customtheme.cs

C# 的地图开发例子（sharp map)

// Copyright 2006 - Morten Nielsen (www.iter.dk)
//
// This file is part of SharpMap.
// SharpMap is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// SharpMap is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with SharpMap; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Collections.Generic;
using System.Text;

namespace SharpMap.Rendering.Thematics
{
	/// <summary>
	/// The CustomTheme class is used for defining your own thematic rendering by using a custom get-style-delegate.
	/// </summary>
	public class CustomTheme : ITheme
	{
		/// <summary>
		/// Custom Style Delegate method
		/// </summary>
		/// <remarks>
		/// The GetStyle delegate is used for determining the style of a feature using the <see cref="StyleDelegate"/> property.
		/// The method must take a <see cref="SharpMap.Data.FeatureDataRow"/> and return an <see cref="SharpMap.Styles.IStyle"/>.
		/// If the method returns null, the default style will be used for rendering.
		/// <para>
		/// <example>
		/// The following example can used for highlighting all features where the attribute "NAME" starts with "S".
		/// <code lang="C#">
		/// SharpMap.Rendering.Thematics.CustomTheme iTheme = new SharpMap.Rendering.Thematics.CustomTheme(GetCustomStyle);
		/// SharpMap.Styles.VectorStyle defaultstyle = new SharpMap.Styles.VectorStyle(); //Create default renderstyle
		/// defaultstyle.Fill = Brushes.Gray;
		/// iTheme.DefaultStyle = defaultstyle;
		/// 
		/// [...]
		/// 
		/// //Set up delegate for determining fill-color.
		/// //Delegate will fill all objects with a yellow color where the attribute "NAME" starts with "S".
		/// private static SharpMap.Styles.VectorStyle GetCustomStyle(SharpMap.Data.FeatureDataRow row)
		/// {
		/// 
		/// 	if (row["NAME"].ToString().StartsWith("S"))
		/// 	{
		/// 		SharpMap.Styles.VectorStyle style = new SharpMap.Styles.VectorStyle();
		/// 		style.Fill = Brushes.Yellow;
		/// 		return style;
		/// 	}
		/// 	else
		/// 		return null; //Return null which will render the default style
		/// }
		/// </code>
		/// </example>
		/// </para>
		/// </remarks>
		/// <param name="dr">Feature</param>
		/// <returns>Style to be applied to feature</returns>
		public delegate SharpMap.Styles.IStyle GetStyleMethod(SharpMap.Data.FeatureDataRow dr);

		private SharpMap.Styles.IStyle _DefaultStyle;

		/// <summary>
		/// Gets or sets the default style when an attribute isn't found in any bucket
		/// </summary>
		public SharpMap.Styles.IStyle DefaultStyle
		{
			get { return _DefaultStyle; }
			set { _DefaultStyle = value; }
		}

		private GetStyleMethod _getStyleDelegate;

		/// <summary>
		/// Gets or sets the style delegate used for determining the style of a feature
		/// </summary>
		/// <remarks>
		/// The delegate must take a <see cref="SharpMap.Data.FeatureDataRow"/> and return an <see cref="SharpMap.Styles.IStyle"/>.
		/// If the method returns null, the default style will be used for rendering.
		/// <example>
		/// The example below creates a delegate that can be used for assigning the rendering of a road theme. If the road-class
		/// is larger than '3', it will be rendered using a thick red line.
		/// <code lang="C#">
		/// private static SharpMap.Styles.VectorStyle GetRoadStyle(SharpMap.Data.FeatureDataRow row)
		/// {
		///		SharpMap.Styles.VectorStyle style = new SharpMap.Styles.VectorStyle();
		///		if(((int)row["RoadClass"])>3)
		///			style.Line = new Pen(Color.Red,5f);
		///		else
		///			style.Line = new Pen(Color.Black,1f);
		///		return style;
		/// }
		/// </code>
		/// </example>
		/// </remarks>
		/// <seealso cref="GetStyleMethod"/>
		public GetStyleMethod StyleDelegate
		{
			get { return _getStyleDelegate; }
			set { _getStyleDelegate = value; }
		}
	

		/// <summary>
		/// Initializes a new instance of the <see cref="CustomTheme"/> class
		/// </summary>
		/// <param name="getStyleMethod"></param>
		public CustomTheme(GetStyleMethod getStyleMethod)
		{
			_getStyleDelegate = getStyleMethod;
		}


		#region ITheme Members

		/// <summary>
		/// Returns the <see cref="System.Drawing.Color">color</see> based on an attribute value
		/// </summary>
		/// <param name="row">DataRow</param>
		/// <returns>Style generated by GetStyle-Delegate</returns>
		public SharpMap.Styles.IStyle GetStyle(SharpMap.Data.FeatureDataRow row)
		{
			SharpMap.Styles.IStyle style = _getStyleDelegate(row);
			if (style != null)
				return style;
			else
				return _DefaultStyle;
		}

		#endregion
}
}