圖片水印的處理詳解

import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;

import javax.imageio.ImageIO;

public class WaterMark {
    /**
     * 圖片水印處理
     * @param srcImgPath 原圖片路徑
     * @param outImgPath 水印後打出路徑
     * @param watermarkStr 水印內容
     */
    public void mark(String srcImgPath, String outImgPath, String watermarkStr) {
        try {
            //讀取原圖片信息
            File srcImgFile = new File(srcImgPath);
            Image srcImg = ImageIO.read(srcImgFile);
            //獲取原圖的高度和寬度
            int srcImgWidth = srcImg.getWidth(null);
            int srcImgHeight = srcImg.getHeight(null);
            //加水印
            BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight,BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bufImg.createGraphics();
            g.drawImage(srcImg, 0, 0, srcImgWidth, srcImgHeight, null);
            //設置水印樣式
            Font font = new Font("Courier New", Font.PLAIN, 12);
            g.setFont(font);
            int x = srcImgWidth - getWatermarkLength(watermarkStr, g) - 3;
            int y = srcImgHeight - 3;
            g.drawString(watermarkStr, x, y);
            g.dispose();
            // 輸出圖片
            FileOutputStream outImgStream = new FileOutputStream(outImgPath);
            ImageIO.write(bufImg, "jpg", outImgStream);
            outImgStream.flush();
            outImgStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //獲取水印文字總長度
    public int getWatermarkLength(String str, Graphics2D g) {
        return g.getFontMetrics(g.getFont()).charsWidth(str.toCharArray(), 0, str.length());
    }

    public static void main(String[] args) { // 原圖位置, 輸出圖片位置, 水印文字
        new WaterMark().mark(args[0], args[1], args[2]);
    }
}