/** 
  * Map Scale Selection Panel for Rob's Moving Map package
  * @author Robert J Morton YE572246C
  * @version 27 November 1997
*/
/*  This class contains a group of 3 radio buttons for choosing which of the
    three map scales is to be used. */

import javax.swing.*;     // Java Swing GUI utilities
import java.awt.*;        // Java Abstract Windowing Toolkit
import java.awt.event.*;  // for the new-fangled 1.1 event handling

public class selmap extends JPanel implements navconst {

  // what the hell this is for, I don't know!
  private static final long serialVersionUID = 2011L;

  private static selmap sm;  // reference to current object
  private airmap am;         // reference to the air map object
  private movmap mm;         // object reference to the main applet
  private Color bg;          // background colour for buttons
  private int I = 3;         // number of buttons
  private ButtonGroup G;     // reference for a JRadioButton group

  // references to the individual JRadioButtones within the Group
  private JRadioButton a, b, c;

  private double 
    Scale,  // scaling factor of currently-selected map size
    S[],    // array for the 3 possible scaling factors
    da,     // angular increment for drawing guide circle dots
    A[];    // array of the above for each of the 3 map sizes


  selmap(movmap mm) {  // construct the radio button panel
    sm = this;         // reference to sel map object
    this.bg = bg;      // background colour for selector buttons
    this.mm = mm;      // local variable for object reference to main applet
    setOpaque(false);

    // to make the buttons lie in a single column
    setLayout(new GridLayout(I,1 ));

    G = new ButtonGroup();   // Create a Group for the following buttons

    // Create and add the radio buttons to the Group and to this panel.
    a = new JRadioButton("", false); G.add(a); add(a); 
    b = new JRadioButton("", true);  G.add(b); add(b); 
    c = new JRadioButton("", false); G.add(c); add(c); 

    // Create Item Listeners for them and set them transparent.
    a.addItemListener(new mapbut(0, this)); a.setOpaque(false);
    b.addItemListener(new mapbut(1, this)); b.setOpaque(false);
    c.addItemListener(new mapbut(2, this)); c.setOpaque(false);

    S = new double[3];     // create the array for the scaling factors
    S[0] = KPR;            // scaling factor for 300 by 300 map
    S[1] = KPR * 3 / 2;    // scaling factor for 200 by 200 map
    S[2] = KPR * 3;        // scaling factor for 100 by 100 map
    Scale = S[1];          // preselect 200 by 200 as default scale

    A = new double[3];     // create array for map sizes
    A[2] = Math.PI / 120;  // does 120 dots round the guide circle
    A[1] = Math.PI / 80;   // does 80 dots round the guide circle
    A[0] = Math.PI / 40;   // does 40 dots round the guide circle
    da = A[1];             // circle incrementer for drawing guide circles
  }

  void setAirmap(airmap am) {this.am = am;}

  void selectMap(int i) {  // MAP SCALE i HAS JUST BEEN SELECTED
    Scale = S[i];          // so set the appropriate scaling factor
    da = A[i];             // set angular increment for drawing guide
    am.atualizar();        // circle dots then update the air map.
  }

  double getScale(){return Scale;}  // access the currently selected map scale
  double getMapSize(){return da;}   // return map size selection range 1 to 3
}


// LISTENS FOR EVENTS FROM THE MAP SCALE SELECTION BUTTONS
class mapbut implements ItemListener {
  int id;     // one of the above events
  selmap ap;  // the application that called: always the above applet!

  // constructor for a new JRadioButton event
  public mapbut(int id, selmap ap) {
    this.id = id;  // set id number pertaining to this instance of 'mapbut'
    this.ap = ap;  // set the reference to the instance of the applet
  }                // from which it came. (there will only be one instance)

  // a JRadioButton event has occurred from JRadioButton 'id'
  public void itemStateChanged(ItemEvent e) {
    switch(id) {
      case 0: ap.selectMap(0); break;
      case 1: ap.selectMap(1); break;
      case 2: ap.selectMap(2);
    }
  }
}