* TextBoxBase.cs: Use the new SuspendRecalc/ResumeRecalc methods

[mono-project.git] / mcs / class / Managed.Windows.Forms / System.Windows.Forms / RichTextBox.cs

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2005-2006 Novell, Inc. (http://www.novell.com)
//
// Authors:
//      Peter Bartok    <pbartok@novell.com>
//
//

// NOT COMPLETE

// #define DEBUG

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.Text;
using RTF=System.Windows.Forms.RTF;

namespace System.Windows.Forms {
        public class RichTextBox : TextBoxBase {
                #region Local Variables
                internal bool           auto_word_select;
                internal int            bullet_indent;
                internal bool           can_redo;
                internal bool           detect_urls;
                internal string         redo_action_name;
                internal int            margin_right;
                internal string         undo_action_name;
                internal float          zoom;

                private RTF.TextMap     rtf_text_map;
                private int             rtf_skip_width;
                private int             rtf_skip_count;
                private StringBuilder   rtf_line;
                private SolidBrush      rtf_color;
                private RTF.Font        rtf_rtffont;
                private int             rtf_rtffont_size;
                private FontStyle       rtf_rtfstyle;
                private HorizontalAlignment rtf_rtfalign;
                private int             rtf_cursor_x;
                private int             rtf_cursor_y;
                private int             rtf_chars;
                #endregion      // Local Variables

                #region Public Constructors
                public RichTextBox() {
                        accepts_return = true;
                        auto_word_select = false;
                        bullet_indent = 0;
                        can_redo = false;
                        detect_urls = true;
                        max_length = Int32.MaxValue;
                        redo_action_name = string.Empty;
                        margin_right = 0;
                        undo_action_name = string.Empty;
                        zoom = 1;
                        base.Multiline = true;
                        document.CRLFSize = 1;

                        scrollbars = RichTextBoxScrollBars.Both;
                        alignment = HorizontalAlignment.Left;
                        LostFocus += new EventHandler(RichTextBox_LostFocus);
                        GotFocus += new EventHandler(RichTextBox_GotFocus);
                        BackColor = ThemeEngine.Current.ColorWindow;
                        ForeColor = ThemeEngine.Current.ColorWindowText;
                        base.HScrolled += new EventHandler(RichTextBox_HScrolled);
                        base.VScrolled += new EventHandler(RichTextBox_VScrolled);

#if NET_2_0
                        SetStyle (ControlStyles.StandardDoubleClick, false);
#endif
                }
                #endregion      // Public Constructors

                #region Private & Internal Methods
                private void RichTextBox_LostFocus(object sender, EventArgs e) {
                        Invalidate();
                }

                private void RichTextBox_GotFocus(object sender, EventArgs e) {
                        Invalidate();
                }
                #endregion      // Private & Internal Methods

                #region Public Instance Properties
                public override bool AllowDrop {
                        get {
                                return base.AllowDrop;
                        }

                        set {
                                base.AllowDrop = value;
                        }
                }

                [DefaultValue(false)]
                [Localizable(true)]
                public override bool AutoSize {
                        get {
                                return auto_size;
                        }

                        set {
                                base.AutoSize = value;
                        }
                }

                [DefaultValue(false)]
                public bool AutoWordSelection {
                        get {
                                return auto_word_select;
                        }

                        set {
                                auto_word_select = true;
                        }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public override System.Drawing.Image BackgroundImage {
                        get { return base.BackgroundImage; }
                        set { base.BackgroundImage = value; }
                }

                [DefaultValue(0)]
                [Localizable(true)]
                public int BulletIndent {
                        get {
                                return bullet_indent;
                        }

                        set {
                                bullet_indent = value;
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public bool CanRedo {
                        get {
                                return can_redo;
                        }
                }

                [DefaultValue(true)]
                public bool DetectUrls {
                        get {
                                return detect_urls;
                        }

                        set {
                                detect_urls = true;
                        }
                }

                public override Font Font {
                        get {
                                return base.Font;
                        }

                        set {
                                if (font != value) {
                                        Line    start;
                                        Line    end;

                                        if (auto_size) {
                                                if (PreferredHeight != Height) {
                                                        Height = PreferredHeight;
                                                }
                                        }

                                        base.Font = value;

                                        // Font changes always set the whole doc to that font
                                        start = document.GetLine(1);
                                        end = document.GetLine(document.Lines);
                                        document.FormatText(start, 1, end, end.text.Length + 1, base.Font, null, null, FormatSpecified.Font);
                                }
                        }
                }

                public override Color ForeColor {
                        get {
                                return base.ForeColor;
                        }

                        set {
                                base.ForeColor = value;
                        }
                }

                [DefaultValue(Int32.MaxValue)]
                public override int MaxLength {
                        get {
                                return base.max_length;
                        }

                        set {
                                base.max_length = value;
                        }
                }

                [DefaultValue(true)]
                public override bool Multiline {
                        get {
                                return multiline;
                        }

                        set {
                                base.Multiline = value;
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public string RedoActionName {
                        get {
                                return redo_action_name;
                        }
                }

                [DefaultValue(0)]
                [Localizable(true)]
                [MonoTODO("Teach TextControl.RecalculateLine to consider the right margin as well")]
                public int RightMargin {
                        get {
                                return margin_right;
                        }

                        set {
                                margin_right = value;
                        }
                }

                [Browsable(false)]
                [DefaultValue("")]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public string Rtf {
                        get {
                                Line            start_line;
                                Line            end_line;

                                start_line = document.GetLine(1);
                                end_line = document.GetLine(document.Lines);
                                return GenerateRTF(start_line, 0, end_line, end_line.text.Length).ToString();
                        }

                        set {
                                MemoryStream    data;

                                document.Empty();
                                data = new MemoryStream(Encoding.ASCII.GetBytes(value), false);

                                InsertRTFFromStream(data, 0, 1);

