Java旋转图片工具类

版权声明：欢迎转载，转载请注明出处。 https://blog.csdn.net/x541211190/article/details/80784713

前言：

本文提供可以任意角度（最小精度1度），旋转图片的Java工具类，旋转后的图片不会失真或丢失边角，根据角度参数，重新绘制图片，达到无损旋转的目的。

一.图片工具类

import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * 旋转图片工具类
 * @author 大脑补丁
 *
 */
public class RotateImageUtil {

	/**
	 * 
	 * @param bufferedImage
	 *            图片
	 * @param angel
	 *            旋转角度
	 * @return
	 */
	public static BufferedImage rotateImage(BufferedImage bufferedImage, int angel) {
		if (bufferedImage == null) {
			return null;
		}
		if (angel < 0) {
			// 将负数角度，纠正为正数角度
			angel = angel + 360;
		}
		int imageWidth = bufferedImage.getWidth(null);
		int imageHeight = bufferedImage.getHeight(null);
		// 计算重新绘制图片的尺寸
		Rectangle rectangle = calculatorRotatedSize(new Rectangle(new Dimension(imageWidth, imageHeight)), angel);
	    // 获取原始图片的透明度
		int type = bufferedImage.getColorModel().getTransparency();
		BufferedImage newImage = null;
		newImage = new BufferedImage(rectangle.width, rectangle.height, type);
		Graphics2D graphics = newImage.createGraphics();
		// 平移位置
		graphics.translate((rectangle.width - imageWidth) / 2, (rectangle.height - imageHeight) / 2);
		// 旋转角度
		graphics.rotate(Math.toRadians(angel), imageWidth / 2, imageHeight / 2);
		// 绘图
		graphics.drawImage(bufferedImage, null, null);
		return newImage;
	}

	/**
	 * 旋转图片
	 * 
	 * @param image
	 *            图片
	 * @param angel
	 *            旋转角度
	 * @return
	 */
	public static BufferedImage rotateImage(Image image, int angel) {
		if (image == null) {
			return null;
		}
		if (angel < 0) {
			// 将负数角度，纠正为正数角度
			angel = angel + 360;
		}
		int imageWidth = image.getWidth(null);
		int imageHeight = image.getHeight(null);
		Rectangle rectangle = calculatorRotatedSize(new Rectangle(new Dimension(imageWidth, imageHeight)), angel);
		BufferedImage newImage = null;
		newImage = new BufferedImage(rectangle.width, rectangle.height, BufferedImage.TYPE_INT_RGB);
		Graphics2D graphics = newImage.createGraphics();
		// transform
		graphics.translate((rectangle.width - imageWidth) / 2, (rectangle.height - imageHeight) / 2);
		graphics.rotate(Math.toRadians(angel), imageWidth / 2, imageHeight / 2);
		graphics.drawImage(image, null, null);
		return newImage;
	}

	/**
	 * 计算旋转后的尺寸
	 * 
	 * @param src
	 * @param angel
	 * @return
	 */
	private static Rectangle calculatorRotatedSize(Rectangle src, int angel) {
		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 java.awt.Rectangle(new Dimension(des_width, des_height));
	}
	/**
	 * 获取网络图片流（附加）
	 * 
	 * @param url
	 * @return
	 */
	public static InputStream getImageStream(String url) {
		try {
			HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
			connection.setReadTimeout(5000);
			connection.setConnectTimeout(5000);
			connection.setRequestMethod("GET");
			if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
				InputStream inputStream = connection.getInputStream();
				return inputStream;
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}
}

二.使用示例：

我们来用此工具类，旋转百度翻译的Logo图片，并保存到本地：

图片地址：https://fanyi.bdstatic.com/static/translation/img/header/logo_cbfea26.png

1.将获取网络图片

参考：《Java获取网络图片转化为输入流》，提供Java获取网络图片的方法getImageStream(String url)。

2.旋转图片

public static void main(String[] args) {
		String url = "https://fanyi.bdstatic.com/static/translation/img/header/logo_cbfea26.png";
		// 将网络图片转为BufferedImage
		try {
			BufferedImage bufferedImage = ImageIO.read(RotateImageUtil.getImageStream(url));
			// 调用图片旋转工具类，旋转图片
			BufferedImage rotateImage = RotateImageUtil.rotateImage(bufferedImage, 45);
			// 截取URL中的图片名称和后缀
			String fileName = url.substring(url.lastIndexOf("/") + 1, url.length());
			// 截取图片后缀名（.png）,以保持图片格式不变
			String imgSuffix = url.substring(url.lastIndexOf(".") + 1, url.length());
			// 将旋转后的图片保存到D盘根目录下
			File file = new File("D:\\", fileName);
			ImageIO.write(rotateImage, imgSuffix, file);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

###3.旋转前后对比

原图：

旋转45度后：