Highlight words in a pdf using itextsharp, not displaying highlighted word in browser

Question

Highlighted words are not displaying in browser using itextsharp.

Adobe

Browser

CODE

Answer 1

You are using a Markup annotation to highlight text. That's great! There's nothing wrong with your code, nor with iText. However: not all PDF viewers support that functionality.

If you want to see highlighted text in every PDF viewer, a (sub-optimal) workaround could be to add a yellow rectangle to the content stream under the existing content (assuming that the existing content isn't opaque).

This is demonstrated in the HighLightByAddingContent example:

public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
    PdfReader reader = new PdfReader(src);
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
    PdfContentByte canvas = stamper.getUnderContent(1);
    canvas.saveState();
    canvas.setColorFill(BaseColor.YELLOW);
    canvas.rectangle(36, 786, 66, 16);
    canvas.fill();
    canvas.restoreState();
    stamper.close();
    reader.close();
}

In this example, we take a file named hello.pdf and we add a yellow rectangle, with the file hello_highlighted.pdf as result.

Note that you won't see the yellow rectangle if you add it under an opaque shape (e.g. under an image). In that case, you could add a transparent rectangle on top of the existing content.

Update: my example was written in Java. It shouldn't be a problem for a developer to port this to C#. It's only a matter of changing some lower-cases into upper-cases. E.g. stamper.GetUnderContent(1) instead of stamper.getUnderContent(1), canvas.SaveState() instead of canvas.saveState(), and so on.