J2ME综合:如何在MIDP中实现图片放缩

　　

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

/**
 * 图像工具类
 * @author Jagie
 *
 */
public class ImageUtil {
    /**
     * 图像放缩方法
     * @param srcImage 原始的Image对象
     * @param newW 放缩后的Image的宽度
     * @param newH 放缩后的Image的高度
     * @return 放缩后的Image对象
     */
    public static final Image scale(Image srcImage, int newW, int newH) {
        int srcW = srcImage.getWidth();
        int srcH = srcImage.getHeight();
        //先做水平方向上的伸缩变换
        Image tmp = Image.createImage(newW, srcH);
        Graphics g = tmp.getGraphics();
        for (int x = 0; x < newW; x++) {
            g.setClip(x, 0, 1, srcH);
            //按比例放缩
            g.drawImage(srcImage, x - x * srcWnewW, 0,
                        Graphics.LEFT | Graphics.TOP);
        }
        //再做垂直方向上的伸缩变换
        Image dst = Image.createImage(newW, newH);
        g = dst.getGraphics();
        for (int y = 0; y < newH; y++) {
            g.setClip(0, y, newW, 1);
            //按比例放缩
            g.drawImage(tmp, 0, y - y * srcHnewH, Graphics.LEFT | Graphics.TOP);
        }
        return dst;
    }
}


//也许有同学会提出疑问，既然是按x,y方向按等比例放缩，那我写成这样岂不是代码更简洁:
public static final Image scale2(Image srcImage, int newW, int newH) {
    int srcW = srcImage.getWidth();
    int srcH = srcImage.getHeight();
    Image dst = Image.createImage(newW, newH);
    Graphics g = dst.getGraphics();
    for (int x = 0; x < newW; x++) {
        for (int y = 0; y < newH; y++) {
            g.setClip(x, y, 1, 1);
            g.drawImage(srcImage, x - x * srcWnewW, y - y * srcH / newH,
                        Graphics.LEFT
                        | Graphics.TOP);
        }
    }
    return dst;
}