code: func (self *Block) SetRect(x1, y1, x2, y2 int) {
  	self.Rectangle = image.Rect(x1, y1, x2, y2)
  	self.Inner = image.Rect(
  		self.Min.X+1+self.PaddingLeft,
  		self.Min.Y+1+self.PaddingTop,
  		self.Max.X-1-self.PaddingRight,
  		self.Max.Y-1-self.PaddingBottom,
  	)
  }
docs: // SetRect implements the Drawable interface.