Scroll to a specific position.
void pdfScrollBy(PDFViewerHandle viewer, int dx, int dy)
This function is similar to pdfScrollTo, except that it scrolls relative to the current position. A positive dx value scrolls right, a negative dx value scrolls left. Similarly, positive and negative dy values scroll down and up, respectively. For example:
pdfScrollBy(viewer, 5, -10);
would scroll 5 pixels to the right and 10 pixels up from the current position.
pdfScrollBy(viewer, -10, 0);