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Convert PDF to JPG Using iText in Java

In the world of software development, there are often requirements to convert PDF files into image formats like JPG. This can be useful for various reasons, such as displaying PDF content on a web page where browser support for PDF rendering is inconsistent, or for archiving purposes where images are more easily accessible. iText is a well-known Java library that provides a comprehensive set of tools for working with PDF files. In this blog post, we'll explore how to use iText to convert PDF files to JPG images. We'll cover the core concepts, typical usage scenarios, common pitfalls, and best practices to help you implement this conversion effectively in your Java applications.

Table of Contents#

  1. Core Concepts
  2. Typical Usage Scenarios
  3. Setting up the Project
  4. Code Example for Converting PDF to JPG
  5. Common Pitfalls
  6. Best Practices
  7. Conclusion
  8. FAQ
  9. References

Core Concepts#

iText#

iText is a powerful Java library for creating, manipulating, and extracting content from PDF files. It provides a rich API that allows developers to perform various operations on PDF documents, including reading, writing, and modifying their structure and content.

PDF to JPG Conversion#

The process of converting a PDF to a JPG involves reading the PDF file, extracting its content, and then rendering that content into an image. iText helps in reading the PDF, and we can use other Java libraries like Java Advanced Imaging (JAI) or Java 2D to render the PDF content as a JPG image.

Typical Usage Scenarios#

Web Applications#

When building web applications, you may need to display PDF content on web pages. Since not all browsers support PDF rendering natively, converting PDF to JPG allows you to display the content more uniformly across different browsers.

Document Archiving#

PDF files can be large and may require specific software to view. Converting them to JPG images can make them more accessible and easier to archive, especially if you need to store them in a database or a file system.

Image Processing Pipelines#

If you plan to perform further image processing on the PDF content, such as OCR (Optical Character Recognition) or image enhancement, converting the PDF to JPG is often a necessary first step.

Setting up the Project#

To use iText for PDF to JPG conversion, you need to add the iText library to your Java project. If you are using Maven, add the following dependency to your pom.xml file:

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.2</version>
</dependency>

If you are using Gradle, add the following to your build.gradle file:

implementation 'com.itextpdf:itextpdf:5.5.13.2'

Code Example for Extracting Embedded Images from PDF#

iText itself cannot rasterize PDF pages to images—it only handles PDF reading, writing, and parsing of existing embedded content. For full PDF-to-JPG conversion, you need a dedicated rendering library like Apache PDFBox, PDFRenderer, or Ghostscript. However, iText can extract images that are already embedded within a PDF.

import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.parser.PdfImageObject;
import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
import com.itextpdf.text.pdf.parser.RenderListener;
import com.itextpdf.text.pdf.parser.TextRenderInfo;
 
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
 
public class PdfImageExtractor {
 
    public static void extractImagesFromPdf(String pdfFilePath, String outputFolderPath) {
        try {
            PdfReader reader = new PdfReader(pdfFilePath);
            int numberOfPages = reader.getNumberOfPages();
 
            for (int page = 1; page <= numberOfPages; page++) {
                com.itextpdf.text.Rectangle pageSize = reader.getPageSizeWithRotation(page);
                float width = pageSize.getWidth();
                float height = pageSize.getHeight();
 
                BufferedImage image = new BufferedImage((int) width, (int) height, BufferedImage.TYPE_INT_RGB);
 
                PdfReaderContentParser parser = new PdfReaderContentParser(reader);
                parser.processContent(page, new RenderListener() {
                    @Override
                    public void beginTextBlock() {
                    }
 
                    @Override
                    public void renderText(TextRenderInfo renderInfo) {
                    }
 
                    @Override
                    public void endTextBlock() {
                    }
 
                    @Override
                    public void renderImage(com.itextpdf.text.pdf.parser.ImageRenderInfo renderInfo) {
                        try {
                            PdfImageObject pdfImage = renderInfo.getImage();
                            if (pdfImage != null) {
                                java.awt.Image awtImage = pdfImage.getBufferedImage();
                                image.getGraphics().drawImage(awtImage, 0, 0, null);
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                });
 
                File outputFile = new File(outputFolderPath + "/page_" + page + ".jpg");
                ImageIO.write(image, "jpg", outputFile);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    public static void main(String[] args) {
        String pdfFilePath = "input.pdf";
        String outputFolderPath = "output";
        extractImagesFromPdf(pdfFilePath, outputFolderPath);
    }
}

Explanation of the Code#

  1. Initialization: We create a PdfReader object to read the PDF file and get the number of pages.
  2. Page Iteration: We loop through each page of the PDF.
  3. Image Creation: For each page, we create a BufferedImage with the page dimensions.
  4. Image Extraction: We use a RenderListener to extract embedded images from the PDF. Note that this only captures images that are already embedded—text and vector graphics are not rendered.
  5. Image Saving: Finally, we save the BufferedImage as a JPG file using ImageIO.

Note on Full PDF-to-JPG Conversion#

To render an entire PDF page (including text and vector graphics) as a JPG image, you need a rendering library such as Apache PDFBox, PDFRenderer, or Ghostscript. These libraries perform the actual rasterization that iText cannot handle.

Common Pitfalls#

Limited to Embedded Images#

The iText approach shown above only extracts images that are already embedded in the PDF. It does not render text, vector graphics, or the overall page layout. For complete page rendering, use a dedicated rendering library instead.

Memory Issues#

Processing large PDF files can consume significant memory, especially if loading the entire PDF at once. To avoid this, process the PDF page by page as shown in the code example.

Quality Issues#

The image extraction approach may not produce high-quality results for all PDFs. Complex PDF documents with many embedded images or specific image formats may require additional handling.

Font Rendering#

When using a full rendering library for PDF-to-JPG conversion, some PDF files may use custom fonts that are not available on the system. This can lead to missing or incorrect text rendering in the resulting images.

Best Practices#

Use Page-by-Page Processing#

As mentioned earlier, process the PDF page by page to reduce memory usage. This ensures that your application can handle large PDF files without running out of memory.

Choose the Right Rendering Library#

For better quality and more accurate rendering, consider using more advanced rendering libraries in combination with iText, such as Apache PDFBox or PDFRenderer.

Handle Fonts Properly#

If your PDF files use custom fonts, make sure to include the font files in your application or use font substitution techniques to ensure correct text rendering.

Conclusion#

Converting PDF to JPG using iText in Java is a useful technique that can be applied in various real-world scenarios. By understanding the core concepts, following the best practices, and avoiding common pitfalls, you can implement this conversion effectively in your Java applications.

FAQ#

Q1: Can I convert a multi-page PDF to a single JPG?#

A1: The code example provided converts each page of the PDF to a separate JPG. To convert a multi-page PDF to a single JPG, you would need to combine the images of each page into one large image.

Q2: Does iText support all types of PDF files?#

A2: While iText can handle most standard PDF files, there may be some complex or non-standard PDF files that it has difficulty processing. In such cases, you may need to use other libraries or pre-process the PDF.

Q3: How can I improve the quality of the converted JPG images?#

A3: You can improve the quality by using more advanced rendering techniques, choosing the right image format settings (e.g., higher JPG compression quality), and handling fonts properly.

References#

This blog post should give you a solid understanding of how to convert PDF to JPG using iText in Java and help you apply this knowledge in your projects.

2025-10