J2ME中对Image的缩放

a sniplet from the article "Taking Pictures with MMAPI"
http://developers.sun.com/techtopics/mobility/midp/articles/picture/
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创建缩略图
MIDP2.0中可以对图片中的像素进行操作，在MIDP1.0中则不然。本例用Graphics.setClip()实现每一次对一个像素进行绘制。
private Image createThumbnail(Image image) {
int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();

int thumb;
int thumbHeight = -1;

if (thumbHeight == -1)
thumbHeight = thumbWidth * sourceHeight / sourceWidth;

Image thumb = Image.createImage(thumbWidth, thumbHeight);
Graphics g = thumb.getGraphics();

for (int y = 0; y < thumbHeight; y++) {
for (int x = 0; x < thumbWidth; x++) {
g.setClip(x, y, 1, 1);
int dx = x * sourceWidth / thumbWidth;
int dy = y * sourceHeight / thumbHeight;
g.drawImage(image, x - dx, y - dy,
Graphics.LEFT | Graphics.TOP);
}
}

Image immutableThumb = Image.createImage(thumb);

return immutableThumb;
}