func (m *Map) RenderToMemoryUTFGrid(lname string, key string, res uint) (string, error) {
l := &Layer{}
n := int(C.mapnik_map_layer_count(m.m))
for i := 0; i < n; i++ {
ml := C.mapnik_map_get_layer(m.m, C.size_t(i))
defer C.free(unsafe.Pointer(ml))
if C.GoString(C.mapnik_layer_name(ml)) == lname {
l.l = ml
break
}
}
if l.l == nil {
return "", fmt.Errorf("no such layer %s", lname)
}
cs := C.CString(key)
defer C.free(unsafe.Pointer(cs))
g := C.mapnik_map_render_to_grid(m.m, l.l, cs)
if g == nil {
return "", m.lastError()
}
defer C.mapnik_grid_free(g)
json := C.mapnik_grid_to_json(g, C.uint(res))
if json == nil {
return "", m.lastError()
}
defer C.free(unsafe.Pointer(json))
return C.GoString(json), nil
}
func (m *Map) SetActiveLayer(lname string) {
n := int(C.mapnik_map_layer_count(m.m))
for i := 0; i < n; i++ {
l := C.mapnik_map_get_layer(m.m, C.size_t(i))
defer C.free(unsafe.Pointer(l))
if C.GoString(C.mapnik_layer_name(l)) == lname {
C.mapnik_layer_set_active(l, 1)
} else {
C.mapnik_layer_set_active(l, 0)
}
}
}
