namespace Khendys.Controls {

#region Public Enums

// Enum for possible RTF colors public enum RtfColor { Black, Maroon, Green, Olive, Navy, Purple, Teal, Gray, Silver, Red, Lime, Yellow, Blue, Fuchsia, Aqua, White }

#endregion

public class ExRichTextBox : System.Windows.Forms.RichTextBox {

#region My Enums

// Specifies the flags/options for the unmanaged call to the GDI+ method // Metafile.EmfToWmfBits(). private enum EmfToWmfBitsFlags {

// Use the default conversion EmfToWmfBitsFlagsDefault = 0x00000000,

// Embedded the source of the EMF metafiel within the resulting WMF // metafile EmfToWmfBitsFlagsEmbedEmf = 0x00000001,

// Place a 22-byte header in the resulting WMF file. The header is // required for the metafile to be considered placeable. EmfToWmfBitsFlagsIncludePlaceable = 0x00000002,

// Don't simulate clipping by using the XOR operator. EmfToWmfBitsFlagsNoXORClip = 0x00000004 };

#endregion

#region My Structs

// Definitions for colors in an RTF document private struct RtfColorDef { public const string Black = @"\red0\green0\blue0"; public const string Maroon = @"\red128\green0\blue0"; public const string Green = @"\red0\green128\blue0"; public const string Olive = @"\red128\green128\blue0"; public const string Navy = @"\red0\green0\blue128"; public const string Purple = @"\red128\green0\blue128"; public const string Teal = @"\red0\green128\blue128"; public const string Gray = @"\red128\green128\blue128"; public const string Silver = @"\red192\green192\blue192"; public const string Red = @"\red255\green0\blue0"; public const string Lime = @"\red0\green255\blue0"; public const string Yellow = @"\red255\green255\blue0"; public const string Blue = @"\red0\green0\blue255"; public const string Fuchsia = @"\red255\green0\blue255"; public const string Aqua = @"\red0\green255\blue255"; public const string White = @"\red255\green255\blue255"; }

// Control words for RTF font families private struct RtfFontFamilyDef { public const string Unknown = @"\fnil"; public const string Roman = @"\froman"; public const string Swiss = @"\fswiss"; public const string Modern = @"\fmodern"; public const string Script = @"\fscript"; public const string Decor = @"\fdecor"; public const string Technical = @"\ftech"; public const string BiDirect = @"\fbidi"; }

#endregion

#region My Constants

// Not used in this application. Descriptions can be found with documentation // of Windows GDI function SetMapMode private const int MM_TEXT = 1; private const int MM_LOMETRIC = 2; private const int MM_HIMETRIC = 3; private const int MM_LOENGLISH = 4; private const int MM_HIENGLISH = 5; private const int MM_TWIPS = 6;

// Ensures that the metafile maintains a 1:1 aspect ratio private const int MM_ISOTROPIC = 7;

// Allows the x-coordinates and y-coordinates of the metafile to be adjusted // independently private const int MM_ANISOTROPIC = 8;

// Represents an unknown font family private const string FF_UNKNOWN = "UNKNOWN";

// The number of hundredths of millimeters (0.01 mm) in an inch // For more information, see GetImagePrefix() method. private const int HMM_PER_INCH = 2540;

// The number of twips in an inch // For more information, see GetImagePrefix() method. private const int TWIPS_PER_INCH = 1440;

#endregion

#region My Privates

// The default text color private RtfColor textColor;

// The default text background color private RtfColor highlightColor;

// Dictionary that maps color enums to RTF color codes private HybridDictionary rtfColor;

// Dictionary that mapas Framework font families to RTF font families private HybridDictionary rtfFontFamily;

// The horizontal resolution at which the control is being displayed private float xDpi;

// The vertical resolution at which the control is being displayed private float yDpi;

#endregion

#region Elements required to create an RTF document /* RTF HEADER * ---------- * * \rtf[N] - For text to be considered to be RTF, it must be enclosed in this tag. * rtf1 is used because the RichTextBox conforms to RTF Specification * version 1. * \ansi - The character set. * \ansicpg[N] - Specifies that unicode characters might be embedded. ansicpg1252 * is the default used by Windows. * \deff[N] - The default font. \deff0 means the default font is the first font * found. * \deflang[N] - The default language. \deflang1033 specifies US English. * */ private const string RTF_HEADER = @"{\rtf1\ansi\ansicpg1252\deff0\deflang1033";

