void free_gegl_tiledsurf(MyPaintSurface *surface)
{
    MyPaintGeglTiledSurface *self = (MyPaintGeglTiledSurface *)surface;

    mypaint_tiled_surface_destroy(&self->parent);
    g_object_unref(self->buffer);

    free(self);
}
void free_tiledsurf(MyPaintSurface *surface)
{
    MyPaintPythonTiledSurface *self = (MyPaintPythonTiledSurface *)surface;
    mypaint_tiled_surface_destroy(&self->parent);
    free(self);
}