copy/pastefontsligaturespdftex
When I pdflatex text containing "fi", e.g. "infinite", the resulting pdf-file looks correct, e.g. "infinite" is shown in the text. But when I search the pdf file for "infinite", 0 occurrences are found. When I copy "infinite" and paste it, the result is "innite". Searching for "innite" results in 0 occurrences as well.
What causes this behavior? My font not being able to handle ligatures? How can I fix it, such that "fi" is treated the same as any other letter combination?
Add \usepackage{fontspec}. This actually loads the package fontenc, which would solve your problem for pdfLaTeX.
As a result, the ec fonts are loaded instead of the standard Computer Modern fonts, as Ulrike remarked in the comments. For other fonts, other solutions might apply; this answer addresses a standard setup as seen in the OP's MWE.
This is commonly due to bad font information, but is solvable. The ligatures that can give problems are ff fi fl ffi ffl, if a modern font is used.
You can solve at once your problem with
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
%% use this in your preamble
\usepackage{newunicodechar}
\newunicodechar{ff}{ff}
\newunicodechar{fi}{fi}
\newunicodechar{fl}{fl}
\newunicodechar{ffi}{ffi}
\newunicodechar{ffl}{ffl}
%% end of common ligatures
\begin{document}
ff fi fl ffi ffl
\end{document}
The relevant code is between the two %% prefixed lines. Just keep it at hand and paste it when needed.
A “search and replace” can be better, for the production version of the document.
Best Answer
LaTex use ligatures in the text and the PDF-readers treat that as one, unknown character. As far as I remember, I solved the same problem by adding the following two lines in the preamble:
I found this solution in the MinionPro manual, page 7.
I use utf8 encoding in my document, i.e.
Also have a look at Ulrike Fischer’s answer to a similar question regarding Linux Libertine.
glyphtounicodewas included in the MiKTeX-distribution I use, but if it is not included in yours, you can find it at Sarovar.