# How to make the color function from xcolor package work over multiple cells?

Recently I had to prepare a simple picture with multiple graphs of functions. For that purpose, I wanted to color each graph of function accordingly to the displayed function itself. Of course, because I listed the functions I used the align environment. Soon the trouble started arising. First, here is a MWE:

\documentclass{article}
\usepackage{mathtools}
\usepackage{xcolor}

\setlength{\parindent}{0cm}

\begin{document}

\begin{align*}
\color{blue}f(x) &\color{blue} = x+1 \\
\color{red}g(x) &\color{red} = 4 \\
\color{green}h(x) &\color{green} = -\frac{1}{2}x - 2
\end{align*}

\end{document}


The document of course compiles just fine and the output is indeed satisfactory, but since I am dedicated to details I can't help myself but ask: how can I make the color function work over multiple cells? I of course know that the so called "cell", or the alignment symbol & if you will is the source of the problem, since color is only meant for the whole environment or one cell. Any kind of help is much appreciated.

• a table cell is a tex group, so fonts assignments and everything else is scoped to a group it is possible in some cases to make colors not obey tex grouping but latex goes to a lot of effort to make colors act like fonts and you would have to undo all that. May 21 '17 at 17:36
• Hm, sounds like a very complex solution, and I'm not very well versed in deconstruction programming. If you have any idea, please share it with me. For now, I don't know how to get a hold of the problem. May 21 '17 at 17:58
• my strong advice would be not to do it: the whole colour setup is designed to make colours obey tex groups May 21 '17 at 18:27
• You can do it with tikz, it allows math environments inside nodes and you can set node groups that share styles. But don't; You lose what you get from the actual math environment such as equation numbering, easy alignment… It is easier just to copy the \color command to the equation. May 21 '17 at 19:01