pixelator.java

这是我编写的第一个J2ME程序

/*
 * Copyright (c) 2002, 2003 Sun Microsystems, Inc. All Rights Reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistribution of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * - Redistribution in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Sun Microsystems, Inc., 'Java', 'Java'-based
 * names, or the names of contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * You acknowledge that this software is not designed, licensed or
 * intended for use in the design, construction, operation or maintenance
 * of any nuclear facility. $Id: Pixelator.java,v 1.1 2003/05/16 00:16:01 zull Exp $
 */
package com.sun.j2me.blueprints.slugs.client;

import com.sun.j2me.blueprints.slugs.shared.*;
import java.util.Hashtable;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.Graphics;

public class Pixelator {
    private static String color_key;
    private static int[] color_value;
    private static Hashtable images;
    static {
        images = new Hashtable();
    } 

    /**
     * Set up the color table for the pixelator. color_key is a string of
     * color keys, a list of characters, where each character represents
     * one color. Keys should be unique, if you pick 'g' for green, you
     * should use something else for gray. color_value is an array of
     * the actual RGB values for the colors. The lengths of color_key and
     * color_value need to be equal. color_value[0] holds the RGB value
     * for color_key[0], and so forth.
     */
    public static void setColors(String color_key, int[] color_value) {
        if (color_key.length() != color_value.length) {
            throw new RuntimeException("mismatched length for color keys and values");
        } 

        // be defensive, make copies of the values
        // that are being passed in
        Pixelator.color_key = new String(color_key);
        Pixelator.color_value = new int[color_value.length];

        for (int i = 0; i < color_value.length; i++) {
            Pixelator.color_value[i] = color_value[i];
        } 
    } 

    /**
     * Create an image based on a description in 'pattern'. Please note that
     * setColors() needs to be called at least once before the first call
     * to this method, to intialize the color table. 'pattern' is a list
     * of color keys (these keys need to match the ones you set with setColors()),
     * 'image_width' is the width of the image in pixels. The pixelator has an
     * internal image cache, from which it will first try to retrieve the image.
     * If the image is not already defined, it will be created here, and stored
     * in the cache for future reference. To better visualize the image you are
     * creating, you might want to format your source as shown below:
     * <p><code>
     * 
     * String pattern = ""
     * + "..........."
     * + "....XXX...."
     * + "..XXXXXXX.."
     * + ".X.X.X.X.X."
     * + "XX.X.X.X.XX"
     * + ".X.X.X.X.X."
     * + "..XXXXXXX.."
     * + "....XXX...."
     * + "...........";
     * 
     * Pixelator.setColors(".X", new int[] {0x000000, 0x0xffff00});
     * Image img = Pixelator.createImage(pattern, 11);
     * 
     * <p></code>
     */
    public static Image createImage(String pattern, int image_width) {
        Image img;
        int x, y, n, len;

        if (color_key == null) {
            throw new RuntimeException("colors not set up");
        } 

        img = (Image) images.get(pattern);

        if (img != null) {
            return img;
        } 

        len = pattern.length();
        img = Image.createImage(image_width, len / image_width);

        Graphics g = img.getGraphics();

        for (y = 0; y < len / image_width; y++) {
            for (x = 0; x < image_width; x++) {
                n = color_key.indexOf(pattern.charAt(y * image_width + x));

                if (n < 0) {
                    throw new RuntimeException("illegal color");
                } 

                g.setColor(color_value[n]);
                g.drawLine(x, y, x, y);
            } 
        } 

        images.put(pattern, img);

        return img;
    } 

}