ref: d34ddd8775ca8ebad64222911e5dd60069918b54
dir: /figfont.txt/
_____ ___ ____ __ _
| ___||_ _|/ ___| / _| ___ _ __ | |_ ___ _
| |_ | || | _ | |_ / _ \ | '_ \ | __|/ __|(_)
| _| | || |_| || _|| (_) || | | || |_ \__ \ _
|_| |___|\____||_| \___/ |_| |_| \__||___/(_)
The FIGfont Version 2 FIGfont and FIGdriver Standard
=== ======= ======= = ======= === ========= ========
Draft 2.0 Copyright 1996, 1997
by John Cowan and Paul Burton
Portions Copyright 1991, 1993, 1994
by Glenn Chappell and Ian Chai
May be freely copied and distributed.
Figlet lives at: http://www.figlet.org/
_____ __ __
/ ___/__ ___ / /____ ___ / /____
/ /__/ _ \/ _ \/ __/ -_) _ \/ __(_-<
\___/\___/_//_/\__/\__/_//_/\__/___/
INTRODUCTION
BASIC DEFINITIONS AND CONCEPTS
"FIGfont"
"FIGcharacters" and "Sub-characters"
"FIGdriver"
"FIGure"
"FIG"
"Layout Modes"
"Smushing Rules"
"Hardblanks"
CREATING FIGFONTS
The Header Line
Interpretation of Layout Parameters
Setting Layout Parameters Step-by-Step
FIGfont Comments
FIGcharacter Data
- Basic Data Structure
- Character Codes
- Required FIGcharacters
- Code Tagged FIGcharacters
NOTES - AVOIDING ERRORS AND GENERAL ADVICE
CONTROL FILES
Standard Format
Extended Commands
STANDARDIZED CAPABILITIES OF CURRENT AND FUTURE FIGDRIVERS
CHART OF CAPABILITIES OF FIGLET 2.2.2 AND FIGWIN 1.0
INTRODUCTION
============
This document specifies the format of font files, and the associated control
files, used by the FIGlet and FIGWin programs (FIGdrivers). It is written
for designers who wish to build fonts (FIGfonts) usable by either program,
and also serves as a standard for development of future versions or similar
FIGdrivers. Some features explained here are not supported by both programs.
See separate documentation to learn how to use FIGlet or FIGWin.
NOTE: FIGWin 1.0 is packaged with a program called FIGfont Editor for Windows
1.0, which is just that. It does not require a complete understanding of
this document to create FIGfonts. However it is a good idea to become
familiar with the "BASIC DEFINITIONS AND CONCEPTS" information before using
it.
If you design a FIGfont, please send an e-mail announcement to
<figletfonts@figlet.org>, the FIGlet fonts mailing list, and email a copy
to info@figlet.org for us to put it on the ftp site (ftp://ftp.figlet.org/)
BASIC DEFINITIONS AND CONCEPTS
===== =========== === ========
"FIGfont"
A FIGfont is a file which represents the graphical arrangement of characters
representing larger characters. Since a FIGfont file is a text file, it can
be created with any text editing program on any platform. The filename of a
FIGfont file must end with ".flf", which stands for "<F>IG<L>ettering
<F>ont".
"FIGcharacters" and "Sub-characters"
Because FIGfonts describe large characters which consist of smaller
characters, confusion can result when descussing one or the other.
Therefore, the terms "FIGcharacter" and "sub-character" are used,
respectively.
"FIGdriver"
The term FIGdriver is used in this document to encompass FIGlet, FIGWin, and
any future programs which use FIGfonts.
"FIGure"
A FIGure (thusly capitalized) is an image created by a FIGdriver.
"FIG"
A bit of history:
In Spring 1991, inspired by the Email signature of a friend named Frank, and
goaded on by Ian Chai, Glenn Chappell wrote a nifty little 170-line "C"
program called "newban", which would create large letters out of ordinary
text characters. At the time, it was only compiled for UNIX. In hindsight,
we now call it "FIGlet 1.0". FIGlet stands for <F>rank, <I>an, and <G>lenn's
<let>ters. In various incarnations, newban circulated around the net for a
couple of years. It had one font, which included only lowercase letters.
In early 1993, Ian decided newban was due for a few changes, so together Ian
and Glenn added the full ASCII character set, to start with. First, though,
Ian had to find a copy of the source, since Glenn had tossed it away as not
worth the disk space. Ian and Glenn discussed what could be done with it,
decided on a general re-write, and, 7 months later, ended up with 888 lines
of code, 13 FIGfonts and documentation. This was FIGlet 2.0, the first real
release.
To their great surprise, FIGlet took the net by storm. They received floods
of "FIGlet is great!" messages and a new contributed FIGfont about once a
week. To handle all the traffic, Ian quickly set up a mailing list, Daniel
Simmons kindly offered space for an FTP site, several people volunteered to
port FIGlet to non-Unix operating systems, ...and bug reports poured in.
Because of these, and the need to make FIGlet more "international", Ian and
Glenn released a new version of FIGlet which could handle non-ASCII character
sets and right-to-left printing. This was FIGlet 2.1, which, in a couple of
weeks, became figlet 2.1.1. This weighed in at 1314 lines, and there were
over 60 FIGfonts.
By late 1996, FIGlet had quite a following of fans subscribing to its mailing
list. It had been ported to MS-DOS, Macintosh, Amiga, Apple II GS, Atari ST,
Acorn and OS/2. FIGlet had been further updated, and there were nearly 200
FIGfonts.
John Cowan and Paul Burton are two FIGlet fans who decided to create new
versions. While John wrote FIGlet version 2.2 using C, Paul wrote FIGWin
1.0, the first true GUI (Windows) implementation of FIGlet, using Visual
Basic. John and Paul worked together to add new features to FIGfont files
which could be read by both programs, and together wrote this document, which
we hope helps to establish consistency in FIGfonts and help with the creation
of future FIGdrivers. FIGlet 2.2 has about 4800 lines of code, of which
over half is a support library for reading compressed files.
FIGlet 2.2 and FIGWin 1.0 both allow greater flexibility by use of new
information which can be contained in FIGfont files without interfering with
the function of older FIGdrivers.
NOTE: The Macintosh version of FIGlet is still command-line driven as of this
writing, and a GUI version is very much in demand. The FIGlet C code is
written to be easily plugged in to a GUI shell, so it will be a relatively
easy task for a Macintosh developer.
"Layout Modes"
A FIGdriver may arrange FIGcharacters using one of three "layout modes",
which define the spacing between FIGcharacters. The layout mode for the
horizontal axis may differ from the layout mode for the vertical axis. A
default choice is defined for each axis by every FIGfont.
The three layout modes are:
Full Size (Separately called "Full Width" or "Full Height".)
Represents each FIGcharacter occupying the full width or
height of its arrangement of sub-characters as designed.
Fitting Only (Separately called "Kerning or "Vertical Fitting".)
Moves FIGcharacters closer together until they touch.
Typographers use the term "kerning" for this phenomenon
when applied to the horizontal axis, but fitting also
includes this as a vertical behavior, for which there is
apparently no established typographical term.
Smushing (Same term for both axes.)
Moves FIGcharacters one step closer after they touch, so that
they partially occupy the same space. A FIGdriver must decide
what sub-character to display at each junction. There are two
ways of making these decisions: by controlled smushing or by
universal smushing.
Controlled smushing uses a set of "smushing rules" selected by
the designer of a FIGfont. (See "Smushing Rules" below.)
Each rule is a comparison of the two sub-characters which must
be joined to yield what to display at the junction.
Controlled smushing will not always allow smushing to occur,
because the compared sub-characters may not correspond to any
active rule. Wherever smushing cannot occur, fitting occurs
instead.
Universal smushing simply overrides the sub-character from the
earlier FIGcharacter with the sub-character from the later
FIGcharacter. This produces an "overlapping" effect with some
FIGfonts, wherin the latter FIGcharacter may appear to be "in
front".
