[Tex/LaTex] Variable parameters in xcolor package

colormacros

This doesn't work and I'm having trouble thinking of a minimum working example, but I'd like to do something like this where I have a parameter to a command as a variable:

\usepackage{xcolor}
\definecolor{mycolor1}{RGB}{126,169,105}
\definecolor{mycolor2}{RGB}{26,69,15}

\newcommand{\ColorVariable1}{mycolor1}
% or
\DeclareRobustCommand{\RobustColorVariable1}{mycolor1}

to allow me to have several places in the body of my document where I do things like this:

\textcolor{\ColorVariable1}{Some text in a variable color}

and I can change the colors of all those colored text portions with one fell swoop by assigning a new color (as below) to the variable rather than replacing mycolor1 with mycolor2 with an editor global search and replace in all the places in the text as I'm doing now.

\newcommand{\ColorVariable1}{mycolor2}

I know that I can do something similar (but not for parameters) in the body of the document:

\def\somestring{Replace \somestring with this text.}

And something also similar with commands, but this doesn't seem to work for parameters:

\newcommand{name}[num][default]{definition}

Is there any way to do something like this in LaTeX?

Best Answer

Package xcolor provides \colorlet. Defining a "color variable", using it and reassigning the color can be seen in the following example:

\documentclass{article}

\usepackage{xcolor}
\definecolor{mycolor1}{RGB}{126,169,105}
\definecolor{mycolor2}{RGB}{26,69,15}

\colorlet{ColorVariable1}{mycolor1}

\begin{document}
\textcolor{ColorVariable1}{Some text in a variable color}

\verb|\colorlet{ColorVariable1}{mycolor2}|
\colorlet{ColorVariable1}{mycolor2}

\textcolor{ColorVariable1}{The color of the variable color can also be
changed.}
\end{document}

Related Solutions

[Tex/LaTex] Variable-name \newcommand with parameters within another \newcommand

\newcommand{\iitthesis@thesisdatafield}[2]{%
  \@namedef{iitthesis@#1}{#2}}

With

\iitthesis@thesisdatafield{authorEnglish}{Name of Author}

you'd define \iitthesis@authorEnglish to expand to "Name of Author", that is, you'd have issued the equivalent of

\def\iitthesis@authorEnglish{Name of Author}

This wouldn't check for the defined command to be previously undefined. If you want also this check, do

\newcommand{\iitthesis@thesisdatafield}[2]{%
  \expandafter\@ifdefinable\csname iitthesis@#1\endcsname
    {\@namedef{iitthesis@#1}{#2}}}

but for internal commands this isn't usually done.

In your motivation I don't see any need of defining the new command with an argument. If you need also to define a user level command, you can do with the same technique:

\newcommand{\iitthesis@thesisdatafield}[1]{%
  \long\@namedef{#1}##1{\@namedef{iitthesis@#1}{##1}}}

In this case saying

\iitthesis@thesisdatafield{authorEnglish}

would define the command \authorEnglish so that if the user types

\authorEnglish{A. U. Thor}

the effect would be as if doing

\def\iitthesis@authorEnglish{A. U. Thor}

The \long prefix to \@namedef causes \long\def to be executed, so the argument can span one or more paragraphs.

This technique is employed by the LaTeX kernel, where \author{A. U. Thor} actually defines \@author expanding eventually to "A. U. Thor".

[Tex/LaTex] Print zeroes in a sparse matrix in a lighter color

I basically type too many matrices with lots of figures etc. so it's kind of natural to me to use TikZ for this, but understandably, you might not want to use this. However, there is a particular option in matrix library that you can decide on what to do when a particular entry is empty. Here is an example

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}

I like lower triangular matrices so does Gauss while eliminating.
\[
\begin{tikzpicture}[baseline=(current bounding box.center)]% To center the matrix in the equation
\matrix[matrix of math nodes,execute at empty cell={\node[black!20]{0};},%Node color and text "0"
        every left delimiter/.style={xshift=1ex},%tighter delimiter spacing
        every right delimiter/.style={xshift=-1ex},
                left delimiter={(},right delimiter={)}
                ] {
1 &  &  &  &  &  &  &  & \\ 
 & 1 &  &  &  &  &  &  & \\ 
 & \frac{1}{2} & \frac{1}{2} &  &  &  &  &  & \\ 
 &  &  & 1 &  &  &  &  & \\ 
 &  &  &  & 1 &  &  &  & \\ 
 &  &  &  & \frac{1}{2} & \frac{1}{2} &  &  &\\ 
 &  &  & \frac{1}{2} &  &  & \frac{1}{2} &  & \\ 
 &  &  &  & \frac{1}{2} &  &  & \frac{1}{2} & \\ 
 &  &  &  & \frac{1}{4} & \frac{1}{4} &  & \frac{1}{4} & \frac{1}{4} \\
};
\end{tikzpicture}
\]
\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Variable-name \newcommand with parameters within another \newcommand

[Tex/LaTex] Print zeroes in a sparse matrix in a lighter color

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