gnome_canvas_get_scroll_offsets(canvas, &cx, &cy);
ui.hand_scrollto_cx = cx - (pt[0]-ui.hand_refpt[0])*ui.zoom;
ui.hand_scrollto_cy = cy - (pt[1]-ui.hand_refpt[1])*ui.zoom;
gnome_canvas_get_scroll_offsets(canvas, &cx, &cy);
ui.hand_scrollto_cx = cx - (pt[0]-ui.hand_refpt[0])*ui.zoom;
ui.hand_scrollto_cy = cy - (pt[1]-ui.hand_refpt[1])*ui.zoom;