Java图片处理 (文字水印、图片水印、缩放、补白)代码实例

package com.hmw.picmark;

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,width,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<0,0.0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,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,BufferedImage.TYPE_INT_RGB);
			Graphics2D g = bufferedImage.createGraphics();
			g.drawImage(image,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,y + height_1);
			g.dispose();
			ImageIO.write(bufferedImage,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,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,BufferedImage.TYPE_INT_RGB);  
        Graphics2D g = image.createGraphics();  
        g.setColor(Color.white);  
        g.fillRect(0,height);  
        if (width == itemp.getWidth(null))  
          g.drawImage(itemp,(height - itemp.getHeight(null)) / 2,itemp.getWidth(null),itemp.getHeight(null),Color.white,null);  
        else 
          g.drawImage(itemp,(width - itemp.getWidth(null)) / 2,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",5000,0f);
		presstext("C://pic//jpg","旺仔之印","宋体",Font.BOLD|Font.ITALIC,20,Color.BLACK,8f);
		resize("C://pic//4.jpg",1000,500,true);
	}
}