sclass PDFToImages is AutoCloseable {
  // DPI to use for images
  settable int dpi = 150;

  // the loaded document + the page renderer
  PDDocument document;
  PDFRenderer pdfRenderer;
  
  *(File pdfFile) {
    document = loadPDF(pdfFile);
  }
  
  void init {
    pdfRenderer if null = new PDFRenderer(document);
  }
  
  int nPages aka pageCount() { ret document.getNumberOfPages(); }
  
  // pages are counted from 0
  BufferedImage getPageImage(int page) ctex {
    init();
    ret pdfRenderer.renderImageWithDPI(page, dpi, ImageType.RGB);
  }
  
  L<BufferedImage> pageImages() {
    ret virtualList getPageImage(nPages());
  }
  
  close { dispose document; }
}