/// Copies RGB565 (u16) -> RGBA8888 (u8[4]) to the pixels frame.
/// Pixels format: RGBA8.
pub fn draw_rgb565_to_rgba8(src: &[u16], dst_rgba: &mut [u8]) {
    for (i, &px) in src.iter().enumerate() {
        let (r8, g8, b8) = rgb565_to_rgb888(px);
        let o = i * 4;
        dst_rgba[o] = r8;
        dst_rgba[o + 1] = g8;
        dst_rgba[o + 2] = b8;
        dst_rgba[o + 3] = 0xFF;
    }
}

/// Expands RGB565 to RGB888 (high bit replication).
#[inline(always)]
pub fn rgb565_to_rgb888(px: u16) -> (u8, u8, u8) {
    let r5 = ((px >> 11) & 0x1F) as u8;
    let g6 = ((px >> 5) & 0x3F) as u8;
    let b5 = (px & 0x1F) as u8;

    let r8 = (r5 << 3) | (r5 >> 2);
    let g8 = (g6 << 2) | (g6 >> 4);
    let b8 = (b5 << 3) | (b5 >> 2);

    (r8, g8, b8)
}