[metapost] Different colours in a label

[Tommy Ekola]

> 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.


-Tommy Ekola