mapnik.go
func (m *Map) ZoomTo(minx, miny, maxx, maxy float64) {
	bbox := C.mapnik_bbox(C.double(minx), C.double(miny), C.double(maxx), C.double(maxy))
	defer C.mapnik_bbox_free(bbox)
	C.mapnik_map_zoom_to_box(m.m, bbox)
}
func (m *Map) ZoomTo(minx, miny, maxx, maxy float64) {
	bbox := C.mapnik_bbox(C.double(minx), C.double(miny), C.double(maxx), C.double(maxy))
	defer C.mapnik_bbox_free(bbox)
	C.mapnik_map_zoom_to_box(m.m, bbox)
}
// ZoomTo zooms to the given bounding box.