J2ME图片缩放函数

public static Image ZoomImage(Image src, int desW, int desH) {
    Image desImg = null;
    int srcW = src.getWidth(); // 原始图像宽
    int srcH = src.getHeight(); // 原始图像高
    int[] srcBuf = new int[srcW * srcH]; // 原始图片像素信息缓存

    src.getRGB(srcBuf, 0, srcW, 0, 0, srcW, srcH);

    // 计算插值表
    int[] tabY = new int[desH];
    int[] tabX = new int[desW];

    int sb = 0;
    int db = 0;
    int tems = 0;
    int temd = 0;
    int distance = srcH > desH ? srcH : desH;
    for (int i = 0; i <= distance; i++) { /* 垂直方向 */
        tabY[db] = sb;
        tems += srcH;
        temd += desH;
        if (tems > distance) {
            tems -= distance;
            sb++;
        }
        if (temd > distance) {
            temd -= distance;
            db++;
        }
    }

    sb = 0;
    db = 0;
    tems = 0;
    temd = 0;
    distance = srcW > desW ? srcW : desW;
    for (int i = 0; i <= distance; i++) { /* 水平方向 */
        tabX[db] = (short) sb;
        tems += srcW;
        temd += desW;
        if (tems > distance) {
            tems -= distance;
            sb++;
        }
        if (temd > distance) {
            temd -= distance;
            db++;
        }
    }

    // 生成放大缩小后图形像素buf
    int[] desBuf = new int[desW * desH];
    int dx = 0;
    int dy = 0;
    int sy = 0;
    int oldy = -1;
    for (int i = 0; i < desH; i++) {
        if (oldy == tabY[i]) {
            System.arraycopy(desBuf, dy - desW, desBuf, dy, desW);
        } else {
            dx = 0;
            for (int j = 0; j < desW; j++) {
                desBuf[dy + dx] = srcBuf[sy + tabX[j]];
                dx++;
            }
            sy += (tabY[i] - oldy) * srcW;
        }
        oldy = tabY[i];
        dy += desW;
    }

    // 生成图片
    desImg = Image.createRGBImage(desBuf, desW, desH, false);
    return desImg;
}

这个函数是我以前在网上搜罗到的，且不谈效果，性能什么的。只觉得它非常好用。
用了很长时间，可惜不知道是谁。真要谢谢这位作者了。
这个函数使用了midp2.0的getRGB()函数，效率不错，基本上没什么可优化的了。
此外，下面再提供一个midp1.0下可用的缩放函数，它是使用可变图片实现的。可惜这个函数也不是我写的。
转载于kobjects。不过性能确实比较差，毕竟要画那么多点嘛，跟处理图片数据的方法是没有可比性的。
   

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package org.kobjects.lcdui;


import javax.microedition.lcdui.*;


/** This class provides a single static method that allows to scale an image */


public class ScaleImage {

    /**
     * Creates a new, scaled version of the given image.
     *
     * @param src: The source image
     * @param dstW: The destination (scaled) image width
     * @param dstH: The destination (scaled) image height
     * @return Image: A new Image object with the given width and height.
     */

    public static Image scaleImage(Image src, int dstW, int dstH) {
        int srcW = src.getWidth();
        int srcH = src.getHeight();

        Image tmp = Image.createImage(dstW, srcH);
        Graphics g = tmp.getGraphics();

        int delta = (srcW << 16) / dstW;
        int pos = delta / 2;

        for (int x = 0; x < dstW; x++) {
            g.setClip(x, 0, 1, srcH);
            g.drawImage(src, x - (pos >> 16), 0, Graphics.LEFT | Graphics.TOP);
            pos += delta;
        }

        Image dst = Image.createImage(dstW, dstH);
        g = dst.getGraphics();

        delta = (srcH << 16) / dstH;
        pos = delta / 2;

        for (int y = 0; y < dstH; y++) {
            g.setClip(0, y, dstW, 1);
            g.drawImage(tmp, 0, y - (pos >> 16), Graphics.LEFT | Graphics.TOP);
            pos += delta;
        }

        return dst;
    }


}

转自: hunhun1981的专栏 。