labellayer.cs

Sharp Map 用于制作GIS系统S harp Map 用于制作GIS系统S harp Map 用于制作GIS系统

// Copyright 2005, 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.Layers
{
	/// <summary>
	/// Label layer class
	/// </summary>
	/// <example>
	/// Creates a new label layer and sets the label text to the "Name" column in the FeatureDataTable of the datasource
	/// <code lang="C#">
	/// //Set up a label layer
	/// SharpMap.Layers.LabelLayer layLabel = new SharpMap.Layers.LabelLayer("Country labels");
	/// layLabel.DataSource = layCountries.DataSource;
	/// layLabel.Enabled = true;
	/// layLabel.LabelColumn = "Name";
	/// layLabel.Style = new SharpMap.Styles.LabelStyle();
	/// layLabel.Style.CollisionDetection = true;
	/// layLabel.Style.CollisionBuffer = new SizeF(20, 20);
	/// layLabel.Style.ForeColor = Color.White;
	/// layLabel.Style.Font = new Font(FontFamily.GenericSerif, 8);
	/// layLabel.MaxVisible = 90;
	/// layLabel.Style.HorizontalAlignment = SharpMap.Styles.LabelStyle.HorizontalAlignmentEnum.Center;
	/// </code>
	/// </example>
	public class LabelLayer : Layer, IDisposable
	{
		/// <summary>
		/// Labelling behaviour for Multipart geometry collections
		/// </summary>
		public enum MultipartGeometryBehaviourEnum
		{
			/// <summary>
			/// Place label on all parts (default)
			/// </summary>
			All,
			/// <summary>
			/// Place label on object which the greatest length or area.
			/// </summary>
			/// <remarks>
			/// Multipoint geometries will default to <see cref="First"/>
			/// </remarks>
			Largest,
			/// <summary>
			/// The center of the combined geometries
			/// </summary>
			CommonCenter,
			/// <summary>
			/// Center of the first geometry in the collection (fastest method)
			/// </summary>
			First
		}

		/// <summary>
		/// Delegate method for creating advanced label texts
		/// </summary>
		/// <param name="fdr"></param>
		/// <returns></returns>
		public delegate string GetLabelMethod(SharpMap.Data.FeatureDataRow fdr);

		/// <summary>
		/// Creates a new instance of a LabelLayer
		/// </summary>
		public LabelLayer(string layername)
		{
			_Style = new SharpMap.Styles.LabelStyle();
			this.LayerName = layername;
			this.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
			this.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
			_MultipartGeometryBehaviour = MultipartGeometryBehaviourEnum.All;
			_LabelFilter = SharpMap.Rendering.LabelCollisionDetection.SimpleCollisionDetection;
		}

		private MultipartGeometryBehaviourEnum _MultipartGeometryBehaviour;
		/// <summary>
		/// Gets or sets labelling behavior on multipart geometries
		/// </summary>
		/// <remarks>Default value is <see cref="MultipartGeometryBehaviourEnum.All"/></remarks>
		public MultipartGeometryBehaviourEnum MultipartGeometryBehaviour
		{
			get { return _MultipartGeometryBehaviour; }
			set { _MultipartGeometryBehaviour = value; }
		}

		private SharpMap.Rendering.LabelCollisionDetection.LabelFilterMethod _LabelFilter;

		/// <summary>
		/// Filtermethod delegate for performing filtering
		/// </summary>
		/// <remarks>
		/// Default method is <see cref="SharpMap.Rendering.LabelCollisionDetection.SimpleCollisionDetection"/>
		/// </remarks>
		public SharpMap.Rendering.LabelCollisionDetection.LabelFilterMethod LabelFilter
		{
			get { return _LabelFilter; }
			set { _LabelFilter = value; }
		}
	

		private System.Drawing.Drawing2D.SmoothingMode _SmoothingMode;

		/// <summary>
		/// Render whether smoothing (antialiasing) is applied to lines and curves and the edges of filled areas
		/// </summary>
		public System.Drawing.Drawing2D.SmoothingMode SmoothingMode
		{
			get { return _SmoothingMode; }
			set { _SmoothingMode = value; }
		}

		private System.Drawing.Text.TextRenderingHint _TextRenderingHint;

