java图片旋转，

java图片旋转，

转载：http://blog.csdn.net/heliang7/article/details/1088845

java实现图片旋转任意角度

下面是核心代码：

import java.awt.Dimension;  
import java.awt.Graphics2D;  
import java.awt.Image;  
import java.awt.Rectangle;  
import java.awt.image.BufferedImage;  
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

/**
 * 图片旋转工具
 * @author Bob
 *
 */
public class RotateImage {  

	public  BufferedImage Rotate(Image src, int angle) {  
		int src_width = src.getWidth(null);  
		int src_height = src.getHeight(null);  
		Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(src_width, src_height)), angle);  

		BufferedImage res = null;  
		res = new BufferedImage(rect_des.width, rect_des.height, BufferedImage.TYPE_INT_RGB);  
		Graphics2D g2 = res.createGraphics();  
		//将 Graphics2D 上下文的原点平移到当前坐标系中的点 (x, y)
		g2.translate((rect_des.width - src_width) / 2, (rect_des.height - src_height) / 2);  
		//将当前的 Graphics2D Transform 与平移后的旋转转换连接
		g2.rotate(Math.toRadians(angle), src_width / 2, src_height / 2);  

		g2.drawImage(src, null, null);  
		g2.dispose();
		return res;  
	}  
	
	/**
	 * 计算图片的新大小
	 * @param src 图片
	 * @param angle 角度
	 * @return 
	 */
	public  Rectangle CalcRotatedSize(Rectangle src, int angle) {  
		if ((angle >= 90) && (angle / 90 % 2 == 1)) {
			int temp = src.height;
			src.height = src.width;
			src.width = temp;
			angle = angle % 90;
		}

		//根据图片高宽求出旋转半径   a的平方+b的平方=c的平方   是四边形的对角线长度/2    为旋转圆的半径
		double r = Math.sqrt(src.height * src.height + src.width * src.width)/2; 
		double len = 2 * Math.sin(Math.toRadians(angle) / 2) * r;  
		double angle_alpha = (Math.PI - Math.toRadians(angle)) / 2;  
		double angle_dalta_width = Math.atan((double) src.height / src.width);  
		double angle_dalta_height = Math.atan((double) src.width / src.height);  

		int len_dalta_width = (int) (len * Math.cos(Math.PI - angle_alpha - angle_dalta_width));  
		int len_dalta_height = (int) (len * Math.cos(Math.PI - angle_alpha - angle_dalta_height));  
		int des_width = src.width + len_dalta_width * 2;  
		int des_height = src.height + len_dalta_height * 2;  
		return new Rectangle(new Dimension(des_width, des_height));  
	}  

	public static void main(String[] args) {
		try {
			BufferedImage src = ImageIO.read(new File("E:/A.png"));  
			//旋转20度
			BufferedImage des = new RotateImage().Rotate(src, 20);  
			//保存到本地
			ImageIO.write(des, "png", new File("e:/A2223.png"));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}