=========================================================================
Tempora LGC Unicode font package
version 0.2 (October 26, 2005)

Copyright (c) 2005 Alexej Kryukov <alexios@thessalonica.org.ru>.

This font is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

As a special exception, permission is granted to include these font
programs in a Postscript or PDF file that consists of a document that
contains text to be displayed or printed using these fonts, regardless
of the conditions or license applying to the document itself.

This font is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

Abstract
~~~~~~~~

Tempora LGC Unicode is a font family, designed to provide a free  typeface
suitable for word processing in languages which use 3 European alphabets:
Latin, Greek and Cyrillic. It may be especially useful for philologists
(mainly slavists and classicists), since it supports historical Cyrillic
letters available in the Unicode standard (including letters used in
Russian  pre-1918 orthography) as well as all accented combinations and
additional characters needed for fully accented Greek (both classical and
modern). Tempora LGC Unicode is a "smart" font, intended to demonstrate
nicities of the OpenType technologie, applicable to European scripts.

Formats and packages
~~~~~~~~~~~~~~~~~~~~

The Tempora LGC Unicode family is available in several formats, so that
before downloading fonts you should consider with wich software you are
planning to use them:

-- OpenType fonts with PostScript outlines (the nimbus-lgc.*.otf.zip file).
Downloading this package is recommended, if your software can take
advantage of OpenType tables, or at least can deal with *.otf font format
at all. Microsoft Word 2003 and Adobe InDesign are good examples of such
applications.

You can install OTF fonts also in Unix-like systems (since this format is
supported by the FreeType library), but you should be aware of the problems
you may face here. Unfortunately, currently there are just no X11
applications, which would be able to take advantage of OpenType nicities.
Moreover, most applications are even unable to access OpenType kerning
information (stored in GPOS tables). Desktop publishing  system Scribus is
the only exception I am aware of: this program can handle OpenType kerning,
but still provides no support for other OpenType features. However, the
worst thing is that OpenOffice.org (the most powerful free office suite)
currently doesn't support OTF fonts at all.

-- TrueType fonts (the nimbus-lgc.*.ttf.zip file). These fonts will
probably look poor on screen, so that you have to enable font antialiasing
in your system settings (both for MS Windows and Unix/X11) in order to use
them. Download this package only of your software doesn't support Open Type
fonts with postscript outlines (like e. g. OpenOffice.org for Unix-like
systems or any MS Word version earlier than 2003). 

-- FontForge sources (the nimbus-lgc.*.src.zip file). Download this
package only if you have the FontForge font editor and know how to
use it.

Open Type support
~~~~~~~~~~~~~~~~~

Unlike most other fonts with a similar character coverage, Tempora LGC 
Unicode is a "smart" fonts, which utilises various features of the OpenType
technologie in order to simplify the work of philologists, especially
slavists and Greek scholars.

Unfortunately, currently  there are very few applications which can really
use Open Type tables for typesetting Western scripts, and, even worse,
different software vendors may support different sets of Open Type
features in their applications. So, all advanced features available in the
Tempora LGC Unicode family practically may be separated into 3 groups:

1) features supported by MS Uniscribe (and so accessible in applications
which use Uniscribe, like MS Word 2003 and other MS Office 2003
applications). This group includes "smart" accent positioning as well as
automatical composition of accented characters (in case there is a
precomposed character corresponding to a combination of a character with
combining diacritical mark(s), typed by user);

2) features supported by Adobe InDesign. This group includes standard
rules for substitution of Latin ligatures (like "fi" or "fl") or vulgar
fractions, which are present in most OpenType fonts (e. g. from Adobe).
Tempora LGC Unicode also uses the "calt" feature to automatically replace
standard Greek beta (with descender) with the curly form of the glyph in
the middle of the word, as it is required by French rules for typesetting
Greek;

3) features, which currently no software may take advantage of. The most
important of such features is "locl" (i. e. substitution of localized
forms, depending from the current text language). This feature might be
especially important for typesetting Serbian (using the Cyrillic alphabet),
since in Serbian typography some Cyrillic  letters traditionally have a
specific form, different e. g. from their Russian couterparts. I hope the
situation will change and this feature will be supported by future
versions of software.

I know very few about Mac OS, but I suppose some features from the first 2
groups should also work in some applications on Mac OS X "Tiger". I would
be very grateful if somebody can test my fonts on the Mac platform. 

Unfortunately, I am not aware of any free OpenType renderers (e. g. for
Linux/X11 platform), which would be able to provide access to advanced
typography  features for Western scripts. Again, I hope the situation will
change in  future.

Sources and history
~~~~~~~~~~~~~~~~~~~

Although the Tempora LGC Unicode typeface contains many originally designed
glyphs, its main part is still based on some well known sources, also
available under free licenses. These sources include:

1) The free Nimbus Roman No 9 L font family, released by URW and now
distributed with Ghostscript;

2) The Omega Serif family by Yannis Haralambous, designed as a default
font for his Omega typesetting system;

3) Cyrillic glyphs for Nimbus Roman No 9 L, designed bt Valek Filippov
(see ftp://ftp.gnome.ru/fonts/);

4) The FreeSerif font family from FreeFont project, started by Primoz
Peterlin (see http://savannah.nongnu.org/download/freefont/), and now
developed at alioth.debian.org (http://alioth.debian.org/projects/freefont/).