		/// <summary>
		/// Specifies the quality of text rendering
		/// </summary>
		public System.Drawing.Text.TextRenderingHint TextRenderingHint
		{
			get { return _TextRenderingHint; }
			set { _TextRenderingHint = value; }
		}	

		private SharpMap.Data.Providers.IProvider _DataSource;

		/// <summary>
		/// Gets or sets the datasource
		/// </summary>
		public SharpMap.Data.Providers.IProvider DataSource
		{
			get { return _DataSource; }
			set { _DataSource = value; }
		}

		private SharpMap.Styles.LabelStyle _Style;

		/// <summary>
		/// Gets or sets the rendering style of the label layer.
		/// </summary>
		public SharpMap.Styles.LabelStyle Style
		{
			get { return _Style; }
			set { _Style = value; }
		}

		private SharpMap.Rendering.Thematics.ITheme _theme;

		/// <summary>
		/// Gets or sets thematic settings for the layer. Set to null to ignore thematics
		/// </summary>
		public SharpMap.Rendering.Thematics.ITheme Theme
		{
			get { return _theme; }
			set { _theme = value; }
		}

		private string _LabelColumn;

		/// <summary>
		/// Data column or expression where label text is extracted from.
		/// </summary>
		/// <remarks>
		/// This property is overriden by the <see cref="LabelStringDelegate"/>.
		/// </remarks>
		public string LabelColumn
		{
			get { return _LabelColumn; }
			set { _LabelColumn = value; }
		}

		private GetLabelMethod _getLabelMethod;

		/// <summary>
		/// Gets or sets the method for creating a custom label string based on a feature.
		/// </summary>
		/// <remarks>
		/// <para>If this method is not null, it will override the <see cref="LabelColumn"/> value.</para>
		/// <para>The label delegate must take a <see cref="SharpMap.Data.FeatureDataRow"/> and return a string.</para>
		/// <example>
		/// Creating a label-text by combining attributes "ROADNAME" and "STATE" into one string, using
		/// an anonymous delegate:
		/// <code lang="C#">
		/// myLabelLayer.LabelStringDelegate = delegate(SharpMap.Data.FeatureDataRow fdr)
		///				{ return fdr["ROADNAME"].ToString() + ", " + fdr["STATE"].ToString(); };
		/// </code>
		/// </example>
		/// </remarks>
		public GetLabelMethod LabelStringDelegate
		{
			get { return _getLabelMethod; }
			set { _getLabelMethod = value; }
		}
	
		
		private string _RotationColumn;

		/// <summary>
		/// Data column from where the label rotation is derived.
		/// If this is empty, rotation will be zero, or aligned to a linestring.
		/// Rotation are in degrees (positive = clockwise).
		/// </summary>
		public string RotationColumn
		{
			get { return _RotationColumn; }
			set { _RotationColumn = value; }
		}
		
		private int _Priority;

		/// <summary>
		/// A value indication the priority of the label in cases of label-collision detection
		/// </summary>
		public int Priority
		{
			get { return _Priority; }
			set { _Priority = value; }
		}

		/// <summary>
		/// Renders the layer
		/// </summary>
		/// <param name="g">Graphics object reference</param>
		/// <param name="map">Map which is rendered</param>
		public override void Render(System.Drawing.Graphics g, Map map)
		{
			if (this.Style.Enabled && this.Style.MaxVisible >= map.Zoom && this.Style.MinVisible < map.Zoom)
			{
				if (this.DataSource == null)
					throw (new ApplicationException("DataSource property not set on layer '" + this.LayerName + "'"));
				g.TextRenderingHint = this.TextRenderingHint;
				g.SmoothingMode = this.SmoothingMode;

				SharpMap.Geometries.BoundingBox envelope = map.Envelope; //View to render
				if (this.CoordinateTransformation != null)
					envelope = SharpMap.CoordinateSystems.Transformations.GeometryTransform.TransformBox(envelope, this.CoordinateTransformation.MathTransform.Inverse());