Here is a proposed encoding for "Font X". It is not invertible, and it
doesn't have to be. We never send Font X, we only display it upon receipt of
DEC Special Graphics and DEC Technical characters, or when we have selected
"Display Controls".
The DEC Technical Character set leaves nine positions undefined. On a real
DEC VT320, these nine characters all display themselves as reverse question
marks, which is already a legitimate DEC Technical character. So this creates
nine undefined positions in Font X.
Because DEC Technical and DEC Special Graphics have certain characters in
common, or even repeated within a single set, we have certain single Font X
characters representing two or more DEC characters, leaving still more Font X
positions undefined.
Remember, the object of this exercise is to make Font X as compatible with
Apple's Symbol encoding as possible, so if users change the font of Font X
material to Symbol, as much of it as possible will make sense.
I am enclosing two tables. The first is sorted in DEC encoding order. The
second is the same table, sorted in Font X encoding order. There are 297
entries in each table because of the duplicate mappings, but Font X itself
contains exactly 256 positions, of which 23 are undefined (and should
therefore display as boxes on the Mac screen). The undefined characters are
listed, and the duplicate characters are listed as many times as they appear.
The columns in the tables are:
MAC: The first column shows the Font-X encoding in decimal.
DEC: The second column shows the DEC encoding of the character in decimal.
For the DEC Technical Set, the encodings are 8-bit: 160-254.
SET: The third column tells which character-SET this character belongs to:
DC0 = Display Controls for C0.
SGA = DEC Special Graphics, ASCII part (i.e. 02/00 through 05/14).
SGS = DEC Special Graphics, Special part (i.e. 05/15 through 07/14).
DC1 = Display Controls for C1.
TEC = DEC Technical.
FONT-X-NAME: Describes the Font-X character. For Display Controls, the
two characters that should be displayed in a single character cell are given,
followed in parentheses by the actual ASCII (or ISO) name of the character,
for example "Display Ctrl SH (SOH)" means that ASCII 001 (SOH) is displayed
as "SH" in a single character cell, like this:
____
|S |
| H|
----
SYMBOL-NAME: Describes the Apple Symbol character that has the same encoding
as the Font X character. This shows what happens if users display Font X text
in the Apple Symbol font. Each name is preceded by a digit:
0 Means an exact match
1 Means not an exact match, but pretty close, glyphically speaking
2 Means it's a totally different character
I have tried to maximize the number of 0's and minimize the 2's. For DEC
Special Graphics I got:
54 0's
13 1's
28 2's
and for DEC Technical I got:
64 0's
11 1's
21 2's
Overall I got:
118 0's
24 1's
137 2's (including the 64+ "Display Control" characters)
Most of the 2's are because DEC Special graphics contains the first 4 columns
of ASCII, but ASCII is pretty much absent from Symbol.
Display controls, of course, are all 2's, because none of them are in the
Symbol font.
Here is the first table, in DEC encoding order (256 entries):
MAC DEC SET FONT-X-NAME SYMBOL-NAME
Here is the second table, in Font-X encoding order (297 entries because
of all the duplications -- but remember, the duplicate entries are still
only one character in the set. The set contains 256 character positions, of
which 41 are undefined.
MAC DEC SET FONT-X-NAME SYMBOL-NAME
000 000 DC0 Display Ctrl NU (NUL) 2 UNDEFINED
001 001 DC0 Display Ctrl SH (SOH) 2 UNDEFINED
002 002 DC0 Display Ctrl SX (STX) 2 UNDEFINED
003 003 DC0 Display Ctrl EX (ETX) 2 UNDEFINED
004 004 DC0 Display Ctrl ET (EOT) 2 UNDEFINED
005 005 DC0 Display Ctrl EQ (ENQ) 2 UNDEFINED
006 006 DC0 Display Ctrl AK (ACK) 2 UNDEFINED
007 007 DC0 Display Ctrl BL (BEL) 2 UNDEFINED
008 008 DC0 Display Ctrl BS (BS) 2 UNDEFINED
009 009 DC0 Display Ctrl HT (HT) 2 UNDEFINED
009 098 SGS Display Ctrl HT (HT) 2 UNDEFINED
010 010 DC0 Display Ctrl LF (LF) 2 UNDEFINED
010 101 SGS Display Ctrl LF (LF) 2 UNDEFINED
011 011 DC0 Display Ctrl VT (VT) 2 UNDEFINED
011 105 SGS Display Ctrl VT (VT) 2 UNDEFINED
012 012 DC0 Display Ctrl FF (FF) 2 UNDEFINED
012 099 SGS Display Ctrl FF (FF) 2 UNDEFINED
013 013 DC0 Display Ctrl CR (CR) 2 UNDEFINED
013 100 SGS Display Ctrl CR (CR) 2 UNDEFINED
014 014 DC0 Display Ctrl SO (SO) 2 UNDEFINED
015 015 DC0 Display Ctrl SI (SI) 2 UNDEFINED