URW Nimbus Roman No 9 L for a long time was the only free Latin
Times-styled font of reasonable quality, so that it is often used as a
default serif font in Linux/BSD distributions and many free programs.
Nevertheless, it is less perfect than its counterpart from Adobe (i. e.
Adobe Times): I even have an impression that its glyph outlines were, at
least partially, produced by an autotracing tool, and no cleanup was
performed. So, although nothing was changed in the design of Latin glyphs
taken from this font, in most cases I had to perform a cosmetical cleanup
of outlines. Some glyphs were just replaced with their counterparts from
Omega Serif, which have almost the same shape, but a slightly better
technical implementation. I have also corrected kerning and sidebearings
for some letters (in particular, in order to prevent overlap of serifs in
combinations like "KA" or "RA" in italic fonts).

Omega Serif was also used as a source of some supplementary characters
(like additional Latin ligatures), but, of course, mainly of Greek glyphs.
However, lots of corrections have been made before I was satisfied with the
Greek part of my font. The most obvious reason for modifications was the
fact that, although the Omega Serif Greek family has almost perfect glyph
outlines, it looks like the fonts were abandoned half-finished (like the
whole Omega project, which, unfortunately, seems to be half-dead now). Some
(relatively easy to design) glyphs are present only in regular version of
the font, but not in bold and italic shapes. For example, I had to design
myself the capital Koppa (U+03DE) for all versions but regular. The fonts
also contained no precomposed accented combinations (because in the Omega
typesetting system virtual fonts are used to combine different elements of
accented glyphs together).

On the other hand, I was not satisfied with the shapes of Omega Serif Greek
glyphs, mainly because the original Greek font by Yannis Haralambous looks
quite similar to well-known Linotype Times Ten family. There are already
several Unicode Greek fonts which follow this design: in particular I can
mention the Times font distributed with Mac OS X, as well as MgOld Times UC
Pol (now also known as MgOpenCanonica) by Magenta company, and GalatiaSIL
by SIL International. Some of these fonts are available for free. So I
decided to make the Greek part of my font more original. When searching for
a suitable example, I realized that Greek letters, used in some Soviet
books in combination with Cyrillic Obyknovennaya Novaya typeface, have many
common features with Times Ten Greek, but more "classical" look. In fact,
there is nothing strange in this similarity, because most Greek typefaces
traditionally used both in Russian and German printing (including Times
Ten) descend to the famous Greek font used in Teubner classical library. So
I modified most Greek letters, making them closer to Greek Obyknovennaya
Novaya (or directly to the Teubner font for Italic versions), but still
trying to keep their design compatible with the rest of the font. Moreover,
I had to redesign Greek letters in Italic and Bold  Italic fonts almost
completely in order to correct the initially wrong average small letter
height, which didn't correspond to the xheight of the Latin fonts.

Initially I had not planned to modify Cyrillic glyphs by Valek Filippov,
but finally realized, that some glyph shapes were absolutely not acceptable
for me. So, redesigning Cyrillic glyphs became actually the hardest part of
the whole work. I am still not fully satisfied with the result, but I am
sure it is better than the initial version. Since I already started
redesigning Cyrillic glyphs, I decided to add also historical Cyrillic
letters, which were not present in Valek's fonts, in order to make
the whole family more useful for slavists.

Except correcting glyph shapes itself, I had to spend some time adjusting
kerning between Greek and Cyrillic letters. So Tempora LGC, unlike Omega
Serif or Nimbus Roman No 9 L modified by Valek Filippov, has some basic
kerning information for Greek and Cyrillic scripts, which (I hope) will
make it more useful for word processing in the corresponding languages.

The fourth source of Tempora LGC Unicode was FreeSerif from the Freefont
project. In fact, FreeSerif is very similar to Tempora LGC at some points,
because it is based on the same sources, although includes a lot of glyphs
added later. That's why before starting my own project I considered forking
FreeSerif instead. However, the main problem was, that the FreeFont 
project tends to support a maximum possible number of scripts and Unicode
ranges, unfortunately, without sufficient attention to each particular
script. So finally I realized that FreeSerif has too many flaws in its
Greek and Cyrillic parts, so that it would be really too difficult to 
wast my time fixing them. For example:

-- Cyrillic letters are oversized. For example, Cyrillic "A" is
significantly larger than Latin "A", although normally it should be
implemented just as a reference to the later;

-- Some useful Greek glyphs, initially present in Omega Serif, were either
completely abandoned, or replaced with newly designed glyphs with much
uglier shape (that is the case for capital Stigma, U+03E0);

-- Greek capital accented letters (especially those with iota adscript)
are completely unusable due to wrong sidebearings (which cause e. g.
iota adscript to be overstruck with the next character).