/* RTF DOCUMENT AREA * ----------------- * * \viewkind[N] - The type of view or zoom level. \viewkind4 specifies normal view. * \uc[N] - The number of bytes corresponding to a Unicode character. * \pard - Resets to default paragraph properties * \cf[N] - Foreground color. \cf1 refers to the color at index 1 in * the color table * \f[N] - Font number. \f0 refers to the font at index 0 in the font * table. * \fs[N] - Font size in half-points. * */ private const string RTF_DOCUMENT_PRE = @"\viewkind4\uc1\pard\cf1\f0\fs20"; private const string RTF_DOCUMENT_POST = @"\cf0\fs17}"; private string RTF_IMAGE_POST = @"}";

#endregion

#region Accessors

// TOD This can be ommitted along with RemoveBadCharacters // Overrides the default implementation of RTF. This is done because the control // was originally developed to run in an instant messenger that uses the // Jabber XML-based protocol. The framework would throw an exception when the // XML contained the null character, so I filtered out. public new string Rtf { get {return RemoveBadChars(base.Rtf);} set {base.Rtf = value;} }

// The color of the text public RtfColor TextColor { get {return textColor;} set {textColor = value;} }

// The color of the highlight public RtfColor HiglightColor { get {return highlightColor;} set {highlightColor = value;} }

#endregion

#region Constructors

/// <summary> /// Initializes the text colors, creates dictionaries for RTF colors and /// font families, and stores the horizontal and vertical resolution of /// the RichTextBox's graphics context. /// </summary> public ExRichTextBox() : base() {

// Initialize default text and background colors textColor = RtfColor.Black; highlightColor = RtfColor.White;

// Initialize the dictionary mapping color codes to definitions rtfColor = new HybridDictionary(); rtfColor.Add(RtfColor.Aqua, RtfColorDef.Aqua); rtfColor.Add(RtfColor.Black, RtfColorDef.Black); rtfColor.Add(RtfColor.Blue, RtfColorDef.Blue); rtfColor.Add(RtfColor.Fuchsia, RtfColorDef.Fuchsia); rtfColor.Add(RtfColor.Gray, RtfColorDef.Gray); rtfColor.Add(RtfColor.Green, RtfColorDef.Green); rtfColor.Add(RtfColor.Lime, RtfColorDef.Lime); rtfColor.Add(RtfColor.Maroon, RtfColorDef.Maroon); rtfColor.Add(RtfColor.Navy, RtfColorDef.Navy); rtfColor.Add(RtfColor.Olive, RtfColorDef.Olive); rtfColor.Add(RtfColor.Purple, RtfColorDef.Purple); rtfColor.Add(RtfColor.Red, RtfColorDef.Red); rtfColor.Add(RtfColor.Silver, RtfColorDef.Silver); rtfColor.Add(RtfColor.Teal, RtfColorDef.Teal); rtfColor.Add(RtfColor.White, RtfColorDef.White); rtfColor.Add(RtfColor.Yellow, RtfColorDef.Yellow);

// Initialize the dictionary mapping default Framework font families to // RTF font families rtfFontFamily = new HybridDictionary(); rtfFontFamily.Add(FontFamily.GenericMonospace.Name, RtfFontFamilyDef.Modern); rtfFontFamily.Add(FontFamily.GenericSansSerif, RtfFontFamilyDef.Swiss); rtfFontFamily.Add(FontFamily.GenericSerif, RtfFontFamilyDef.Roman); rtfFontFamily.Add(FF_UNKNOWN, RtfFontFamilyDef.Unknown);

// Get the horizontal and vertical resolutions at which the object is // being displayed using(Graphics _graphics = this.CreateGraphics()) { xDpi = _graphics.DpiX; yDpi = _graphics.DpiY; } }

/// <summary> /// Calls the default constructor then sets the text color. /// </summary> /// <param name="_textColor"></param> public ExRichTextBox(RtfColor _textColor) : this() { textColor = _textColor; }

/// <summary> /// Calls the default constructor then sets te text and highlight colors. /// </summary> /// <param name="_textColor"></param> /// <param name="_highlightColor"></param> public ExRichTextBox(RtfColor _textColor, RtfColor _highlightColor) : this() { textColor = _textColor; highlightColor = _highlightColor; }

#endregion

#region Append RTF or Text to RichTextBox Contents

/// <summary> /// Assumes the string passed as a paramter is valid RTF text and attempts /// to append it as RTF to the content of the control. /// </summary> /// <param name="_rtf"></param> public void AppendRtf(string _rtf) {

