mono/mcs/class/System.Web/System.Web.UI.WebControls/WebColorConverter.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 Novell, Inc. (http://www.novell.com)
//
// Authors:
//	Peter Bartok	([email protected])
//
//

using System.Drawing;
using System.Globalization;
using System.ComponentModel;
using System.Security.Permissions;

namespace System.Web.UI.WebControls {

	// CAS
	[AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
	[AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
	public class WebColorConverter : ColorConverter {

		// Converts from string to Color
		public override object ConvertFrom (ITypeDescriptorContext context, CultureInfo culture, object value) 
		{
			if (value is string) 
			{
				string	s;

				s = ((string)value).Trim();
				if (s.Length == 0) 
				{
					return Color.Empty;
				}

				if (culture == null) {
					culture = CultureInfo.InvariantCulture;
				}

				if (s[0] == '#') 
				{
					// Hex

					// MS throws a generic exception, wrapping the specific exception, who knows why...
					try 
					{
						if (s.Length == 7) 
						{
							int	v;
							v = Int32.Parse(s.Substring(1), NumberStyles.HexNumber, culture);

							return Color.FromArgb(255, (v >> 16) & 0xff, (v >> 8) & 0xff, v & 0xff);
						} 
						else 
						{
							return Color.FromArgb(Int32.Parse(s.Substring(1), NumberStyles.HexNumber, culture));
						}
					}

					catch (FormatException e) 
					{
						throw new Exception(s + "is not a valid color value", e);
					}
					catch (System.OverflowException e) 
					{
						throw new Exception(s + " is not a valid color value", e);
					}
				} 
				else 
				{
					// Name or decimal
					int	n = 0;

					try 
					{
						n = Int32.Parse(s, NumberStyles.Integer, culture);
					}

					catch (FormatException e) 
					{
						Color c;

						c = Color.FromName(s);
						if ((c.A != 0) || (c.R != 0) || (c.G != 0) || (c.B != 0)) 
						{
							return c;
						}

						throw new Exception(s + " is not a valid color value", e);
					}

					catch (System.OverflowException e) 
					{
						throw new Exception(s + " is not a valid color value", e);
					}

					catch 
					{
						throw;
					}

					return Color.FromArgb(n);
				}
			}
			return base.ConvertFrom (context, culture, value);
		}

		// Converts from Color to string
		public override object ConvertTo (ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) 
		{
			if (!(value is Color) || destinationType != typeof (string))
				return base.ConvertTo (context, culture, value, destinationType);

			Color c = (Color) value;

			if (culture == null)
				culture = CultureInfo.InvariantCulture;

			string s = c.ToKnownColor ().ToString ();
			if (s != "0")
				return s;

			return String.Concat ("#", c.R.ToString ("X2"), c.G.ToString ("X2"), c.B.ToString ("X2"));
		}
	}
}