code: func (v *ViewPort) MakeVisible(x, y int) {
  	if x < v.limx && x >= v.viewx+v.width {
  		v.viewx = x - (v.width - 1)
  	}
  	if x >= 0 && x < v.viewx {
  		v.viewx = x
  	}
  	if y < v.limy && y >= v.viewy+v.height {
  		v.viewy = y - (v.height - 1)
  	}
  	if y >= 0 && y < v.viewy {
  		v.viewy = y
  	}
  	v.ValidateView()
  }
docs: // MakeVisible moves the ViewPort the minimum necessary to make the given
  // point visible.  This should be called before any content is changed with
  // SetContent, since otherwise it may be possible to move the location onto
  // a region whose contents have been discarded.