scribble.java

CroftSoft Code Library是一个开源的可移植的纯Java游戏库

     package com.croftsoft.apps.scribble;

     import java.applet.*;
     import java.awt.*;

     import com.croftsoft.core.lang.lifecycle.Lifecycle;

     /*********************************************************************
     * Use your mouse to draw on a canvas in multiple colors.
     *
     * @see
     *   Java in a Nutshell, First Edition
     *
     * @version
     *   2002-02-27
     * @since
     *   1996
     * @author
     *   <a href="http://www.croftsoft.com/">David Wallace Croft</a>
     *********************************************************************/

     public final class  Scribble
       extends Applet
       implements Lifecycle
     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////
     {

	private int last_x = 0;
	private int last_y = 0;
	private Color current_color = Color.black;
	private Button clear_button;
	private Choice color_choices;


    public void init() {
	this.setBackground ( Color.white );
	clear_button = new Button ( "Clear" );
     clear_button.setForeground ( Color.magenta );
     clear_button.setBackground ( Color.black );
	this.add ( clear_button );
	color_choices = new Choice ( );
	color_choices.addItem ( "black" );
	color_choices.addItem ( "red" );
	color_choices.addItem ( "yellow" );
	color_choices.addItem ( "green" );
	color_choices.setForeground ( Color.black );
	color_choices.setBackground ( Color.lightGray );
	this.add ( new Label ( "Color:  " ) );
	this.add ( color_choices );
    }

    public boolean mouseDown ( Event e, int x, int y ) {
	last_x = x;
	last_y = y;
	return true;
    }

    public boolean mouseDrag ( Event e, int x, int y ) {
	Graphics g = this.getGraphics ( );
	g.setColor ( current_color );
	g.drawLine ( last_x, last_y, x, y );
	last_x = x;
	last_y = y;
	return true;
    }

    public boolean action ( Event event, Object arg ) {
	if ( event.target == clear_button ) {
		Graphics g = this.getGraphics ( );
		Rectangle r = this.bounds ( );
		g.setColor ( this.getBackground ( ) );
		g.fillRect ( r.x, r.y, r.width, r.height );
		return true;
	}
	else if ( event.target == color_choices ) {
		if ( arg.equals ( "black" ) ) current_color = Color.black;
		else if ( arg.equals ( "red" ) ) current_color = Color.red;
		else if ( arg.equals ( "yellow" ) ) current_color = Color.yellow;
		else if ( arg.equals ( "green" ) ) current_color = Color.green;
		return true;
	}
	else return super.action ( event, arg );
    }

}