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, 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);
	}
}