<%@ WebHandler Language="C#" Class="MapHandler" %>

using System;

using System.Drawing;

using System.Drawing.Imaging;

using System.Globalization;

using System.IO;

using System.Web;

using SharpMap;

using Point=GeoAPI.Geometries.Coordinate;

/// <summary>

/// The maphandler class takes a set of GET or POST parameters and returns a map as PNG (this reminds in many ways of the way a WMS server work).

/// Required parameters are: WIDTH, HEIGHT, ZOOM, X, Y, MAP

/// </summary>

public class MapHandler : IHttpHandler

{

internal static NumberFormatInfo numberFormat_EnUS = new CultureInfo("en-US", false).NumberFormat;

#region IHttpHandler Members

public void ProcessRequest(HttpContext context)

{

int Width = 0;

int Height = 0;

double centerX = 0;

double centerY = 0;

double Zoom = 0;

//Parse request parameters

if (!int.TryParse(context.Request.Params["WIDTH"], out Width))

throw (new ArgumentException("Invalid parameter"));

if (!int.TryParse(context.Request.Params["HEIGHT"], out Height))

throw (new ArgumentException("Invalid parameter"));

if (!double.TryParse(context.Request.Params["ZOOM"], NumberStyles.Float, numberFormat_EnUS, out Zoom))

throw (new ArgumentException("Invalid parameter"));

if (!double.TryParse(context.Request.Params["X"], NumberStyles.Float, numberFormat_EnUS, out centerX))

throw (new ArgumentException("Invalid parameter"));

if (!double.TryParse(context.Request.Params["Y"], NumberStyles.Float, numberFormat_EnUS, out centerY))

throw (new ArgumentException("Invalid parameter"));

if (context.Request.Params["MAP"] == null)

throw (new ArgumentException("Invalid parameter"));

//Params OK

Map map = InitializeMap(context.Request.Params["MAP"], new Size(Width, Height));

if (map == null)

throw (new ArgumentException("Invalid map"));

//Set visible map extents

map.Center = new Point(centerX, centerY);

map.Zoom = Zoom;

//Generate map

Bitmap img = (Bitmap) map.GetMap();

//Stream the image to the client

context.Response.ContentType = "image/png";

MemoryStream MS = new MemoryStream();

img.Save(MS, ImageFormat.Png);

// tidy up

img.Dispose();

byte[] buffer = MS.ToArray();

context.Response.OutputStream.Write(buffer, 0, buffer.Length);

}

public bool IsReusable

{

get { return false; }

}

#endregion

private Map InitializeMap(string MapID, Size size)

{

//Set up the map. We use the method in the App_Code folder for initializing the map

switch (MapID)

{

//Our simple world map was requested

case "SimpleWorld":

return MapHelper.InitializeMap(size);

//Gradient theme layer requested. Based on simplemap

case "Gradient":

return MapHelper.InitializeGradientMap(size);

case "WmsClient":

return MapHelper.InitializeWmsMap(size);

default:

throw new ArgumentException("Invalid map '" + MapID + "' requested");

;

}

}

}