# How does \textit work?

I want to know: how does \textit commands work? Does it use a different font (italic shaped font)? Or is it just a pure LaTeX command that changes text shape to italic?

My main problem: How to make a backward it-shaped text?

• It uses a different font. As to left-handed writing, see tex.stackexchange.com/questions/245751/left-handed-writing. If you replace \ECFSkeetch with \itshape in my answer to that question, you will see backslanted italic. However, the proper way to do it is to design a left-slanted italic font, rather than left-slanting a right-slanted font design. – Steven B. Segletes May 17 '17 at 14:38
• Yes, \itshape calls a different font. However, there is a function \slshape that slants the roman font text. The rightward slant is built in to the command, but I think some clever code can redefine the slant value. See this answer for how to employ FakeSlant when using XeLaTeX: tex.stackexchange.com/questions/128562/… – Steven B. Segletes May 17 '17 at 14:59
• @StevenB.Segletes: no, wait, \slshape invokes a different font too. For example, cmsl for the Computer Modern meta-family. – GuM May 17 '17 at 15:02
• @GustavoMezzetti Darn. Busted! – Steven B. Segletes May 17 '17 at 15:03
• This question has an answer than might help explain the font situation: tex.stackexchange.com/questions/162622/… – Steven B. Segletes May 17 '17 at 15:07

Nothing I'd do, but, with XeLaTeX or LuaLaTeX,…

\documentclass{article}
\usepackage{fontspec}

\newfontface{\backitshape}{lmroman10-italic}[
Extension=.otf,
FakeSlant=-0.4,
]
\DeclareTextFontCommand{\textbackit}{\backitshape}

\begin{document}

Some text \textit{in italic} and \textbackit{backwards tilted italic}

\end{document}


Your title question is easy to answer: \textit chooses a different font.

• +1 Nice answer. Extreme ugly but nevertheless smart. ;-) – Schweinebacke May 17 '17 at 17:03
• @Schweinebacke Somehow I find it not just ugly, but really disturbing on some deep aesthetic level. There are lots of ugly fonts out there, but this one is something else :). And of course +1 for answering the question... even at the price of unleashing that upon the world. – Pont May 17 '17 at 20:30
• That it can be done does not mean that it should be done. I don't know which is the appropriate term, hideous or atrocious. Virtuous TeXing, however ;) – Raoul Kessels May 17 '17 at 21:52