[metapost] Different colours in a label

[Pétiard François]

Tommy Ekola a écrit :
>> I want to typeset a label like that :
>>
>> E=Q(i)
>>
>> where E is in blue and i is in red.
> 
> A not-so-elegant solution is to let metapost color the label. In the code
> below I define a picture for each part of the label that should have the
> same color (blocking other parts of the label with \phantom) and then draw
> each part of the label using different colors.
> 
> beginfig(1);
>   picture p, q, r;
>   p := thelabel(btex $E\phantom{{}=Q(i)}$ etex, (0,0));
>   q := thelabel(btex $\phantom{E}=Q(\phantom{i})$ etex, (0,0));
>   r := thelabel(btex $\phantom{E=Q(}i\phantom{)}$ etex, (0,0));
>   draw p withcolor blue;
>   draw q withcolor black;
>   draw r withcolor red;
> endfig;
> 
> end.
> 
Thank you for your tip.
I have founded a similar solution but, of course, I would prefer dvitomp 
solution. Christian Schenk has promised that for MiKTeX 2.7.

Best regards

F. Pétiard