Unwanted horizontal space in custom section title

Question

I am currently using the following code to produce a fancy section title in LaTeX. However, I am be having trouble figuring out how to get rid of the additional horizontal space before and after the title (Introduction). I'd like the underline to extend only as far as the end of the title with no additional space. I'd also like the blue box's width to be vary according to the width of the section number inside it (so no extra space as in the picture below). How can I achieve this?

\documentclass{article}
\usepackage{lipsum}
\usepackage{xcolor}
\usepackage{calc}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{xcolor, lipsum}
\renewcommand*\thesection{\arabic{section}}
\usepackage[explicit,calcwidth]{titlesec}
\definecolor{myBlue}{HTML}{0088FF}
\titleformat{\section}[block]{\Large\bfseries\sffamily}
{\rlap{\color{red}\rule[-6pt]{\titlewidth}{1pt}}\colorbox{myBlue}{
           \raisebox{0pt}[13pt][3pt]{\makebox[60pt]{
                \selectfont\color{white}{\thesection}}
            }}}
{15pt}
{\color{myBlue}#1}
\titlespacing*{\section}{0pt}{0mm}{0mm}
\begin{document}
\section{Introduction}
\lipsum[1]
\end{document}

The space after the title comes from the unprotected line ending in l. 19 — samcarter_is_at_topanswers.xyz, May 15 '23 at 15:52
And the extra space before the text is from the space before \color{myBlue}. — cabohah, May 15 '23 at 15:52
This does not answer my question in full (though it has solved the introduction problem). I'd also like the blue box to fit tightly around the 1. with no additional horizontal space. — wrb98, May 15 '23 at 16:29
@wrb98 If you don't want additional space, why do you place the section number in a \makebox of fixed width? — samcarter_is_at_topanswers.xyz, May 15 '23 at 16:34
@wrb98 There are still a bunch of unprotected line endings, e.g. lines 15, 16 and 17 — samcarter_is_at_topanswers.xyz, May 15 '23 at 16:35
It might be obvious, but the space before "Introduction" is also created by the sep between the number and the section title which you set explicitly to 15pt. If you want to decrease this, use a shorter length. — Jasper Habicht, May 15 '23 at 16:40

score 1 · Accepted Answer · answered May 15 '23 at 20:56

Don't forget about spaces generated by endlines.

Almost always the explicit option to titlesec is unneeded, like in your case.

I reformatted the code to show more clearly the various nestings. Note the % at the endlines that would generate a space.

The \selectfont declaration you had was useless and has been removed.

\titleformat{\section}[block]
  {\Large\bfseries\sffamily}
  {%
   \rlap{\color{red}\rule[-6pt]{\titlewidth}{1pt}}%
   \colorbox{myBlue}{%
     \raisebox{0pt}[13pt][3pt]{%
       \makebox[60pt]{%
         \color{white}\thesection
       }%
     }%
   }%
  }
  {15pt}
  {\color{myBlue}}

\documentclass{article}
\usepackage{lipsum}
\usepackage{xcolor}
\usepackage{calc}
\usepackage[T1]{fontenc}
\usepackage[calcwidth]{titlesec}
\usepackage{lipsum}
\renewcommand*\thesection{\arabic{section}}
\definecolor{myBlue}{HTML}{0088FF}
\titleformat{\section}[block]
  {\Large\bfseries\sffamily}
  {%
   \rlap{\color{red}\rule[-6pt]{\titlewidth}{1pt}}%
   \colorbox{myBlue}{%
     \raisebox{0pt}[13pt][3pt]{\makebox[60pt]{%
       \color{white}\thesection}%
     }%
   }%
  }
  {15pt}
  {\color{myBlue}}
\titlespacing*{\section}{0pt}{0mm}{0mm}
\begin{document}
\section{Introduction}
\lipsum[1]
\end{document}

Unwanted horizontal space in custom section title

1 Answers1