I want to display PDFs in "night mode", where colors are all inverted --- black is white, white is black, etc. Is there an easy way to do so with PDFNet?
There are several ways you could invert all colors of a page.
the easiest is just to add a white rectangle with a blend mode of
Difference, which will cause all colours to display their inverse.
(I've attached an example PDF with just such an annotation.) The PDFNet
Android SDK makes it easy to add new custom annotations, so it would be
possible to add a button to invert the colours of the page by adding a
That said, there are many other methods for inverting colours if
this one is problematic, such as directly editing the colours of each
PDF element (http://www.pdftron.com/pdfnet/samplecode.html#ElementEdit