linkline.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

// **********************************************************************
// 
// <copyright>
// 
//  BBN Technologies
//  10 Moulton Street
//  Cambridge, MA 02138
//  [phone]
// 
//  Copyright (C) BBNT Solutions LLC. All rights reserved.
// 
// </copyright>
// **********************************************************************
// 
// $Source: /cvs/distapps/openmap/src/openmap/com/bbn/openmap/layer/link/LinkLine.java,v $
// $RCSfile: LinkLine.java,v $
// $Revision: 1.3.2.1 $
// $Date: 2004/10/14 18:27:08 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.layer.link;

import com.bbn.openmap.omGraphics.OMLine;
import com.bbn.openmap.util.Debug;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

/**
 * Read and write a Link protocol version of a line.
 */
public class LinkLine implements LinkGraphicConstants, LinkPropertiesConstants {

    /**
     * Write a line using lat/lon endpoints. The lat/lons are in
     * decimal degrees. .
     * 
     * @param lat_1 latitude of placement of start of line.
     * @param lon_1 longitude of placement of start of line.
     * @param lat_2 latitude of placement of end of line.
     * @param lon_2 longitude of placement of end of line.
     * @param lineType type of line - straight, rhumb, great circle..
     * @param properties Properties containing attributes.
     * @param dos DataOutputStream to write to.
     * @throws IOException
     */
    public static void write(float lat_1, float lon_1, float lat_2,
                             float lon_2, int lineType,
                             LinkProperties properties, DataOutputStream dos)
            throws IOException {
        LinkLine.write(lat_1,
                lon_1,
                lat_2,
                lon_2,
                lineType,
                -1,
                properties,
                dos);
    }

    /**
     * Write a line using lat/lon endpoints. The lat/lons are in
     * decimal degrees. This method gives you the option of specifying
     * a number of segments to use in approximating a curved line.
     * 
     * @param lat_1 latitude of placement of start of line.
     * @param lon_1 longitude of placement of start of line.
     * @param lat_2 latitude of placement of end of line.
     * @param lon_2 longitude of placement of end of line.
     * @param lineType type of line - straight, rhumb, great circle..
     * @param nsegs number of points to use to approximate curved
     *        line..
     * @param properties Properties containing attributes.
     * @param dos DataOutputStream to write to.
     * @throws IOException
     */
    public static void write(float lat_1, float lon_1, float lat_2,
                             float lon_2, int lineType, int nsegs,
                             LinkProperties properties, DataOutputStream dos)
            throws IOException {

        dos.write(Link.LINE_HEADER.getBytes());
        dos.writeInt(GRAPHICTYPE_LINE);
        dos.writeInt(RENDERTYPE_LATLON);
        dos.writeInt(lineType);
        dos.writeFloat(lat_1);
        dos.writeFloat(lon_1);
        dos.writeFloat(lat_2);
        dos.writeFloat(lon_2);
        dos.writeInt(nsegs);
        properties.write(dos);
    }

    /**
     * Write a line with x/y pixel endpoints.
     * 
     * @param x1 Horizontal pixel placement of start of line.
     * @param y1 Vertical pixel placement of start of line.
     * @param x2 Horizontal pixel placement of end of line.
     * @param y2 Vertical pixel placement of end of line.
     * @param properties Properties containing attributes.
     * @param dos DataOutputStream to write to.
     * @throws IOException
     */
    public static void write(int x1, int y1, int x2, int y2,
                             LinkProperties properties, DataOutputStream dos)
            throws IOException {

        dos.write(Link.LINE_HEADER.getBytes());
        dos.writeInt(GRAPHICTYPE_LINE);
        dos.writeInt(RENDERTYPE_XY);
        dos.writeInt(x1);
        dos.writeInt(y1);
        dos.writeInt(x2);
        dos.writeInt(y2);
        properties.write(dos);
    }