A FIGfont which does not specify any smushing rules for a
particular axis indicates that universal smushing is to occur
when smushing is requested. Therefore, it is not possible for
a FIGfont designer to "forbid" smushing. However there are
ways to ensure that smushing does not cause a FIGfont to be
illegible when smushed. This is especially important for
smaller FIGfonts. (See "Hardblanks" for details.)
For vertical fitting or smushing, entire lines of output FIGcharacters are
"moved" as a unit.
Not all FIGdrivers do vertical fitting or smushing. At present, FIGWin 1.0
does, but FIGlet 2.2 does not. Further, while FIGlet 2.2 allows the user to
override the FIGfont designer's set of smushing rules, FIGWin 1.0 does not.
NOTE: In the documentation of FIGlet versions prior to 2.2, the term
"smushmode" was used to mean the layout mode, and this term further included
the smushing rules (if any) to be applied. However, since the layout mode
may or may not involve smushing, we are straying from the use of this
somewhat misleading term.
"Smushing Rules"
Again, smushing rules are for controlled smushing. If none are defined to be
active in a FIGfont, universal smushing occurs instead.
Generally, if a FIGfont is "drawn at the borders" using sub-characters
"-_|/\[]{}()<>", you will want to use controlled smushing by selecting from
the rules below. Otherwise, if your FIGfont uses a lot of other
sub-characters, do not select any rules and universal smushing will occur
instead. (See "Hardblanks" below if your FIGfont is very small and would
become illegible if smushed.) Experimentation is the best way to make these
decisions.
There are six possible horizontal smushing rules and five possible vertical
smushing rules. Below is a description of all of the rules.
NOTE: Ignore the "code values" for now. They are explained later.
The Six Horizontal Smushing Rules
Rule 1: EQUAL CHARACTER SMUSHING (code value 1)
Two sub-characters are smushed into a single sub-character
if they are the same. This rule does not smush
hardblanks. (See "Hardblanks" below.)
Rule 2: UNDERSCORE SMUSHING (code value 2)
An underscore ("_") will be replaced by any of: "|", "/",
"\", "[", "]", "{", "}", "(", ")", "<" or ">".
Rule 3: HIERARCHY SMUSHING (code value 4)
A hierarchy of six classes is used: "|", "/\", "[]", "{}",
"()", and "<>". When two smushing sub-characters are
from different classes, the one from the latter class
will be used.
Rule 4: OPPOSITE PAIR SMUSHING (code value 8)
Smushes opposing brackets ("[]" or "]["), braces ("{}" or
"}{") and parentheses ("()" or ")(") together, replacing
any such pair with a vertical bar ("|").
Rule 5: BIG X SMUSHING (code value 16)
Smushes "/\" into "|", "\/" into "Y", and "><" into "X".
Note that "<>" is not smushed in any way by this rule.
The name "BIG X" is historical; originally all three pairs
were smushed into "X".
Rule 6: HARDBLANK SMUSHING (code value 32)
Smushes two hardblanks together, replacing them with a
single hardblank. (See "Hardblanks" below.)
The Five Vertical Smushing Rules
Rule 1: EQUAL CHARACTER SMUSHING (code value 256)
Same as horizontal smushing rule 1.
Rule 2: UNDERSCORE SMUSHING (code value 512)
Same as horizontal smushing rule 2.
Rule 3: HIERARCHY SMUSHING (code value 1024)
Same as horizontal smushing rule 3.
Rule 4: HORIZONTAL LINE SMUSHING (code value 2048)
Smushes stacked pairs of "-" and "_", replacing them with
a single "=" sub-character. It does not matter which is
found above the other. Note that vertical smushing rule 1
will smush IDENTICAL pairs of horizontal lines, while this
rule smushes horizontal lines consisting of DIFFERENT
sub-characters.
Rule 5: VERTICAL LINE SUPERSMUSHING (code value 4096)
This one rule is different from all others, in that it
"supersmushes" vertical lines consisting of several
vertical bars ("|"). This creates the illusion that
FIGcharacters have slid vertically against each other.
Supersmushing continues until any sub-characters other
than "|" would have to be smushed. Supersmushing can
produce impressive results, but it is seldom possible,
since other sub-characters would usually have to be
considered for smushing as soon as any such stacked
vertical lines are encountered.
"Hardblanks"
A hardblank is a special sub-character which is displayed as a blank (space)
in rendered FIGures, but is treated more like a "visible" sub-character when
fitting or smushing horizontally. Therefore, hardblanks keep adjacent
FIGcharacters a certain distance apart.
NOTE: Hardblanks act the same as blanks for vertical operations.
Hardblanks have three purposes:
1) Hardblanks are used to create the blank (space) FIGcharacter.
Usually the space FIGcharacter is simply one or two vertical
columns of hardblanks. Some slanted FIGfonts as shown below
have a diagonal arrangement of hardblanks instead.
2) Hardblanks can prevent "unreasonable" fitting or smushing.
Normally when fitting or smushing, the blank (space)
sub-character is considered "vacant space". In the following
example, a capital "C" FIGcharacter is smushed with a "minus"
FIGcharacter.
______ ______
/ ____/ / ____/
/ / ____ >>-Becomes-> / / ____
/ /___ /___/ / /__/___/
\____/ \____/
The FIGure above looks like a capital G. To prevent this, a
FIGfont designer might place a hardblank in the center of the
capital C. In the following example, the hardblank is
represented as a "$":
______ ______
/ ____/ / ____/
/ / $ ____ >>-Becomes-> / / ____
/ /___ /___/ / /___/___/
\____/ \____/
Using hardblanks in this manner ensures that FIGcharacters
with a lot of empty space will not be unreasonably "invaded"
by adjacent FIGcharacters. Generally, FIGcharacters such as
capital C, L or T, or small punctuation marks such as commas,
may contain hardblanks, since they may contain a lot of vacant
space which is "accessible" from either side.
3) Hardblanks can prevent smushing from making FIGfonts illegible.
This legitimate purpose of hardblanks is often overused. If a
FIGfont designer is absolutely sure that smushing "visible"
sub-characters would make their FIGfont illegible, hardblanks
may be positioned at the end of each row of sub-characters,
against the visible sub-characters, creating a barrier.
With older FIGdrivers, using hardblanks for this purpose meant
that FIGcharacters would have to be separated by at least one
blank in output FIGures, since only a hardblank could smush
with another hardblank. However with the advent of universal
smushing, this is no longer necessary. Hardblanks ARE
overriden by any visible sub-character when performing
universal smushing. Hardblanks still represent a "stopping
point", but only AFTER their locations are occupied.
NOTE: Earlier it was stated that universal smushing overrides
the sub-character from the former FIGcharacter with the
sub-character from the latter FIGcharacter. Hardblanks (and
blanks or spaces) are the exception to this rule; they will
always be overriden by visible sub-characters, regardless of
which FIGcharacter contains the hardblank. This ensures that
no visible sub-characters "disappear".
Therefore, one can design a FIGfont with a default behavior of
universal smushing, while the output FIGure would LOOK like
the effect of fitting, or even full size if additional
hardblanks are used. If a user "scales down" the layout mode
to fitting, the result would look like "extra spacing" between
FIGcharacters.
Taking this concept further, a FIGcharacter may also include
extra blanks (spaces) on the left side of each FIGcharacter,
which would define the FIGcharacter's width as slightly larger
than required for the visible sub-characters and hardblanks.
With such a FIGfont, a user who further "scales down" the
layout mode to full size would see even greater spacing.
These techniques prevent horizontal smushing from causing a
FIGfont to become illegible, while offering greater
flexibility of output to users.
NOTE: These techniques cannot be used to prevent vertical
smushing of visible sub-characters, since hardblanks are not
respected in the vertical axis. Although it is possible to
select only one vertical smushing rule which involves only
sub-characters which are not used in your FIGfont, it is
recommend that you do NOT do so. In our opinion, most users
would prefer to get what they ask for, rather than being
told, in effect: "I, the FIGfont designer, have decided that
you wouldn't like the results of vertical smushing, so I have
prevented you from trying it." Instead, we recommend setting
the default behavior to either fitting or full height, and
either allowing universal smushing, or selecting vertical
smushing rules which seem most appropriate. A user of your
FIGfont will quickly see why you did not choose smushing as
the default vertical layout mode, and will agree with you.
