It seems likely that otftotfm may also work on pre-OpenType TrueType fonts because the OpenType font format is essentially the same as the TrueType format with potentially additional tables. At least, when I did cursory search on my computer I could not find any TrueType fonts that proved to be incompatible with otftotfm.

Therefore, if you want to use a TrueType font with pdfLaTeX you should ignore the instructions I give in ∃xistential Type Fonts in LaTeX, Part Three: pdfTeX and TrueType and use the same instructions as I gave for OpenType fonts in Fonts in LaTeX, Part Two: pdfTeX and OpenType. For your convenience, I have also created an updated the zip file for the example that uses otftotfm instead of ttf2tfm.

In the previous part of this tutorial, I explained how to put together the minimal infrastructure needed to use an OpenType font with pdfLaTeX.  However, I used the tool otftotfm to generate the font metrics TeX needs to lay out text. However, otftotfm only supports OpenType fonts that use PostScript font outlines, as opposed to TrueType font outlines. So in this part of the tutorial I will explain how to put together the necessary infrastructure for TrueType fonts. In preparation for that, we will first make a few changes to what we had done earlier.

For those that would find it useful, I've put together a  zip file containing all the files from the tutorials (except the fonts, which I don't want to deal with distributing).

Firstly, we are going to move the uses of \DeclareUnicodeCharacter out of UPagella.fd and into uenc.def:

 
\ProvidesFile{uenc.def}
% We are declaring an encoding named "U"
\DeclareFontEncoding{U}{}{}
 
% Technically these are not "allowed" in .def files,
% but this is really the logical place to put the
% declarations.
 
% τ (0x03C4) maps to 0xF8 in the encoding
\DeclareUnicodeCharacter{03C4}{\char"F8}
% ε (0x03B5) maps to 0xF9 in the encoding
\DeclareUnicodeCharacter{03B5}{\char"F9}
% χ (0x03C7) maps to 0xFA in the encoding
\DeclareUnicodeCharacter{03C7}{\char"FA}

As I mention in the comments, the documentation on font encoding definition files does not list \DeclareUnicodeCharacter to be one of the allowed declarations in a such a file, but it works, and it seems like the more logical place to configure it than in the font definition file.

Now that we have removed the uses of \DeclareUnicodeCharacter from UPagella.fd, it looks like:

 
\ProvidesFile{UPagella.fd}
 
% Delcaring a font family called "Pagella" for the encoding "U"
\DeclareFontFamily{U}{Pagella}{}
 
% Declare that font family "Pagella", for encoding "U", has a shape
% with weight medium (m) and normal (n) slant (in otherwords, upright)
\DeclareFontShape{U}{Pagella}{m}{n}{
  % For all sizes...
  <->
  % ... use the font named
  TeXGyrePagella-Regular--custom--base
}{}

I am going to use Deja Vu Sans as the example TrueType font. Fortunately, if you followed everything from the second part of the tutorial, there is not much that needs to be done.

First, we need to generate metrics for Deja Vu Sans. As before, if you are using TeX Live, you'll have the necessary program:

% ttf2tfm DejaVuSans.ttf -q -T custom
ttf2tfm: WARNING: Cannot find character `compwordmark'
         specified in input encoding.
...
...
ttf2tfm: WARNING: Cannot find character `zdotaccent'
         specified in input encoding.
DejaVuSans   DejaVuSans.ttf Encoding=custom.enc

The program ttf2tfm is kind of unusual in that it first takes the filename argument and then all the options. So we've passed it the TrueType font we want to generate metrics for, DejaVuSans.ttf, the option -q to tell it not to print quite so much information, and the option -T custom which tells it to use the encoding defined in the file custom.enc we created in previous part.

Unlike otftotfm, ttf2tfm does not generate an entry that we could use in our map file, custom.map, so we need to write one ourselves. You will want to start with the map we generated by otftotfm for Tex Gyre Pagella, and you will want to add the line:

DejaVuSans <custom.enc <DejaVuSans.ttf

This says to map the TeX font name DejaVuSans to the file DejaVuSans.ttf using the encoding custom.enc. To learn more about the format of map files, there is a section on them in the pdfTeX manual.

Now we just need to create a font definition file for Deja Vu Sans. However, it is essentially the same as the one we created for TeX Gyre Pagella:

 
\ProvidesFile{UDejaVuSans.fd}
 
% Delcaring a font family called "DejaVuSans" for the encoding "U"
\DeclareFontFamily{U}{DejaVuSans}{}
 
% Declare that font family "DejaVuSans", for encoding "U", has a shape
% with weight medium (m) and normal (n) slant (in otherwords, upright)
\DeclareFontShape{U}{DejaVuSans}{m}{n}{
  % For all sizes...
  <->
  % ... use the font named
  DejaVuSans
}{}

We have just replaced all occurrences of Pagella with DejaVuSans.

Finally, we just need to update our example document to use Deja Vu Sans:

 
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[U]{fontenc}
\pdfmapfile{+custom.map}
\renewcommand{\rmdefault}{Pagella}
\renewcommand{\sfdefault}{DejaVuSans} 
 
\begin{document}
Testing pdfLaTeX!
 
