如何使用Java PDFBox以编程方式将图像插入AcroForm字段？

Question

我创建了带有3个标签的简单PDF文档：名字，姓氏和照片。然后，我使用Adobe Acrobat PRO DC在AcroForm图层中添加了2个“文本字段”和一个“图像字段”。

因此，如果我要填写表格，可以在常规的Acrobat Reader中打开此PDF文件，并通过键入名字，姓氏进行填写，并插入照片，然后单击图像占位符并在打开的对话框窗口中选择照片。

但是我该如何以编程方式做同样的事情？创建了使用Apache PDFBox库（版本2.0.7）查找表单字段并插入值的简单Java应用程序。

我可以轻松填充“文本编辑”字段，但无法弄清楚如何插入图像：

public class AcroFormPopulator {

    public static void main(String[] args) {

        AcroFormPopulator abd = new AcroFormPopulator();
        try {
            abd.populateAndCopy("test.pdf", "generated.pdf");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void populateAndCopy(String originalPdf, String targetPdf) throws IOException {
        File file = new File(originalPdf);

        PDDocument document = PDDocument.load(file);
        PDAcroForm acroForm = document.getDocumentCatalog().getAcroForm();

        Map<String, String> data = new HashMap<>();
        data.put("firstName", "Mike");
        data.put("lastName", "Taylor");
        data.put("photo_af_image", "photo.jpeg");

        for (Map.Entry<String, String> item : data.entrySet()) {
            PDField field = acroForm.getField(item.getKey());
            if (field != null) {

                if (field instanceof PDTextField) {
                    field.setValue(item.getValue());

                } else if (field instanceof PDPushButton) {
                    File imageFile = new File(item.getValue());

                    PDPushButton pdPushButton = (PDPushButton) field;
                    // do not see way to isert image

                } else {
                    System.err.println("No field found with name:" + item.getKey());
                }
            } else {
                System.err.println("No field found with name:" + item.getKey());
            }
        }

        document.save(targetPdf);
        document.close();
        System.out.println("Populated!");
    }
}

我已经分辨出一件奇怪的事情-在Acrobat Pro DC中它说我添加了Image Field，但是我通过生成的名称获得的唯一字段是：'photo_af_image'是按钮类型-PDPushButton（这就是为什么我检查（PDPushButton的字段实例） ），但与Image无关。

如何将图像插入AcroForm“ photo_af_image”字段，使其适合Acrobat Pro DC创建的盒子的大小？

Answer 1

我终于找到并建立了不错的解决方案。该解决方案的目标是：

1. 使用简单的工具使用文本和图像占位符创建表单层，这可以由非程序员完成，并且不需要操纵低级PDF结构；
2. 由表单创建者使用简单的工具来驱动插入图像的大小；尺寸取决于高度，但宽度将根据比例进行调整；

以下通过acroForm占位符插入图像的解决方案的主要思想是：

1. 您必须迭代acroForm层并查找具有相应占位符名称的按钮；
2. 如果发现的字段为PDPushButton类型，则获取其第一个小部件；
3. 从图像文件创建PDImageXObject；
4. 使用PDImageXObject创建PDAppearanceStream并设置相同的x和y位置，并调整高度和宽度以匹配占位符的高度；
5. 将此PDAppearanceStream设置为小部件；
6. 您可以选择将文档展平以将acroform布局合并到主文档

这是代码：

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.imageio.ImageIO;

import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.graphics.image.LosslessFactory;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.pdmodel.interactive.action.PDAction;
import org.apache.pdfbox.pdmodel.interactive.action.PDActionHide;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceDictionary;
import org.apache.pdfbox.pdmodel.interactive.annotation.PDAppearanceStream;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
import org.apache.pdfbox.pdmodel.interactive.form.PDField;
import org.apache.pdfbox.pdmodel.interactive.form.PDPushButton;
import org.apache.pdfbox.pdmodel.interactive.form.PDTextField;

