how to export or render model to image in Open3D Viewer module on condition of window hidden?

[as010101]

Checklist

• I have searched for similar issues.
• For Python issues, I have tested with the latest development wheel.
• I have checked the release documentation and the latest documentation (for main branch).

My Question

Im trying to load model then render it as image, I had tried to use OffscreenRendering module, but it cant show texture . So I decide to render model as image in Open3D Viewer module, when I set windows show as false, windows hidden, but when I call ExportCurrentImage after LoadGeometry and SetGeometry. I cant get the model image, How can I export image on condition of window hidden?

void Application::AddWindow(std::shared_ptr<Window> window) {

   window->OnResize();  // so we get an initial resize

   window->Show(true);

   impl_->windows_.insert(window);

}