code: func (c *Canvas) Clear(color color.Color) {
  	c.gf.Dirty()
  
  	rgba := pixel.ToRGBA(color)
  
  	// color masking
  	rgba = rgba.Mul(pixel.RGBA{
  		R: float64(c.col[0]),
  		G: float64(c.col[1]),
  		B: float64(c.col[2]),
  		A: float64(c.col[3]),
  	})
  
  	mainthread.CallNonBlock(func() {
  		c.setGlhfBounds()
  		c.gf.Frame().Begin()
  		glhf.Clear(
  			float32(rgba.R),
  			float32(rgba.G),
  			float32(rgba.B),
  			float32(rgba.A),
  		)
  		c.gf.Frame().End()
  	})
  }
docs: // Clear fills the whole Canvas with a single color.