code: func (v *ViewPort) Resize(x, y, width, height int) {
  	if v.v == nil {
  		return
  	}
  	px, py := v.v.Size()
  	if x >= 0 && x < px {
  		v.physx = x
  	}
  	if y >= 0 && y < py {
  		v.physy = y
  	}
  	if width < 0 {
  		width = px - x
  	}
  	if height < 0 {
  		height = py - y
  	}
  	if width <= x+px {
  		v.width = width
  	}
  	if height <= y+py {
  		v.height = height
  	}
  }
docs: // Resize is called by the enclosing view to change the size of the ViewPort,
  // usually in response to a window resize event.  The x, y refer are the
  // ViewPort's location relative to the parent View.  A negative value for either
  // width or height will cause the ViewPort to expand to fill to the end of parent
  // View in the relevant dimension.