");
				rtfText.AppendLine ();
			}
			
			var rtf = new StringBuilder();

			rtf.Append (@"{\rtf1\ansi\deff0\adeflang1025");
			
			// font table
			rtf.Append (@"{\fonttbl");

			rtf.Append (@"{\f0\fnil\fprq1\fcharset128 " + options.Font.Family + ";}");

			rtf.Append ("}");
			
			rtf.Append (CreateColorTable (colorList));
			
			rtf.Append (@"\viewkind4\uc1\pard");

			rtf.Append (@"\f0");
			try {
				string fontName = options.Font.ToString ();
				double fontSize = Double.Parse (fontName.Substring (fontName.LastIndexOf (' ')  + 1), System.Globalization.CultureInfo.InvariantCulture) * 2;
				rtf.Append (@"\fs");
				rtf.Append (fontSize);
			} catch (Exception) {};
			rtf.Append (@"\cf1");
			rtf.Append (rtfText.ToString ());
			rtf.Append("}");
			return rtf.ToString ();
		}
		public static string GenerateRtf (List<List<ColoredSegment>> chunks, Mono.TextEditor.Highlighting.ColorScheme style, ITextEditorOptions options)
		{
			var rtfText = new StringBuilder ();
			var colorList = new List<Cairo.Color> ();

			bool isItalic = false;
			bool isBold = false;
			int curColor = -1;
			foreach (var line in chunks) {
				bool appendSpace = false;
				foreach (var chunk in line) {
					var chunkStyle = style.GetChunkStyle (chunk.Style);
					if (isBold != (chunkStyle.FontWeight == Xwt.Drawing.FontWeight.Bold)) {
						isBold = chunkStyle.FontWeight == Xwt.Drawing.FontWeight.Bold;
						rtfText.Append (isBold ? @"\b" : @"\b0");
						appendSpace = true;
					}
					if (isItalic != (chunkStyle.FontStyle == Xwt.Drawing.FontStyle.Italic)) {
						isItalic = chunkStyle.FontStyle == Xwt.Drawing.FontStyle.Italic;
						rtfText.Append (isItalic ? @"\i" : @"\i0");
						appendSpace = true;
					}
					var foreground = style.GetForeground (chunkStyle);
					if (!colorList.Contains (foreground)) 
						colorList.Add (foreground);
					int color = colorList.IndexOf (foreground);
					if (curColor != color) {
						curColor = color;
						rtfText.Append (@"\cf" + (curColor + 1));
						appendSpace = true;
					}
					AppendRtfText (rtfText, chunk.Text, ref appendSpace);
				}
				rtfText.AppendLine (@"\line");
			}
			
			var rtf = new StringBuilder();

			rtf.AppendLine (@"{\rtf1\ansi\deff0\adeflang1025");
			rtf.AppendLine (@"{\fonttbl");
			rtf.AppendLine (@"{\f0\fnil\fprq1\fcharset128 " + options.Font.Family + ";}");
			rtf.AppendLine ("}");
			rtf.Append (CreateColorTable (colorList));
			rtf.AppendLine (@"\viewkind4\uc1\pard");
			rtf.AppendLine (@"\f0");
			try {
				string fontName = options.Font.ToString ();
				double fontSize = Double.Parse (fontName.Substring (fontName.LastIndexOf (' ')  + 1), System.Globalization.CultureInfo.InvariantCulture) * 2;
				rtf.Append (@"\fs");
				rtf.Append (fontSize);
			} catch (Exception) {};
			rtf.AppendLine (@"\cf1");
			rtf.Append (rtfText.ToString ());
			rtf.Append("}");
			return rtf.ToString ();
		}