Evenly spaced boxes filling the whole page

Question

I'm trying to vertically fill the whole height of a page with 3 evenly spaced boxes. This is what I have now

\documentclass{article}
\usepackage[showframe]{geometry}
\usepackage[many]{tcolorbox}
\usepackage{calc}
\usepackage{lipsum}
\newlength{\boxheight}
\setlength{\boxheight}{136.80573pt}
\newlength{\vertspace}
\setlength{\vertspace}{(\textheight - 3\boxheight)/2 - 7pt}
% ----------------
\begin{document}
\begin{tcolorbox}[sharp corners, draft]
\lipsum[1]
\end{tcolorbox}
\vspace{\vertspace}

\begin{tcolorbox}[sharp corners]
\lipsum[1]
\end{tcolorbox}
\vspace{\vertspace}

\begin{tcolorbox}[sharp corners]
\lipsum[1]
\end{tcolorbox}
\end{document}

the -7pt in the definition of \vertspace is the vertical space between two boxes given by a new paragraph. As you can see there's still a little bit of space left at the bottom, but I'm not sure why. Even if I use \vfill, the space at the bottom remains.

How should I calculate \vertspace? Is there a better way to go about it?

Answer 1

You can use fill space there is no need to calculate the space between boxes. Also it is almost always best to leave a blank line before \vspace.

The small gap at the bottom is de to the fact that the frame drawn is leaving for the usual case of text on the last line so there is for descenders such as y and g . If you want the bottom of the last box to fill that space rather than sit on the last baseline on the page then you can add a negative space the depth of `\strutbox.

\documentclass{article}
\usepackage[showframe]{geometry}
\usepackage[many]{tcolorbox}
\usepackage{calc}
\usepackage{lipsum}
\newlength{\boxheight}


% ----------------
\begin{document}
\begin{tcolorbox}[sharp corners, draft]
\lipsum[1]
\end{tcolorbox}

\vspace{\fill}

\begin{tcolorbox}[sharp corners]
\lipsum[1]
\end{tcolorbox}

\vspace{\fill}

\begin{tcolorbox}[sharp corners]
\lipsum[1]
\end{tcolorbox}

\vspace{-\dp\strutbox}

\end{document}