Integral sign from Txfonts

Question

There were several questions for this, but none answer my doubt completely. My initial code is as follows (compiled with pdflatex):

\documentclass[11pt,a4paper,notitlepage,onecolumn,oneside]{mwart}
\usepackage[top=2.5cm, bottom=2.5cm, left=2cm, right=2cm]{geometry} 
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{upgreek} 
\usepackage[polish]{babel}
\usepackage[utf8]{inputenc}
\usepackage[OT4]{fontenc}
\usepackage{graphicx}
\usepackage{color}
\usepackage{xcolor}

I followed the advice to create a new symbol:

\DeclareMathOperator*{\uint}{\scalerel*{\rotatebox{8}{$\!\textstyle\int\!$}}{\int}}

but it's still worse than one observed in Txfonts

http://piotrkosoft.net/pub/mirrors/CTAN/fonts/txfonts/doc/txfontsdocA4.pdf

Is it possible to use this single integral sign? Many thanks in advance.

Previous posts: Integral Sign $\int...$ How to Obtain a Bold Upright Integral Sign?

Answer 1

To begin with, use \usepackage[T1]{fontenc}. The standard fonts have covered Polish for more than twenty years and the OT4 kludges are no longer needed.

If you want to use the integral signs from the TX fonts (I'm not sure why), you can define a new symbol font.

\documentclass[11pt,a4paper,notitlepage,onecolumn,oneside]{mwart}
\usepackage[top=2.5cm, bottom=2.5cm, left=2cm, right=2cm]{geometry} 

\usepackage[T1]{fontenc}
%\usepackage[utf8]{inputenc} % unneeded with recent LaTeX
\usepackage[polish]{babel}

%\usepackage{amsfonts} % unneeded with amssymb
\let\lll\relax % to avoid the error
\usepackage{amssymb}
\usepackage{amsmath}

% not needed for the example
%\usepackage{upgreek} 
%\usepackage{graphicx}
%\usepackage{color} % unneeded with xcolor
%\usepackage{xcolor}

\DeclareSymbolFont{TXlargesymbols}{OMX}{txex}{m}{n}
\SetSymbolFont{TXlargesymbols}{bold}{OMX}{txex}{bx}{n}
\DeclareFontSubstitution{OMX}{txex}{m}{n}

\DeclareMathSymbol{\intop}{\mathop}{TXlargesymbols}{"52}
\DeclareMathSymbol{\ointop}{\mathop}{TXlargesymbols}{"48}

\begin{document}

\[
\int_1^x\frac{1}{t}\,dt + \oint_\gamma \frac{1}{z}\,dz+\iint+\iiint
\]

\end{document}

Answer 2

Although you’re using the legacy tools with seven-bit(!) fonts, in the modern toolchain, you can do this with the range= option of \setmathfont. For example, to use the integral symbols from STIX Two Math in unicode-math:

\setmathfont[range={"222B-"2233,"2A0B-"2A1C},Scale=MatchUppercase]{XITS Math}

You can add the StylisticSet=8 option to get the alternative upright integrals.