On Tue, 12 Jul 2016, Hans Hagen wrote:

> On 7/12/2016 5:07 PM, Aditya Mahajan wrote:
>> On Tue, 12 Jul 2016, Hans Hagen wrote:
>>
>>> On 7/12/2016 3:44 PM, Henri Menke wrote:
>>>> Dear Hans,
>>>>
>>>> thanks for your reply.  Indeed there are color definitions in
>>>> `pgfutil-context.def`.  However, they are commented out with the 
> message
>>>>
>>>>> % no need for x colors (users can load it if needed)
>>>>> ...
>>>>> %\pgfutil@definecolor{gray}{gray}{0.5}
>>>>
>>>> If I add
>>>>
>>>>> \csname pgfutil@definecolor\endcsname{gray}{gray}{0.5}
>>>>
>>>> to my document the gray shows up fine.  So that's for sure a feasible
>>>> workaround.
>>>>
>>>> Can you comment on the phrase »no need for x colors (users can load it
>>>> if needed)«?  I'm not quite sure what it means and it suggests that
>>>> there exists a proper solution to my color problem.
>>>
>>> normally you want the same colors in tikz images as in context so then
>>> defining them in tikz is creating incompatibilities (your case is the
>>> reverse and a-typical)
>>
>> However, without such redefinitions, tikz does not understand ConTeXt
>> colors. I use a similar workaround in my documents as well.
>
> I have no clue what you mean.
>
> \definecolor[red][g=1]
>
> \startTEXpage
>     \starttikzpicture
>        \fill[red] (0,0) circle (1cm);
>     \stoptikzpicture
> \stopTEXpage
>
> works ok here and gives green. So, one can collect a list of colors 
> defined in tikz in a colo-imp-tikz.mkiv and load that one if needed.

I guess it is a bug with pgfplots rather than tikz (which also means that 
it may be easier to pursuade pgfplot maintainers to use low level tikz 
interface, since tikz is already playing nice with context).

\usemodule[tikz,pgfplots]
\definecolor[red][g=1]

\startmode[bug]
\unprotect
\pgfutil@definecolor{red}   {rgb} {0,1,0}
\protect
\stopmode

\starttext
\startTEXpage
      \starttikzpicture
        \startaxis
          \addplot[color=red] coordinates { (0,0) (1,1) };
        \stopaxis
      \stoptikzpicture
\stopTEXpage
\stoptext

Aditya