Mega Code Archive
Hex Color Util
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using System;
using System.Drawing;
namespace Heckel.EasyTools.Diagramming
{
public static class HexColorUtil
//
// Util class to convert hexadecimal represenations of colors used in html
// to .NET framework colors. Hexadecimal colors are defined in this notation:
// #8080FF
//
// This code is free of copyrights and can be redistributed freely
//
// Written by Sandro Todesco, 2002, sandro@todesco.com,
// http://www.todesco.com
//
{
public static String ReverseString(String inStr)
// Helper Method that reverses a String.
{
String outStr;
int counter;
outStr = "";
for (counter = inStr.Length - 1; counter >= 0; counter--)
{
outStr = outStr + inStr[counter];
}
return outStr;
}
public static int HexToInt(String hexstr)
// This method converts a hexvalues string as 80FF into a integer.
// Note that you may not put a '#' at the beginning of string! There
// is not much error checking in this method. If the string does not
// represent a valid hexadecimal value it returns 0.
{
int counter, hexint;
char[] hexarr;
hexint = 0;
hexstr = hexstr.ToUpper();
hexarr = hexstr.ToCharArray();
for (counter = hexarr.Length - 1; counter >= 0; counter--)
{
if ((hexarr[counter] >= '0') && (hexarr[counter] <= '9'))
{
hexint += (hexarr[counter] - 48) * ((int)(Math.Pow(16, hexarr.Length - 1 - counter)));
}
else
{
if ((hexarr[counter] >= 'A') && (hexarr[counter] <= 'F'))
{
hexint += (hexarr[counter] - 55) * ((int)(Math.Pow(16, hexarr.Length - 1 - counter)));
}
else
{
hexint = 0;
break;
}
}
}
return hexint;
}
public static String IntToHex(int hexint)
// This method converts a integer into a hexadecimal string representing the
// int value. The returned string will look like this: 55FF. Note that there is
// no leading '#' in the returned string!
{
int counter, reminder;
String hexstr;
counter = 1;
hexstr = "";
while (hexint + 15 > Math.Pow(16, counter - 1))
{
reminder = (int)(hexint % Math.Pow(16, counter));
reminder = (int)(reminder / Math.Pow(16, counter - 1));
if (reminder <= 9)
{
hexstr = hexstr + (char)(reminder + 48);
}
else
{
hexstr = hexstr + (char)(reminder + 55);
}
hexint -= reminder;
counter++;
}
return ReverseString(hexstr);
}
public static String IntToHex(int hexint, int length)
// This version of the IntToHex method returns a hexadecimal string representing the
// int value in the given minimum length. If the hexadecimal string is shorter then the
// length parameter the missing characters will be filled up with leading zeroes.
// Note that the returend string though is not truncated if the value exeeds the length!
{
String hexstr, ret;
int counter;
hexstr = IntToHex(hexint);
ret = "";
if (hexstr.Length < length)
{
for (counter = 0; counter < (length - hexstr.Length); counter++)
{
ret = ret + "0";
}
}
return ret + hexstr;
}
public static Color HexToColor(String hexString)
// Translates a html hexadecimal definition of a color into a .NET Framework Color.
// The input string must start with a '#' character and be followed by 6 hexadecimal
// digits. The digits A-F are not case sensitive. If the conversion was not successfull
// the color white will be returned.
{
Color actColor;
int r, g, b;
r = 0;
g = 0;
b = 0;
if ((hexString.StartsWith("#")) && (hexString.Length == 7))
{
r = HexToInt(hexString.Substring(1, 2));
g = HexToInt(hexString.Substring(3, 2));
b = HexToInt(hexString.Substring(5, 2));
actColor = Color.FromArgb(r, g, b);
}
else
{
actColor = Color.White;
}
return actColor;
}
public static String ColorToHex(Color actColor)
// Translates a .NET Framework Color into a string containing the html hexadecimal
// representation of a color. The string has a leading '#' character that is followed
// by 6 hexadecimal digits.
{
return "#" + IntToHex(actColor.R, 2) + IntToHex(actColor.G, 2) + IntToHex(actColor.B, 2);
}
}
}
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