/// Copies RGBA8888 pixels in canonical RGBA raw order into the `pixels` RGBA8 frame.
pub fn draw_rgba8888_to_rgba8(src: &[u32], dst_rgba: &mut [u8]) {
    for (i, &px) in src.iter().enumerate() {
        let o = i * 4;
        dst_rgba[o] = ((px >> 24) & 0xFF) as u8;
        dst_rgba[o + 1] = ((px >> 16) & 0xFF) as u8;
        dst_rgba[o + 2] = ((px >> 8) & 0xFF) as u8;
        dst_rgba[o + 3] = (px & 0xFF) as u8;
    }
}

#[cfg(test)]
mod tests {
    use super::draw_rgba8888_to_rgba8;

    #[test]
    fn draw_rgba8888_to_rgba8_preserves_channel_order_and_alpha() {
        let src = [0x12345678, 0xABCDEF01];
        let mut dst = [0; 8];

        draw_rgba8888_to_rgba8(&src, &mut dst);

        assert_eq!(dst, [0x12, 0x34, 0x56, 0x78, 0xAB, 0xCD, 0xEF, 0x01]);
    }
}