java 图片旋转

转载自：http://blog.csdn.net/mengfei86/article/details/6821553

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Transparency;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;

public class ImageChange {

	public static InputStream rotateImg(BufferedImage image, int degree, Color bgcolor) throws IOException {

		int iw = image.getWidth();//原始图象的宽度 
		int ih = image.getHeight();//原始图象的高度
		int w = 0;
		int h = 0;
		int x = 0;
		int y = 0;
		degree = degree % 360;
		if (degree < 0)
			degree = 360 + degree;//将角度转换到0-360度之间
		double ang = Math.toRadians(degree);//将角度转为弧度

		/**
		 *确定旋转后的图象的高度和宽度
		 */

		if (degree == 180 || degree == 0 || degree == 360) {
			w = iw;
			h = ih;
		} else if (degree == 90 || degree == 270) {
			w = ih;
			h = iw;
		} else {
			int d = iw + ih;
			w = (int) (d * Math.abs(Math.cos(ang)));
			h = (int) (d * Math.abs(Math.sin(ang)));
		}

		x = (w / 2) - (iw / 2);//确定原点坐标
		y = (h / 2) - (ih / 2);
		BufferedImage rotatedImage = new BufferedImage(w, h, image.getType());
		Graphics2D gs = (Graphics2D)rotatedImage.getGraphics();
		if(bgcolor==null){
			rotatedImage  = gs.getDeviceConfiguration().createCompatibleImage(w, h, Transparency.TRANSLUCENT);
		}else{
			gs.setColor(bgcolor);
			gs.fillRect(0, 0, w, h);//以给定颜色绘制旋转后图片的背景
		}
		
		AffineTransform at = new AffineTransform();
		at.rotate(ang, w / 2, h / 2);//旋转图象
		at.translate(x, y);
		AffineTransformOp op = new AffineTransformOp(at, AffineTransformOp.TYPE_BICUBIC);
		op.filter(image, rotatedImage);
		image = rotatedImage;
		
		ByteArrayOutputStream  byteOut= new ByteArrayOutputStream();
		ImageOutputStream iamgeOut = ImageIO.createImageOutputStream(byteOut);
		
		ImageIO.write(image, "png", iamgeOut);
		InputStream  inputStream = new ByteArrayInputStream(byteOut.toByteArray());
		
		return inputStream;
	}
	
	
}