                                data.Close();

                                Invalidate();
                        }
                }

                [DefaultValue(RichTextBoxScrollBars.Both)]
                [Localizable(true)]
                public RichTextBoxScrollBars ScrollBars {
                        get {
                                return scrollbars;
                        }

                        set {
                                scrollbars = value;
                        }
                }

                [Browsable(false)]
                [DefaultValue("")]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public string SelectedRtf {
                        get {
                                return GenerateRTF(document.selection_start.line, document.selection_start.pos, document.selection_end.line, document.selection_end.pos).ToString();
                        }

                        set {
                                MemoryStream    data;
                                int             x;
                                int             y;
                                int             sel_start;
                                int             chars;
                                Line            line;
                                LineTag         tag;

                                if (document.selection_visible) {
                                        document.ReplaceSelection("", false);
                                }

                                sel_start = document.LineTagToCharIndex(document.selection_start.line, document.selection_start.pos);

                                data = new MemoryStream(Encoding.ASCII.GetBytes(value), false);
                                InsertRTFFromStream(data, document.selection_start.pos, document.selection_start.line.line_no, out x, out y, out chars);
                                data.Close();

                                document.CharIndexToLineTag(sel_start + chars + (y - document.selection_start.line.line_no) * 2, out line, out tag, out sel_start);
                                document.SetSelection(line, sel_start);
                                document.PositionCaret(line, sel_start);
                                document.DisplayCaret();
                                ScrollToCaret();
                                OnTextChanged(EventArgs.Empty);
                        }
                }

                [Browsable(false)]
                [DefaultValue("")]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public override string SelectedText {
                        get {
                                return base.SelectedText;
                        }

                        set {
                                base.SelectedText = value;
                        }
                }

                [Browsable(false)]
                [DefaultValue(HorizontalAlignment.Left)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public HorizontalAlignment SelectionAlignment {
                        get {
                                HorizontalAlignment     align;
                                Line                    start;
                                Line                    end;
                                Line                    line;

                                start = document.ParagraphStart(document.selection_start.line);
                                align = start.alignment;

                                end = document.ParagraphEnd(document.selection_end.line);

                                line = start;

                                while (true) {
                                        if (line.alignment != align) {
                                                return HorizontalAlignment.Left;
                                        }

                                        if (line == end) {
                                                break;
                                        }
                                        line = document.GetLine(line.line_no + 1);
                                }

                                return align;
                        }

                        set {
                                Line                    start;
                                Line                    end;
                                Line                    line;

                                start = document.ParagraphStart(document.selection_start.line);

                                end = document.ParagraphEnd(document.selection_end.line);

                                line = start;

                                while (true) {
                                        line.alignment = value;

                                        if (line == end) {
                                                break;
                                        }
                                        line = document.GetLine(line.line_no + 1);
                                }
                                this.CalculateDocument();
                        }
                }

                [Browsable(false)]
                [DefaultValue(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public bool SelectionBullet {
                        get {
                                return false;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DefaultValue(0)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public int SelectionCharOffset {
                        get {
                                return 0;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public Color SelectionColor {
                        get {
                                Color   color;
                                LineTag start;
                                LineTag end;
                                LineTag tag;

                                start = document.selection_start.tag;
                                end = document.selection_end.tag;
                                color = ((SolidBrush)document.selection_start.tag.color).Color;

                                tag = start;
                                while (true) {
                                        if (!color.Equals(((SolidBrush)tag.color).Color)) {
                                                return Color.Empty;
                                        }

                                        if (tag == end) {
                                                break;
                                        }

                                        tag = document.NextTag(tag);

                                        if (tag == null) {
                                                break;
                                        }
                                }

                                return color;
                        }

                        set {
                                FontDefinition  attributes;
                                int             sel_start;
                                int             sel_end;

                                attributes = new FontDefinition();
                                attributes.color = value;

                                sel_start = document.LineTagToCharIndex(document.selection_start.line, document.selection_start.pos);
                                sel_end = document.LineTagToCharIndex(document.selection_end.line, document.selection_end.pos);

                                document.FormatText(document.selection_start.line, document.selection_start.pos + 1, document.selection_end.line, document.selection_end.pos + 1, attributes);

                                document.CharIndexToLineTag(sel_start, out document.selection_start.line, out document.selection_start.tag, out document.selection_start.pos);
                                document.CharIndexToLineTag(sel_end, out document.selection_end.line, out document.selection_end.tag, out document.selection_end.pos);

                                document.UpdateView(document.selection_start.line, 0);
                                document.AlignCaret();
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public Font SelectionFont {
                        get {
                                Font    font;
                                LineTag start;
                                LineTag end;
                                LineTag tag;

                                start = document.selection_start.tag;
                                end = document.selection_end.tag;
                                font = document.selection_start.tag.font;

                                tag = start;
                                while (true) {
                                        if (!font.Equals(tag.font)) {
                                                return null;
                                        }

                                        if (tag == end) {
                                                break;
                                        }

                                        tag = document.NextTag(tag);

                                        if (tag == null) {
                                                break;
                                        }
                                }

                                return font;
                        }

                        set {
                                FontDefinition  attributes;
                                int             sel_start;
                                int             sel_end;

                                attributes = new FontDefinition();
                                attributes.font_obj = value;

                                sel_start = document.LineTagToCharIndex(document.selection_start.line, document.selection_start.pos);
                                sel_end = document.LineTagToCharIndex(document.selection_end.line, document.selection_end.pos);

                                document.FormatText(document.selection_start.line, document.selection_start.pos + 1, document.selection_end.line, document.selection_end.pos + 1, attributes);

                                document.CharIndexToLineTag(sel_start, out document.selection_start.line, out document.selection_start.tag, out document.selection_start.pos);
                                document.CharIndexToLineTag(sel_end, out document.selection_end.line, out document.selection_end.tag, out document.selection_end.pos);

