图片处理工具类（图片压缩与图片裁剪）

中作中由于需要对图片进行压缩和裁剪，因此参考网上的各种方法写了以下工具类

package com.qxgf.xyz0.utils;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.awt.image.ConvolveOp;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.awt.image.Kernel;
import java.io.File;

import javax.imageio.ImageIO;

/**
 * 图片处理工具类
 * @author Administrator
 * 
 */
public class ImgUtil {

	/**
	 * 图片压缩
	 * @param srcImgFile 原始图片文件
	 * @param toImgFile 压缩后保存的目标图片文件
	 */
	public static void compress(File srcImgFile, File toImgFile) {
		try {
			Image image = ImageIO.read(srcImgFile);
			int imageWidth = image.getWidth(null);
			int imageHeight = image.getHeight(null);
			float scale = 1.0f;
			if (imageWidth > 1280 || imageHeight > 1024) { //宽或高大于一定值，则进行尺寸上的压缩
				scale = getRatio(imageWidth, imageHeight, 1280, 1024);
			}
			imageWidth = (int) (scale * imageWidth);
			imageHeight = (int) (scale * imageHeight);

			image = image.getScaledInstance(imageWidth, imageHeight,Image.SCALE_AREA_AVERAGING);
			BufferedImage bufferedImage = new BufferedImage(imageWidth,imageHeight, BufferedImage.TYPE_INT_RGB);
			Graphics2D g2 = bufferedImage.createGraphics();

			g2.drawImage(image, 0, 0, imageWidth, imageHeight, Color.white,null);
			g2.dispose();

			// 以下代码用于提高图片清晰度
			float[] kernelData2 = { -0.125f, -0.125f, -0.125f, -0.125f, 2,-0.125f, -0.125f, -0.125f, -0.125f };
			Kernel kernel = new Kernel(3, 3, kernelData2);
			ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);
			bufferedImage = cOp.filter(bufferedImage, null);

			ImageIO.write(bufferedImage, "jpeg", toImgFile);
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException("图片压缩失败....");
		}
	}

	/**
	 * 获取压缩比率值
	 * @param currWidth
	 * @param currHeight
	 * @param afterWidth
	 * @param afterHeight
	 * @return
	 */
	private static float getRatio(int currWidth, int currHeight,int afterWidth, int afterHeight) {
		float ratio = 1.0f;
		float widthRatio = (float) afterWidth / currWidth;
		float heightRatio = (float) afterHeight / currHeight;
		if (widthRatio < 1.0 || heightRatio < 1.0) {
			ratio = widthRatio <= heightRatio ? widthRatio : heightRatio;
		}
		return ratio;
	}

	/**
	 * 图片裁切
	 * @param srcImgFile 原始图片文件
	 * @param toImgFile 裁切后保存的目标文件
	 * @param imgCrop 裁剪参数对象实例
	 */
	public static void crop(File srcImgFile, File toImgFile, ImgCrop imgCrop) {
		try {
			BufferedImage srcBufferedImg = ImageIO.read(srcImgFile);
			int srcWidth = srcBufferedImg.getWidth();
			int srcHeight = srcBufferedImg.getHeight();
			//由于比率精确度原因，允许20像素的误差
			int cropImgTotalWidth = imgCrop.getX() + imgCrop.getWidth();
			int cropImgTotalHeight = imgCrop.getY() + imgCrop.getHeight();
			if (srcWidth >= cropImgTotalWidth-20 && srcHeight >= cropImgTotalHeight-20) {
				ImageFilter cropFilter = null;
				if(srcWidth < cropImgTotalWidth && srcHeight < cropImgTotalHeight) {//纠正X，Y误差
					cropFilter = new CropImageFilter(imgCrop.getX(),imgCrop.getY(), srcWidth-imgCrop.getX(), srcHeight-imgCrop.getY());
				}else if(srcWidth < cropImgTotalWidth) {//纠正X误差
					cropFilter = new CropImageFilter(imgCrop.getX(),imgCrop.getY(), srcWidth-imgCrop.getX(), imgCrop.getHeight());
				}else if(srcHeight < imgCrop.getHeight()) {//纠正Y误差
					cropFilter = new CropImageFilter(imgCrop.getX(),imgCrop.getY(), imgCrop.getWidth(), srcHeight-imgCrop.getY());
				}else {
					cropFilter = new CropImageFilter(imgCrop.getX(),imgCrop.getY(), imgCrop.getWidth(), imgCrop.getHeight());
				}
				Image img = Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(srcBufferedImg.getSource(),cropFilter));
				BufferedImage toBufferedImg = new BufferedImage(imgCrop.getWidth(), imgCrop.getHeight(),BufferedImage.TYPE_INT_RGB);
				Graphics g = toBufferedImg.getGraphics();
				g.drawImage(img, 0, 0, null);
				g.dispose();
				ImageIO.write(toBufferedImg,FunctionUtil.getFileSuffix(toImgFile.getName()),toImgFile);
			}
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException("图片裁剪失败....");
		}
	}

	/**
	 * 图片裁剪信息包装类
	 * @author Administrator
	 */
	public static class ImgCrop {
		private Integer x; //起点X坐标
		private Integer y; //起点Y坐标
		private Integer width;//宽度
		private Integer height;//高度
		private Float ratio = 1.0f; //参数比率（因为图片的裁剪可能并不是在原图大小上进行的）
		
		public ImgCrop() {}

		public ImgCrop(Integer x, Integer y, Integer width, Integer height, Float ratio) {
			this.x = x;
			this.y = y;
			this.width = width;
			this.height = height;
			this.ratio = ratio == null ? this.ratio : ratio;
		}

	

		public Integer getX() {
			//取最小整数，不可用四舍五入法，否则可能导致裁剪值超出范围
			return Math.round(ratio*x - 0.5f); 
		}

		public void setX(Integer x) {
			this.x = x;
		}

		public Integer getY() {
			//取最小整数，不可用四舍五入法，否则可能导致裁剪值超出范围
			return Math.round(ratio*y - 0.5f);
		}

		public void setY(Integer y) {
			this.y = y;
		}

		public Integer getWidth() {
			//取最小整数，不可用四舍五入法，否则可能导致裁剪值超出范围
			return Math.round(ratio*width - 0.5f);
		}

		public void setWidth(Integer width) {
			this.width = width;
		}

		public Integer getHeight() {
			//取最小整数，不可用四舍五入法，否则可能导致裁剪值超出范围
			return Math.round(ratio*height - 0.5f);
		}

		public void setHeight(Integer height) {
			this.height = height;
		}

		public Float getRatio() {
			return ratio;
		}

		public void setRatio(Float ratio) {
			this.ratio = ratio;
		}

	}

}