Hi,
you can take a look at onSingleTap method of PDFView class, where it get the rect of a selected annotation and convert it to screen size in this way:
[m_annot getRect:&m_annot_rect];
m_annot_rect.left = [vpage GetX] - self.contentOffset.x * m_scale + [vpage ToDIBX:m_annot_rect.left];
m_annot_rect.right = [vpage GetX] - self.contentOffset.x * m_scale + [vpage ToDIBX:m_annot_rect.right];
float tmp = m_annot_rect.top;
m_annot_rect.top = [vpage GetY] - self.contentOffset.y * m_scale + [vpage ToDIBY:m_annot_rect.bottom];
m_annot_rect.bottom = [vpage GetY] - self.contentOffset.y * m_scale + [vpage ToDIBY:tmp];
Then you can get the CGRect with something like:
CGRectMake(m_annot_rect.left, m_annot_rect.top, m_annot_rect.right - m_annot_rect.left, m_annot_rect.bottom - m_annot_rect.top)