TestWatermark.java

package com.zdcf.test;

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.imageio.ImageIO;
public class TestWatermark {
/**
* 图片水印
* @param pressimg 水印图片
* @param targetimg 目标图片
* @param location 位置：1、左上角，2、右上角，3、左下角，4、右下角，5、正中间
* @param alpha 透明度
*/
public static void pressImage(String pressimg, String targetimg, int location, float alpha) {
try {
//读取目标图片
File img = new File(targetimg);
Image src = ImageIO.read(img);
int width = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
g.drawImage(src, 0, 0, width, height, null);
//水印文件
Image src_biao = ImageIO.read(new File(pressimg));
int width_biao = src_biao.getWidth(null);
int height_biao = src_biao.getHeight(null);
//如果水印图片高或者宽大于目标图片是做的处理,使其水印宽或高等于目标图片的宽高，并且等比例缩放
int new_width_biao = width_biao;
int new_height_biao = height_biao;
if(width_biao > width){
new_width_biao = width;
new_height_biao = (int) ((double)new_width_biao/width_biao*height);
}
if(new_height_biao > height){
new_height_biao = height;
new_width_biao = (int) ((double)new_height_biao/height_biao*new_width_biao);
}
//根据位置参数确定坐标位置
int x = 0;
int y = 0;
switch(location)
{
case 1:
break;
case 2:
	x = width - new_width_biao;
break;
case 3:
y = height - new_height_biao;
break;
case 4:
	x = width - new_width_biao;
	y = height -new_height_biao;
break;
case 5:
	x = (width - new_width_biao)/2;
	y = (height - new_height_biao)/2;
break;
default:
break;
}
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
g.drawImage(src_biao, x, y, new_width_biao, new_height_biao, null);
//水印文件结束
g.dispose();
ImageIO.write( image, "png", img);
} catch (Exception e) {
e.printStackTrace();
}
}
}