public class AcroFormPopulator {

    public static void main(String[] args) {
        AcroFormPopulator abd = new AcroFormPopulator();
        try {
            Map<String, String> data = new HashMap<>();
            data.put("firstName", "Mike");
            data.put("lastName", "Taylor");
            data.put("dateTime", (new Date()).toString());
            data.put("photo_af_image", "photo1.jpg");
            data.put("photo2_af_image", "photo2.jpg");
            data.put("photo3_af_image", "photo3.jpg");

            abd.populateAndCopy("test.pdf", "generated.pdf", data);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void populateAndCopy(String originalPdf, String targetPdf, Map<String, String> data) throws IOException {
        File file = new File(originalPdf);
        PDDocument document = PDDocument.load(file);
        PDAcroForm acroForm = document.getDocumentCatalog().getAcroForm();

        for (Map.Entry<String, String> item : data.entrySet()) {
            String key = item.getKey();
            PDField field = acroForm.getField(key);
            if (field != null) {
                System.out.print("Form field with placeholder name: '" + key + "' found");

                if (field instanceof PDTextField) {
                    System.out.println("(type: " + field.getClass().getSimpleName() + ")");
                    field.setValue(item.getValue());
                    System.out.println("value is set to: '" + item.getValue() + "'");

                } else if (field instanceof PDPushButton) {
                    System.out.println("(type: " + field.getClass().getSimpleName() + ")");
                    PDPushButton pdPushButton = (PDPushButton) field;

                    List<PDAnnotationWidget> widgets = pdPushButton.getWidgets();
                    if (widgets != null && widgets.size() > 0) {
                        PDAnnotationWidget annotationWidget = widgets.get(0); // just need one widget

                        String filePath = item.getValue();
                        File imageFile = new File(filePath);

                        if (imageFile.exists()) {
                            /*
                             * BufferedImage bufferedImage = ImageIO.read(imageFile); 
                             * PDImageXObject pdImageXObject = LosslessFactory.createFromImage(document, bufferedImage);
                             */
                            PDImageXObject pdImageXObject = PDImageXObject.createFromFile(filePath, document);
                            float imageScaleRatio = (float) pdImageXObject.getHeight() / (float) pdImageXObject.getWidth();

                            PDRectangle buttonPosition = getFieldArea(pdPushButton);
                            float height = buttonPosition.getHeight();
                            float width = height / imageScaleRatio;
                            float x = buttonPosition.getLowerLeftX();
                            float y = buttonPosition.getLowerLeftY();

                            PDAppearanceStream pdAppearanceStream = new PDAppearanceStream(document);
                            pdAppearanceStream.setResources(new PDResources());
                            try (PDPageContentStream pdPageContentStream = new PDPageContentStream(document, pdAppearanceStream)) {
                                pdPageContentStream.drawImage(pdImageXObject, x, y, width, height);
                            }
                            pdAppearanceStream.setBBox(new PDRectangle(x, y, width, height));

                            PDAppearanceDictionary pdAppearanceDictionary = annotationWidget.getAppearance();
                            if (pdAppearanceDictionary == null) {
                                pdAppearanceDictionary = new PDAppearanceDictionary();
                                annotationWidget.setAppearance(pdAppearanceDictionary);
                            }

                            pdAppearanceDictionary.setNormalAppearance(pdAppearanceStream);
                            System.out.println("Image '" + filePath + "' inserted");

                        } else {
                            System.err.println("File " + filePath + " not found");
                        }
                    } else {
                        System.err.println("Missconfiguration of placeholder: '" + key + "' - no widgets(actions) found");
                    }
                } else {
                    System.err.print("Unexpected form field type found with placeholder name: '" + key + "'");
                }
            } else {
                System.err.println("No field found with name:" + key);
            }
        }

        // you can optionally flatten the document to merge acroform lay to main one
        acroForm.flatten();

        document.save(targetPdf);
        document.close();
        System.out.println("Done");
    }

    private PDRectangle getFieldArea(PDField field) {
        COSDictionary fieldDict = field.getCOSObject();
        COSArray fieldAreaArray = (COSArray) fieldDict.getDictionaryObject(COSName.RECT);
        return new PDRectangle(fieldAreaArray);
    }
}

请让我知道是否有更好的解决方案或可以改进的代码。