Add images to the RichTextBox Control

Using System;
Using System. Collections. Specialized;
Using System. Drawing;
Using System. Drawing. Imaging;
Using System. IO;
Using System. Runtime. InteropServices;
Using System. Text;
Using System. Windows. Forms;

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.
Emftowmfbitsflagsinclasdeplaceable = 0x00000002,

// Dont 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 = @ "ed0green0lue0 ";
Public const string Maroon = @ "ed128green0lue0 ";
Public const string Green = @ "ed0green128lue0 ";
Public const string Olive = @ "ed128green128lue0 ";
Public const string Navy = @ "ed0green0lue128 ";
Public const string Purple = @ "ed128green0lue128 ";
Public const string Teal = @ "ed0green128lue128 ";
Public const string Gray = @ "ed128green128lue128 ";
Public const string Silver = @ "ed192green192lue192 ";
Public const string Red = @ "ed255green0lue0 ";
Public const string Lime = @ "ed0green255lue0 ";
Public const string Yellow = @ "ed255green255lue0 ";
Public const string Blue = @ "ed0green0lue255 ";
Public const string Fuchsia = @ "ed255green0lue255 ";
Public const string Aqua = @ "ed0green255lue255 ";
Public const string White = @ "ed255green255lue255 ";
}

// 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) 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
*----------
*
* Tf [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 = @ "{tf1ansiansicpg1252deff0deflang1033 ";

/* 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 = @ "viewkind4uc1pardcf1f0fs20 ";
Private const string RTF_DOCUMENT_POST = @ "cf0fs17 }";
Private string RTF_IMAGE_POST = @"}";

# Endregion

# Region Accessors

// TODO: This can be ommitted along with RemoveBadCha