Having all one single line with black background and text in white

Question

I want to have one line of text with black background and the text in white. The line is alone and so it can be one paragraph.

I would like the coloration for the full width of the line and not only for the text.

The solution must work inside one minipage.

Answer 1

You can use a combination of \colorbox:

\documentclass{article}
\usepackage{xcolor}
\usepackage{showframe}
\usepackage{adjustbox}


\newcommand*\mylineI[1]{%
\par\noindent
\colorbox{black}{\makebox[\dimexpr\linewidth-2\fboxsep\relax][l]{\strut\color{white}#1}}%
\par}

\newcommand*\mylineII[1]{%
  \par\noindent\adjustbox{bgcolor=black,innercode={\color{white}}{},}%
                     {\makebox[\linewidth][l]{\strut #1}}%
  \par%
}
\begin{document}
\mylineI{Text Text Text Text}

\mylineII{Text Text Text Text}

\end{document}
\myline{Text Text Text Text}
\end{document}

EDIT: The second command uses the package adjustbox. So you have some extra options.

Of course the code can be extended width extra spacing and \xspace.

Answer 2

How about this?

\colorbox{black}{%
\begin{minipage}[b]{\dimexpr\textwidth-2\fboxsep\relax}
\strut\color{white}hello
\end{minipage}%
}

A new environment to do the equivalent is

\setlength\fboxsep{0pt}
\makeatletter\newenvironment{blackbox}
    {\noindent\begin{lrbox}{\@tempboxa}\begin{minipage}[b]{\dimexpr\textwidth-2\fboxsep\relax}\strut\color{white}}
    {\end{minipage}\end{lrbox}\colorbox{black}{\usebox{\@tempboxa}}}
\makeatother

which will give the same result with

\begin{blackbox}
hello
\end{blackbox}

Note that this leads to an overfull box if unless \setlength\fboxsep{0pt} is used before it. With that, the output looks like