// Move caret to the end of the text this.Select(this.TextLength, 0);

// Since SelectedRtf is null, this will append the string to the // end of the existing RTF this.SelectedRtf = _rtf; }

/// <summary> /// Assumes that the string passed as a parameter is valid RTF text and /// attempts to insert it as RTF into the content of the control. /// </summary> /// <remarks> /// NOTE: The text is inserted wherever the caret is at the time of the call, /// and if any text is selected, that text is replaced. /// </remarks> /// <param name="_rtf"></param> public void InsertRtf(string _rtf) { this.SelectedRtf = _rtf; }

/// <summary> /// Appends the text using the current font, text, and highlight colors. /// </summary> /// <param name="_text"></param> public void AppendTextAsRtf(string _text) { AppendTextAsRtf(_text, this.Font); }

/// <summary> /// Appends the text using the given font, and current text and highlight /// colors. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> public void AppendTextAsRtf(string _text, Font _font) { AppendTextAsRtf(_text, _font, textColor); } /// <summary> /// Appends the text using the given font and text color, and the current /// highlight color. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> /// <param name="_color"></param> public void AppendTextAsRtf(string _text, Font _font, RtfColor _textColor) { AppendTextAsRtf(_text, _font, _textColor, highlightColor); }

/// <summary> /// Appends the text using the given font, text, and highlight colors. Simply /// moves the caret to the end of the RichTextBox's text and makes a call to /// insert. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> /// <param name="_textColor"></param> /// <param name="_backColor"></param> public void AppendTextAsRtf(string _text, Font _font, RtfColor _textColor, RtfColor _backColor) { // Move carret to the end of the text this.Select(this.TextLength, 0);

InsertTextAsRtf(_text, _font, _textColor, _backColor); }

#endregion

#region Insert Plain Text

/// <summary> /// Inserts the text using the current font, text, and highlight colors. /// </summary> /// <param name="_text"></param> public void InsertTextAsRtf(string _text) { InsertTextAsRtf(_text, this.Font); }

/// <summary> /// Inserts the text using the given font, and current text and highlight /// colors. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> public void InsertTextAsRtf(string _text, Font _font) { InsertTextAsRtf(_text, _font, textColor); } /// <summary> /// Inserts the text using the given font and text color, and the current /// highlight color. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> /// <param name="_color"></param> public void InsertTextAsRtf(string _text, Font _font, RtfColor _textColor) { InsertTextAsRtf(_text, _font, _textColor, highlightColor); }

/// <summary> /// Inserts the text using the given font and text color, and the current /// highlight color. /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> /// <param name="_color"></param> public void InsertTextAsRtf(string _text, Font _font, RtfColor _textColor) { InsertTextAsRtf(_text, _font, _textColor, highlightColor); }

/// <summary> /// Inserts the text using the given font, text, and highlight colors. The /// text is wrapped in RTF codes so that the specified formatting is kept. /// You can only assign valid RTF to the RichTextBox.Rtf property, else /// an exception is thrown. The RTF string should follow this format ... /// /// {\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{[FONTS]}{\colortbl ;[COLORS]}} /// \viewkind4\uc1\pard\cf1\f0\fs20 [DOCUMENT AREA] } /// /// </summary> /// <remarks> /// NOTE: The text is inserted wherever the caret is at the time of the call, /// and if any text is selected, that text is replaced. /// </remarks> /// <param name="_text"></param> /// <param name="_font"></param> /// <param name="_color"></param> /// <param name="_color"></param> public void InsertTextAsRtf(string _text, Font _font, RtfColor _textColor, RtfColor _backColor) {

StringBuilder _rtf = new StringBuilder();

// Append the RTF header _rtf.Append(RTF_HEADER);

// Create the font table from the font passed in and append it to the // RTF string _rtf.Append(GetFontTable(_font));

// Create the color table from the colors passed in and append it to the // RTF string _rtf.Append(GetColorTable(_textColor, _backColor));

// Create the document area from the text to be added as RTF and append // it to the RTF string. _rtf.Append(GetDocumentArea(_text, _font));

this.SelectedRtf = _rtf.ToString(); }

/// <summary> /// Creates the Document Area of the RTF being inserted. The document area /// (in this case) consists of the text being added as RTF and all the /// formatting specified in the Font object passed in. This should have the /// form ... /// /// \viewkind4\uc1\pard\cf1\f0\fs20 [DOCUMENT AREA] } /// /// </summary> /// <param name="_text"></param> /// <param name="_font"></param> /// <returns> /// The document area as a string. /// </returns> private string GetDocumentArea(string _text, Font _font) {