                                document.UpdateView(document.selection_start.line, 0);
                                document.AlignCaret();

                        }
                }

                [Browsable(false)]
                [DefaultValue(0)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public int SelectionHangingIndent {
                        get {
                                return 0;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DefaultValue(0)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public int SelectionIndent {
                        get {
                                return 0;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public override int SelectionLength {
                        get {
                                return base.SelectionLength;
                        }

                        set {
                                base.SelectionLength = value;
                        }
                }

                [Browsable(false)]
                [DefaultValue(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public bool SelectionProtected {
                        get {
                                return false;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DefaultValue(0)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public int SelectionRightIndent {
                        get {
                                return 0;
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                [MonoTODO]
                public int[] SelectionTabs {
                        get {
                                return new int[0];
                        }

                        set {
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public RichTextBoxSelectionTypes SelectionType {
                        get {
                                if (document.selection_start == document.selection_end) {
                                        return RichTextBoxSelectionTypes.Empty;
                                }

                                // Lazy, but works
                                if (SelectedText.Length > 1) {
                                        return RichTextBoxSelectionTypes.MultiChar | RichTextBoxSelectionTypes.Text;
                                }

                                return RichTextBoxSelectionTypes.Text;
                        }
                }

                [DefaultValue(false)]
                [MonoTODO]
                public bool ShowSelectionMargin {
                        get {
                                return false;
                        }

                        set {
                        }
                }

                [Localizable(true)]
                public override string Text {
                        get {
                                return base.Text;
                        }

                        set {
                                base.Text = value;
                        }
                }

                [Browsable(false)]
                public override int TextLength {
                        get {
                                return base.TextLength;
                        }
                }

                [Browsable(false)]
                [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
                public string UndoActionName {
                        get {
                                return document.undo.UndoName;
                        }
                }

                [Localizable(true)]
                [DefaultValue(1)]
                public float ZoomFactor {
                        get {
                                return zoom;
                        }

                        set {
                                zoom = value;
                        }
                }
                #endregion      // Public Instance Properties

                #region Protected Instance Properties
                protected override CreateParams CreateParams {
                        get {
                                return base.CreateParams;
                        }
                }

                protected override Size DefaultSize {
                        get {
                                return new Size(100, 96);
                        }
                }
                #endregion      // Protected Instance Properties

                #region Public Instance Methods
                public bool CanPaste(DataFormats.Format clipFormat) {
                        if ((clipFormat.Name == DataFormats.Rtf) ||
                                (clipFormat.Name == DataFormats.Text) ||
                                (clipFormat.Name == DataFormats.UnicodeText)) {
                                        return true;
                        }
                        return false;
                }

                public int Find(char[] characterSet) {
                        return Find(characterSet, -1, -1);
                }

                public int Find(char[] characterSet, int start) {
                        return Find(characterSet, start, -1);
                }

                public int Find(char[] characterSet, int start, int end) {
                        Document.Marker start_mark;
                        Document.Marker end_mark;
                        Document.Marker result;

                        if (start == -1) {
                                document.GetMarker(out start_mark, true);
                        } else {
                                Line line;
                                LineTag tag;
                                int pos;

                                start_mark = new Document.Marker();

                                document.CharIndexToLineTag(start, out line, out tag, out pos);
                                start_mark.line = line;
                                start_mark.tag = tag;
                                start_mark.pos = pos;
                        }

                        if (end == -1) {
                                document.GetMarker(out end_mark, false);
                        } else {
                                Line line;
                                LineTag tag;
                                int pos;

                                end_mark = new Document.Marker();

                                document.CharIndexToLineTag(end, out line, out tag, out pos);
                                end_mark.line = line;
                                end_mark.tag = tag;
                                end_mark.pos = pos;
                        }

                        if (document.FindChars(characterSet, start_mark, end_mark, out result)) {
                                return document.LineTagToCharIndex(result.line, result.pos);
                        }

                        return -1;
                }

                public int Find(string str) {
                        return Find(str, -1, -1, RichTextBoxFinds.None);
                }

                public int Find(string str, int start, int end, RichTextBoxFinds options) {
                        Document.Marker start_mark;
                        Document.Marker end_mark;
                        Document.Marker result;

                        if (start == -1) {
                                document.GetMarker(out start_mark, true);
                        } else {
                                Line line;
                                LineTag tag;
                                int pos;

                                start_mark = new Document.Marker();

                                document.CharIndexToLineTag(start, out line, out tag, out pos);

                                start_mark.line = line;
                                start_mark.tag = tag;
                                start_mark.pos = pos;
                        }

                        if (end == -1) {
                                document.GetMarker(out end_mark, false);
                        } else {
                                Line line;
                                LineTag tag;
                                int pos;

                                end_mark = new Document.Marker();

                                document.CharIndexToLineTag(end, out line, out tag, out pos);

                                end_mark.line = line;
                                end_mark.tag = tag;
                                end_mark.pos = pos;
                        }

                        if (document.Find(str, start_mark, end_mark, out result, options)) {
                                return document.LineTagToCharIndex(result.line, result.pos);
                        }

                        return -1;
                }

                public int Find(string str, int start, RichTextBoxFinds options) {
                        return Find(str, start, -1, options);
                }

                public int Find(string str, RichTextBoxFinds options) {
                        return Find(str, -1, -1, options);
                }

                public char GetCharFromPosition(Point pt) {
                        LineTag tag;
                        int     pos;

                        PointToTagPos(pt, out tag, out pos);

                        if (pos >= tag.line.text.Length) {
                                return '\n';
                        }

                        return tag.line.text[pos];
                        
                }

                public int GetCharIndexFromPosition(Point pt) {
                        LineTag tag;
                        int     pos;

                        PointToTagPos(pt, out tag, out pos);