"Character Sets" and "Character Codes"
When you type using your keyboard, you are actually sending your computer a
series of numbers. Each number must be interpreted by your computer so that
it knows what character to display. The computer uses a list of definitions,
called a "character set". The numbers which represent each character are
called "character codes".
There are many character sets, most of which are internationally accepted as
standards. By far, the most common character set is ASCII, which stands for
"American Standard Code for Information Interchange". ASCII identifies its
characters with codes ranging from 0 to 127.
NOTE: The term "ASCII art" has become well-understood to mean artistic images
which consist of characters on your screen (such as FIGures).
For a list of the printable ASCII characters with the corresponding codes,
see the section "REQUIRED CHARACTERS" below. The other ASCII codes in the
range of 0 through 31 are "control characters" such as carriage-return
(code 13), linefeed/newline (code 10), tab (code 9), backspace (code 8) or
null (code 0). Code 127 is a delete in ASCII.
Getting more technical for just a moment: A byte consisting of 8 bits (eight
1's or 0's) may represent a number from 0 to 255. Therefore, most computers
have DIRECT access to 256 characters at any given time. A character set
which includes 256 characters is called an 8-bit character set.
For Latin-based languages, ASCII is almost always the first half of a larger
8-bit character set. Latin-1 is the most common example of an 8-bit
character set. Latin-1 includes all of ASCII, and adds characters with codes
from 128 to 255 which include umlauted ("double-dotted") letters and
characters with various other accents. In the United States, Windows and
most Unix systems have Latin-1 directly available.
Most modern systems allow the possibility of changing 8-bit character sets.
On Windows systems, character sets are referred to as "code pages". There
are many other character sets which are not mentioned here. DOS has its own
character set (which also has international variants) that includes graphics
characters for drawing lines. It is also an extension of ASCII.
For some languages, 8-bit character sets are insufficient, particularly on
East Asian systems. Therefore, some systems allow 2 bytes for each
character, which multiplies the 256 possibilties by 256, resulting in 65536
possible characters. (Much more than the world will ever need.)
Unicode is a character set standard which is intended to fulfill the
worldwide need for a single character set which includes all characters used
worldwide. Unicode includes character codes from 0 to 65535, although at
present, only about 22,000 characters have been officially assigned and named
by the Unicode Consortium. The alphabets and other writing systems
representable with Unicode include all Latin-alphabet systems, Greek,
Russian and other Cyrillic-alphabet systems, Hebrew, Arabic, the various
languages of India, Chinese, Japanese, Korean, and others. The existing
Unicode symbols include chess pieces, astrological signs, gaming symbols,
telephones, pointing fingers, etc. --- just about any type of FIGcharacter
you may wish to create. Unicode is constantly (but slowly) being extended
to handle new writing systems and symbols. Information on Unicode is
available at http://www.unicode.org and at ftp://unicode.org .
Unicode, Latin-1, and ASCII all specify the same meanings for overlapping
character codes: ASCII 65 = Latin-1 65 = Unicode 65 = "A", formally known
as "LATIN CAPITAL LETTER A".
Since a keyboard usually has only about 100 keys, your computer may contain
a program called a "keyboard map", which will interpret certain keystrokes
or combinations of keystrokes as different character codes. Keyboard maps
use "mapping tables" to make these determinations. The appropriate keyboard
activity for a given character code may involve several keystrokes. Almost
all systems are capable of handling at least 8-bit character sets (containing
256 characters), so there is always an active keyboard map, at least for
those characters which are not actually painted on the keys. (United States
users may not even know that their computer can interpret special keystrokes.
Such keystrokes may be something similar to holding down the ALT key while
typing a character code on the numeric keypad. Try it!)
Below are characters 160 through 255, AS REPRESENTED ON YOUR SYSTEM.
������������������������������������������������
������������������������������������������������
IMPORTANT NOTE: Depending on which character set is active on your system,
you may see different characters. This document (like all computer
documents) does not contains characters per se, only bytes. What you see
above is your particular computer's representation of these byte values.
In other words, your active character set. However, if it is Latin-1, the
first visible character is an inverted "!", and the last is an umlauted "y".
Although we can safely assume your computer has ASCII, it does not
necessarily have the Latin-1 character set active.
What does all this have to do with FIGfonts???
First, it should be evident that it is best to use only ASCII characters for
sub-characters when possible. This will ensure portability to different
platforms.
FIGlet has gained international popularity, but early versions were made to
handle only FIGcharacters with assigned character codes corresponding to
ASCII. So, over the years there have been four methods used to create
"virtual mapping tables" within the program itself:
The first method was simply to create FIGcharacters which do not
look like the ASCII character set implies. For example, a
FIGfont might contain Greek letters, and within its comments, it
may say, "If you type A, you'll get a Greek Alpha" etc. With
the advent of newer features, it is preferable not to use this
method. Instead, when possible, add new FIGcharacters to
existing FIGfonts or create new FIGfonts with FIGcharacters coded
to match the expectations of ASCII/Latin-1/Unicode, and create an
appropriate control file. (See "CONTROL FILES" below.) Remember
that Unicode includes almost any character for which you may want
to create a FIGcharacter.
The second method was very specific, to accommodate the German
audience. A special option was added to the FIGlet program
which would re-route input characters "[", "\", and "]" to
umlauted A, O and U, while "{", "|", and "}" would become the
respective lowercase versions of these. Also, "~" was made to
become the s-z character when this special option was used. This
was called "the -D option." The addition of this feature meant
that all compatible FIGfonts must contain these Deutsch (German)
FIGcharacters, in addition to the ASCII FIGcharacters. Although
this option is still available in the most recent version, it is
no longer necessary, as the same result can be achieved by the
newer features described below. However, the requirement for
Deutsch FIGcharacters remains for backward compatibility. (Or at
least zero-width FIGcharacters in their place.)
Later, FIGlet was made to accept control files, which are quite
literally a form of mapping table. (See "CONTROL FILES" below.)
This was a significant advance for internationalization.
FIGlet 2.2 can now accept specially encoded formats of input
text which imply more than one byte per character.
CREATING FIGFONTS
======== ========
NOTE: FIGWin 1.0 is packaged with a program called FIGfont Editor for Windows
1.0, which is just that. There is no need to read further if you intend to
use it. However, the section "CONTROL FILES" below is still relevant.
Since a FIGfont file is a text file, it can be created with any text editing
program on any platform, and will still be compatible with FIGdrivers on all
operating systems, except that the bytes used to indicate the end of each
text line may vary. (PC's use carriage return and linefeed at the end of
each line, Macintosh uses carriage return only, and UNIX uses linefeed only.)
This minor difference among operating systems is handled easily by setting
your FTP program to ASCII mode during upload or download. So there is no
need to be concerned about this as long as you remember to do this during
file transfer.
The filename of a FIGfont file must end with ".flf", which stands for
"<F>IG<L>ettering <F>ont". The first part of the filename should contain
only letters, and should be lowercase on operating systems which permit case
sensitive filenames. The filename should be unique in the first 8
characters, since some older file systems truncate longer filenames.
It is easier to modify an existing FIGfont than it is to create a new one
from scratch. The first step is to read and understand this document.
You may want to load "standard.flf" or another FIGfont into a text editor as
an example while you read.
A FIGfont file contains three portions: a header line, comments, and
FIGcharacter data.
THE HEADER LINE
The header line gives information about the FIGfont. Here is an example
showing the names of all parameters:
flf2a$ 6 5 20 15 3 0 143 229 NOTE: The first five characters in
| | | | | | | | | | the entire file must be "flf2a".
/ / | | | | | | | \
Signature / / | | | | | \ Codetag_Count
Hardblank / / | | | \ Full_Layout*
Height / | | \ Print_Direction
Baseline / \ Comment_Lines
Max_Length Old_Layout*
* The two layout parameters are closely related and fairly complex.
(See "INTERPRETATION OF LAYOUT PARAMETERS".)
