PDF to image using Java

Take a look at the articles:

1) PdftoImage-Convert PDF to Image by using PdfRenderer library, direct link to source code
2) Java: Generating PDF and Previewing it as an Image – iText and PDF Renderer

You will need a PDF renderer. There are a few more or less good ones on the market (ICEPdf, pdfrenderer), but without, you will have to rely on external tools. The free PDF renderers also cannot render embedded fonts, and so will only be good for creating thumbnails (what you eventually want).

My favorite external tool is Ghostscript, which can convert PDFs to images with a single command line invocation.

This converts Postscript (and PDF?) files to bmp for us, just as a guide to modify for your needs (Know you need the env vars for gs to work!):

pushd 
setlocal

Set BIN_DIR=C:\Program Files\IKOffice_ACME\bin
Set GS=C:\Program Files\IKOffice_ACME\gs
Set GS_DLL=%GS%\gs8.54\bin\gsdll32.dll
Set GS_LIB=%GS%\gs8.54\lib;%GS%\gs8.54\Resource;%GS%\fonts
Set Path=%Path%;%GS%\gs8.54\bin
Set Path=%Path%;%GS%\gs8.54\lib

call "%GS%\gs8.54\bin\gswin32c.exe" -q -dSAFER -dNOPAUSE -dBATCH -sDEVICE#bmpmono -r600x600 -sOutputFile#%2 -f %1

endlocal
popd

UPDATE: pdfbox is now able to embed fonts, so no need for Ghostscript anymore.

Apache PDF Box can convert PDFs to jpg,bmp,wbmp,png, and gif.

The library even comes with a command line utility called PDFToImage to do this.

If you download the source code and look at the PDFToImage class you should be able to figure out how to use PDF Box to convert PDFs to images from your own Java code.

In Ghost4J library (http://ghost4j.sourceforge.net), since version 0.4.0 you can use a SimpleRenderer to do the job with few lines of code:

1. Load PDF or PS file (use PSDocument class for that):

       PDFDocument document = new PDFDocument();
       document.load(new File("input.pdf"));
   

2. Create the renderer

       SimpleRenderer renderer = new SimpleRenderer();
   
       // set resolution (in DPI)
       renderer.setResolution(300);
   

3. Render

       List<Image> images = renderer.render(document);
   

Then you can do what you want with your image objects, for example, you can write them as PNG like this:

            for (int i = 0; i < images.size(); i++) {
                ImageIO.write((RenderedImage) images.get(i), "png", new File((i + 1) + ".png"));
            }

Note: Ghost4J uses the native Ghostscript C API so you need to have a Ghostscript installed on your box.

I hope it will help you :)