                        return document.LineTagToCharIndex(tag.line, pos);
                }

                public int GetLineFromCharIndex(int index) {
                        Line    line;
                        LineTag tag;
                        int     pos;

                        document.CharIndexToLineTag(index, out line, out tag, out pos);

                        return line.LineNo - 1;
                }

                public Point GetPositionFromCharIndex(int index) {
                        Line    line;
                        LineTag tag;
                        int     pos;

                        document.CharIndexToLineTag(index, out line, out tag, out pos);

                        return new Point((int)line.widths[pos] + 1, line.Y + 1);
                }

                public void LoadFile(System.IO.Stream data, RichTextBoxStreamType fileType) {
                        document.Empty();

                        // FIXME - ignoring unicode
                        if (fileType == RichTextBoxStreamType.PlainText) {
                                StringBuilder   sb;
                                int             count;
                                byte[]          buffer;

                                try {
                                        sb = new StringBuilder((int)data.Length);
                                        buffer = new byte[1024];
                                } catch {
                                        throw new IOException("Not enough memory to load document");
                                }

                                count = 0;
                                while (count < data.Length) {
                                        count += data.Read(buffer, count, 1024);
                                        sb.Append(buffer);
                                }
                                base.Text = sb.ToString();
                                return;
                        }

                        InsertRTFFromStream(data, 0, 1);

                        document.PositionCaret (document.GetLine (1), 0);
                        document.SetSelectionToCaret (true);
                        ScrollToCaret ();
                }

                [MonoTODO("Make smarter RTF detection?")]
                public void LoadFile(string path) {
                        if (path.EndsWith(".rtf")) {
                                LoadFile(path, RichTextBoxStreamType.RichText);
                        } else {
                                LoadFile(path, RichTextBoxStreamType.PlainText);
                        }
                }

                public void LoadFile(string path, RichTextBoxStreamType fileType) {
                        FileStream      data;

                        data = null;


                        try {
                                data = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, 1024);

                                LoadFile(data, fileType);
                        }
#if !DEBUG
                        catch {
                                throw new IOException("Could not open file " + path);
                        }
#endif
                        finally {
                                if (data != null) {
                                        data.Close();
                                }
                        }
                }

                public void Paste(DataFormats.Format clipFormat) {
                        base.Paste(Clipboard.GetDataObject(), clipFormat, false);
                }

                [MonoTODO()]
                public void Redo() {
                }

                public void SaveFile(Stream data, RichTextBoxStreamType fileType) {
                        Encoding        encoding;
                        int             i;
                        Byte[]          bytes;


                        if (fileType == RichTextBoxStreamType.UnicodePlainText) {
                                encoding = Encoding.Unicode;
                        } else {
                                encoding = Encoding.ASCII;
                        }

                        switch(fileType) {
                                case RichTextBoxStreamType.PlainText: 
                                case RichTextBoxStreamType.TextTextOleObjs: 
                                case RichTextBoxStreamType.UnicodePlainText: {
                                        if (!multiline) {
                                                bytes = encoding.GetBytes(document.Root.text.ToString());
                                                data.Write(bytes, 0, bytes.Length);
                                                return;
                                        }

                                        for (i = 1; i < document.Lines; i++) {
                                                bytes = encoding.GetBytes(document.GetLine(i).text.ToString() + Environment.NewLine);
                                                data.Write(bytes, 0, bytes.Length);
                                        }
                                        bytes = encoding.GetBytes(document.GetLine(document.Lines).text.ToString());
                                        data.Write(bytes, 0, bytes.Length);
                                        return;
                                }
                        }

                        // If we're here we're saving RTF
                        Line            start_line;
                        Line            end_line;
                        StringBuilder   rtf;
                        int             current;
                        int             total;

                        start_line = document.GetLine(1);
                        end_line = document.GetLine(document.Lines);
                        rtf = GenerateRTF(start_line, 0, end_line, end_line.text.Length);
                        total = rtf.Length;
                        bytes = new Byte[4096];

                        // Let's chunk it so we don't use up all memory...
                        for (i = 0; i < total; i += 1024) {
                                if ((i + 1024) < total) {
                                        current = encoding.GetBytes(rtf.ToString(i, 1024), 0, 1024, bytes, 0);
                                } else {
                                        current = total - i;
                                        current = encoding.GetBytes(rtf.ToString(i, current), 0, current, bytes, 0);
                                }
                                data.Write(bytes, 0, current);
                        }
                }

                public void SaveFile(string path) {
                        if (path.EndsWith(".rtf")) {
                                SaveFile(path, RichTextBoxStreamType.RichText);
                        } else {
                                SaveFile(path, RichTextBoxStreamType.PlainText);
                        }
                }

                public void SaveFile(string path, RichTextBoxStreamType fileType) {
                        FileStream      data;

                        data = null;

//                      try {
                                data = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None, 1024, false);
                                SaveFile(data, fileType);
//                      }

//                      catch {
//                              throw new IOException("Could not write document to file " + path);
//                      }

//                      finally {
                                if (data != null) {
                                        data.Close();
                                }
//                      }
                }

