Bad:Converting pdf to images - pdf

Question

Convert class:
public void getImage(String pdfFilename) throws Exception{
List<byte[]> listImg = new ArrayList<>();
try (final PDDocument document = PDDocument.load(new File(pdfFilename))){
PDFRenderer pdfRenderer = new PDFRenderer(document);
for (int page = 0; page < document.getNumberOfPages(); ++page)
{
File file = new File("C:\\path1\\"+page+".png");
BufferedImage bim = pdfRenderer.renderImage(page);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(bim, "png",file);
System.out.println("!!!!");
// System.out.println(Arrays.toString(listImg.get(page)));
}
document.close();
} catch (IOException e){
System.err.println("Exception while trying to create pdf document - " + e);
}
}
Everything works well. All pdf files are converted, but if I use the class shw (this is very necessary for my project):
PdfDocument srcDoc = new PdfDocument(new PdfReader(DEST1));
Rectangle rect = srcDoc.getFirstPage().getPageSize();
System.out.println(rect);
Rectangle pageSize = new Rectangle(rect.getWidth(), rect.getHeight());
PdfDocument pdfDoc = new PdfDocument(new PdfWriter(dest));
pdfDoc.setDefaultPageSize(new PageSize(pageSize));
System.out.println(srcDoc.getNumberOfPages());
PdfCanvas content = new PdfCanvas(pdfDoc.addNewPage());
int n = 0;
for (int i =1 ; i <= srcDoc.getNumberOfPages(); i++) {
PdfFormXObject page = srcDoc.getPage(i).copyAsFormXObject(pdfDoc);
content.clip();
content.newPath();
content.addXObject(page,MainPdf.right_Margin-MainPdf.left_Margin,0);
content = new PdfCanvas(pdfDoc.addNewPage());
for (double y = 4.251969f; y <= 595; y += 14.1732) {
content.moveTo(0, y);
content.lineTo(420, y);
}
for (double x = 0; x <= 420; x += 14.1732) {
content.moveTo(x, 0);
content.lineTo(x, 595);
}
content.closePathStroke();
}
srcDoc.close();
pdfDoc.close();
}
Those images that have been converted to empty (contain nothing inside themselves, just a white background). Pdf not empty.
pdf:https://dropmefiles.com/UXedd
images:

Answer 1

The cause was the call
content.clip();
in the itext segment. This clips with an empty path. Adobe Reader ignores this, but PDFBox doesn't, so the current clipping path is empty so that nothing gets seen.
Per one of the comments, removing that call solves the problem. (I suspect that content.newPath(); isn't needed either)
I have also tried other viewers: PDF.js and GhostScript don't display it, Chrome and Edge display it.