Q:
SetBackgroundColor is not working for me. The method SetBackgroundColor:g:b:a: but nothing affected
A:
The values are 0-255. I suspect you are using values from 0-1. Also you will need to trigger a redraw, if you are doing this on the fly.
For example
[self.pdfViewCtrl SetBackgroundColor:255 g:0 b:255: a:255; // magenta background [self.pdfViewCtrl Update]; // optional