                #endregion      // Public Instance Methods

                #region Protected Instance Methods
                protected virtual object CreateRichEditOleCallback() {
                        throw new NotImplementedException();
                }

                protected override void OnBackColorChanged(EventArgs e) {
                        base.OnBackColorChanged (e);
                }

                protected virtual void OnContentsResized(ContentsResizedEventArgs e) {
                        ContentsResizedEventHandler eh = (ContentsResizedEventHandler)(Events [ContentsResizedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override void OnContextMenuChanged(EventArgs e) {
                        base.OnContextMenuChanged (e);
                }

                protected override void OnHandleCreated(EventArgs e) {
                        base.OnHandleCreated (e);
                }

                protected override void OnHandleDestroyed(EventArgs e) {
                        base.OnHandleDestroyed (e);
                }

                protected virtual void OnHScroll(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [HScrollEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                [MonoTODO("Determine when to call this")]
                protected virtual void OnImeChange(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [ImeChangeEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnLinkClicked(LinkClickedEventArgs e) {
                        LinkClickedEventHandler eh = (LinkClickedEventHandler)(Events [LinkClickedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected virtual void OnProtected(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [ProtectedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override void OnRightToLeftChanged(EventArgs e) {
                        base.OnRightToLeftChanged (e);
                }

                protected virtual void OnSelectionChanged(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [SelectionChangedEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override void OnSystemColorsChanged(EventArgs e) {
                        base.OnSystemColorsChanged (e);
                }

                protected override void OnTextChanged(EventArgs e) {
                        base.OnTextChanged (e);
                }

                protected virtual void OnVScroll(EventArgs e) {
                        EventHandler eh = (EventHandler)(Events [VScrollEvent]);
                        if (eh != null)
                                eh (this, e);
                }

                protected override void WndProc(ref Message m) {
                        base.WndProc (ref m);
                }
                #endregion      // Protected Instance Methods

                #region Events
                static object ContentsResizedEvent = new object ();
                static object HScrollEvent = new object ();
                static object ImeChangeEvent = new object ();
                static object LinkClickedEvent = new object ();
                static object ProtectedEvent = new object ();
                static object SelectionChangedEvent = new object ();
                static object VScrollEvent = new object ();

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event EventHandler BackgroundImageChanged {
                        add { base.BackgroundImageChanged += value; }
                        remove { base.BackgroundImageChanged -= value; }
                }

                public event ContentsResizedEventHandler ContentsResized {
                        add { Events.AddHandler (ContentsResizedEvent, value); }
                        remove { Events.RemoveHandler (ContentsResizedEvent, value); }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event EventHandler DoubleClick {
                        add { base.DoubleClick += value; }
                        remove { base.DoubleClick -= value; }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event DragEventHandler DragDrop {
                        add { base.DragDrop += value; }
                        remove { base.DragDrop -= value; }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event DragEventHandler DragEnter {
                        add { base.DragEnter += value; }
                        remove { base.DragEnter -= value; }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event EventHandler DragLeave {
                        add { base.DragLeave += value; }
                        remove { base.DragLeave -= value; }
                }


                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event DragEventHandler DragOver {
                        add { base.DragOver += value; }
                        remove { base.DragOver -= value; }
                }


                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event GiveFeedbackEventHandler GiveFeedback {
                        add { base.GiveFeedback += value; }
                        remove { base.GiveFeedback -= value; }
                }

                public event EventHandler HScroll {
                        add { Events.AddHandler (HScrollEvent, value); }
                        remove { Events.RemoveHandler (HScrollEvent, value); }
                }

                public event EventHandler ImeChange {
                        add { Events.AddHandler (ImeChangeEvent, value); }
                        remove { Events.RemoveHandler (ImeChangeEvent, value); }
                }

                public event LinkClickedEventHandler LinkClicked {
                        add { Events.AddHandler (LinkClickedEvent, value); }
                        remove { Events.RemoveHandler (LinkClickedEvent, value); }
                }

                public event EventHandler Protected {
                        add { Events.AddHandler (ProtectedEvent, value); }
                        remove { Events.RemoveHandler (ProtectedEvent, value); }
                }

                [Browsable(false)]
                [EditorBrowsable(EditorBrowsableState.Never)]
                public new event QueryContinueDragEventHandler QueryContinueDrag {
                        add { base.QueryContinueDrag += value; }
                        remove { base.QueryContinueDrag -= value; }
                }

                public event EventHandler SelectionChanged {
                        add { Events.AddHandler (SelectionChangedEvent, value); }
                        remove { Events.RemoveHandler (SelectionChangedEvent, value); }
                }

                public event EventHandler VScroll {
                        add { Events.AddHandler (VScrollEvent, value); }
                        remove { Events.RemoveHandler (VScrollEvent, value); }
                }
                #endregion      // Events

                #region Private Methods

                internal override void SelectWord ()
                {
                        document.ExpandSelection(CaretSelection.Word, false);
                }

                private void HandleControl(RTF.RTF rtf) {
//                      Console.WriteLine ("HANDLING MAJOR:  {0}      MINOR:  {1}", rtf.Major, rtf.Minor);
                        switch(rtf.Major) {
                                case RTF.Major.Unicode: {
                                        switch(rtf.Minor) {
                                                case Minor.UnicodeCharBytes: {
                                                        rtf_skip_width = rtf.Param;
                                                        break;
                                                }

                                                case Minor.UnicodeChar: {
                                                        rtf_skip_count += rtf_skip_width;
                                                        rtf_line.Append((char)rtf.Param);
                                                        break;
                                                }
                                        }
                                        break;
                                }

                                case RTF.Major.Destination: {
//                                      Console.Write("[Got Destination control {0}]", rtf.Minor);
                                        rtf.SkipGroup();
                                        break;
                                }

                                case RTF.Major.CharAttr: {
                                        switch(rtf.Minor) {
                                                case Minor.ForeColor: {
                                                        System.Windows.Forms.RTF.Color  color;

                                                        color = System.Windows.Forms.RTF.Color.GetColor(rtf, rtf.Param);
                                                        
                                                        if (color != null) {
                                                                FlushText(rtf, false);
                                                                if (color.Red == -1 && color.Green == -1 && color.Blue == -1) {
                                                                        this.rtf_color = new SolidBrush(ForeColor);
                                                                } else {
                                                                        this.rtf_color = new SolidBrush(Color.FromArgb(color.Red, color.Green, color.Blue));
                                                                }
                                                                FlushText (rtf, false);
                                                        }
                                                        break;
                                                }

                                                case Minor.FontSize: {
                                                        FlushText(rtf, false);
                                                        this.rtf_rtffont_size = rtf.Param / 2;
                                                        break;
                                                }

