Java如何实现图片的叠加与拼接操作

关于Java实现图片的叠加与拼接的文章网络上确实很多，碰巧小编开发工作中也遇到这些问题，就做了简要的梳理，作为笔记以备不时之需。

Java对图片的处理主要使用的是BufferedImage类。

BufferedImage 子类描述具有可访问图像数据缓冲区的 Image。BufferedImage 由图像数据的 ColorModel 和 Raster 组成。Raster 的 SampleModel 中 band 的数量和类型必须与 ColorModel 所要求的数量和类型相匹配，以表示其颜色和 alpha 分量。所有 BufferedImage 对象的左上角坐标都为 (0, 0)。因此，用来构造 BufferedImage 的任何 Raster 都必须满足：minX=0 且 minY=0。此类依靠 Raster 的数据获取方法、数据设置方法，以及 ColorModel 的颜色特征化方法。

以上主要来源于官方文档，我们来时直接写实践代码吧。

首先将文件转化为BufferedImage对象，这里给出两种读取文件并转化为BufferedImage对象的方法。

  public static BufferedImage getBufferedImage(String fileUrl)
      throws IOException {
    File f = new File(fileUrl);
    return ImageIO.read(f);
  }  
  
  
  public static BufferedImage getBufferedImageDestUrl(String destUrl) {
    HttpURLConnection conn = null;
    BufferedImage image = null;
    try {
      URL url = new URL(destUrl);
      conn = (HttpURLConnection) url.openConnection();
      if (conn.getResponseCode() == 200) {
 image = ImageIO.read(conn.getInputStream());
 return image;
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      conn.disconnect();
    }
    return image;
  }

接下来是将BufferedImage对象保存到本地，具体方法如下:

  public static void generateSaveFile(BufferedImage buffImg, String savePath) {
    int temp = savePath.lastIndexOf(".") + 1;
    try {
      File outFile = new File(savePath);
      if(!outFile.exists()){
 outFile.createNewFile();
      }
      ImageIO.write(buffImg, savePath.substring(temp), outFile);
      System.out.println("ImageIO write...");
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

以上作为准备部分，现在开始图片叠加的实现方法：

  public static BufferedImage overlyingImage(BufferedImage buffImg, BufferedImage waterImg, int x, int y, float alpha) throws IOException {

    // 创建Graphics2D对象，用在底图对象上绘图
    Graphics2D g2d = buffImg.createGraphics();
    int waterImgWidth = waterImg.getWidth();// 获取层图的宽度
    int waterImgHeight = waterImg.getHeight();// 获取层图的高度
    // 在图形和图像中实现混合和透明效果
    g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
    // 绘制
    g2d.drawImage(waterImg, x, y, waterImgWidth, waterImgHeight, null);
    g2d.dispose();// 释放图形上下文使用的系统资源
    return buffImg;
  }

图片拼接的实现方法：

  public static BufferedImage mergeImage(BufferedImage img1,
      BufferedImage img2, boolean isHorizontal) throws IOException {
    int w1 = img1.getWidth();
    int h1 = img1.getHeight();
    int w2 = img2.getWidth();
    int h2 = img2.getHeight();

    // 从图片中读取RGB
    int[] ImageArrayOne = new int[w1 * h1];
    ImageArrayOne = img1.getRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 逐行扫描图像中各个像素的RGB到数组中
    int[] ImageArrayTwo = new int[w2 * h2];
    ImageArrayTwo = img2.getRGB(0, 0, w2, h2, ImageArrayTwo, 0, w2);

    // 生成新图片
    BufferedImage DestImage = null;
    if (isHorizontal) { // 水平方向合并
      DestImage = new BufferedImage(w1+w2, h1, BufferedImage.TYPE_INT_RGB);
      DestImage.setRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 设置上半部分或左半部分的RGB
      DestImage.setRGB(w1, 0, w2, h2, ImageArrayTwo, 0, w2);
    } else { // 垂直方向合并
      DestImage = new BufferedImage(w1, h1 + h2, BufferedImage.TYPE_INT_RGB);
      DestImage.setRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 设置上半部分或左半部分的RGB
      DestImage.setRGB(0, h1, w2, h2, ImageArrayTwo, 0, w2); // 设置下半部分的RGB
    }

    return DestImage;
  }

测试方法如下：

  public static void overlyingImageTest() {

    String sourceFilePath = "D://test//test1.jpg";
    String waterFilePath = "D://test//test2.jpg";
    String saveFilePath = "D://test//overlyingImageNew.jpg";
    try {
      BufferedImage bufferImage1 = getBufferedImage(sourceFilePath);
      BufferedImage bufferImage2 = getBufferedImage(waterFilePath);

      // 构建叠加层
      BufferedImage buffImg = overlyingImage(bufferImage1, bufferImage2, 0, 0, 1.0f);
      // 输出水印图片
      generateSaveFile(buffImg, saveFilePath);
    } catch (IOException e) {
      e.printStackTrace();
    }

  }
  
  
  
  public static void imageMargeTest() {
    // 读取待合并的文件
    BufferedImage bi1 = null;
    BufferedImage bi2 = null;
    // 调用mergeImage方法获得合并后的图像
    BufferedImage destImg = null;
    System.out.println("下面是垂直合并的情况：");
    String saveFilePath = "D://test//new1.jpg";
    String divingPath = "D://test//new2.jpg";
    String margeImagePath = "D://test//margeNew.jpg";
    try {
      bi1 = getBufferedImage(saveFilePath);
      bi2 = getBufferedImage(divingPath);
      // 调用mergeImage方法获得合并后的图像
      destImg = mergeImage(bi1, bi2, false);
    } catch (IOException e) {
      e.printStackTrace();
    }
    // 保存图像
    generateSaveFile(destImg, margeImagePath);
    System.out.println("垂直合并完毕!");
  }

  public static void main(String[] args) {
    // 测试图片的叠加
    overlyingImageTest();
    // 测试图片的垂直合并
    imageMargeTest();
  }

