package platform.edu.resource.utils;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
/**
 * 圖片工具類
 * @author hjn
 * @version 1.0 2013-11-26
 *
 */
public class ImageUtil {
/**
 * 圖片等比縮放居中剪裁
 * 不管尺寸不等的圖片生成的縮略圖都是同一尺寸，方便用于頁面展示
 * @param imageSrc圖片所在路徑
 * @param thumbWidth縮略圖寬度
 * @param thumbHeight縮略圖長度
 * @param outFilePath縮略圖存放路徑
 * @throws InterruptedException
 * @throws IOException
 */
public static void createImgThumbnail(String imgSrc, int thumbWidth, int thumbHeight, String outFilePath) throws InterruptedException, IOException {
File imageFile=new File(imgSrc);
BufferedImage image = ImageIO.read(imageFile);
Integer width = image.getWidth();
Integer height = image.getHeight();
double i = (double) width / (double) height;
double j = (double) thumbWidth / (double) thumbHeight;
int[] d = new int[2];
int x = 0;
int y = 0;
if (i > j) {
d[1] = thumbHeight;
d[0] = (int) (thumbHeight * i);
y = 0;
x = (d[0] - thumbWidth) / 2;
} else {
d[0] = thumbWidth;
d[1] = (int) (thumbWidth / i);
x = 0;
y = (d[1] - thumbHeight) / 2;
}
File outFile = new File(outFilePath);
if (!outFile.getParentFile().exists()) {
outFile.getParentFile().mkdirs();
}
/*等比例縮放*/
BufferedImage newImage = new BufferedImage(d[0],d[1],image.getType());
    Graphics g = newImage.getGraphics();
    g.drawImage(image, 0,0,d[0],d[1],null);
    g.dispose();
    /*居中剪裁*/
newImage = newImage.getSubimage(x, y, thumbWidth, thumbHeight);
ImageIO.write(newImage, imageFile.getName().substring(imageFile.getName().lastIndexOf(".") + 1), outFile);
}
}