StringBuilder _doc = new StringBuilder(); // Append the standard RTF document area control string _doc.Append(RTF_DOCUMENT_PRE);

// Set the highlight color (the color behind the text) to the // third color in the color table. See GetColorTable for more details. _doc.Append(@"\highlight2");

// If the font is bold, attach corresponding tag if (_font.Bold) _doc.Append(@"\b");

// If the font is italic, attach corresponding tag if (_font.Italic) _doc.Append(@"\i");

// If the font is strikeout, attach corresponding tag if (_font.Strikeout) _doc.Append(@"\strike");

// If the font is underlined, attach corresponding tag if (_font.Underline) _doc.Append(@"\ul");

// Set the font to the first font in the font table. // See GetFontTable for more details. _doc.Append(@"\f0");

// Set the size of the font. In RTF, font size is measured in // half-points, so the font size is twice the value obtained from // Font.SizeInPoints _doc.Append(@"\fs"); _doc.Append((int)Math.Round((2 * _font.SizeInPoints)));

// Apppend a space before starting actual text (for clarity) _doc.Append(@" ");

// Append actual text, however, replace newlines with RTF \par. // Any other special text should be handled here (e.g.) tabs, etc. _doc.Append(_text.Replace("\n", @"\par "));

// RTF isn't strict when it comes to closing control words, but what the // heck ...

// Remove the highlight _doc.Append(@"\highlight0");

// If font is bold, close tag if (_font.Bold) _doc.Append(@"\b0");

// If font is italic, close tag if (_font.Italic) _doc.Append(@"\i0");

// If font is strikeout, close tag if (_font.Strikeout) _doc.Append(@"\strike0");

// If font is underlined, cloes tag if (_font.Underline) _doc.Append(@"\ulnone");

// Revert back to default font and size _doc.Append(@"\f0"); _doc.Append(@"\fs20");

// Close the document area control string _doc.Append(RTF_DOCUMENT_POST);

return _doc.ToString(); }

#endregion

#region Insert Image

/// <summary> /// Inserts an image into the RichTextBox. The image is wrapped in a Windows /// Format Metafile, because although Microsoft discourages the use of a WMF, /// the RichTextBox (and even MS Word), wraps an image in a WMF before inserting /// the image into a document. The WMF is attached in HEX format (a string of /// HEX numbers). /// /// The RTF Specification v1.6 says that you should be able to insert bitmaps, /// .jpegs, .gifs, .pngs, and Enhanced Metafiles (.emf) directly into an RTF /// document without the WMF wrapper. This works fine with MS Word, /// however, when you don't wrap images in a WMF, WordPad and /// RichTextBoxes simply ignore them. Both use the riched20.dll or msfted.dll. /// </summary> /// <remarks> /// NOTE: The image is inserted wherever the caret is at the time of the call, /// and if any text is selected, that text is replaced. /// </remarks> /// <param name="_image"></param> public void InsertImage(Image _image) {

StringBuilder _rtf = new StringBuilder();

// Append the RTF header _rtf.Append(RTF_HEADER);

// Create the font table using the RichTextBox's current font and append // it to the RTF string _rtf.Append(GetFontTable(this.Font));

// Create the image control string and append it to the RTF string _rtf.Append(GetImagePrefix(_image));

// Create the Windows Metafile and append its bytes in HEX format _rtf.Append(GetRtfImage(_image));

// Close the RTF image control string _rtf.Append(RTF_IMAGE_POST);

