About ASCII and ASCII Art

by Joan G. Stark

 

What is ASCII?

ASCII (ask'-ee) is an acronym for "American Standard Code for
Information Interchange." This standard was developed by the American
National Standards Institute. It is a coding scheme which assigns numeric
values to letters, numbers, punctuation marks, and other certain characters
such as control codes. By standardizing the values for these characters,
ASCII enables computers and computer programs to exchange
information. ASCII is the basic coding system which computers use to
communicate with one another.

The ASCII character set consists of 128 characters (numbered from 0 to
127) which are standard on nearly all types of computers. The first 32
characters (0 to 31) are assigned to communication and printer control
codes-- non-printing characters --these include the control codes for
signalling end of transmission, a beep, escape,
backspace, and more. The last ASCII character, 127, is another control
code representing the 'Delete' key. The other characters (32 to 126) are
the ones which appear on a "standard" keyboard. These are the
characters which are used to create ASCII art.

The ASCII characters used in ASCII art are the 95 characters from #32 to #126, as
follows.

032 [space] 048 0 064 @ 080 P 096 ` 112 p
033 ! 049 1 065 A 081 Q 097 a 113 q
034 " 050 2 066 B 082 R 098 b 114 r
035 # 051 3 067 C 083 S 099 c 115 s
036 $ 052 4 068 D 084 T 100 d 116 t
037 % 053 5 069 E 085 U 101 e 117 u
038 & 054 6 070 F 086 V 102 f 118 v
039 ' 055 7 071 G 087 W 103 g 119 w
040 ( 056 8 072 H 088 X 104 h 120 x
041 ) 057 9 073 I 089 Y 105 i 121 y
042 * 058 : 074 J 090 Z 106 j 122 z
043 + 059 ; 075 K 091 [ 107 k 123 {
044 , 060 < 076 L 092 \ 108 l 124 |
045 - 061 = 077 M 093 ] 109 m 125 }
046 . 062 > 078 N 094 ^ 110 n 126 ~
047 / 063 ? 079 O 095 _ 111 o

There is another character set which consists of the ASCII character set
with another 128 characters (128-255), for special characters such as the
copyright symbol and various accented letters. Some people have
inaccurately called this set "extended ASCII" or "high ASCII". These higher
number coded characters are assigned to variable sets of characters by
computer manufacturers and software developers. You should **NOT**
use these characters in ASCII art, though, because they are not
standardized -- even though the addition of more characters offers an
opportunity for more flexibility in creating an ASCII picture, it really
decreases the number of people who can properly view your creation. This
defeats the purpose of the universalitality of ASCII art.

These extended codes are not as interchangable among different
programs and computers as are the standard ASCII characters. IBM, for
example, uses a group of extended ASCII characters generally called the
IBM extended character set for its personal computers. Apple Computer
uses a similar but different group of extended characters for its Macintosh
line of computers. Thus, whereas the ASCII character set is universal
among microcomputer hardware and software, the extended characters
can be interpreted correctly only if a program, computer, or printer is
designed for it. This is why these characters are not included in the ASCII
art pictures. ASCII pictures can look very skewed if they have the
misplaced characters in them. (Just imagine a picture with solid squares
where someone had carefully placed a character!)

By keeping to the 32-126 range of ASCII codes, not only will people see
your ASCII artwork as you intended them to view it, but you will maximize
the number of your viewers.



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What is ASCII Art?


Essentially, ASCII artwork denotes pictures which are created without
using graphics. They are "non-graphical graphics". Its palette is limited to
the symbols and characters that you have available to you on your
computer keyboard. Specifically those 95 which are listed on the above
ASCII chart. International symbols, such as the UK pound sterling sign, are
not considered to be ASCII characters because they are not universal on
all systems.

In order to view ASCII art correctly, you must display it in a font that has
uniform character width. This is also known as a "fixed-pitch font." Your
browser should have some provision for setting a fixed font. Fixed-pitch
fonts include "Courier", "FixedSys", or "Monaco". This is important
because viewing ASCII art in proportional spacing will cause it to look
skewed. ASCII Art is not made in proportional fonts because the letter
widths vary from font to font. Even if you know what font the pictures were
created in, it still tends to look skewed. ASCII art is universal-- but only if it
is created and viewed in a fixed-pitch font and without any non-ASCII
characters.

I get a lot of mail asking me why the ASCII art looks fine on my website
and it looks skewed on their system. Check the font!!!! ASCII art **must**
be created and viewed in the fixed-pitch font. (AOL and WebTV users--
you ONLY have capabilities for a proportional font-- you will not be able to
see the ASCII art properly unless you copy/paste it to notepad or a text
editor in the proper font; or unless you print it out).