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。
/* Copyright (c) 2002,2003, Stefan Haustein, Oberhausen, Rhld., Germany
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the “Software”), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE. */
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;
}
}
它们的使用方法都是一目了然，提供原始图片对象以及目标宽度跟高度，它就生成新的图片，在成像效果上，感觉都差不多，我觉得第一个方法更好。
在J2ME平台下，也没有必要去最求效果的极致，够用就好。再次感谢以上两个函数的作者。
转自: hunhun1981的专栏 。