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Subject: Re: [boost] [gil] undocumented/unintended concept requirements in color_convert
From: Dave Abrahams (dave_at_[hidden])
Date: 2013-03-30 23:29:20

on Sun Mar 17 2013, Michael Marcin <> wrote:

> I was trying to add other color spaces support and noticed that the
> rgb to cmyk converter contains:
> typedef typename channel_type<P2>::type T2;
> T2 x = channel_traits<T2>::max_value()-get_color(dst,black_t());
> if (x>0.0001f) {
> float x1 = channel_traits<T2>::max_value()/float(x);
> T2 should model:
> but this code additionally requires T2 to be greater-than comparable
> to float and convertible to float.

This shows that the authors of that library didn't use archetypes to
test that component.

Dave Abrahams

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