this.SelectedRtf = _rtf.ToString(); }

/// <summary> /// Creates the RTF control string that describes the image being inserted. /// This description (in this case) specifies that the image is an /// MM_ANISOTROPIC metafile, meaning that both X and Y axes can be scaled /// independently. The control string also gives the images current dimensions, /// and its target dimensions, so if you want to control the size of the /// image being inserted, this would be the place to do it. The prefix should /// have the form ... /// /// {\pict\wmetafile8\picw[A]\pich[b]\picwgoal[C]\pichgoal[D] /// /// where ... /// /// A = current width of the metafile in hundredths of millimeters (0.01mm) /// = Image Width in Inches * Number of (0.01mm) per inch /// = (Image Width in Pixels / Graphics Context's Horizontal Resolution) * 2540 /// = (Image Width in Pixels / Graphics.DpiX) * 2540 /// /// B = current height of the metafile in hundredths of millimeters (0.01mm) /// = Image Height in Inches * Number of (0.01mm) per inch /// = (Image Height in Pixels / Graphics Context's Vertical Resolution) * 2540 /// = (Image Height in Pixels / Graphics.DpiX) * 2540 /// /// C = target width of the metafile in twips /// = Image Width in Inches * Number of twips per inch /// = (Image Width in Pixels / Graphics Context's Horizontal Resolution) * 1440 /// = (Image Width in Pixels / Graphics.DpiX) * 1440 /// /// D = target height of the metafile in twips /// = Image Height in Inches * Number of twips per inch /// = (Image Height in Pixels / Graphics Context's Horizontal Resolution) * 1440 /// = (Image Height in Pixels / Graphics.DpiX) * 1440 /// /// </summary> /// <remarks> /// The Graphics Context's resolution is simply the current resolution at which /// windows is being displayed. Normally it's 96 dpi, but instead of assuming /// I just added the code. /// /// According to Ken Howe at pbdr.com, "Twips are screen-independent units /// used to ensure that the placement and proportion of screen elements in /// your screen application are the same on all display systems." /// /// Units Used /// ---------- /// 1 Twip = 1/20 Point /// 1 Point = 1/72 Inch /// 1 Twip = 1/1440 Inch /// /// 1 Inch = 2.54 cm /// 1 Inch = 25.4 mm /// 1 Inch = 2540 (0.01)mm /// </remarks> /// <param name="_image"></param> /// <returns></returns> private string GetImagePrefix(Image _image) {

StringBuilder _rtf = new StringBuilder();

// Calculate the current width of the image in (0.01)mm int picw = (int)Math.Round((_image.Width / xDpi) * HMM_PER_INCH);

// Calculate the current height of the image in (0.01)mm int pich = (int)Math.Round((_image.Height / yDpi) * HMM_PER_INCH);

// Calculate the target width of the image in twips int picwgoal = (int)Math.Round((_image.Width / xDpi) * TWIPS_PER_INCH);

// Calculate the target height of the image in twips int pichgoal = (int)Math.Round((_image.Height / yDpi) * TWIPS_PER_INCH);

// Append values to RTF string _rtf.Append(@"{\pict\wmetafile8"); _rtf.Append(@"\picw"); _rtf.Append(picw); _rtf.Append(@"\pich"); _rtf.Append(pich); _rtf.Append(@"\picwgoal"); _rtf.Append(picwgoal); _rtf.Append(@"\pichgoal"); _rtf.Append(pichgoal); _rtf.Append(" ");

return _rtf.ToString(); }

/// <summary> /// Use the EmfToWmfBits function in the GDI+ specification to convert a /// Enhanced Metafile to a Windows Metafile /// </summary> /// <param name="_hEmf"> /// A handle to the Enhanced Metafile to be converted /// </param> /// <param name="_bufferSize"> /// The size of the buffer used to store the Windows Metafile bits returned /// </param> /// <param name="_buffer"> /// An array of bytes used to hold the Windows Metafile bits returned /// </param> /// <param name="_mappingMode"> /// The mapping mode of the image. This control uses MM_ANISOTROPIC. /// </param> /// <param name="_flags"> /// Flags used to specify the format of the Windows Metafile returned /// </param> [DllImportAttribute("gdiplus.dll")] private static extern uint GdipEmfToWmfBits (IntPtr _hEmf, uint _bufferSize, byte[] _buffer, int _mappingMode, EmfToWmfBitsFlags _flags);

/// <summary> /// Wraps the image in an Enhanced Metafile by drawing the image onto the /// graphics context, then converts the Enhanced Metafile to a Windows /// Metafile, and finally appends the bits of the Windows Metafile in HEX /// to a string and returns the string. /// </summary> /// <param name="_image"></param> /// <returns> /// A string containing the bits of a Windows Metafile in HEX /// </returns> private string GetRtfImage(Image _image) {

StringBuilder _rtf = null;

// Used to store the enhanced metafile MemoryStream _stream = null;

// Used to create the metafile and draw the image Graphics _graphics = null;

// The enhanced metafile Metafile _metaFile = null;

