Bar over/under integral symbol

Question

I try to typeset bar over/under integral symbol with

\overline\int,\underline\int

But the line looks too long, any solution?

Answer 1

This should do (not in script styles)

\documentclass{article}

\makeatletter
\newcommand\tint{\mathop{\mathpalette\tb@int{t}}\!\int}
\newcommand\bint{\mathop{\mathpalette\tb@int{b}}\!\int}
\newcommand\tb@int[2]{%
  \sbox\z@{$\m@th#1\int$}%
  \if#2t%
    \rlap{\hbox to\wd\z@{%
      \hfil
      \vrule width .35em height \dimexpr\ht\z@+1.4pt\relax depth -\dimexpr\ht\z@+1pt\relax
      \kern.05em % a small correction on the top
    }}
  \else
    \rlap{\hbox to\wd\z@{%
      \vrule width .35em height -\dimexpr\dp\z@+1pt\relax depth \dimexpr\dp\z@+1.4pt\relax
      \hfil
    }}
  \fi
}
\makeatother

\begin{document}
\[
\tint_a^b f(t)\,dt=\bint_a^b f(t)\,dt
\textstyle
\tint_a^b f(t)\,dt=\bint_a^b f(t)\,dt
\]
\end{document}

Answer 2

How about this?

$$\mathop{\smash{\hspace{4.44444pt}\overline{\hspace{-4.44444pt}\int}}\vphantom{\int}}
\nolimits^b_{\hspace{-4.44444pt}a}$$

Answer 3

\documentclass[a4paper]{paper}
\usepackage{STIX}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}

\begin{document}

\[ \upint\limits_{a}^{b} f(x) \ \text{d}x \ \ \ \lowint\limits_{a}^{b} f(x) \ \text{d}x \]

\end{document}

Answer 4

For typing the upper and lower Darboux integrals, you could use

\[\overline{\int_{a}^{b}}f dx = \underline{\int_{a}^{b}} f dx\]