/**
 * @(#)DrawPanel.java
 *
 * This is an interactive applet.  Allows the user to select a color from, 
 * the popupmenu. Click in the panel or as mouse enters or exits applet, draw
 * circles at mouse location.
 */
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.lang.Class;

/** 
 * Draw Panel
 * Implements Action listener. An array (colorNames) is used to store the Names
 * of the colors to be listed in the menu.  A second array (colors) is used to 
 * store the Color value associated with the string value in colorNames.  Sets 
 * the Color value using ActionListener. MouseEvent is used to detect whether or
 * not the mouse event is the popupTrigger for the popup-menu. This will show the
 * color menu at the location clicked in the applet. Then mouse event used to
 * draw circles (left mouse click) at the location clicked or on entering and 
 * exiting the applet.
 * 
 * @param: Input: None
 */

public class DrawPanel extends Applet implements ActionListener{

/** Initalize a String array with labels for the colors in the menu */
	private String[] colorNames ={"Black", "Cyan","Green",
								  "Magenta","Orange"};
/** Initalize a Color array with color values in the menu */
	private Color[] colors = {Color.black,Color.cyan, Color.green,
							  Color.magenta, Color.orange};
	private PopupMenu menu;

/** Create popup menu and add items */
	public void init(){
		setBackground(Color.white);
		menu = new PopupMenu();
/** Enable mouse events */
		enableEvents(AWTEvent.MOUSE_EVENT_MASK);
		MenuItem colorName;
/** Add items to the menu and add action Listener to each item */
		for(int i=0; i<colorNames.length; i++){
			colorName = new MenuItem(colorNames[i]);
			menu.add(colorName);
			colorName.addActionListener(this);
/** Seperate items in the menu */
			menu.addSeparator();
		}
/**Add menu */
		add(menu);
	}
/**processMouseEvent
 * Gets menu, and location of mouse click and shows the menu at 
 * the clicked location. If mouse event is not the popup-menu
 * then calls the graphics library to draw a solid oval bound 
 * by a specified rectangle. The left and top values are set to
 * the x & y coordinates - 25, and the width and size are set to
 * 20. Super processMouseEvent is called for other mouseListener 
 * events defined.
 * 
 * @param: event: Processes mouse events
 * @return: whether or not this mouse event is the popup-menu. 
 */	
	public void processMouseEvent(MouseEvent event){
		if(event.isPopupTrigger())
			menu.show(event.getComponent(), event.getX(),event.getY());
/** draw a solid oval bound by a specified rectangle. */		
			getGraphics().fillOval(event.getX()- 25,
								   event.getY()- 25,
								   20,20);
				super.processMouseEvent(event);
			
			};
/**actionPerformed
 * Sets the foreground color to the color selected from 
 * the popup-menu. getActionCommand returns the string label 
 * associated with the action.  Then calls colorNamed with the
 * label and then sets the foreground color.
 * 
 * @param: event: Called when an action occurs. 
 */	
	public void actionPerformed(ActionEvent event){
		setForeground(colorNamed(event.getActionCommand()));
	}
/**colorNamed
 * Called from actionPerformed. Sets the string label with 
 * with the color value and returns the color value.
 * 
 * @param: String label.
 * @return: the color value of the string label.
 */	
	private Color colorNamed(String colorName){
		for(int i=0; i<colorNames.length; i++)
			if(colorNames[i].equals(colorName))
			return(colors[i]);
		return(Color.black);
	}
}