Greek: τεχ.
 
\begin{sffamily}
Testing pdfLaTeX!
 
Greek: τεχ.
\end{sffamily}
\end{document}

Here we have used \renewcommand to set the default sans serif font, \sfdefault, to be DejaVuSans. In the body of the document, we've copied the text and surrounded it with the sffamily environment to have it typeset in sans serif.

Now we have everything we need to run pdflatex:

% pdflatex test-pdflatex.tex
This is pdfTeXk, Version 3.141592-1.40.3 (Web2C 7.5.6)
 %&-line parsing enabled.
...
...
(./test-pdflatex.aux) (./upagella.fd) (./udejavusans.fd) [1]
(./test-pdflatex.aux) ){custom.enc}{a_qnnnfc.enc}<./TeXGyrePage
lla-Regular.pfb>
Output written on test-pdflatex.pdf (1 page, 34857 bytes).
Transcript written on test-pdflatex.log.

And we have the desired output:

And that's everything you need to get started with TrueType fonts and pdfLaTeX. Again, if you encounter any problems or notice any omissions, let me kow. I'll do some investigation and there will possibly be a fourth part on using fontinst.

Looking at the comments on reddit, I figured that I would say that luatex does resolve pdfTeX's internal limitation of 256 glyphs that I mentioned in part two, and it should directly support OpenType fonts with PostScript outlines.

However, my understanding is that the authors of luatex do not intend to make using TrueType and OpenType fonts as simple as XeTeX directly.  Instead, luatex merely makes the machinery available for someone else to build upon.  So someone will need to write a LaTeX package for luatex to put it all together, and as far as I know, no one has done this yet (let me know if I'm wrong!).  Also, while the plan is for luatex to eventually be merged back into pdfTeX, I think it is an overstatement to say that it will happen "soon".  The current luatex roadmap says that a "production" ready version will be available in August 2009.  I doubt that the merge back to pdfTeX will happen any sooner than 2010 given that.  But yes, in the long term I think luatex will be a great thing.

It also sounds like I should probably write a fourth part to my tutorial on using fontinst.  I've never personally used it myself, and when I first started working with OpenType fonts and LaTeX I wasn't aware of its existence.  Therefore, I wrote otftofd.  So it might take a bit longer to write as I will have to learn it at the same time.

XeLaTeX also has the advantage of not only giving easy access to modern fonts, but also accepting Unicode input files.

The first thing you need to do is find out if you have XeLaTeX installed, and if it is a sufficiently up to date version. This is easiest to do from the command-line:

% xelatex
This is XeTeXk, Version 3.141592-2.2-0.996 (Web2C 7.5.6)
%&-line parsing enabled.
**^C

This is the version that I am using for the tutorial, and is what comes with TeX Live 2007. I highly recommend just installing and using the entire TeX Live CD/DVD, even if you're using a Linux system that offers TeX Live packages, because, in particular for Debian/Ubuntu, I've found that the default installation often doesn't install some important packages, and it can be a pain sort through all the available packages using Synaptics or whatnot to find what it didn't install.

I am also assuming that you are using a (modern) Unix or MacOS X system. I assume that most of this material should also apply when using Windows, but if someone can comment, let me know.

Now, as an example, say you want to use the Pagella font from the TeX Gyre project. First download them and install the fonts (the otf files) as you normally would on your computer. Under MacOS X, this means using Font Book. If you double-click on an otf file it will load Font Book for you and there will be dialog with a button to install the font. If you load Font Book yourself, you can use the "Add Fonts..." menu item under the File menu to select the files. Under a modern Unix, I would recommend just placing the otf files in your ~/.fonts folder, though I think file managers like Nautilus also understand how to install fonts.

And that was all the installation work necessary; as I said, XeLaTeX is the easiest solution unless you have specialized needs. Now just create a small LaTeX document:

 
\documentclass{article}
\usepackage{fontspec}
\setromanfont{TeX Gyre Pagella}
\begin{document}
Testing XeLaTeX!
 
Greek: τεχ.
\end{document}

The fontspec package isn't necessary, but it makes dealing with fonts in XeLaTeX much easier, for example it defines the convenient \setromanfont command. You can learn more about all of its great features from its beautifully formatted manual.

The other thing you might need to know is what XeLaTeX thinks your font is called. If you're using TeX Live, like I suggest, you will have the program otfinfo at your disposal that can do that for you:

% otfinfo --family texgyrepagella-regular.otf
TeX Gyre Pagella

Note that despite its name, otfinfo will also work on ttf files, assuming that they include OpenType data in them. The other option is to use Font Book on MacOS X or fc-list from the command-line in Unix.

Now you just run xelatex:

% xelatex test.tex
This is XeTeXk, Version 3.141592-2.2-0.996 (Web2C 7.5.6)
%&-line parsing enabled.
entering extended mode
(./test.tex
...
...
Output written on test.pdf (1 page).
Transcript written on test.log.

And you have your document:

I think that is about everything you need to know, but if you try this tutorial out and find that something doesn't work, let me know.  If you have more specialized or demanding typographical needs, you may want to use pdfTeX and pdfLaTeX, and part two of the tutorial will explain how to do the necessary configuration to use TrueType and OpenType fonts with them.