code: func ToRGBA(c color.Color) RGBA {
  	if c, ok := c.(RGBA); ok {
  		return c
  	}
  	r, g, b, a := c.RGBA()
  	return RGBA{
  		float64(r) / 0xffff,
  		float64(g) / 0xffff,
  		float64(b) / 0xffff,
  		float64(a) / 0xffff,
  	}
  }
docs: // ToRGBA converts a color to RGBA format. Using this function is preferred to using RGBAModel, for
  // performance (using RGBAModel introduces additional unnecessary allocations).