For those desiring a quick explanation, the above line indicates that this
FIGfont uses "$" to represent the hardblank in FIGcharacter data, it has
FIGcharacters which are 6 lines tall, 5 of which are above the baseline, no
line in the FIGfont data is more than 20 columns wide, the default horizontal
layout is represented by the number 15, there are 3 comment lines, the
default print direction for this FIGfont is left-to-right, a complete
description of default and possible horizontal and vertical layouts is
represented by the number 143, and there are 229 code-tagged characters.
The first seven parameters are required. The last three (Direction,
Full_Layout, and Codetag_Count, are not. This allows for backward
compatibility with older FIGfonts, but a FIGfont without these parameters would
force a FIGdriver to "guess" (by means not described in this document) the
information it would expect to find in Full_Layout. For this reason, inclusion
of all parameters is strongly recommended.
Future versions of this standard may add more parameters after Codetag_Count.
A description of each parameter follows:
Signature
The signature is the first five characters: "flf2a". The first four
characters "flf2" identify the file as compatible with FIGlet version 2.0 or
later (and FIGWin 1.0). The "a" is currently ignored, but cannot be omitted.
Different characters in the "a" location may mean something in future
versions of this standard. If so, you can be sure your FIGfonts will still
work if this character is "a".
Hardblank
Immediately following the signature is the hardblank character. The
hardblank character in the header line defines which sub-character will be
used to represent hardblanks in the FIGcharacter data.
By convention, the usual hardblank is a "$", but it can be any character
except a blank (space), a carriage-return, a newline (linefeed) or a null
character. If you want the entire printable ASCII set available to use, make
the hardblank a "delete" character (character code 127). With the exception
of delete, it is inadvisable to use non-printable characters as a hardblank.
Height
The Height parameter specifies the consistent height of every FIGcharacter,
measured in sub-characters. Note that ALL FIGcharacters in a given FIGfont
have the same height, since this includes any empty space above or below.
This is a measurement from the top of the tallest FIGcharacter to the bottom
of the lowest hanging FIGcharacter, such as a lowercase g.
Baseline
The Baseline parameter is the number of lines of sub-characters from the
baseline of a FIGcharacter to the top of the tallest FIGcharacter. The
baseline of a FIGfont is an imaginary line on top of which capital letters
would rest, while the tails of lowercase g, j, p, q, and y may hang below.
In other words, Baseline is the height of a FIGcharacter, ignoring any
descenders.
This parameter does not affect the output of FIGlet 2.2 or FIGWin 1.0, but
future versions or other future FIGdrivers may use it. The Baseline
parameter should be correctly set to reflect the true baseline as described
above. It is an error for Baseline to be less than 1 or greater than the
Height parameter.
Max_Length
The Max_Length parameter is the maximum length of any line describing a
FIGcharacter. This is usually the width of the widest FIGcharacter, plus 2
(to accommodate endmarks as described later.) However, you can (and probably
should) set Max_Length slightly larger than this as a safety measure in case
your FIGfont is edited to include wider FIGcharacters. FIGlet (but not
FIGWin 1.0) uses this number to minimize the memory taken up by a FIGfont,
which is important in the case of FIGfonts with many FIGcharacters.
Old_Layout
(See "INTERPRETATION OF LAYOUT PARAMETERS" below.)
Comment_Lines
Between the first line and the actual FIGcharacters of the FIGfont are the
comment lines. The Comment_Lines parameter specifies how many lines there
are. Comments are optional, but recommended to properly document the origin
of a FIGfont.
Print_Direction
The Print_Direction parameter tells which direction the font is to be
printed by default. A value of 0 means left-to-right, and 1 means
right-to-left. If this parameter is absent, 0 (left-to-right) is assumed.
Print_Direction may not specify vertical print, although FIGdrivers are
capable of vertical print. Versions of FIGlet prior to 2.1 ignore this
parameter.
Full_Layout
(See "INTERPRETATION OF LAYOUT PARAMETERS" just below.)
Codetag_Count
Indicates the number of code-tagged (non-required) FIGcharacters in this
FIGfont. This is always equal to the total number of FIGcharacters in the font
minus 102. This parameter is typically ignored by FIGdrivers, but can be
used to verify that no characters are missing from the end of the FIGfont.
The chkfont program will display the number of codetagged characters
in the FIGfont on which it is run, making it easy to insert this parameter
after a FIGfont is written.
INTERPRETATION OF LAYOUT PARAMETERS
Full_Layout describes ALL information about horizontal and vertical layout:
the default layout modes and potential smushing rules, even when smushing is
not a default layout mode.
Old_Layout does not include all of the information desired by the most
recent FIGdrivers, which is the inspiration for the creation of the new
Full_Layout parameter. Old_Layout is still required for backward
compatibility, and FIGdrivers must be able to interpret FIGfonts which do not
have the Full_Layout parameter. (See "STANDARDIZED CAPABILITIES OF CURRENT
AND FUTURE FIGDRIVERS".)
Versions of FIGlet prior to 2.2 do not recognize the Full_Layout parameter.
Documentation accompanying FIGlet versions prior to 2.2 refer to Old_Layout
as "smushmode", which is somewhat misleading since it can indicate layout
modes other than smushing.
Old_Layout and Full_Layout must contain some redundant information.
Setting the layout parameters is a matter of adding numbers together ("code
values"). What follows is a chart of the meanings of all code values.
(You may skip down to "SETTING LAYOUT PARAMETERS STEP BY STEP" if you prefer,
or if you find this portion confusing.)
Full_Layout: (Legal values 0 to 32767)
1 Apply horizontal smushing rule 1 when smushing
2 Apply horizontal smushing rule 2 when smushing
4 Apply horizontal smushing rule 3 when smushing
8 Apply horizontal smushing rule 4 when smushing
16 Apply horizontal smushing rule 5 when smushing
32 Apply horizontal smushing rule 6 when smushing
64 Horizontal fitting (kerning) by default
128 Horizontal smushing by default (Overrides 64)
256 Apply vertical smushing rule 1 when smushing
512 Apply vertical smushing rule 2 when smushing
1024 Apply vertical smushing rule 3 when smushing
2048 Apply vertical smushing rule 4 when smushing
4096 Apply vertical smushing rule 5 when smushing
8192 Vertical fitting by default
16384 Vertical smushing by default (Overrides 8192)
When no smushing rules are included in Full_Layout for a given axis, the
meaning is that universal smushing shall occur, either by default or when
requested.
Old_Layout: (Legal values -1 to 63)
-1 Full-width layout by default
0 Horizontal fitting (kerning) layout by default*
1 Apply horizontal smushing rule 1 by default
2 Apply horizontal smushing rule 2 by default
4 Apply horizontal smushing rule 3 by default
8 Apply horizontal smushing rule 4 by default
16 Apply horizontal smushing rule 5 by default
32 Apply horizontal smushing rule 6 by default
* When Full_Layout indicates UNIVERSAL smushing as a horizontal default
(i.e., when none of the code values of horizontal smushing rules are included
and code value 128 is included in Full_Layout) Old_Layout must be set to 0
(zero). Older FIGdrivers which cannot read the Full_Layout parameter are
also incapable of universal smushing. Therefore they would be directed to
the "next best thing", which is horizontal fitting (kerning).
NOTE: You should NOT add the -1 value to any positive code value for
Old_Layout. This would be a logical contradiction.
See "STANDARDIZED CAPABILITIES OF CURRENT AND FUTURE FIGDRIVERS" for the
behavior of a FIGdriver when the Full_Layout parameter is absent (presumably
in an older FIGfont).
The following rules establish consistency between Old_Layout and Full_Layout.
If full width is to be the horizontal default:
Old_Layout must be -1.
Full_Layout must NOT include code values 64 nor 128.
If horizontal fitting (kerning) is to be default:
Old_Layout must be 0.
Full_Layout must include code value 64.
Full_Layout must NOT include code value 128.
If CONTROLLED smushing is to be the horizontal default:
Old_Layout must be a positive number, represented by the added
code values of all desired horizontal smushing rules.
