source: josm/trunk/src/org/openstreetmap/josm/gui/MapScaler.java@ 9997

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.gui;

import static org.openstreetmap.josm.gui.help.HelpUtil.ht;
import static org.openstreetmap.josm.tools.I18n.marktr;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.geom.Rectangle2D;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleValue;
import javax.swing.JComponent;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.gui.help.Helpful;

/**
 * Map scale bar, displaying the distance in meter that correspond to 100 px on screen.
 * @since 115
 */
public class MapScaler extends JComponent implements Helpful, Accessible {

    private final NavigatableComponent mv;

    private static final int PADDING_RIGHT = 100;

    /**
     * Constructs a new {@code MapScaler}.
     * @param mv map view
     */
    public MapScaler(NavigatableComponent mv) {
        this.mv = mv;
        setSize(100+PADDING_RIGHT, 30);
        setOpaque(false);
    }

    @Override
    public void paint(Graphics g) {
        String text = mv.getDist100PixelText();
        Rectangle2D bound = g.getFontMetrics().getStringBounds(text, g);
        g.setColor(getColor());
        g.drawLine(0, 5, 99, 5);
        g.drawLine(0, 0, 0, 10);
        g.drawLine(99, 0, 99, 10);
        g.drawLine(49, 3, 49, 7);
        g.drawLine(24, 3, 24, 7);
        g.drawLine(74, 3, 74, 7);
        g.drawString(text, (int) (100-bound.getWidth()/2), 23);
        g.drawString("0", 0, 23);
    }

    /**
     * Returns the color of map scaler.
     * @return the color of map scaler
     */
    public static Color getColor() {
        return Main.pref.getColor(marktr("scale"), Color.white);
    }

    @Override
    public String helpTopic() {
        return ht("/MapView/Scaler");
    }

    @Override
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleMapScaler();
        }
        return accessibleContext;
    }

    class AccessibleMapScaler extends AccessibleJComponent implements AccessibleValue {

        @Override
        public Number getCurrentAccessibleValue() {
            return mv.getDist100Pixel();
        }

        @Override
        public boolean setCurrentAccessibleValue(Number n) {
            return false;
        }

        @Override
        public Number getMinimumAccessibleValue() {
            return null;
        }

        @Override
        public Number getMaximumAccessibleValue() {
            return null;
        }
    }
}