                                                case Minor.FontNum: {
                                                        System.Windows.Forms.RTF.Font   font;

                                                        font = System.Windows.Forms.RTF.Font.GetFont(rtf, rtf.Param);
                                                        if (font != null) {
                                                                FlushText(rtf, false);
                                                                this.rtf_rtffont = font;
                                                        }
                                                        break;
                                                }

                                                case Minor.Plain: {
                                                        FlushText(rtf, false);
                                                        rtf_rtfstyle = FontStyle.Regular;
                                                        break;
                                                }

                                                case Minor.Bold: {
                                                        FlushText(rtf, false);
                                                        if (rtf.Param == RTF.RTF.NoParam) {
                                                                rtf_rtfstyle |= FontStyle.Bold;
                                                        } else {
                                                                rtf_rtfstyle &= ~FontStyle.Bold;
                                                        }
                                                        break;
                                                }

                                                case Minor.Italic: {
                                                        FlushText(rtf, false);
                                                        if (rtf.Param == RTF.RTF.NoParam) {
                                                                rtf_rtfstyle |= FontStyle.Italic;
                                                        } else {
                                                                rtf_rtfstyle &= ~FontStyle.Italic;
                                                        }
                                                        break;
                                                }

                                                case Minor.StrikeThru: {
                                                        FlushText(rtf, false);
                                                        if (rtf.Param == RTF.RTF.NoParam) {
                                                                rtf_rtfstyle |= FontStyle.Strikeout;
                                                        } else {
                                                                rtf_rtfstyle &= ~FontStyle.Strikeout;
                                                        }
                                                        break;
                                                }

                                                case Minor.Underline: {
                                                        FlushText(rtf, false);
                                                        if (rtf.Param == RTF.RTF.NoParam) {
                                                                rtf_rtfstyle |= FontStyle.Underline;
                                                        } else {
                                                                rtf_rtfstyle = rtf_rtfstyle & ~FontStyle.Underline;
                                                        }
                                                        break;
                                                }

                                                case Minor.NoUnderline: {
                                                        FlushText(rtf, false);
                                                        rtf_rtfstyle &= ~FontStyle.Underline;
                                                        break;
                                                }
                                        }
                                        break;
                                }

                                case RTF.Major.SpecialChar: {
                                        //Console.Write("[Got SpecialChar control {0}]", rtf.Minor);
                                        SpecialChar(rtf);
                                        break;
                                }
                        }
                }

                private void SpecialChar(RTF.RTF rtf) {
                        switch(rtf.Minor) {
                                case Minor.Page:
                                case Minor.Sect:
                                case Minor.Row:
                                case Minor.Line:
                                case Minor.Par: {
                                        FlushText(rtf, true);
                                        break;
                                }

                                case Minor.Cell: {
                                        Console.Write(" ");
                                        break;
                                }

                                case Minor.NoBrkSpace: {
                                        Console.Write(" ");
                                        break;
                                }

                                case Minor.Tab: {
                                        rtf_line.Append ("\t");
//                                      FlushText (rtf, false);
                                        break;
                                }

                                case Minor.NoReqHyphen:
                                case Minor.NoBrkHyphen: {
                                        rtf_line.Append ("-");
//                                      FlushText (rtf, false);
                                        break;
                                }

                                case Minor.Bullet: {
                                        Console.WriteLine("*");
                                        break;
                                }

                        case Minor.WidowCtrl:
                                break;

                                case Minor.EmDash: {
                                rtf_line.Append ("\u2014");
                                        break;
                                }

                                case Minor.EnDash: {
                                        rtf_line.Append ("\u2013");
                                        break;
                                }
/*
                                case Minor.LQuote: {
                                        Console.Write("\u2018");
                                        break;
                                }

                                case Minor.RQuote: {
                                        Console.Write("\u2019");
                                        break;
                                }

                                case Minor.LDblQuote: {
                                        Console.Write("\u201C");
                                        break;
                                }

                                case Minor.RDblQuote: {
                                        Console.Write("\u201D");
                                        break;
                                }
*/
                                default: {
//                                      Console.WriteLine ("skipped special char:   {0}", rtf.Minor);
//                                      rtf.SkipGroup();
                                        break;
                                }
                        }
                }

                private void HandleText(RTF.RTF rtf) {
                        if (rtf_skip_count > 0) {
                                rtf_skip_count--;
                                return;
                        }

                        if ((RTF.StandardCharCode)rtf.Minor != RTF.StandardCharCode.nothing) {
                                rtf_line.Append(rtf_text_map[(RTF.StandardCharCode)rtf.Minor]);
                        } else {
                                if ((int)rtf.Major > 31 && (int)rtf.Major < 128) {
                                        rtf_line.Append((char)rtf.Major);
                                } else {
                                        //rtf_line.Append((char)rtf.Major);
                                        Console.Write("[Literal:0x{0:X2}]", (int)rtf.Major);
                                }
                        }
                }

                private void FlushText(RTF.RTF rtf, bool newline) {
                        int             length;
                        Font            font;

                        length = rtf_line.Length;
                        if (!newline && (length == 0)) {
                                return;
                        }

                        if (rtf_rtffont == null) {
                                // First font in table is default
                                rtf_rtffont = System.Windows.Forms.RTF.Font.GetFont(rtf, 0);
                        }

                        font = new Font(rtf_rtffont.Name, rtf_rtffont_size, rtf_rtfstyle);

                        if (rtf_color == null) {
                                System.Windows.Forms.RTF.Color color;

                                // First color in table is default
                                color = System.Windows.Forms.RTF.Color.GetColor(rtf, 0);

                                if ((color == null) || (color.Red == -1 && color.Green == -1 && color.Blue == -1)) {
                                        rtf_color = new SolidBrush(ForeColor);
                                } else {
                                        rtf_color = new SolidBrush(Color.FromArgb(color.Red, color.Green, color.Blue));
                                }
                                
