How to prevent the model from going outside the viewport

Hello! I have a problem with model movement inside a viewport. Now I can move the model outside of the viewport boundaries, but I want to set a padding to the viewport for preventing the model from going to nowhere. I want always see the model inside the viewport and block moving it out of the window. I tried to set view size and viewer size but it didn't work. And also I am a little bit confused about which settings to tweak (V3d_Viewer, V3d_View, AIS_InteractiveContext or Aspect_NeutralWindow). I will extremely appreciate your help!