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java高质量缩放图片
编辑时间:2018-10-24 11:31:48 作者:田泽 浏览量:677

可按照比例缩放,也可以指定宽高

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 {
/**
*
* @param originalFile 原文件
* @param resizedFile 压缩目标文件
* @param newWidth 压缩后的图片宽度
* @param quality 压缩质量(0到1之间,越高质量越好)
* @throws IOException
*/

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);
//比例缩放
if (iWidth > iHeight) {
resizedImage = i.getScaledInstance(newWidth, (newWidth * iHeight)
/ iWidth, Image.SCALE_SMOOTH);
} else {
resizedImage = i.getScaledInstance((newWidth * iWidth) / iHeight,
newWidth, Image.SCALE_SMOOTH);
}
//指定宽高
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, 0, temp.getWidth(null), temp.getHeight(null));
g.drawImage(temp, 0, 0, null);
g.dispose();

// Soften.
float softenFactor = 0.05f;
float[] softenArray = { 0, softenFactor, 0, softenFactor,
1 - (softenFactor * 4), softenFactor, 0, softenFactor, 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:P7.gif");
resize(originalImage, new File("c:P7-0.jpg"),150, 0.7f);
resize(originalImage, new File("c:P7-1.jpg"),150, 1f);
}
}



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