Java实现的图片高质量缩放类定义与用法示例

package com.test;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import javax.swing.*;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.Kernel;
import java.awt.image.ConvolveOp;
public class ImageUtil {
  public static void resize(File originalFile,File resizedFile,int newWidth,float quality) throws IOException {
    if (quality > 1) {
      throw new IllegalArgumentException(
          "Quality has to be between 0 and 1");
    }
    ImageIcon ii = new ImageIcon(originalFile.getCanonicalPath());
    Image i = ii.getImage();
    Image resizedImage = null;
    int iWidth = i.getWidth(null);
    int iHeight = i.getHeight(null);
    if (iWidth > iHeight) {
      resizedImage = i.getScaledInstance(newWidth,(newWidth * iHeight)
          / iWidth,Image.SCALE_SMOOTH);
    } else {
      resizedImage = i.getScaledInstance((newWidth * iWidth) / iHeight,newWidth,Image.SCALE_SMOOTH);
    }
    // This code ensures that all the pixels in the image are loaded.
    Image temp = new ImageIcon(resizedImage).getImage();
    // Create the buffered image.
    BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null),temp.getHeight(null),BufferedImage.TYPE_INT_RGB);
    // Copy image to buffered image.
    Graphics g = bufferedImage.createGraphics();
    // Clear background and paint the image.
    g.setColor(Color.white);
    g.fillRect(0,temp.getWidth(null),temp.getHeight(null));
    g.drawImage(temp,null);
    g.dispose();
    // Soften.
    float softenFactor = 0.05f;
    float[] softenArray = { 0,softenFactor,1 - (softenFactor * 4),0 };
    Kernel kernel = new Kernel(3,3,softenArray);
    ConvolveOp cOp = new ConvolveOp(kernel,ConvolveOp.EDGE_NO_OP,null);
    bufferedImage = cOp.filter(bufferedImage,null);
    // Write the jpeg to a file.
    FileOutputStream out = new FileOutputStream(resizedFile);
    // Encodes image as a JPEG data stream
    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
    JPEGEncodeParam param = encoder
        .getDefaultJPEGEncodeParam(bufferedImage);
    param.setQuality(quality,true);
    encoder.setJPEGEncodeParam(param);
    encoder.encode(bufferedImage);
  } // Example usage
  public static void main(String[] args) throws IOException {
//    File originalImage = new File("C:11.jpg");
//    resize(originalImage,new File("c:11-0.jpg"),150,0.7f);
//    resize(originalImage,new File("c:11-1.jpg"),1f);
     File originalImage = new File("C:1207.gif");
     resize(originalImage,new File("c:1207-0.jpg"),0.7f);
     resize(originalImage,new File("c:1207-1.jpg"),1f);
  }
}