Java水印图片处理

今天需要用Java程序给图片加水印，于是在网上找到了一段代码，感觉很好，于是记录了下来，原来的网址给忘了：

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

/**
 * 图片工具类， 图片水印，文字水印，缩放，补白等
 * 
 * @author Carl He
 */
public final class ImageUtils {
    /** 图片格式：JPG */
    private static final String PICTRUE_FORMATE_JPG = "jpg";

    private ImageUtils() {
    }

    /**
     * 添加图片水印
     * 
     * @param targetImg
     *            目标图片路径，如：C://myPictrue//1.jpg
     * @param waterImg
     *            水印图片路径，如：C://myPictrue//logo.png
     * @param x
     *            水印图片距离目标图片左侧的偏移量，如果x<0, 则在正中间
     * @param y
     *            水印图片距离目标图片上侧的偏移量，如果y<0, 则在正中间
     * @param alpha
     *            透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)
     */
    public final static void pressImage(String targetImg, String waterImg,
            int x, int y, float alpha) {
        try {
            File file = new File(targetImg);
            Image image = ImageIO.read(file);
            int width = image.getWidth(null);
            int height = image.getHeight(null);
            BufferedImage bufferedImage = new BufferedImage(width, height,
                    BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bufferedImage.createGraphics();
            g.drawImage(image, 0, 0, width, height, null);

            Image waterImage = ImageIO.read(new File(waterImg)); // 水印文件
            int width_1 = waterImage.getWidth(null);
            int height_1 = waterImage.getHeight(null);
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,
                    alpha));

            int widthDiff = width - width_1;
            int heightDiff = height - height_1;
            if (x < 0) {
                x = widthDiff / 2;
            } else if (x > widthDiff) {
                x = widthDiff;
            }
            if (y < 0) {
                y = heightDiff / 2;
            } else if (y > heightDiff) {
                y = heightDiff;
            }
            g.drawImage(waterImage, x, y, width_1, height_1, null); // 水印文件结束
            g.dispose();
            ImageIO.write(bufferedImage, PICTRUE_FORMATE_JPG, file);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 添加文字水印
     * 
     * @param targetImg
     *            目标图片路径，如：C://myPictrue//1.jpg
     * @param pressText
     *            水印文字， 如：中国证券网
     * @param fontName
     *            字体名称， 如：宋体
     * @param fontStyle
     *            字体样式，如：粗体和斜体(Font.BOLD|Font.ITALIC)
     * @param fontSize
     *            字体大小，单位为像素
     * @param color
     *            字体颜色
     * @param x
     *            水印文字距离目标图片左侧的偏移量，如果x<0, 则在正中间
     * @param y
     *            水印文字距离目标图片上侧的偏移量，如果y<0, 则在正中间
     * @param alpha
     *            透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)
     */
    public static void pressText(String targetImg, String pressText,
            String fontName, int fontStyle, int fontSize, Color color, int x,
            int y, float alpha) {
        try {
            File file = new File(targetImg);

            Image image = ImageIO.read(file);
            int width = image.getWidth(null);
            int height = image.getHeight(null);
            BufferedImage bufferedImage = new BufferedImage(width, height,
                    BufferedImage.TYPE_INT_RGB);
            Graphics2D g = bufferedImage.createGraphics();
            g.drawImage(image, 0, 0, width, height, null);
            g.setFont(new Font(fontName, fontStyle, fontSize));
            g.setColor(color);
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,
                    alpha));

            int width_1 = fontSize * getLength(pressText);
            int height_1 = fontSize;
            int widthDiff = width - width_1;
            int heightDiff = height - height_1;
            if (x < 0) {
                x = widthDiff / 2;
            } else if (x > widthDiff) {
                x = widthDiff;
            }
            if (y < 0) {
                y = heightDiff / 2;
            } else if (y > heightDiff) {
                y = heightDiff;
            }

            g.drawString(pressText, x, y + height_1);
            g.dispose();
            ImageIO.write(bufferedImage, PICTRUE_FORMATE_JPG, file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取字符长度，一个汉字作为 1 个字符, 一个英文字母作为 0.5 个字符
     * 
     * @param text
     * @return 字符长度，如：text="中国",返回 2；text="test",返回 2；text="中国ABC",返回 4.
     */
    public static int getLength(String text) {
        int textLength = text.length();
        int length = textLength;
        for (int i = 0; i < textLength; i++) {
            if (String.valueOf(text.charAt(i)).getBytes().length > 1) {
                length++;
            }
        }
        return (length % 2 == 0) ? length / 2 : length / 2 + 1;
    }

    /**
     * 图片缩放
     * 
     * @param filePath
     *            图片路径
     * @param height
     *            高度
     * @param width
     *            宽度
     * @param bb
     *            比例不对时是否需要补白
     */
    public static void resize(String filePath, int height, int width, boolean bb) {
        try {
            double ratio = 0; // 缩放比例
            File f = new File(filePath);
            BufferedImage bi = ImageIO.read(f);
            Image itemp = bi.getScaledInstance(width, height,
                    BufferedImage.SCALE_SMOOTH);
            // 计算比例
            if ((bi.getHeight() > height) || (bi.getWidth() > width)) {
                if (bi.getHeight() > bi.getWidth()) {
                    ratio = (new Integer(height)).doubleValue()
                            / bi.getHeight();
                } else {
                    ratio = (new Integer(width)).doubleValue() / bi.getWidth();
                }
                AffineTransformOp op = new AffineTransformOp(
                        AffineTransform.getScaleInstance(ratio, ratio), null);
                itemp = op.filter(bi, null);
            }
            if (bb) {
                BufferedImage image = new BufferedImage(width, height,
                        BufferedImage.TYPE_INT_RGB);
                Graphics2D g = image.createGraphics();
                g.setColor(Color.white);
                g.fillRect(0, 0, width, height);
                if (width == itemp.getWidth(null))
                    g.drawImage(itemp, 0, (height - itemp.getHeight(null)) / 2,
                            itemp.getWidth(null), itemp.getHeight(null),
                            Color.white, null);
                else
                    g.drawImage(itemp, (width - itemp.getWidth(null)) / 2, 0,
                            itemp.getWidth(null), itemp.getHeight(null),
                            Color.white, null);
                g.dispose();
                itemp = image;
            }
            ImageIO.write((BufferedImage) itemp, "jpg", f);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {
        pressImage("C://pic//jpg", "C://pic//test.gif", 5000, 5000, 0f);
        pressText("C://pic//jpg", "旺仔之印", "宋体", Font.BOLD | Font.ITALIC, 20,
                Color.BLACK, 0, 0, 8f);
        resize("C://pic//4.jpg", 1000, 500, true);
    }
}