source: josm/src/org/openstreetmap/josm/gui/download/WorldChooser.java@ 283

package org.openstreetmap.josm.gui.download;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
import java.beans.PropertyChangeListener;
import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.coor.EastNorth;
import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.projection.Projection;
import org.openstreetmap.josm.gui.MapMover;
import org.openstreetmap.josm.gui.MapScaler;
import org.openstreetmap.josm.gui.NavigatableComponent;
import org.openstreetmap.josm.gui.SelectionManager;
import org.openstreetmap.josm.gui.SelectionManager.SelectionEnded;


/**
 * A component that let the user select a lat/lon bounding box from zooming
 * into the world as a picture and selecting a region.
 *
 * The component has to be of the aspect ration 2:1 to look good.
 *
 * @author imi
 */
public class WorldChooser extends NavigatableComponent implements DownloadSelection {

        /**
         * The world as picture.
         */
        private ImageIcon world;

        /**
         * Maximum scale level
         */
        private double scaleMax;

        /**
         * Mark this rectangle (lat/lon values) when painting.
         */
        private EastNorth markerMin, markerMax;

        private Projection projection;

        /**
         * Create the chooser component.
         */
        public WorldChooser() {
                URL path = Main.class.getResource("/images/world.jpg");
                world = new ImageIcon(path);
                center = new EastNorth(world.getIconWidth()/2, world.getIconHeight()/2);
                setPreferredSize(new Dimension(400, 200));

                projection = new Projection() {
                        public EastNorth latlon2eastNorth(LatLon p) {
                                return new EastNorth(
                                                (p.lon()+180) / 360 * world.getIconWidth(),
                                                (p.lat()+90) / 180 * world.getIconHeight());
                        }
                        public LatLon eastNorth2latlon(EastNorth p) {
                                return new LatLon(
                                                p.north()*180/world.getIconHeight() - 90,
                                                p.east()*360/world.getIconWidth() - 180);
                        }
                        @Override public String toString() {
                                return "WorldChooser";
                        }
            public String getCacheDirectoryName() {
                throw new UnsupportedOperationException();
            }
                        public double scaleFactor() {
                    return 1.0 / world.getIconWidth();
            }

                };

                MapScaler scaler = new MapScaler(this, projection);
                add(scaler);
                scaler.setLocation(10,10);

                setMinimumSize(new Dimension(350, 350/2));
        }

        public void addGui(final DownloadDialog gui) {
                JPanel temp = new JPanel();
                temp.setLayout(new BorderLayout());
                temp.add(this, BorderLayout.CENTER);
                temp.add(new JLabel(tr("You can use the mouse or Ctrl+Arrow keys/./ to zoom and pan.")), BorderLayout.SOUTH);
                gui.tabpane.add(temp, "Map");
                new MapMover(this, temp);               
                SelectionEnded selListener = new SelectionEnded(){
                        public void selectionEnded(Rectangle r, boolean alt, boolean shift, boolean ctrl) {
                                markerMin = getEastNorth(r.x, r.y+r.height);
                                markerMax = getEastNorth(r.x+r.width, r.y);
                                LatLon min = getProjection().eastNorth2latlon(markerMin);
                                LatLon max = getProjection().eastNorth2latlon(markerMax);
                                gui.minlat = min.lat();
                                gui.minlon = min.lon();
                                gui.maxlat = max.lat();
                                gui.maxlon = max.lon();
                                gui.boundingBoxChanged(WorldChooser.this);
                                repaint();
                        }
                        public void addPropertyChangeListener(PropertyChangeListener listener) {}
                        public void removePropertyChangeListener(PropertyChangeListener listener) {}
                };
                SelectionManager sm = new SelectionManager(selListener, false, this);
                sm.register(this);
    }

        public void boundingBoxChanged(DownloadDialog gui) {
                markerMin = getProjection().latlon2eastNorth(new LatLon(gui.minlat, gui.minlon));
                markerMax = getProjection().latlon2eastNorth(new LatLon(gui.maxlat, gui.maxlon));
                repaint();
        }

        /**
         * Set the scale as well as the preferred size.
         */
        @Override public void setPreferredSize(Dimension preferredSize) {
                super.setPreferredSize(preferredSize);
                scale = world.getIconWidth()/preferredSize.getWidth();
                scaleMax = scale;
        }

        /**
         * Draw the current selected region.
         */
        @Override public void paint(Graphics g) {
                EastNorth tl = getEastNorth(0,0);
                EastNorth br = getEastNorth(getWidth(),getHeight());
                g.drawImage(world.getImage(),0,0,getWidth(),getHeight(),(int)tl.east(),(int)tl.north(),(int)br.east(),(int)br.north(), null);

                // draw marker rect
                if (markerMin != null && markerMax != null) {
                        Point p1 = getPoint(markerMin);
                        Point p2 = getPoint(markerMax);
                        double x = Math.min(p1.x, p2.x);
                        double y = Math.min(p1.y, p2.y);
                        double w = Math.max(p1.x, p2.x) - x;
                        double h = Math.max(p1.y, p2.y) - y;
                        if (w < 1)
                                w = 1;
                        if (h < 1)
                                h = 1;
                        g.setColor(Color.YELLOW);
                        g.drawRect((int)x, (int)y, (int)w, (int)h);
                }
                super.paint(g);
        }

        @Override public void zoomTo(EastNorth newCenter, double scale) {
                if (getWidth() != 0 && scale > scaleMax) {
                        scale = scaleMax;
                        newCenter = center;
                }
                super.zoomTo(newCenter, scale);
        }

        /**
         * Always use our image projection mode.
         */
        @Override protected Projection getProjection() {
                return projection;
        }
}