I want to make a command that prints the argument with a font which is one point smaller than the current one.
For example, if a document has 11pt font, the command has to print with 10pt. If the document has 10pt font, I want the command to print with 9pt font.
I don't want this to be bound to the document's font size though. If the command is used in an environment that defines the font to be Xpt, I want the command to produce a text with the font size (X-1)pt
You can also use the package relsize, which allows for what you need. Consider this MWE:
\documentclass{article}
\usepackage{relsize}
\begin{document}
This is normal size font.
\smaller
And this is one point smaller.
\end{document}
The current font size is stored in the macro \f@size:
\RequirePackage{fix-cm} % or use a scalable font
\documentclass{article}
\makeatletter
\newcommand{\oneptsmaller}[1]{%
\begingroup
\fontsize{\dimexpr\f@size pt-1pt}{\f@baselineskip}\selectfont
#1%
\endgroup
}
\makeatother
\begin{document}
\fontname\font\ \oneptsmaller{\fontname\font}
\large
\fontname\font\ \oneptsmaller{\fontname\font}
\footnotesize
\fontname\font\ \oneptsmaller{\fontname\font}
\end{document}
With a scalable font, say \usepackage{baskervald},
Note: \fontname\font is used just to show what font is currently used. In the case of ybvr8t there is no at clause because the font is at its natural size of 10pt.
\scalebox... a good idea? I'm using it like \newcommand{\scalefont}[2][0]{... with the hard-coded 1pt replaced by +#1pt. Seems to work well. :-)
I personnally do it with my beloved fontspec and XelaTex. Here's an example with Libertine (because it's beautiful).
\usepackage{fontspec}
\setmainfont[Ligatures=TeX,]{Linux Libertine O}
\newfontfamily{\ninetypercent}[Scale=0.90]{Linux Libertine O}
\newcommand{\ninety}[1]{{\ninetypercent #1}
Doing this your \ninety{text} will be 10% smaller than your base font. To get a 10pt size from a 11pt you juste have to do a quick math and set the scaling parameter to 0.909 if you want to be ultra precise.
And that way you can decrease any font size by the factor you fancy (that can be 3.5%, 50%, etc...) and it would always be relative to your base fontsize.
I agree that it's a bit overkill but fontspec has a lot of very sweat features to play with.
An improvement on what egreg proposed, it is possible to have it parametric as follows:
\documentclass[12pt]{article}
%: ==== N pt smaller
\makeatletter
\newcommand{\hbFontSmaller}[2]{%
\begingroup
\fontsize{\dimexpr\f@size pt-#1pt}{\f@baselineskip}\selectfont
#2%
\endgroup
}
\makeatother
% ====
\begin{document}
Abcde
\hbFontSmaller{1}{Abcde}
\hbFontSmaller{2}{Abcde}
\hbFontSmaller{3}{Abcde}
\hbFontSmaller{4}{Abcde}
\hbFontSmaller{5}{Abcde}
\hbFontSmaller{6}{Abcde}
\hbFontSmaller{7}{Abcde}
\hbFontSmaller{8}{Abcde}
Abcde
\end{document}
\smallshould be the font switch you search for.\smallis not always one point smaller, for two reasons: (1) It is an asolute size, depending on document class point size. (2) It is possible for a document class definition to make it a different size. My belief is that the OP wants to have a macro that reads the current size (which is not necessarily the document class size), calculates one point less, then applies the smaller size.\smallerdoes not choose a font one point smaller, but will switch to the next declaration among the predefined ones; which may be one point smaller or not.