// Render returns the map as an encoded image.
func (m *Map) Render(opts RenderOpts) ([]byte, error) {
scaleFactor := opts.ScaleFactor
if scaleFactor == 0.0 {
scaleFactor = 1.0
}
i := C.mapnik_map_render_to_image(m.m, C.double(opts.Scale), C.double(scaleFactor))
if i == nil {
return nil, m.lastError()
}
defer C.mapnik_image_free(i)
if opts.Format == "raw" {
size := 0
raw := C.mapnik_image_to_raw(i, (*C.size_t)(unsafe.Pointer(&size)))
return C.GoBytes(unsafe.Pointer(raw), C.int(size)), nil
}
var format *C.char
if opts.Format != "" {
format = C.CString(opts.Format)
} else {
format = C.CString("png256")
}
b := C.mapnik_image_to_blob(i, format)
if b == nil {
return nil, errors.New("mapnik: " + C.GoString(C.mapnik_image_last_error(i)))
}
C.free(unsafe.Pointer(format))
defer C.mapnik_image_blob_free(b)
return C.GoBytes(unsafe.Pointer(b.ptr), C.int(b.len)), nil
}
// RenderImage returns the map as an unencoded image.Image.
func (m *Map) RenderImage(opts RenderOpts) (*image.NRGBA, error) {
scaleFactor := opts.ScaleFactor
if scaleFactor == 0.0 {
scaleFactor = 1.0
}
i := C.mapnik_map_render_to_image(m.m, C.double(opts.Scale), C.double(scaleFactor))
if i == nil {
return nil, m.lastError()
}
defer C.mapnik_image_free(i)
size := 0
raw := C.mapnik_image_to_raw(i, (*C.size_t)(unsafe.Pointer(&size)))
b := C.GoBytes(unsafe.Pointer(raw), C.int(size))
img := &image.NRGBA{
Pix: b,
Stride: int(m.width * 4),
Rect: image.Rect(0, 0, int(m.width), int(m.height)),
}
return img, nil
}