I followed your example code to do a zoom in\out, and that's all fine.
But I cannot
figure out how to zoom based on percentage, e.g how do I make it 75%
125% in size. If you have some example code for that, then it would be
great to get that.
pdfview.SetZoom(1) - which is the default, will set the zoom factor to
default PDF user coordinates where 1 point is 1/72 of an inch.
To zoom in 75% you just need to multiply the current zoom factor by
the percentage. For example,
double percent_zoom = 75;
pdfview.SetZoom(pdfview.GetZoom() * (percent_zoom + 100.0)/100.0);