Java：使用 PDFBox 库从图像创建 PDF 页面

问题
我需要将图像（主要是 JPEG）直接转换为 PDF 文档的 PDF 页面。

可能是图像大小不同。

每个 PDF 页面都应具有与图像相同的精确尺寸。

所以每个页面只包含全分辨率图像。

我怎样才能做到这一点，即页面设置为图像/内容的尺寸？

因为我看到 PDF 文件具有不同的页面大小和方向，但是如何使用 PDFBox 实现这一点？

回答
我已经用以下代码解决了这个问题：

1. PDDocument document = new PDDocument();
   
2. InputStream in = new FileInputStream(someImage);
   
3. BufferedImage bimg = ImageIO.read(in);
   
4. float width = bimg.getWidth();
   
5. float height = bimg.getHeight();
   
6. PDPage page = new PDPage(new PDRectangle(width, height));
   
7. document.addPage(page);
   
8. PDXObjectImage img = new PDJpeg(document, new FileInputStream(someImage));
   
9. PDPageContentStream contentStream = new PDPageContentStream(document, page);
   
10. contentStream.drawImage(img, 0, 0);
    
11. contentStream.close();
    
12. in.close();
    
13. 
    
14. document.save("test.pdf");
    
15. document.close();

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为了完整起见，PDFBox 2+ API 的当前 PDFBox 示例中的代码

1. /*
   
2. * Licensed to the Apache Software Foundation (ASF) under one or more
   
3. * contributor license agreements.  See the NOTICE file distributed with
   
4. * this work for additional information regarding copyright ownership.
   
5. * The ASF licenses this file to You under the Apache License, Version 2.0
   
6. * (the "License"); you may not use this file except in compliance with
   
7. * the License.  You may obtain a copy of the License at
   
8. *
   
9. *      http://www.apache.org/licenses/LICENSE-2.0
   
10. *
    
11. * Unless required by applicable law or agreed to in writing, software
    
12. * distributed under the License is distributed on an "AS IS" BASIS,
    
13. * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    
14. * See the License for the specific language governing permissions and
    
15. * limitations under the License.
    
16. */
    
17. package org.apache.pdfbox.examples.pdmodel;
    
18. 
    
19. import java.io.File;
    
20. import java.io.IOException;
    
21. import org.apache.pdfbox.pdmodel.PDDocument;
    
22. import org.apache.pdfbox.pdmodel.PDPage;
    
23. import org.apache.pdfbox.pdmodel.PDPageContentStream;
    
24. import org.apache.pdfbox.pdmodel.PDPageContentStream.AppendMode;
    
25. import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
    
26. 
    
27. /**
    
28. * This is an example that creates a reads a document and adds an image to it..
    
29. *
    
30. * The example is taken from the pdf file format specification.
    
31. *
    
32. * @author Ben Litchfield
    
33. */
    
34. public class AddImageToPDF
    
35. {
    
36.     /**
    
37.      * Add an image to an existing PDF document.
    
38.      *
    
39.      * @param inputFile The input PDF to add the image to.
    
40.      * @param imagePath The filename of the image to put in the PDF.
    
41.      * @param outputFile The file to write to the pdf to.
    
42.      *
    
43.      * @throws IOException If there is an error writing the data.
    
44.      */
    
45.     public void createPDFFromImage( String inputFile, String imagePath, String outputFile )
    
46.             throws IOException
    
47.     {
    
48.         try (PDDocument doc = PDDocument.load(new File(inputFile)))
    
49.         {
    
50.             //we will add the image to the first page.
    
51.             PDPage page = doc.getPage(0);
    
52. 
    
53.             // createFromFile is the easiest way with an image file
    
54.             // if you already have the image in a BufferedImage,
    
55.             // call LosslessFactory.createFromImage() instead
    
56.             PDImageXObject pdImage = PDImageXObject.createFromFile(imagePath, doc);
    
57. 
    
58.             try (PDPageContentStream contentStream = new PDPageContentStream(doc, page, AppendMode.APPEND, true, true))
    
59.             {
    
60.                 // contentStream.drawImage(ximage, 20, 20 );
    
61.                 // better method inspired by http://stackoverflow.com/a/22318681/535646
    
62.                 // reduce this value if the image is too large
    
63.                 float scale = 1f;
    
64.                 contentStream.drawImage(pdImage, 20, 20, pdImage.getWidth() * scale, pdImage.getHeight() * scale);
    
65.             }
    
66.             doc.save(outputFile);
    
67.         }
    
68.     }
    
69. 
    
70.     /**
    
71.      * This will load a PDF document and add a single image on it.
    
72.      * <br>
    
73.      * see usage() for commandline
    
74.      *
    
75.      * @param args Command line arguments.
    
76.      */
    
77.     public static void main(String[] args) throws IOException
    
78.     {
    
79.         AddImageToPDF app = new AddImageToPDF();
    
80.         if( args.length != 3 )
    
81.         {
    
82.             app.usage();
    
83.         }
    
84.         else
    
85.         {
    
86.             app.createPDFFromImage( args[0], args[1], args[2] );
    
87.         }
    
88.     }
    
89. 
    
90.     /**
    
91.      * This will print out a message telling how to use this example.
    
92.      */
    
93.     private void usage()
    
94.     {
    
95.         System.err.println( "usage: " + this.getClass().getName() + " <input-pdf> <image> <output-pdf>" );
    
96.     }
    
97. }

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