Java：使用PDFBox1库从图像创建PDF页面

Question

我需要将图像（主要是JPEG）直接转换为PDF文档的PDF页面。
可能是图像的大小不同。

每个PDF页面应该具有与图像相同的精确尺寸。
因此每个页面只包含全分辨率的图像。

如何实现这一点，一个页面被设置为图像/内容的尺寸？
因为我看到PDF文件有不同的页面大小和方向，但如何用PDFbox做到这一点？

Answer 1

注意（Valentin Waeselynck的评论：从PDFBox 2+开始，您现在将使用PDImagexObject.CreateFromFile或PDImagexObject.CreateFromFile或JPEGFactory.CreateFromStream。注意，LosslessFactory.CreateFromImage的空间效率要低得多。请参阅:https://PDFBox.apache.org/2.0/migration.html#working-with-images

PDFBox 1的解决方案：

我已经用下面的代码解决了这个问题：

PDDocument document = new PDDocument();
InputStream in = new FileInputStream(someImage);
BufferedImage bimg = ImageIO.read(in);
float width = bimg.getWidth();
float height = bimg.getHeight();
PDPage page = new PDPage(new PDRectangle(width, height));
document.addPage(page); 
PDXObjectImage img = new PDJpeg(document, new FileInputStream(someImage));
PDPageContentStream contentStream = new PDPageContentStream(document, page);
contentStream.drawImage(img, 0, 0);
contentStream.close();
in.close();

document.save("test.pdf");
document.close();

为了完整起见，请参阅PDFBox 2+API的当前PDFBox示例（https://svn.apache.org/repos/asf/PDFBox/trunk/examples/src/main/java/org/apache/PDFBox/examples/pdmodel/addimageTopdf.java）

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
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 *      http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.pdfbox.examples.pdmodel;

import java.io.File;
import java.io.IOException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.PDPageContentStream.AppendMode;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;

/**
 * This is an example that creates a reads a document and adds an image to it..
 *
 * The example is taken from the pdf file format specification.
 *
 * @author Ben Litchfield
 */
public class AddImageToPDF
{
    /**
     * Add an image to an existing PDF document.
     *
     * @param inputFile The input PDF to add the image to.
     * @param imagePath The filename of the image to put in the PDF.
     * @param outputFile The file to write to the pdf to.
     *
     * @throws IOException If there is an error writing the data.
     */
    public void createPDFFromImage( String inputFile, String imagePath, String outputFile )
            throws IOException
    {
        try (PDDocument doc = PDDocument.load(new File(inputFile)))
        {
            //we will add the image to the first page.
            PDPage page = doc.getPage(0);

            // createFromFile is the easiest way with an image file
            // if you already have the image in a BufferedImage, 
            // call LosslessFactory.createFromImage() instead
            PDImageXObject pdImage = PDImageXObject.createFromFile(imagePath, doc);

            try (PDPageContentStream contentStream = new PDPageContentStream(doc, page, AppendMode.APPEND, true, true))
            {
                // contentStream.drawImage(ximage, 20, 20 );
                // better method inspired by http://stackoverflow.com/a/22318681/535646
                // reduce this value if the image is too large
                float scale = 1f;
                contentStream.drawImage(pdImage, 20, 20, pdImage.getWidth() * scale, pdImage.getHeight() * scale);
            }
            doc.save(outputFile);
        }
    }

    /**
     * This will load a PDF document and add a single image on it.
     * <br>
     * see usage() for commandline
     *
     * @param args Command line arguments.
     */
    public static void main(String[] args) throws IOException
    {
        AddImageToPDF app = new AddImageToPDF();
        if( args.length != 3 )
        {
            app.usage();
        }
        else
        {
            app.createPDFFromImage( args[0], args[1], args[2] );
        }
    }

    /**
     * This will print out a message telling how to use this example.
     */
    private void usage()
    {
        System.err.println( "usage: " + this.getClass().getName() + " <input-pdf> <image> <output-pdf>" );
    }
}