Of course, the fonts contain no kerning information for Greek and
Cyrillic scripts.

On the other hand, FreeSerif includes some really useful and well-designed
characters, added by its developers. So, although I couldn't completely
base my font on FreeSerif, I used it as a source of some glyphs, like
vulgar fractions or musical signs.

Greek glyphs implementation
~~~~~~~~~~~~~~~~~~~~~~~~~~~

In this paragraph I am trying to describe several situations where accented
Greek glyphs, defined in Unicode, can be designed by various ways, and the
decisions I finally made in these cases.

First, anybody who often deals with Unicode Greek knows that Unicode
includes a set of accented vowels with Greek tonos (primarily intended for
use in monotonic Greek), and another set of similar combinations with
Greek acute (oxia). Omega Serif also includes both a special tonos (which
have a vertical shape) and an acute accent. However, Yannis Haralambous
himself now states in his articles that monotonic tonos is actually the
same accent as polytonic oxia, and so they should have exactly the same
shape. That's why he recommends to always use "monotonic" combinations
with tonos even for classical Greek (which, of course, would be impossible
with any fonts which have a "vertical" tonos). I think, this position has
very good reasons, and so I haven't included vertical tonos into my font,
so that both the combinations with tonos from the basic Greek Unicode block
and the combinations with oxia from the extended Greek block have exactly the
same shape and actually refer to the same glyphs.

Greek circumflex is another diacritical mark which often becomes a matter
of discussions. I know, that some (mostly English and American) classicists
prefer porsonic (lunate) circumflex, similar to inverted breve, mainly
because this form is characteristic of most Greek fonts traditionally used
in English and American typography. So, although Times Ten itself has
tilde-shaped  circumflex, in some Greek fonts which mostly follow its
design this form is replaced with the lunate version. To my mind, this
modification is quite inappropriate, because, as I have explained above,
this type of Greek Times descends to German typefaces of 19th century, and
so it should follow the traditions of continental European typography,
where tilde-shaped circumflex was always preferred. Of course this reason
is especially actual for my font, which stands even closer to the prototype
(i. e. the Teubner typeface), when Times Ten does. So, don't  ask me to
implement a version with "porsonic" circumflex: I shan't.

Combinations of Greek vowels with "mute" iota, defined in Unicode, is one
more important group of glyphs, which may be designed by various ways,
depending from a font designer's preferences. Most ancient Greek language
manuals say that mute iota (called iota subscript) is written below
lowercase letters, but after uppercase vowels it should be replaced with
regular small iota, written inline and so called iota adscript. Currently
most Unicode Greek fonts follow this convention, and many classicists even
suppose any over implementations of capital combinations with mute iota to
be illegal.

However, iota subscript below capital letters also may occur in some
editions. In particular, this orthography is very common for liturgical
books of the Greek Orthodox church. Particularly I prefer this typographic
tradition, not only because it is inherited from fine Greek typography of
the past centuries, but also for the following reason. If mute iota is
designed as a regular iota and printed inline, it should behave as a
separate character. This means that, when letterspacing for the surrounding
text is changed, the distance between the iota and the preceding vowel
should be scaled too. Of course this is impossible if both characters are
implemented as a single glyph.

That's why in Tempora LGC Unicode mute iota is implemented as iota
subscriptum in all accented combinations with capital vowels. Note that 
*unaccented* capital vowels with mute iota represent a special case: unlike
their accented counterparts, they are used in upper case only, i. e. may
occur only in a fully capitalized text. So for these glyphs (namely,
Unicode characters U+1FBC, U+1FCC, U+1FFC) I have chosen a special version
of iota adscript (alrady present in the original fonts by Yannis
Haralambous), which is similar to full-sized *capital* Iota, but has a
smaller hight. To my mind, this shape will better match to the design of
surrounding capital glyphs.

Such an implementation of capital vowels with mute iota has nothing wrong
by itself, but, of course, it would be nice to allow replacing each of
affected Unicode codepoints with a pair of glyphs: the vowel itself and a
regular iota. Theoretically, this can be done by applying an OpenType
feature, but, unfortunately, I am not aware of any suitable OpenType
feature, which:

-- can be used for replacing a single glyph with two or more glyphs, as in
our case;

-- can be disabled if user don't like it.

So for now I can't provide an alternative for the implementation which
looks preferred for me. If you absolutely don't like capital vowels with
iota subscript, at least you can always type regular iota as a separate
character.

Thanks
~~~~~~

I would like to thank:

-- George Williams for his excellent FontForge program
(http://fontforge.sourceforge.net), and especially for his responsiveness
in fixing bugs and adding new features. Without his help this package
would never be released!

-- Tavmjong Bah (Tav), who kindly granted me his Perl scripts (originally
written for his Arev fonts, see http://tavmjong.free.fr/FONTS/) used to
convert separate kerning pairs defined in a FontForge source file into
kerning classes.

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