code: func (v *ViewPort) SetContentSize(width, height int, locked bool) {
  	v.limx = width
  	v.limy = height
  	v.locked = locked
  	v.ValidateView()
  }
docs: // SetContentSize sets the size of the content area; this is used to limit
  // scrolling and view moment.  If locked is true, then the content size will
  // not automatically grow even if content is placed outside of this area
  // with the SetContent() method.  If false, and content is drawn outside
  // of the existing size, then the size will automatically grow to include
  // the new content.