                        }

                        rtf_chars += rtf_line.Length;

                        if (rtf_cursor_x == 0) {
                                document.Add(rtf_cursor_y, rtf_line.ToString(), rtf_rtfalign, font, rtf_color);
                        } else {
                                Line    line;

                                line = document.GetLine(rtf_cursor_y);
                                if (rtf_line.Length > 0) {
                                        document.InsertString(line, rtf_cursor_x, rtf_line.ToString());
                                        document.FormatText(line, rtf_cursor_x + 1, line, rtf_cursor_x + 1 + length, font, rtf_color, null, FormatSpecified.Font | FormatSpecified.Color); // FormatText is 1-based
                                }
                                if (newline) {
                                        document.Split(line, rtf_cursor_x + length);
                                }
                        }

                        if (newline) {
                                rtf_cursor_x = 0;
                                rtf_cursor_y++;
                        } else {
                                rtf_cursor_x += length;
                        }
                        rtf_line.Length = 0;    // Empty line
                }

                private void InsertRTFFromStream(Stream data, int cursor_x, int cursor_y) {
                        int     x;
                        int     y;
                        int     chars;

                        InsertRTFFromStream(data, cursor_x, cursor_y, out x, out y, out chars);
                }

                private void InsertRTFFromStream(Stream data, int cursor_x, int cursor_y, out int to_x, out int to_y, out int chars) {
                        RTF.RTF         rtf;

                        rtf = new RTF.RTF(data);

                        // Prepare
                        rtf.ClassCallback[RTF.TokenClass.Text] = new RTF.ClassDelegate(HandleText);
                        rtf.ClassCallback[RTF.TokenClass.Control] = new RTF.ClassDelegate(HandleControl);

                        rtf_skip_width = 0;
                        rtf_skip_count = 0;
                        rtf_line = new StringBuilder();
                        rtf_color = null;
                        rtf_rtffont_size = (int)this.Font.Size;
                        rtf_rtfalign = HorizontalAlignment.Left;
                        rtf_rtfstyle = FontStyle.Regular;
                        rtf_rtffont = null;
                        rtf_cursor_x = cursor_x;
                        rtf_cursor_y = cursor_y;
                        rtf_chars = 0;
                        rtf.DefaultFont(this.Font.Name);

                        rtf_text_map = new RTF.TextMap();
                        RTF.TextMap.SetupStandardTable(rtf_text_map.Table);

                        document.SuspendRecalc ();

                        try {
                                rtf.Read();     // That's it
                                FlushText(rtf, false);

                        }


                        catch (RTF.RTFException e) {
#if DEBUG
                                throw e;
#endif
                                // Seems to be plain text or broken RTF
                                Console.WriteLine("RTF Parsing failure: {0}", e.Message);
                        }                     

                        to_x = rtf_cursor_x;
                        to_y = rtf_cursor_y;
                        chars = rtf_chars;

                        document.RecalculateDocument(CreateGraphicsInternal(), cursor_y, document.Lines, false);
                        document.ResumeRecalc (true);

                        document.Invalidate (document.GetLine(cursor_y), 0, document.GetLine(document.Lines), -1);
                }

                private void RichTextBox_HScrolled(object sender, EventArgs e) {
                        OnHScroll(e);
                }

                private void RichTextBox_VScrolled(object sender, EventArgs e) {
                        OnVScroll(e);
                }

                private void PointToTagPos(Point pt, out LineTag tag, out int pos) {
                        Point p;

                        p = pt;

                        if (p.X >= document.ViewPortWidth) {
                                p.X = document.ViewPortWidth - 1;
                        } else if (p.X < 0) {
                                p.X = 0;
                        }

                        if (p.Y >= document.ViewPortHeight) {
                                p.Y = document.ViewPortHeight - 1;
                        } else if (p.Y < 0) {
                                p.Y = 0;
                        }

                        tag = document.FindCursor(p.X + document.ViewPortX, p.Y + document.ViewPortY, out pos);
                }

                private void EmitRTFFontProperties(StringBuilder rtf, int prev_index, int font_index, Font prev_font, Font font) {
                        if (prev_index != font_index) {
                                rtf.Append(String.Format("\\f{0}", font_index));        // Font table entry
                        }

                        if ((prev_font == null) || (prev_font.Size != font.Size)) {
                                rtf.Append(String.Format("\\fs{0}", (int)(font.Size * 2)));             // Font size
                        }

                        if ((prev_font == null) || (font.Bold != prev_font.Bold)) {
                                if (font.Bold) {
                                        rtf.Append("\\b");
                                } else {
                                        if (prev_font != null) {
                                                rtf.Append("\\b0");
                                        }
                                }
                        }

                        if ((prev_font == null) || (font.Italic != prev_font.Italic)) {
                                if (font.Italic) {
                                        rtf.Append("\\i");
                                } else {
                                        if (prev_font != null) {
                                                rtf.Append("\\i0");
                                        }
                                }
                        }

                        if ((prev_font == null) || (font.Strikeout != prev_font.Strikeout)) {
                                if (font.Strikeout) {
                                        rtf.Append("\\strike");
                                } else {
                                        if (prev_font != null) {
                                                rtf.Append("\\strike0");
                                        }
                                }
                        }

                        if ((prev_font == null) || (font.Underline != prev_font.Underline)) {
                                if (font.Underline) {
                                        rtf.Append("\\ul");
                                } else {
                                        if (prev_font != null) {
                                                rtf.Append("\\ul0");
                                        }
                                }
                        }
                }

                [MonoTODO("Emit unicode and other special characters properly")]
                private void EmitRTFText(StringBuilder rtf, string text) {
                        rtf.Append(text);
                }