整体代码如下：

package ImagePackage;

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.imageio.ImageIO;



public class ImageMerge {

  
  public static BufferedImage getBufferedImage(String fileUrl)
      throws IOException {
    File f = new File(fileUrl);
    return ImageIO.read(f);
  }
  
  
  
  public static BufferedImage getBufferedImageDestUrl(String destUrl) {
    HttpURLConnection conn = null;
    BufferedImage image = null;
    try {
      URL url = new URL(destUrl);
      conn = (HttpURLConnection) url.openConnection();
      if (conn.getResponseCode() == 200) {
 image = ImageIO.read(conn.getInputStream());
 return image;
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      conn.disconnect();
    }
    return image;
  }
  
  
  public static void generateSaveFile(BufferedImage buffImg, String savePath) {
    int temp = savePath.lastIndexOf(".") + 1;
    try {
      File outFile = new File(savePath);
      if(!outFile.exists()){
 outFile.createNewFile();
      }
      ImageIO.write(buffImg, savePath.substring(temp), outFile);
      System.out.println("ImageIO write...");
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  
  
  public static BufferedImage overlyingImage(BufferedImage buffImg, BufferedImage waterImg, int x, int y, float alpha) throws IOException {

    // 创建Graphics2D对象，用在底图对象上绘图
    Graphics2D g2d = buffImg.createGraphics();
    int waterImgWidth = waterImg.getWidth();// 获取层图的宽度
    int waterImgHeight = waterImg.getHeight();// 获取层图的高度
    // 在图形和图像中实现混合和透明效果
    g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
    // 绘制
    g2d.drawImage(waterImg, x, y, waterImgWidth, waterImgHeight, null);
    g2d.dispose();// 释放图形上下文使用的系统资源
    return buffImg;
  }
  
  
  
  public static BufferedImage mergeImage(BufferedImage img1,
      BufferedImage img2, boolean isHorizontal) throws IOException {
    int w1 = img1.getWidth();
    int h1 = img1.getHeight();
    int w2 = img2.getWidth();
    int h2 = img2.getHeight();

    // 从图片中读取RGB
    int[] ImageArrayOne = new int[w1 * h1];
    ImageArrayOne = img1.getRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 逐行扫描图像中各个像素的RGB到数组中
    int[] ImageArrayTwo = new int[w2 * h2];
    ImageArrayTwo = img2.getRGB(0, 0, w2, h2, ImageArrayTwo, 0, w2);

    // 生成新图片
    BufferedImage DestImage = null;
    if (isHorizontal) { // 水平方向合并
      DestImage = new BufferedImage(w1+w2, h1, BufferedImage.TYPE_INT_RGB);
      DestImage.setRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 设置上半部分或左半部分的RGB
      DestImage.setRGB(w1, 0, w2, h2, ImageArrayTwo, 0, w2);
    } else { // 垂直方向合并
      DestImage = new BufferedImage(w1, h1 + h2, BufferedImage.TYPE_INT_RGB);
      DestImage.setRGB(0, 0, w1, h1, ImageArrayOne, 0, w1); // 设置上半部分或左半部分的RGB
      DestImage.setRGB(0, h1, w2, h2, ImageArrayTwo, 0, w2); // 设置下半部分的RGB
    }

    return DestImage;
  }

  
  public static void overlyingImageTest() {

    String sourceFilePath = "D://test//test1.jpg";
    String waterFilePath = "D://test//test2.jpg";
    String saveFilePath = "D://test//overlyingImageNew.jpg";
    try {
      BufferedImage bufferImage1 = getBufferedImage(sourceFilePath);
      BufferedImage bufferImage2 = getBufferedImage(waterFilePath);

      // 构建叠加层
      BufferedImage buffImg = overlyingImage(bufferImage1, bufferImage2, 0, 0, 1.0f);
      // 输出水印图片
      generateSaveFile(buffImg, saveFilePath);
    } catch (IOException e) {
      e.printStackTrace();
    }

  }
  
  
  
  public static void imageMargeTest() {
    // 读取待合并的文件
    BufferedImage bi1 = null;
    BufferedImage bi2 = null;
    // 调用mergeImage方法获得合并后的图像
    BufferedImage destImg = null;
    System.out.println("下面是垂直合并的情况：");
    String saveFilePath = "D://test//new1.jpg";
    String divingPath = "D://test//new2.jpg";
    String margeImagePath = "D://test//margeNew.jpg";
    try {
      bi1 = getBufferedImage(saveFilePath);
      bi2 = getBufferedImage(divingPath);
      // 调用mergeImage方法获得合并后的图像
      destImg = mergeImage(bi1, bi2, false);
    } catch (IOException e) {
      e.printStackTrace();
    }
    // 保存图像
    generateSaveFile(destImg, margeImagePath);
    System.out.println("垂直合并完毕!");
  }

  public static void main(String[] args) {
    // 测试图片的叠加
    overlyingImageTest();
    // 测试图片的垂直合并
    imageMargeTest();
  }

}

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