[Tex/LaTex] How to adjust the size and placement of chapter heading in report class

Question

How could I adjust the size and placement of chapter heading in my custom class? I am using report class as my base. When I used titlesec package inside my custom class, it threw error

! Package titlesec Error: Not allowed in `easy'
settings.

Answer 1

The error message indicates that you were trying to use the "easy setup" with \titleformat* in a wrong way. For substantial formatting modifications, use the non-starred variant \titleformat and for changing the spacing, use \titlespacing*. Below are the default settings, which you can change according to your needs:

\usepackage{titlesec}

\titleformat{\chapter}[display]
  {\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge}
\titlespacing*{\chapter}
  {0pt}{50pt}{40pt}

For example, to center the title, reduce the space before from 50pt to 30pt and the space after from 40pt to 20pt, you can do:

\documentclass{report}
\usepackage{titlesec}
\usepackage{lipsum}

\titleformat{\chapter}[display]
  {\normalfont\huge\bfseries\filcenter}{\chaptertitlename\ \thechapter}{20pt}{\Huge}
\titlespacing*{\chapter}
  {0pt}{30pt}{20pt}

\begin{document}
\chapter{Test Chapter}
\lipsum[4]
\end{document}