for(usize, 0 ... 239) |y| {
        for(usize, 0 ... 319) |x| {
            var c = Color{
                .R = @truncate(u8, 255 * x / 319),
                .G = @truncate(u8, y),
                .B = 0,
            };
            try bmp.set(x, y, c);
        }
    }