Full_Layout must include the code values for the SAME set of
horizontal smushing rules as included in Old_Layout.
Full_Layout must include code value 128.
If UNIVERSAL smushing is to be the horizontal default:
Old_Layout must be 0.
Full_Layout must include code value 128.
Full_Layout must NOT include any code value under 64.
In general terms, if Old_Layout specifies horizontal smushing rules,
Full_Layout must specify the same set of horizontal rules, and both must
indicate the same horizontal default layout mode.
SETTING LAYOUT PARAMETERS STEP-BY-STEP
The following step-by-step process will yield correct and consistent values
for the two layout parameters. You may skip this if you find the
explanations above easier to use.
Step 1: Start with 0 for both numbers.
Write "Old_Layout" and "Full_Layout" on a piece of paper.
Write the number 0 next to each.
The number 0 may be crossed out and changed several times below.
Go to step 2.
Step 2: Set the DEFAULT HORIZONTAL LAYOUT MODE.
If you want to use FULL WIDTH as the default
Make Old_Layout -1
Go to step 3.
If you want to use HORIZONTAL FITTING (kerning) as the default
Make Full_Layout 64
Go to step 3.
If you want to use HORIZONTAL SMUSHING as the default
Make Full_Layout 128
Go to step 3.
Step 3: Specify HOW TO SMUSH HORIZONTALLY WHEN SMUSHING.
If you want to use UNIVERSAL smushing for the horizontal axis
Go to step 4.
If you want to use CONTROLLED smushing for the horizontal axis
Add together the code values for all the horizontal smushing
rules you want from the list below to get the horizontal
smushing rules total.
EQUAL CHARACTER SMUSHING 1
UNDERSCORE SMUSHING 2
HIERARCHY SMUSHING 4
OPPOSITE PAIR SMUSHING 8
BIG X SMUSHING 16
HARDBLANK SMUSHING 32
Horizontal smushing rules total: ___
If Full_Layout is currently 128
Change Old_Layout to the horizontal smushing rules total.
Increase Full_Layout by the horizontal smushing rules total.
Go to Step 4.
If Full_Layout is currently 0 or 64
Increase Full_Layout by the horizontal smusing rules total.
Go to Step 4.
Step 4: Set the DEFAULT VERTICAL LAYOUT MODE.
If you want to use FULL HEIGHT as the default
Go to step 5.
If you want to use VERTICAL FITTING as the default
Increase Full_Layout by 8192.
Go to step 5.
If you want to use VERTICAL SMUSHING as the default
Increase Full_Layout by 16384.
Go to step 5.
Step 5: Specify HOW TO SMUSH VERTICALLY WHEN SMUSHING.
If you want to use UNIVERSAL smushing for the vertical axis
Go to step 6.
If you want to use CONTROLLED smushing for the vertical axis
Add together the code values for all the vertical smushing
rules you want from the list below to get the vertical
smushing rules total.
EQUAL CHARACTER SMUSHING 256
UNDERSCORE SMUSHING 512
HIERARCHY SMUSHING 1024
HORIZONTAL LINE SMUSHING 2048
VERTICAL LINE SUPERSMUSHING 4096
Vertical smushing rules total: ____
Increase Full_Layout by the vertical smushing rules total.
Go to step 6.
Step 6: You're done.
The resulting value of Old_Layout will be a number from -1 to 63.
The resulting value of Full_Layout will be a number from 0 and 32767.
FIGFONT COMMENTS
After the header line are FIGfont comments. The comments can be as many
lines as you like, but should at least include your name and Email address.
Here is an example which also shows the header line.
flf2a$ 6 5 20 15 3 0 143
Example by Glenn Chappell <ggc@uiuc.edu> 8/94
Permission is hereby given to modify this font, as long as the
modifier's name is placed on a comment line.
Comments are not required, but they are appreciated. Please comment your
FIGfonts.
Remember to adjust the Comment_Lines parameter as you add lines to your
comments. Don't forget that blank lines DO count.
FIGCHARACTER DATA
============ ====
The FIGcharacter data begins on the next line after the comments and
continues to the end of the file.
BASIC DATA STRUCTURE
The sub-characters in the file are given exactly as they should be output,
with two exceptions:
1) Hardblanks should be the hardblank character specified in the
header line, not a blank (space).
2) Every line has one or two endmark characters, whose column
locations define the width of each FIGcharacter.
In most FIGfonts, the endmark character is either "@" or "#". The FIGdriver
will eliminate the last block of consecutive equal characters from each line
of sub-characters when the font is read in. By convention, the last line of
a FIGcharacter has two endmarks, while all the rest have one. This makes it
easy to see where FIGcharacters begin and end. No line should have more
than two endmarks.
Below is an example of the first few FIGcharacters, taken from small.flf.
NOTE: The line drawn below consisting of "|" represents the left margin of
your editor. It is NOT part of the FIGfont. Also note that hardblanks are
represented as "$" in this FIGfont, as would be described in the header line.
|$@
|$@
blank/space |$@
|$@
|$@@
| _ @
|| |@
exclamation point ||_|@
|(_)@
| @@
| _ _ @
|( | )@
double quote | V V @
| $ @
| @@
| _ _ @
| _| | |_ @
number sign ||_ . _|@
||_ _|@
| |_|_| @@
| @
| ||_@
dollar sign |(_-<@
|/ _/@
| || @@
Notice that each FIGcharacter occupies the same number of lines (6 lines, in
this case), which must also be expressed in the header line as the Height
parameter.
Also notice that for every FIGcharacter, there must be a consistent width
(length) for each line once the endmarks are removed. To do otherwise would
be an error.
Be aware of the vertical alignment of each FIGcharacter within its height,
so that all FIGcharacters will be properly lined up when printed.
If one of the last sub-characters in a particular FIGcharacter is "@", you
should use another character for the endmark in that FIGcharacter so that
the intended "@" is not interpreted as an endmark. "#" is a common
alternative.
Load a few existing FIGfonts into your favorite text editor for other
examples.
REQUIRED FIGCHARACTERS
Some FIGcharacters are required, and must be represented in a specific order.
Specifically: all of the printable character codes from ASCII shown in the
table below, in order, plus character codes 196, 214, 220, 228, 246, 252,
and 223, in that order. In Latin-1, these extra 7 characters represent the
following German characters: umlauted "A", "O", "U", "a", "o" and "u"; and
also "ess-zed".
Printable portion of the ASCII character set:
32 (blank/space) 64 @ 96 `
33 ! 65 A 97 a
34 " 66 B 98 b
35 # 67 C 99 c
36 $ 68 D 100 d
37 % 69 E 101 e
38 & 70 F 102 f
39 ' 71 G 103 g
40 ( 72 H 104 h
41 ) 73 I 105 i
42 * 74 J 106 j
43 + 75 K 107 k
44 , 76 L 108 l
45 - 77 M 109 m
46 . 78 N 110 n
47 / 79 O 111 o
48 0 80 P 112 p
49 1 81 Q 113 q
50 2 82 R 114 r
51 3 83 S 115 s
52 4 84 T 116 t
53 5 85 U 117 u
54 6 86 V 118 v
55 7 87 W 119 w
56 8 88 X 120 x
57 9 89 Y 121 y
58 : 90 Z 122 z
59 ; 91 [ 123 {
60 < 92 \ 124 |
61 = 93 ] 125 }
62 > 94 ^ 126 ~
63 ? 95 _
Additional required Deutsch FIGcharacters, in order:
196 (umlauted "A" -- two dots over letter "A")
214 (umlauted "O" -- two dots over letter "O")
220 (umlauted "U" -- two dots over letter "U")
228 (umlauted "a" -- two dots over letter "a")
246 (umlauted "o" -- two dots over letter "o")
252 (umlauted "u" -- two dots over letter "u")
223 ("ess-zed" -- see FIGcharacter illustration below)
___
/ _ \
| |/ /
Ess-zed >>---> | |\ \
| ||_/
|_|
If you do not wish to define FIGcharacters for all of those required above,
you MAY create "empty" FIGcharacters in their place by placing endmarks flush
with the left margin. The Deutsch FIGcharacters are commonly created as
empty. If your FIGfont includes only capital letters, please copy them to
the appropriate lowercase locations, rather than leaving lowercase letters
empty. A FIGfont which does not include at least all ASCII letters, a space,
and a few basic punctuation marks will probably frustrate some users. (For
example "@" is more frequently desired as a FIGcharacter than you may think,
since Email addresses may be written as FIGures.)
