If this property is set to true, XpdfText will discard any invisible text. This isn't generally useful – most of the time you'll want the OCRed text. But in cases where a non-image PDF file is OCRed, it can end up with duplicated text, and this option will discard the OCR text.
There are two different ways to represent invisible text in PDF:
- by setting the text "render mode" to 3 (invisible)
- by setting the alpha (transparency) to 0
discardInvisibleTextwill discard text drawn with either of those techniques.
It's also possible to hide text in other ways, e.g., by placing it
behind the image.
discardInvisibleText does not discard