// Handle to the device context used to create the metafile IntPtr _hdc;

try { _rtf = new StringBuilder(); _stream = new MemoryStream();

// Get a graphics context from the RichTextBox using(_graphics = this.CreateGraphics()) {

// Get the device context from the graphics context _hdc = _graphics.GetHdc();

// Create a new Enhanced Metafile from the device context _metaFile = new Metafile(_stream, _hdc);

// Release the device context _graphics.ReleaseHdc(_hdc); }

// Get a graphics context from the Enhanced Metafile using(_graphics = Graphics.FromImage(_metaFile)) {

// Draw the image on the Enhanced Metafile _graphics.DrawImage(_image, new Rectangle(0, 0, _image.Width, _image.Height));

}

// Get the handle of the Enhanced Metafile IntPtr _hEmf = _metaFile.GetHenhmetafile();

// A call to EmfToWmfBits with a null buffer return the size of the // buffer need to store the WMF bits. Use this to get the buffer // size. uint _bufferSize = GdipEmfToWmfBits(_hEmf, 0, null, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);

// Create an array to hold the bits byte[] _buffer = new byte[_bufferSize];

// A call to EmfToWmfBits with a valid buffer copies the bits into the // buffer an returns the number of bits in the WMF. uint _convertedSize = GdipEmfToWmfBits(_hEmf, _bufferSize, _buffer, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);

// Append the bits to the RTF string for(int i = 0; i < _buffer.Length; ++i) { _rtf.Append(String.Format("{0:X2}", _buffer[i])); }

return _rtf.ToString(); } finally { if(_graphics != null) _graphics.Dispose(); if(_metaFile != null) _metaFile.Dispose(); if(_stream != null) _stream.Close(); } } #endregion

#region RTF Helpers

/// <summary> /// Creates a font table from a font object. When an Insert or Append /// operation is performed a font is either specified or the default font /// is used. In any case, on any Insert or Append, only one font is used, /// thus the font table will always contain a single font. The font table /// should have the form ... /// /// {\fonttbl{\f0\[FAMILY]\fcharset0 [FONT_NAME];} /// </summary> /// <param name="_font"></param> /// <returns></returns> private string GetFontTable(Font _font) {

StringBuilder _fontTable = new StringBuilder();

// Append table control string _fontTable.Append(@"{\fonttbl{\f0"); _fontTable.Append(@"\"); // If the font's family corresponds to an RTF family, append the // RTF family name, else, append the RTF for unknown font family. if (rtfFontFamily.Contains(_font.FontFamily.Name)) _fontTable.Append(rtfFontFamily[_font.FontFamily.Name]); else _fontTable.Append(rtfFontFamily[FF_UNKNOWN]);

// \fcharset specifies the character set of a font in the font table. // 0 is for ANSI. _fontTable.Append(@"\fcharset0 ");

// Append the name of the font _fontTable.Append(_font.Name);

// Close control string _fontTable.Append(@";}}");

return _fontTable.ToString(); }

/// <summary> /// Creates a font table from the RtfColor structure. When an Insert or Append /// operation is performed, _textColor and _backColor are either specified /// or the default is used. In any case, on any Insert or Append, only three /// colors are used. The default color of the RichTextBox (signified by a /// semicolon (;) without a definition), is always the first color (index 0) in /// the color table. The second color is always the text color, and the third /// is always the highlight color (color behind the text). The color table /// should have the form ... /// /// {\colortbl ;[TEXT_COLOR];[HIGHLIGHT_COLOR];} /// /// </summary> /// <param name="_textColor"></param> /// <param name="_backColor"></param> /// <returns></returns> private string GetColorTable(RtfColor _textColor, RtfColor _backColor) {

StringBuilder _colorTable = new StringBuilder();

// Append color table control string and default font (;) _colorTable.Append(@"{\colortbl ;");

// Append the text color _colorTable.Append(rtfColor[_textColor]); _colorTable.Append(@";");

// Append the highlight color _colorTable.Append(rtfColor[_backColor]); _colorTable.Append(@";}\n"); return _colorTable.ToString(); }

/// <summary> /// Called by overrided RichTextBox.Rtf accessor. /// Removes the null character from the RTF. This is residue from developing /// the control for a specific instant messaging protocol and can be ommitted. /// </summary> /// <param name="_originalRtf"></param> /// <returns>RTF without null character</returns> private string RemoveBadChars(string _originalRtf) { return _originalRtf.Replace("\0", ""); }

#endregion } }