CODE TAGGED FIGCHARACTERS
After the required FIGcharacters, you may create FIGcharacters with any
character code in the range of -2147483648 to +2147483647. (Over four
billion possibilities, which is "virtual infinity" for this purpose.)
One exception: character code -1 is NOT allowed for technical reasons.
It is advisable to assign character codes such that the appearance of your
FIGcharacters matches the expectations of ASCII/Latin-1/Unicode, with a few
exceptions:
1) If a FIGcharacter with code 0 is present, it is treated
specially. It is a FIGfont's "missing character". Whenever
the FIGdriver is told to print a character which doesn't exist
in the current FIGfont, it will print FIGcharacter 0. If there
is no FIGcharacter 0, nothing will be printed.
2) If a FIGfont contains a non-Latin alphabet in character codes
in the ASCII range 32-126 (which is discouraged), we have found
it helpful to include a human-readable translation table as one
of the FIGcharacters instead of a "glyph". Typically, the "~"
would contain this table. The translation table FIGcharacter
would contain a list of all the special characters in the
FIGfont, along with the ASCII characters to which they
correspond. Keep this table no more than 79 columns wide.
(Thanks to Gedaliah Friedenberg for this idea.)
3) In more extensive Unicode fonts, you can assign a negative
character code (other than -1) to one or more translation
tables, similar to #2 above. (All Unicode character codes are
positive.) And, you will most likely suggest within the
comments that a user access one of several control files (See
"CONTROL FILES" below) to gain access to Latin-2, Latin-3, or
other 8-bit standardized character sets. The control files may
redirect the "~" character to one of the negative character codes so
that the translation table would display the table when "~" is
given for input. Doing this allows you to still have a "~"
FIGcharacter for those who do not use a control file.
Those FIGcharacters which are not required must have an explicit character
code in a separate line preceding them, called a "code tag". A code tag
contains the value of the character code, followed by whitespace (a few
spaces), and perhaps an optional comment. The comment is usually the name of
the FIGcharacter. The Unicode Consortium has assigned formal names to all
officially accepted characters, and these may be used. An entire code tag,
including the comment, should not occupy more than 95 columns. (Over 100
characters here may make older versions of FIGlet crash.)
Here is an example, showing two code tagged FIGcharacters after the last two
required Deutsch FIGcharacters. Again, the line drawn below consisting of
"|" represents the left margin of your editor, and is NOT part of the FIGfont.
| _ _ @
|(_) (_)@
|| | | |@
|| |_| |@
| \__,_|@
| @@
| ___ @
| / _ \@
|| |/ /@
|| |\ \@
|| ||_/@
||_| @@
|161 INVERTED EXCLAMATION MARK
| _ @
|(_)@
|| |@
|| |@
||_|@
| @@
|162 CENT SIGN
| _ @
| | | @
| / __)@
|| (__ @
| \ )@
| |_| @@
A character code may be expressed in decimal (as shown above, numbers we're
all familiar with), or in Octal (seldom used) or in hexadecimal.
Character codes expressed in octal must be preceded by "0" (zero), and if
negative, "-" (minus) must precede the "0". There are eight octal digits:
01234567. You may recall octal numbers from school as "base 8 numbers".
Character codes expressed in hexadecimal must be preceded by "0x" or "0X".
(That's also a zero.) If negative, the "-" must precede the "0x". There are
16 hexadecimal digits: 01234567890ABCDEF. (The "letter-digits" may also be
lowercase.) Hexadecimal is "base 16".
It is common to express character codes less than 256 (in the range of an
8-bit character set) as decimal, while FIGfonts which extend into the Unicode
range would have character codes expressed in hexadecimal. This is because
the Unicode Standard expresses character codes in hexadecimal, which is
helpful for programmers.
The code tagged FIGcharacters may be listed in any order, but simple
sequential order is recommended.
If two or more FIGcharacters have the same character code, the last one in
the FIGfont is the one used. It is common for the Deutsch FIGcharacters to
be given twice in a FIGfont, just to maintain a consistent order for the
Latin-1 range (128 to 255).
It is not advisable to assign character codes in the range of 1 to 31, since
this range includes control characters in ASCII. Character code 127 is a
delete in ASCII, and is also not advised. Character codes 128 to 159 are
additional control characters in Latin-1, and they too should not be used.
All of the above are legal, technically, but are not part of what is legal
for input, so they could only be accessed by use of a control file.
(See "CONTROL FILES" below.) If you are still tempted to use them, consider
negative character codes instead, which are meaningless in all standardized
character sets.
Again, the character code -1 is illegal for technical reasons.
NOTES - AVOIDING ERRORS AND GENERAL ADVICE
===== ======== ====== === ======= ======
It is very important that every character in a font has the same height, and,
once the endmarks are removed, that all the lines constituting a single
FIGcharacter have the same length. Be careful also that no lines in the font
file have trailing blanks (spaces), as the FIGdriver will take these to be
the endmarks. (FIGWin 1.0 will not consider blanks to be endmarks.)
Errors in a FIGfont can be detected by using the "chkfont" program,
part of the standard FIGlet package, and also available, as of this
writing from http://www.figlet.org/
�
For FIGWin users, the FIGWin program will report errors when a FIGfont is
read in; it is less forgiving than FIGlet, which can produce nonsense if the
FIGfont is incorrectly formatted.
Remember that sub-characters outside of the ASCII range will not necessarily
display the same way on your system as on others.
The blank (space) FIGcharacter should usually consist of one or two columns
of hardblanks and nothing else; slanted fonts are an exception to this rule.
If the space FIGcharacter does not contain any hardblanks, it will disappear
when horizontal fitting (kerning) or smushing occurs.
Again, if you design a FIGfont, please let us know!
CONTROL FILES
======= =====
A FIGfont control file is a separate text file, associated with one or more
FIGfonts, that indicates how to map input characters into FIGfont character
codes. By default, FIGdrivers read single bytes from the input source and
interpret them as Latin-1 FIGcharacters.
FIGlet version 2.2 (and later) can optionally interpret its input as DBCS or
UTF-8 characters, making it possible to access FIGcharacters with codes
outside the Latin-1 range (greater than 255).
In addition, though, all versions of FIGlet can use control files to
transform specific character codes (or ranges of codes) as other codes
(or ranges). Multiple control files can be specified, in which case multiple
stages of transformation are performed.
The filename of a control file always ends with ".flc".
CONTROL FILE FORMAT
Control files contain several kinds of lines. Lines beginning with "#", as
well as blank lines, are comment lines and are ignored. All other lines are
command lines, with one of the following formats:
t inchar outchar
t inchar1-inchar2 outchar1-outchar2
number number
f
h
j
b
u
g{0|1|2|3} {94|96|94x94} [char]
g{L|R} {0|1|2|3}
where "inchar", "outchar", and "char" are either Latin-1 characters
representing their own codes, or else are numeric character codes preceded by
a "\" character; and "number" is a numeric character code with no preceding
"\" character.
Thus "A" represents the code 65, as does "\65", and "\0x100" represents the
code 256 (100 in hexadecimal). In addition, "\ " (backslash followed by a
space) represents the code 32 (space), and the following backslash sequences
are also understood:
\a code 7 (a bell/alert)
\b code 8 (a backspace)
\e code 27 (an ESC character)
\f code 12 (a form feed)
\n code 10 (a newline/line feed)
\r code 13 (a carriage return)
\t code 9 (a horizontal tab)
\v code 11 (a vertical tab)
\\ code 92 (a backslash)
All of these combinations except perhaps "\\" are very unlikely to be used,
but they are provided just in case they are needed.
Whitespace characters are used between "t" and "inchar" and between "inchar"
and "outchar", but not around the "-" characters used in the second type of
"t" command.