    /**
     * Write a line located at an x/y pixel offset from a lat/lon
     * location.
     * 
     * @param lat_1 latitude of placement of line.
     * @param lon_1 longitude of placement of line.
     * @param x1 Horizontal pixel offset of start of line.
     * @param y1 Vertical pixel offset of start of line.
     * @param x2 Horizontal pixel offset of end of line.
     * @param y2 Vertical pixel offset of end of line.
     * @param properties Properties containing attributes.
     * @param dos DataOutputStream to write to.
     * @throws IOException
     */
    public static void write(float lat_1, float lon_1, int x1, int y1, int x2,
                             int y2, LinkProperties properties,
                             DataOutputStream dos) throws IOException {

        dos.write(Link.LINE_HEADER.getBytes());
        dos.writeInt(GRAPHICTYPE_LINE);
        dos.writeInt(RENDERTYPE_OFFSET);
        dos.writeFloat(lat_1);
        dos.writeFloat(lon_1);
        dos.writeInt(x1);
        dos.writeInt(y1);
        dos.writeInt(x2);
        dos.writeInt(y2);
        properties.write(dos);
    }

    /**
     * Write an OMLine to the link.
     */
    public static void write(OMLine line, Link link, LinkProperties props)
            throws IOException {

        switch (line.getRenderType()) {
        case OMLine.RENDERTYPE_LATLON:
            float[] ll = line.getLL();
            LinkLine.write(ll[0],
                    ll[1],
                    ll[2],
                    ll[3],
                    line.getLineType(),
                    line.getNumSegs(),
                    props,
                    link.dos);
            break;
        case OMLine.RENDERTYPE_XY:
            int[] pts = line.getPts();
            LinkLine.write(pts[0], pts[1], pts[2], pts[3], props, link.dos);
            break;
        case OMLine.RENDERTYPE_OFFSET:
            ll = line.getLL();
            pts = line.getPts();
            LinkLine.write(ll[0],
                    ll[1],
                    pts[0],
                    pts[1],
                    pts[2],
                    pts[3],
                    props,
                    link.dos);
            break;
        default:
            Debug.error("LinkLine.write: line rendertype unknown.");
        }
    }

    /**
     * Read the line Link protocol off a DataInputStream, and create
     * an OMLine from it. Assumes that the header has already been
     * read.
     * 
     * @param dis DataInputStream to read from.
     * @return OMLine
     * @throws IOException
     * @see com.bbn.openmap.omGraphics.OMLine
     */
    public static OMLine read(DataInputStream dis) throws IOException {

        OMLine line = null;

        float lat_1 = 0.0f;
        float lon_1 = 0.0f;
        float lat_2 = 0.0f;
        float lon_2 = 0.0f;

        int x1 = 0;
        int y1 = 0;
        int x2 = 0;
        int y2 = 0;
        int nsegs = -1;

        int renderType = dis.readInt();

        switch (renderType) {
        case RENDERTYPE_LATLON:
            int lineType = dis.readInt();
            lat_1 = dis.readFloat();
            lon_1 = dis.readFloat();
            lat_2 = dis.readFloat();
            lon_2 = dis.readFloat();
            nsegs = dis.readInt();

            line = new OMLine(lat_1, lon_1, lat_2, lon_2, lineType, nsegs);
            break;
        case RENDERTYPE_XY:
            x1 = dis.readInt();
            y1 = dis.readInt();
            x2 = dis.readInt();
            y2 = dis.readInt();

            line = new OMLine(x1, y1, x2, y2);
            break;
        case RENDERTYPE_OFFSET:
            lat_1 = dis.readFloat();
            lon_1 = dis.readFloat();
            x1 = dis.readInt();
            y1 = dis.readInt();
            x2 = dis.readInt();
            y2 = dis.readInt();

            line = new OMLine(lat_1, lon_1, x1, y1, x2, y2);
            break;
        default:
        }

        LinkProperties properties = new LinkProperties(dis);
        if (line != null) {
            properties.setProperties(line);
        }
        return line;
    }
}