code: func (g *Gui) drawFrameCorners(v *View, fgColor, bgColor Attribute) error {
  	runeTL, runeTR, runeBL, runeBR := '┌', '┐', '└', '┘'
  	if g.ASCII {
  		runeTL, runeTR, runeBL, runeBR = '+', '+', '+', '+'
  	}
  
  	corners := []struct {
  		x, y int
  		ch   rune
  	}{{v.x0, v.y0, runeTL}, {v.x1, v.y0, runeTR}, {v.x0, v.y1, runeBL}, {v.x1, v.y1, runeBR}}
  
  	for _, c := range corners {
  		if c.x >= 0 && c.y >= 0 && c.x < g.maxX && c.y < g.maxY {
  			if err := g.SetRune(c.x, c.y, c.ch, fgColor, bgColor); err != nil {
  				return err
  			}
  		}
  	}
  	return nil
  }
docs: // drawFrameCorners draws the corners of the view.