                // start_pos and end_pos are 0-based
                private StringBuilder GenerateRTF(Line start_line, int start_pos, Line end_line, int end_pos) {
                        StringBuilder   sb;
                        ArrayList       fonts;
                        ArrayList       colors;
                        Color           color;
                        Font            font;
                        Line            line;
                        LineTag         tag;
                        int             pos;
                        int             line_no;
                        int             line_len;
                        int             i;
                        int             length;

                        sb = new StringBuilder();
                        fonts = new ArrayList(10);
                        colors = new ArrayList(10);

                        // Two runs, first we parse to determine tables;
                        // and unlike most of our processing here we work on tags

                        line = start_line;
                        line_no = start_line.line_no;
                        pos = start_pos;

                        // Add default font and color; to optimize document content we don't
                        // use this.Font and this.ForeColor but the font/color from the first tag
                        tag = LineTag.FindTag(start_line, pos);
                        font = tag.font;
                        color = ((SolidBrush)tag.color).Color;
                        fonts.Add(font.Name);
                        colors.Add(color);

                        while (line_no <= end_line.line_no) {
                                line = document.GetLine(line_no);
                                tag = LineTag.FindTag(line, pos);

                                if (line_no != end_line.line_no) {
                                        line_len = line.text.Length;
                                } else {
                                        line_len = end_pos;
                                }

                                while (pos < line_len) {
                                        if (tag.font.Name != font.Name) {
                                                font = tag.font;
                                                if (!fonts.Contains(font.Name)) {
                                                        fonts.Add(font.Name);
                                                }
                                        }

                                        if (((SolidBrush)tag.color).Color != color) {
                                                color = ((SolidBrush)tag.color).Color;
                                                if (!colors.Contains(color)) {
                                                        colors.Add(color);
                                                }
                                        }

                                        pos = tag.start + tag.length - 1;
                                        tag = tag.next;
                                }
                                pos = 0;
                                line_no++;
                        }

                        // We have the tables, emit the header
                        sb.Append("{\\rtf1\\ansi");
                        sb.Append("\\ansicpg1252");     // FIXME - is this correct?

                        // Default Font
                        sb.Append(String.Format("\\deff{0}", fonts.IndexOf(this.Font.Name)));

                        // Default Language 
                        sb.Append("\\deflang1033\n");   // FIXME - always 1033?

                        // Emit the font table
                        sb.Append("{\\fonttbl");
                        for (i = 0; i < fonts.Count; i++) {
                                sb.Append(String.Format("{{\\f{0}", i));        // {Font 
                                sb.Append("\\fnil");                    // Family
                                sb.Append("\\fcharset0 ");              // Charset ANSI<space>
                                sb.Append((string)fonts[i]);            // Font name
                                sb.Append(";}");                        // }
                        }
                        sb.Append("}\n");

                        // Emit the color table (if needed)
                        if ((colors.Count > 1) || ((((Color)colors[0]).R != this.ForeColor.R) || (((Color)colors[0]).G != this.ForeColor.G) || (((Color)colors[0]).B != this.ForeColor.B))) {
                                sb.Append("{\\colortbl ");                      // Header and NO! default color
                                for (i = 0; i < colors.Count; i++) {
                                        sb.Append(String.Format("\\red{0}", ((Color)colors[i]).R));
                                        sb.Append(String.Format("\\green{0}", ((Color)colors[i]).G));
                                        sb.Append(String.Format("\\blue{0}", ((Color)colors[i]).B));
                                        sb.Append(";");
                                }
                                sb.Append("}\n");
                        }

                        sb.Append("{\\*\\generator Mono RichTextBox;}");
                        // Emit initial paragraph settings
                        tag = LineTag.FindTag(start_line, start_pos);
                        sb.Append("\\pard");    // Reset to default paragraph properties
                        EmitRTFFontProperties(sb, -1, fonts.IndexOf(tag.font.Name), null, tag.font);    // Font properties
                        sb.Append(" ");         // Space separator

                        font = tag.font;
                        color = (Color)colors[0];
                        line = start_line;
                        line_no = start_line.line_no;
                        pos = start_pos;

                        while (line_no <= end_line.line_no) {
                                line = document.GetLine(line_no);
                                tag = LineTag.FindTag(line, pos);

                                if (line_no != end_line.line_no) {
                                        line_len = line.text.Length;
                                } else {
                                        line_len = end_pos;
                                }

                                while (pos < line_len) {
                                        length = sb.Length;

                                        if (tag.font != font) {
                                                EmitRTFFontProperties(sb, fonts.IndexOf(font.Name), fonts.IndexOf(tag.font.Name), font, tag.font);
                                                font = tag.font;
                                        }

                                        if (((SolidBrush)tag.color).Color != color) {
                                                color = ((SolidBrush)tag.color).Color;
                                                sb.Append(String.Format("\\cf{0}", colors.IndexOf(color)));
                                        }
                                        if (length != sb.Length) {
                                                sb.Append(" "); // Emit space to separate keywords from text
                                        }

                                        // Emit the string itself
                                        if (line_no != end_line.line_no) {
                                                EmitRTFText(sb, tag.line.text.ToString(pos, tag.start + tag.length - pos - 1));
                                        } else {
                                                if (end_pos < (tag.start + tag.length - 1)) {
                                                        // Emit partial tag only, end_pos is inside this tag
                                                        EmitRTFText(sb, tag.line.text.ToString(pos, end_pos - pos));
                                                } else {
                                                        EmitRTFText(sb, tag.line.text.ToString(pos, tag.start + tag.length - pos - 1));
                                                }
                                        }

                                        pos = tag.start + tag.length - 1;
                                        tag = tag.next;
                                }
                                if (pos >= line.text.Length) {
                                        if (!line.soft_break) {
                                                sb.Append("\\par\n");
                                        }
                                }
                                pos = 0;
                                line_no++;
                        }

                        sb.Append("}\n");

                        return sb;
                }
                #endregion      // Private Methods
        }
}