老生常谈了，直接看代码。bufferedimage.getColorModel().getTransparency()以获得原始图片透明度用于生成缓存图，在缓存图进行相应操作即可。
/**
* 旋转图片为指定角度
*
* @param bufferedimage
* 目标图像
* @param degree
* 旋转角度
* @return
*/
public static BufferedImage rotateImage(final BufferedImage bufferedimage,
final int degree) {
int w = bufferedimage.getWidth();
int h = bufferedimage.getHeight();
int type = bufferedimage.getColorModel().getTransparency();
BufferedImage img;
Graphics2D graphics2d;
(graphics2d = (img = new BufferedImage(w, h, type))
.createGraphics()).setRenderingHint(
RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
graphics2d.rotate(Math.toRadians(degree), w / 2, h / 2);
graphics2d.drawImage(bufferedimage, 0, 0, null);
graphics2d.dispose();
return img;
}
/**
* 变更图像为指定大小
*
* @param bufferedimage
* 目标图像
* @param w
* 宽
* @param h
* 高
* @return
*/
public static BufferedImage resizeImage(final BufferedImage bufferedimage,
final int w, final int h) {
int type = bufferedimage.getColorModel().getTransparency();
BufferedImage img;
Graphics2D graphics2d;
(graphics2d = (img = createImage(w, h, type))
.createGraphics()).setRenderingHint(
RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
graphics2d.drawImage(bufferedimage, 0, 0, w, h, 0, 0, bufferedimage
.getWidth(), bufferedimage.getHeight(), null);
graphics2d.dispose();
return img;
}
/**
* 水平翻转图像
*
* @param bufferedimage 目标图像
* @return
*/
public static BufferedImage flipImage(final BufferedImage bufferedimage) {
int w = bufferedimage.getWidth();
int h = bufferedimage.getHeight();
BufferedImage img;
Graphics2D graphics2d;
(graphics2d = (img = createImage(w, h, bufferedimage
.getColorModel().getTransparency())).createGraphics())
.drawImage(bufferedimage, 0, 0, w, h, w, 0, 0, h, null);
graphics2d.dispose();
return img;
}
本文转自 cping 51CTO博客，原文链接:http://blog.51cto.com/cping1982/130066