The term "string" refers to any number of characters represented in the
format given above. The characters begin after the whitespace following the
letter "s", and continue to the end of the line.
Anything following the first letter of an "f", "h", "j", or "u" command is
ignored.
The first type of "t" command transforms characters with the code "inchar"
into characters with the code "outchar". The second type of "t" command
transforms characters in the range "inchar1" to "inchar2" as the
corresponding codes in the range "outchar1" to "outchar2". Both ranges must
be of the same size. The form "number number" is equivalent to a "t"
command of the first type, and is provided for compatibility with the mapping
tables issued by the Unicode Consortium.
Multiple transformation stages can be encoded in a single control file by
using "f" commands to separate the stages.
Versions of FIGlet before 2.1 required that the first line of a control file
consist of the signature string "flc2a". This signature line is still
permitted in FIGlet 2.2 and later versions, but is no longer required.
Here is an example of a control file. The blanks at the beginning of each
line are for readability only, and are not part of the file.
The following control file:
flc2a
t # $
t A-Z a-z
will map the "#" character to "$", and will also convert uppercase ASCII to
lowercase ASCII.
If a number of consecutive "t" commands are given, then for each character
processed, only the first applicable command (if any) will be executed.
Consider this control file:
t A B
t B A
It will swap the characters "A" and "B". If the FIGdriver reads an "A", the
first command will change "A" to "B", in which case the second will not be
executed. If the FIGdriver reads a "B", the first command will have no
effect, and the second command will change "B" to "A". Here is another
control file:
t A B
t A C
In this example, the second line is never executed. In short, a sequence of
"t" lines "does what it ought to".
More complex files, in which a single character is acted upon by several "t"
commands, can be set up using an "f" command. For example:
flc2a
t a-z A-Z
f
t Q ~
This control file specifies two transformation stages. In the first stage,
lowercase ASCII letters are changed to their uppercase equivalents. The
second stage maps any Q (whether original or a converted "q") into the "~"
character. If the "f" command were omitted, "q" characters would remain "Q"
and not be converted to "~".
EXTENDED COMMANDS
The "h", "j", "b", "u", and "g" commands are only understood by FIGlet
version 2.2 or later. They control how a FIGdriver interprets bytes in the
input. By default, the FIGdriver interprets each byte of input as a distinct
character. This mode is suitable for most character encodings. All these
commands are logically acted on before any other control file commands, no
matter where in the sequence of control files they appear. They are also
mutually exclusive; if more than one of these commands is found, only the
last is acted on. Multiple "g" commands are permitted, however.
The "h" command forces the input to be interpreted in HZ mode, which is used
for the HZ character encoding of Chinese text. In this mode, the sequence
"~{" (which is removed from the input) signals that all following characters
are two bytes long until the sequence "~}" is detected. In addition, the
sequence "~~" is changed to just "~", and all other two-byte sequences
beginning with "~" are removed from the input. The character code
corresponding to a two-byte character is:
first character * 256 + second character
The "j" command forces the input to be interpreted in Shift-JIS mode (also
called "MS-Kanji mode"). Input bytes in the ranges 128-159 and 224-239 are
read as the high-order byte of a two-byte character; all other bytes are
interpreted as one-byte characters. The value of a two-byte character is
determined in the same way as in HZ mode.
The "b" command forces the input to be interpreted in DBCS mode, which is
suitable for processing HZ or Shift-GB Chinese text or Korean text. Input
bytes in the ranges 128-255 are read as the high-order byte of a two-byte
character; all other bytes are interpreted as one-byte characters. The
value of a two-byte character is determined in the same way as in HZ mode.
The "u" command forces the input to be interpreted in UTF-8 mode, which
causes any input byte in the range 0x80 to 0xFF to be interpreted as the
first byte of a multi-byte Unicode (ISO 10646) character. UTF-8 characters
can be from 1 to 6 bytes long. An incorrectly formatted sequence is
interpreted as the character 128 (normally an unused control character).
Otherwise, the input is allowed to contain ISO 2022 escape sequences, which
are decoded to generate appropriate character codes. These character codes
are *not* a subset of Unicode, but may be more useful in processing East
Asian text. A brief explanation of ISO 2022 is given here in order to
clarify how a FIGdriver should interpret it. The "g" command provides
information for the ISO 2022 interpreter, and is explained below.
ISO 2022 text is specified using a mixture of registered character sets.
At any time, up to four character sets may be available. Character sets
have one of three sizes: single-byte character sets with 94 characters
(e.g. ASCII), single-byte character sets with 96 characters (e.g. the top
halves of ISO Latin-1 to Latin-5), or double-byte character sets with
94 x 94 characters (e.g. JIS 0208X-1983). Each registered character set has
a standard designating byte in the range 48 to 125; the bytes are unique withi
n character set sizes, but may be reused across sizes. For example, byte 66
designates the 94-character set ASCII, the 96-character set ISO Latin-2 (top
half), and the 94 x 94 Japanese character set JIS 0208X-1983. In this
document, the designating byte of a character set will be represented by <D>.
The four available character sets are labeled G0, G1, G2, and G3. Initially,
G0 is the 94-character set ASCII, and G1 is the 96-character set ISO Latin-1
(top half). The other character sets are unassigned. The following escape
sequences (where ESC = the byte 27) specify changes to the available
character sets:
ESC ( <D> Set G0 to the 94-character set <D>
ESC ) <D> Set G1 to the 94-character set <D>
ESC * <D> Set G2 to the 94-character set <D>
ESC + <D> Set G3 to the 94-character set <D>
ESC - <D> Set G1 to the 96-character set <D>
ESC . <D> Set G2 to the 96-character set <D>
ESC / <D> Set G3 to the 96-character set <D>
ESC $ <D> Set G0 to the 94 x 94 character set <D>
ESC $ ( <D> Set G0 to the 94 x 94 character set <D>
ESC $ ) <D> Set G1 to the 94 x 94 character set <D>
ESC $ * <D> Set G2 to the 94 x 94 character set <D>
ESC $ + <D> Set G3 to the 94 x 94 character set <D>
Note that G0 may not be a 96-character set, and that there are two ways to
specify a 94 x 94 character set in G0, of which the first is deprecated.
ISO 2022 decoding affects input bytes in the ranges 33 to 126 and 160 to 255,
known as "the left half" and "the right half" respectively. All other bytes,
unless they belong to a control sequence shown in this document, remain
unchanged. Initially, the left half is interpreted as character set G0,
and the right half as character set G1. This can be changed by the following
control sequences:
SI (byte 15) Interpret the left half as G1 characters
SO (byte 14) Interpret the left half as G0 characters
ESC n Interpret the left half as G2 characters
ESC o Interpret the left half as G3 characters
ESC ~ Interpret the right half as G1 characters
ESC } Interpret the right half as G2 characters
ESC | Interpret the right half as G3 characters
SS2 (byte 142) Interpret next character only as G2
ESC N Interpret next character only as G2
SS3 (byte 143) Interpret next character only as G3
ESC O Interpret next character only as G3
This rich schema may be used in various ways. In ISO-2022-JP, the Japanese
flavor of ISO 2022, only the bytes 33-126 and the G0 character set is used,
and escape sequences are used to switch between ASCII, ISO-646-JP (the
Japanese national variant of ASCII), and JIS 0208X-1983. In other versions,
the G1 character set has 94 x 94 size, and so any byte in the range 160-255
is automatically the first byte of a double-byte character.
FIGdrivers that support ISO 2022 do so in the following way. Each character i
is decoded and assigned to a character set <D>.
If the character belongs to a 94-bit character set,
then if its value exceeds 128, it is reduced by 128,
and the value 65536 * <D> is added to it,
unless <D> is 66 (ASCII).
If the character belongs to a 96-bit character set,
then if its value is less than 128, it is increased by 128,
and the value 65536 * <D> is added to it,
unless <D> is 65 (ISO Latin-1).
If the character belongs to a 94 x 94 character set,
then the value is the sum of:
the first byte * 256,
plus the second byte,
plus the value 65536 * <D>.
