pixel |=
    (color.red as u32) >> (8 - self.screen_info.red.length) << self.screen_info.red.offset;
pixel |= (color.green as u32) >> (8 - self.screen_info.green.length)
    << self.screen_info.green.offset;
pixel |= (color.blue as u32) >> (8 - self.screen_info.blue.length)
    << self.screen_info.blue.offset;
pixel |= (color.alpha as u32) >> (8 - self.screen_info.transp.length)
    << self.screen_info.transp.offset;


let new_color = Some(Color {
    red: (color.red as f32 * opacity + prev_color.red as f32 * rev_opacity)
        as u8,
    green: (color.green as f32 * opacity
        + prev_color.green as f32 * rev_opacity)
        as u8,
    blue: (color.blue as f32 * opacity
        + prev_color.blue as f32 * rev_opacity)
        as u8,
    alpha: 255,
});