Question

朋友们，我正在使用PDFBox 2.0.6。我已经成功地从pdf文件中提取图像，但是现在它正在为单个pdf页面创建一个图像。但问题在于可能没有。 pdf页面中的图像，我希望每个嵌入的图像都应该作为单个图像本身提取。

这是代码，

import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;

public class DemoPdf {

    public static void main(String args[]) throws Exception {
        //Loading an existing PDF document
        File file = new File("C:/Users/ADMIN/Downloads/Vehicle_Photographs.pdf");
        PDDocument document = PDDocument.load(file);
        //Instantiating the PDFRenderer class
        PDFRenderer renderer = new PDFRenderer(document);
        File imageFolder = new File("C:/Users/ADMIN/Desktop/image");

        for (int page = 0; page < document.getNumberOfPages(); ++page) {
            //Rendering an image from the PDF document
            BufferedImage image = renderer.renderImage(page);
            //Writing the image to a file
            ImageIO.write(image, "JPEG", new File(imageFolder+"/" + page +".jpg"));
            System.out.println("Image created"+ page);
        }
        //Closing the document
        document.close();
    }

}

在PDFBox中是否可以将所有嵌入的图像作为单独的图像提取，谢谢

Answer 1

是。可以从pdf中提取所有页面中的所有图像。

您可以参考此链接extract images from pdf using PDFBox。

这里的基本思想是，使用PDFStreamEngine扩展类，并覆盖processOperator方法。为所有页面调用PDFStreamEngine.processPage。如果传递给processOperator的对象是图像对象，则从对象获取BufferedImage，然后保存它。

Answer 2

扩展PDFStreamEngine并重写processOperator之类的东西

 @Override
protected void processOperator( Operator operator, List<COSBase> operands) throws IOException
{
    String operation = operator.getName();
    if( "Do".equals(operation) )
    {
        COSName objectName = (COSName) operands.get( 0 );
        PDXObject xobject = getResources().getXObject( objectName );
        if( xobject instanceof PDImageXObject)
        {
            PDImageXObject image = (PDImageXObject)xobject;
            int imageWidth = image.getWidth();
            int imageHeight = image.getHeight();

            // same image to local
            BufferedImage bImage = new BufferedImage(imageWidth,imageHeight,BufferedImage.TYPE_INT_ARGB);
            bImage = image.getImage();
            ImageIO.write(bImage,"PNG",new File("c:\\temp\\image_"+imageNumber+".png"));

            imageNumber++;

        }
        else 
        {

        }
    }
    else
    {
        super.processOperator( operator, operands);
    }
}

Answer 3

此答案与@jprism相似。但这是给那些只想将其复制并粘贴以在演示中使用的代码的人准备的。

import org.apache.pdfbox.contentstream.PDFStreamEngine;
import org.apache.pdfbox.contentstream.operator.Operator;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.graphics.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.UUID;

public class ExtractImagesUseCase extends PDFStreamEngine{
    private final String filePath;
    private final String outputDir;

    // Constructor
    public ExtractImagesUseCase(String filePath,
                                String outputDir){
        this.filePath = filePath;
        this.outputDir = outputDir;
    }

    // Execute
    public void execute(){
        try{
            File file = new File(filePath);
            PDDocument document = PDDocument.load(file);

            for(PDPage page : document.getPages()){
                processPage(page);
            }

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

    @Override
    protected void processOperator(Operator operator, List<COSBase> operands) throws IOException{
        String operation = operator.getName();

        if("Do".equals(operation)){
            COSName objectName = (COSName) operands.get(0);
            PDXObject pdxObject = getResources().getXObject(objectName);

            if(pdxObject instanceof PDImageXObject){
                // Image
                PDImageXObject image = (PDImageXObject) pdxObject;
                BufferedImage bImage = image.getImage();

                // File
                String randomName = UUID.randomUUID().toString();
                File outputFile = new File(outputDir,randomName + ".png");

                // Write image to file
                ImageIO.write(bImage, "PNG", outputFile);

            }else if(pdxObject instanceof PDFormXObject){
                PDFormXObject form = (PDFormXObject) pdxObject;
                showForm(form);
            }
        }

        else super.processOperator(operator, operands);
    }
}

演示

public class ExtractImageDemo{
    public static void main(String[] args){
        String filePath = "C:\\Users\\John\\Downloads\\Documents\\sample-file.pdf";
        String outputDir = "C:\\Users\\John\\Downloads\\Documents\\Output";

        ExtractImagesUseCase useCase = new ExtractImagesUseCase(
                filePath,
                outputDir
        );
        useCase.execute();
    }
}

使用PDFBox从单个PDF页面中提取多个嵌入图像

3 个答案: