package zh.test.utils;
 
import java.awt.*;
import java.awt.image.BufferedImage;
 
/**
 * 圖片旋轉工具類
 */
public class RotateImage {
 
  /**
   * 對圖片進行旋轉
   *
   * @param src  被旋轉圖片
   * @param angel 旋轉角度
   * @return 旋轉后的圖片
   */
  public static BufferedImage Rotate(Image src, int angel) {
    int src_width = src.getWidth(null);
    int src_height = src.getHeight(null);
    // 計算旋轉后圖片的尺寸
    Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(
        src_width, src_height)), angel);
    BufferedImage res = null;
    res = new BufferedImage(rect_des.width, rect_des.height,
        BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = res.createGraphics();
    // 進行轉換
    g2.translate((rect_des.width - src_width) / 2,
        (rect_des.height - src_height) / 2);
    g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2);
 
    g2.drawImage(src, null, null);
    return res;
  }
 
  /**
   * 計算旋轉后的圖片
   *
   * @param src  被旋轉的圖片
   * @param angel 旋轉角度
   * @return 旋轉后的圖片
   */
  public static Rectangle CalcRotatedSize(Rectangle src, int angel) {
    // 如果旋轉的角度大于90度做相應的轉換
    if (angel >= 90) {
      if (angel / 90 % 2 == 1) {
        int temp = src.height;
        src.height = src.width;
        src.width = temp;
      }
      angel = angel % 90;
    }
 
    double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
    double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
    double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
    double angel_dalta_width = Math.atan((double) src.height / src.width);
    double angel_dalta_height = Math.atan((double) src.width / src.height);
 
    int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha
        - angel_dalta_width));
    int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
        - angel_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));
  }
}

package zh.test.controller;
 
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import zh.test.utils.RotateImage;
 
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
 
/**
 * 測試圖片旋轉
 */
@RestController
@RequestMapping(value = "/test")
public class TestController {
 
  @RequestMapping(method = RequestMethod.POST)
  public void testImgRotate(MultipartFile multipartFile) throws Exception {
    BufferedImage src = ImageIO.read(multipartFile.getInputStream());
    //順時針旋轉90度
    BufferedImage des1 = RotateImage.Rotate(src, 90);
    ImageIO.write(des1, "jpg", new File("e:/90.jpg"));
    //順時針旋轉180度
    BufferedImage des2 = RotateImage.Rotate(src, 180);
    ImageIO.write(des2, "jpg", new File("c:/180.jpg"));
    //順時針旋轉270度
    BufferedImage des3 = RotateImage.Rotate(src, 270);
    ImageIO.write(des3, "jpg", new File("c:/270.jpg"));
 
  }
 
}