Any way to change color of \not

Question

I often use command \not just to cancel off symbols in my equations and i would need an advice on how to change the color of this command.

Have a look at the cancel package manual and the disclaimer in the end. — percusse, Jun 03 '12 at 20:44
Related Question: Diagonal strikeout starting too low and ending too high. — Peter Grill, Jun 04 '12 at 00:31

score 5 · Answer 1 · edited Jun 04 '12 at 05:05

As mentioned by percusse in the comments, it is better to use cancel package since \not can not strike out more than one variable (say (x+y)). You can define a macro to change the color of strike line as your need:

\documentclass{article}
\usepackage{xcolor}
\usepackage[thicklines]{cancel}
% \renewcommand*{\CancelColor}{\color{red}}%%if only one color is enough
\newcommand*{\mynot}[1]{\renewcommand{\CancelColor}{\color{#1}}\cancel}
\begin{document}
  \[
    \mynot{red}{\in}
  \]
  \[
    (\mynot{green}{x+y})(x-y)
  \]
  \[
    \mynot{black}{x+y}
  \]
  \mynot{blue}{This}  is  cancelled  out. % \cancel works in text mode also.
\end{document}

enter image description here

The OP does not seem to ask about canceling complete expressions but about negating single relation symbols. For this purpose \not is quite sufficient. Furthermore the author of »cancel« explicitly discourages users from using the package (at the very end of its manual). — Thorsten Donig, Jun 05 '12 at 18:52

score 4 · Answer 2 · answered Jun 03 '12 at 20:39

4

A very simple method would be to temporarily change the text color and then switch back to black. This can be done by a new command.

\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage{xcolor}

\newcommand*{\cnot}[1][black]{\color{#1}\not\color{black}}

\begin{document}
  \[
    \cnot[red]\in
  \]
\end{document}

The new command takes an arbitrary color as optional argument.

answered Jun 03 '12 at 20:39

Thorsten Donig

46,014

5

\newcommand*{\cnot}[1][black]{\mathrel{\color{#1}\not}} would avoid restating the current color. – egreg Jun 03 '12 at 20:55
2

Even more, the "current color" might not be black. – lockstep Jun 03 '12 at 21:00
do you need fontenc as part of the MWE? – cmhughes Jun 03 '12 at 21:55
@egreg: Hm, I always forget things like \mathrel. – Thorsten Donig Jun 05 '12 at 18:46
@lockstep: The probability that the current color is not black is vanishingly low. – Thorsten Donig Jun 05 '12 at 18:47
@cmhughes: Not really. But it can't do any harm. – Thorsten Donig Jun 05 '12 at 18:48
2

@ThorstenDonig A casual user might think that T1 and fontenc are essential for the solution. – egreg Jun 05 '12 at 19:21
egreg has made my point- I always try and make my MWE as minimal as possible and load only the packages that are required. – cmhughes Jun 05 '12 at 20:25

score 2 · Accepted Answer · answered Oct 23 '15 at 12:38

Some similar command for obtaining colored \cancelto (some math package is probably missing)

\documentclass{article}
\usepackage{xcolor}
\usepackage{cancel}
\newcommand\crossout[3][black]{\renewcommand\CancelColor{\color{#1}}\cancelto{#2}{#3}}
\begin{document}
  $\crossout[red]{\infty}{a^2} +   \crossout[blue]{0}{b^2}  =   \crossout[green]{\infty}{c^2} $
\end{document}

Any way to change color of \not

3 Answers3