Re: [boost] [gil] undocumented/unintended concept requirements in color_convert

on Sun Mar 17 2013, Michael Marcin <mike.marcin-AT-gmail.com> 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: http://www.boost.org/doc/libs/1_53_0/libs/gil/doc/html/g_i_l_0264.html

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. http://www.boost.org/doc/libs/1_53_0/libs/concept_check/concept_covering.htm -- Dave Abrahams