Thus, the character code 65 ("A") in ASCII remains 65, the character code
196 in ISO Latin-1 ("A-umlaut") remains 196, the character code 65 (0x41)
in ISO-646-JP (whose <D> is 74 = 0x4A) becomes 0x4A0041 =4849729, and the
two-byte sequence 33 33 (0x21 0x21) in JIS 0208X-1983 (whose <D> is
65 = 0x41) becomes 0x412121 = 4268321. These codes may be used in compiling
FIGfonts suitable for use with ISO 2022 encoded text.
The initial settings of G0 through G3 and their assignments to the left half
and the right half can be altered in a control file by using "g" commands,
as follows:
g {0|1|2|3} {94|96|94x94} [<D>]
specifies that one of G0-G3 is a 94, 96, or 94x94 character set with
designating character <D>. If no designating character is specified, then a
<D> value of zero is assumed.
For example, the list of control commands:
g 0 94 B
g 1 96 A
sets the G0 character set to ASCII (94-character set "B") and the G1
character set to the top half of Latin-1 (96-character set "A"). (This is the
default setting).
To change the initial assignments of G0 to the left half and G1 to the right
half, "g" commands of the form
g {L|R} {0|1|2|3}
For example, the command:
g R 2
causes right-half bytes (in the range 160-255) to be interpreted as G2.
Whether these bytes are interpreted singly or in pairs depends on the type
of character set that is currently available as G2.
Spaces may be freely used or omitted in "g" commands.
The standard FIGlet distribution contains mapping tables for Latin-2 (ISO 8859-2),
Latin-3 (ISO 8859-3), Latin-4 (ISO 8859-4), and Latin-5 (ISO 8859-9). They
can be used with the font "standard.flf", which contains all the characters
used in these standards.
STANDARDIZED CAPABILITIES OF CURRENT AND FUTURE FIGDRIVERS
============ ============ == ======= === ====== ==========
We assert the following as the "Law" of our intentions:
PROFIT
All future FIGdrivers shall be FREE OF CHARGE to the general public via the
Internet. Any advertisements of other works by the author must be in
documentation only, and limited to ONE "screenful", and shall not appear by
normal program behavior, nor interfere with normal behavior. No FIGdriver
shall disable itself after a set period of time or request "donations".
No FIGdriver shall offer any other FIGdriver with improved capability for
creating FIGures in exchange for money.
REQUIRED FEATURES OF FUTURE VERSIONS
Future FIGdrivers must read and process FIGfont files as described in this
document, but are not necessarily expected to process control files, smush,
perform fitting or kerning, perform vertical operations, or even produce
multiple lines in output FIGures.
FIGDRIVER NAMES
Future FIGdrivers must be named to include capitalized "FIG" and shall have
an incremental version number specific to its own platform.
BACKWARDS COMPATIBILITY OF FUTURE VERSIONS
Any future FIGdriver created for the same platform as an existing FIGdriver,
and using the same name as the existing FIGdriver, shall be considered a new
version of the preceding FIGdriver, and shall contain all historical comments
of updates to past versions on the same platform, and shall have full
capability of the preceding versions. If the source code is not provided to
the general public, it shall be at least provided to any potential developers
of later versions, and such comments relating to past versions shall be
accessible to any user by other means or documentation. If a new program is
created on a platform that already has an existing FIGdriver, it must be
given a new and distinct name. This allows multiple FIGdrivers to exist for
the same platform with different capabilities.
The format of FIGfonts may not be modified to be non-backwards compatible
UNLESS:
1) The new format is easily editable as an ASCII text file,
beginning with the characters "flf" followed by a sequential
number.
2) At least all of the same information can be derived from the
new format as the prior format (currently "flf2"). This
includes the main comments which give credit to the FIGfont
designer.
3) Individuals are found who are willing and have the ability to
either port or develop versions for at least UNIX, DOS,
Windows, and Amiga which will read both the new formats AND the
prior format (currently "flf2"), and retain the capability of
past versions. It is intended that this will be expanded to
include Macintosh if a GUI version exists. This list of
required operating systems may be reduced if an operating
system falls out of popularity or increased if a new operating
system for which there is a FIGdriver comes into greater
popularity, according to the consensus of opinions of past
developers for the most popular operating systems.
4) A C, Java, or other version must always exist which can
receive input and instructions either from a command line, a
file, or directly over the internet so that FIGures can be
obtained from internet-based services without the need to
download any FIGdriver.
5) All existing FIGfonts available from the "official" point of
distribution (http://www.figlet.org/),
must be converted to the new format, and offered for download
alongsidethe new versions.
THE FUNCTION OF WORD WRAPPING
All future FIGdrivers should duplicate these behaviors, unless a version is
only capable of outputting one-line FIGures, which is acceptable as long no
preceding versions exist for its platform which can output multiple-line
FIGures.
FIGdrivers which perform word wrapping do so by watching for blanks (spaces)
in input text, making sure that the FIGure is no more wide than the maximum
width allowed.
Input text may also include linebreaks, so that a user may specify where
lines begin or end instead of relying on the word wrapping of the FIGdriver.
(Linebreaks are represented by different bytes on different platforms, so
each FIGdriver must watch for the appropriate linebreaks for its particular
platform.)
When a FIGdriver word wraps and there are several consecutive blanks in input
text where the wrapping occurred, the FIGdriver will disregard all blanks
until the next non-blank input character is encountered. However, if blanks
in input text immediately follow a linebreak, or if blanks are the first
characters in the input text, the blanks will be "printed", moving any
visible FIGcharacters which follow on the same output line to the right.
Similarly, if an image is right-aligned, and blanks immediately precede
linebreaks or the end of input text, a FIGdriver will move an entire line of
output FIGcharacters to the left to make room for the blank FIGcharacters
until the left margin is encountered. (If the print direction is
right-to-left, everything stated in this paragraph is reversed.)
Word processing programs or text editors usually behave similarly in all
regards to word wrapping.
GENERAL INTENT FOR CROSS-PLATFORM PORTABILITY
Currently, all versions of FIGlet are compiled from C code, while FIGWin 1.0
is written in Visual Basic. Over time it is intended that a later version of
FIGWin will be created using a GUI C programming language, and that the
FIGlet C code shall continue to be written to be easily "plugged in" to a
GUI shell. It is preferable for developers of FIGdrivers for new platforms
to use C or a GUI version of C, so that when the core rendering engine of
FIGlet is updated, it will be portable to other platforms.
CONTROL FILE COMMANDS
New control file commands may be added to later versions of this standard.
However, the commands "c", "d", and "s" are permanently reserved and may
never be given a meaning.
FILE COMPRESSION
FIGfonts (and control files) are often quite long, especially if many
FIGcharacters are included, or if the FIGcharacters are large. Therefore,
some FIGdrivers (at present, only FIGlet version 2.2 or later) allow
compressed FIGfonts and control files.
The standard for FIG compression is to place the FIGfont or control file into
a ZIP archive. ZIP archives can be created by the proprietary program PKZIP
on DOS and Windows platforms, or by the free program Info-ZIP ZIP on almost
all platforms. More information on ZIP can be obtained at
http://www.cdrom.com/pub/infozip/Info-Zip.html .
The ZIP archive must contain only a single file. Any files in the archive
after the first are ignored by FIGdrivers. In addition, the standard
extension ".zip" of the archive must be changed to ".flf" or ".flc" as
appropriate. It does not matter what the name of the file within the
archive is.
CHART OF CAPABILITIES OF FIGLET 2.2 AND FIGWIN 1.0
===== == ============ == ====== === === ====== ===
The following chart lists all capabilities which are either new with the
release of both FIGdrivers, or is not a common capability among both.
FIGlet 2.2 FIGWIN 1.0
Interpreting the Full_Layout parameter: Yes Yes
Universal smushing: Yes Yes
Supporting multi-byte input text formats: Yes No
Processing control files: Yes No
Changing default smushing rules: Yes No
Bundled with a GUI editor of FIGfonts: No Yes
Vertical fitting and smushing: No Yes
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