Re: [color_convert] RGB to CMYK approximation

From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2020-04-02 08:07:35

On Wed, 1 Apr 2020 at 21:19, Mateusz Loskot <mateusz_at_[hidden]> wrote:
>
> Any CMYK gurus or fans out there?
> Here is an example of RGB colors convertible to CMYK:
>
> // 8-bit signed white color
> gil::rgb8s_pixel_t p2{(char)128, (char)128, (char)128};
> gil::cmyk8s_pixel_t c2;
> gil::color_convert(p2, c2);    // c2 = {?, ?, ?, ?}
>
> // 8-bit signed black color
> gil::rgb8s_pixel_t p3{(char)-127, (char)-127, (char)-127};
> gil::cmyk8s_pixel_t c3;
> gil::color_convert(p3, c3);    // c3 = {?, ?, ?, ?}
>
> Spoiler: both give the same CMYK color :)

The values above may seem like a mistake, well,
it kind of was, but in fact there is no difference
valid range w/o overflow

rgb8s_pixel_t p2{(char)127, (char)127, (char)127};
rgb8s_pixel_t p3{(char)-128, (char)-128, (char)-128};

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net