j2me图片的高效翻转

转自: imuse的专栏

在MIDP1.0中开发者自己实现翻转，在MIDP2.0中系统已经提供了翻转方法，但有些机型翻转效果不正确（厂商实现问题），所以自己实现翻转
方法。本想一次将图读到一个int数数组，然后进行变换，但如果图片过大，会内存溢出，所以通过对图片的每行进行变换来达到高效翻转。如果你有更高效的方
法欢迎讨论。

import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;

/** *//** 
 * @功能：实现图片的高效翻转
 * @作者: imuse
 * @MAIL: postzhu@hotmail.com
 *  
 */

public class ImageUtil …{
    

    /** *//**
     * 无变化
     * */
    public final static int TRANS_NONE = 0;

    /** *//**
     * 顺时针翻转90度
     * */
    public final static int TRANS_ROT90 = 5;

    /** *//**
     * 顺时针翻转180度
     * */
    public final static int TRANS_ROT180 = 3;

    /** *//**
     * 顺时针翻转270度
     * */
    public final static int TRANS_ROT270 = 6;
    
    /** *//**
     * 水平镜像翻转
     * */
    public final static int TRANS_MIRROR = 2;

    /** *//**
     * 水平镜像翻转并顺时针翻转90度
     * */
    public final static int TRANS_MIRROR_ROT90 = 7;

    /** *//**
     * 水平镜像翻转并顺时针翻转180度
     * */
    public final static int TRANS_MIRROR_ROT180 = 1;

    /** *//**
     * 水平镜像翻转并顺时针翻转270度
     * */
    public final static int TRANS_MIRROR_ROT270 = 4;

    /** *//**
     * @功能 实现图片的翻转
     * @参数 Image srcImage    原图<br>int transform 翻转方向<br>
     * @返回值 转换后的图片
     * */
    public static Image transformImage(Image srcImage, int transform) …{
        int srcW = srcImage.getWidth();
        int srcH = srcImage.getHeight();

        Image imgRet = null;
        switch (transform) …{
        case TRANS_NONE:
            imgRet = srcImage;
            break;
        case TRANS_ROT90: 
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        951
                 *         5678        062
                 *         90ab        a73
                 *                     b84
                 * */
                int[] srcRGB = new int[srcW];
    
                imgRet = Image.createImage(srcH, srcW);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    g.drawRGB(srcRGB, 0, 1, srcH – i – 1, 0, 1, srcW, true);
                }
            }
            break;
        case TRANS_ROT180: 
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        ba09
                 *         5678        8765
                 *         90ab        4321
                 *                     
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcW, srcH);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    arrayExchange(srcRGB);
                    g.drawRGB(srcRGB, 0, srcW, 0, srcH–1–i, srcW, 1, true);
                }
            }
            break;
        case TRANS_ROT270: 
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        48b
                 *         5678        37a
                 *         90ab        260
                 *                     159
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcH, srcW);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    arrayExchange(srcRGB);
                    g.drawRGB(srcRGB, 0, 1, i, 0, 1, srcW, true);
                }
            }
            break;
        case TRANS_MIRROR: 
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        4321
                 *         5678        8765
                 *         90ab        ba09
                 *                     
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcW, srcH);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    arrayExchange(srcRGB);
                    g.drawRGB(srcRGB, 0, srcW, 0, i, srcW, 1, true);
                }
            }
            break;
        case TRANS_MIRROR_ROT90: 
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        b84
                 *         5678        a73
                 *         90ab        062
                 *                     951
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcH, srcW);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    arrayExchange(srcRGB);
                    g.drawRGB(srcRGB, 0, 1, srcH – i – 1, 0, 1, srcW, true);
                }
            }
            break;
        case TRANS_MIRROR_ROT180:
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        90ab
                 *         5678        5678
                 *         90ab        1234
                 *                     
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcW, srcH);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    g.drawRGB(srcRGB, 0, srcW, 0, srcH–1–i, srcW, 1, true);
                }
            }
            break;
        case TRANS_MIRROR_ROT270:
            …{
                /** *//**
                 * 原:            目标:
                 *         1234        159
                 *         5678        260
                 *         90ab        37a
                 *                     48b
                 * */
                int[] srcRGB = new int[srcW];
                
                imgRet = Image.createImage(srcH, srcW);
                Graphics g = imgRet.getGraphics();
                for (int i = 0; i < srcH; i++) …{
                    srcImage.getRGB(srcRGB, 0, srcW, 0, i, srcW, 1);
                    g.drawRGB(srcRGB, 0, 1, i, 0, 1, srcW, true);
                }
            }
            break;
        default:
            imgRet = srcImage;
            break;
        }
        return imgRet;
    }

    /** *//**
     * @功能 翻转一个INT数组
     * @参数 要转换的INT数组
     * @返回值    无
     * */
    public static final void arrayExchange(int[] b)…{
        int nCount = b.length;
        int nLen = nCount/2;
        nCount—;
        
        for (int i = 0; i < nLen; i++) …{
            int nTemp = b[i];
            b[i] = b[nCount–i];
            b[nCount–i] = nTemp;
        }
    }
}