On Fri, Feb 11, 2022 at 10:19:22AM +0100, Javier Martinez Canillas wrote:
> Pull the per-line conversion logic into a separate helper function.
>
> This will allow to do line-by-line conversion in other helpers that
> convert to a gray8 format.
...
> +static void drm_fb_xrgb8888_to_gray8_line(u8 *dst, const u32 *src, unsigned int pixels)
> +{
> + unsigned int x;
> +
> + for (x = 0; x < pixels; x++) {
> + u8 r = (*src & 0x00ff0000) >> 16;
> + u8 g = (*src & 0x0000ff00) >> 8;
> + u8 b = *src & 0x000000ff;
> +
> + /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
> + *dst++ = (3 * r + 6 * g + b) / 10;
> + src++;
> + }
Can be done as
while (pixels--) {
...
}
or
do {
...
} while (--pixels);
> +}
--
With Best Regards,
Andy Shevchenko