016 016 DC0 Display Ctrl DL (DLE) 2 UNDEFINED
017 017 DC0 Display Ctrl D1 (DC1) 2 UNDEFINED
018 018 DC0 Display Ctrl D2 (DC2) 2 UNDEFINED
019 019 DC0 Display Ctrl D3 (DC3) 2 UNDEFINED
020 020 DC0 Display Ctrl D4 (DC4) 2 UNDEFINED
021 021 DC0 Display Ctrl NK (NAK) 2 UNDEFINED
022 022 DC0 Display Ctrl SY (SYN) 2 UNDEFINED
023 023 DC0 Display Ctrl EB (ETB) 2 UNDEFINED
024 024 DC0 Display Ctrl CN (CAN) 2 UNDEFINED
025 025 DC0 Display Ctrl EM (EM) 2 UNDEFINED
026 026 DC0 Display Ctrl SU (SUB) 2 UNDEFINED
027 027 DC0 Display Ctrl EC (ESC) 2 UNDEFINED
028 028 DC0 Display Ctrl FS (FS) 2 UNDEFINED
029 029 DC0 Display Ctrl GS (GS) 2 UNDEFINED
030 030 DC0 Display Ctrl RS (RS) 2 UNDEFINED
031 031 DC0 Display Ctrl US (US) 2 UNDEFINED
032 032 SGA Space 0 Space
032 095 SGA Space 0 Space
033 033 SGA Exclamation mark 0 Exclamation mark
034 125 SGS Pound Sterling Sign 2 For Every (upside down A)
035 035 SGA Number sign 0 Number sign
036 036 SGA Dollar sign 2 There Exists (backwards E)
037 037 SGA Percent sign 0 Percent sign
038 038 SGA Ampersand 0 Ampersand
039 112 SGS Horizontal Line - Scan 3 2 Such that
040 040 SGA Left Parenthesis 0 Left Parenthesis
041 041 SGA Right Parenthesis 0 Right Parenthesis
042 042 SGA Asterisk 1 Centered asterisk
043 043 SGA Plus Sign 0 Plus sign
044 044 SGA Comma 0 Comma
045 045 SGA Hyphen, Minus Sign 0 Minus sign
046 046 SGA Period, Full Stop 0 Period
047 047 SGA Solidus, Slash 0 Solidus, slash
048 048 SGA Digit Zero 0 Digit Zero
049 049 SGA Digit One 0 Digit One
050 050 SGA Digit Two 0 Digit Two
051 051 SGA Digit Three 0 Digit Three
052 052 SGA Digit Four 0 Digit Four
053 053 SGA Digit Five 0 Digit Five
054 054 SGA Digit Six 0 Digit Six
055 055 SGA Digit Seven 0 Digit Seven
056 056 SGA Digit Eight 0 Digit Eight
057 057 SGA Digit Nine 0 Digit Nine
058 058 SGA Colon 0 Colon
059 059 SGA Semicolon 0 Semicolon
060 060 SGA Left angle bracket 0 Left angle bracket
061 061 SGA Equals sign 0 Equals sign
062 062 SGA Right angle bracket 0 Right angle bracket
063 063 SGA Question mark 0 Question mark
064 064 SGA Commercial At sign 2 Identical to
065 065 SGA Capital Letter A 0 Capital Greek Alpha
066 066 SGA Capital Letter B 0 Capital Greek Beta
067 067 SGA Capital Letter C 2 Capital Greek Chi
068 068 SGA Capital Letter D 2 Capital Greek Delta
069 069 SGA Capital Letter E 0 Capital Greek Epsilon
070 070 SGA Capital Letter F 2 Capital Greek Fi
071 071 SGA Capital Letter G 2 Capital Greek Gamma
072 072 SGA Capital Letter H 0 Capital Greek Eta
073 073 SGA Capital Letter I 0 Capital Greek Iota
074 074 SGA Capital Letter J 2 Alternate lowercase theta
075 075 SGA Capital Letter K 0 Capital Greek Kappa
076 076 SGA Capital Letter L 2 Capital Greek Lambda
077 077 SGA Capital Letter M 0 Capital Greek Mu
078 078 SGA Capital Letter N 0 Capital Greek Nu
079 079 SGA Capital Letter O 0 Capital Greek Omicron
080 080 SGA Capital Letter P 2 Capital Greek Pi
081 081 SGA Capital Letter Q 2 Capital Greek Theta
082 082 SGA Capital Letter R 2 Capital Greek Rho
083 083 SGA Capital Letter S 2 Capital Greek Sigma
084 084 SGA Capital Letter T 0 Capital Greek Tau
085 085 SGA Capital Letter U 2 Capital Greek Upsilon
086 086 SGA Capital Letter V 2 Alternate lowercase sigma
087 087 SGA Capital Letter W 2 Capital Greek Omega
088 088 SGA Capital Letter X 2 Capital Greek Xi
089 089 SGA Capital Letter Y 2 Capital Greek Psi
090 090 SGA Capital Letter Z 0 Capital Greek Zeta
091 091 SGA Left Square Bracket 0 Left square bracket
092 192 TEC Therefore sign 0 Therefore sign
093 093 SGA Right Square Bracket 0 Right square bracket
094 118 SGS Box-Drawing T Bottom 1 Perpendicular (inverted T)
095 115 SGS Horizontal Line - Scan 9 1 Underscore
096 111 SGS Horizontal Line - Scan 1 1 Extension for radical
097 225 TEC Lowercase Greek alpha 0 Lowercase Greek alpha
098 226 TEC Lowercase Greek beta 0 Lowercase Greek beta
099 227 TEC Lowercase Greek chi 0 Lowercase Greek chi
100 228 TEC Lowercase Greek delta 0 Lowercase Greek delta
101 229 TEC Lowercase Greek epsilon 0 Lowercase Greek epsilon
102 230 TEC Lowercase Greek fi 0 Lowercase Greek fi
103 231 TEC Lowercase Greek gamma 0 Lowercase Greek gamma
104 232 TEC Lowercase Greek eta 0 Lowercase Greek eta
105 233 TEC Lowercase Greek iota 0 Lowercase Greek iota
106 119 SGS Box-Drawing T Top 2 Alternate greek theta
107 235 TEC Lowercase Greek kappa 0 Lowercase Greek kappa
108 236 TEC Lowercase Greek lambda 0 Lowercase Greek lambda
109 110 SGS Vert/Horiz Cross Centered 2 Lowercase Greek mu
110 238 TEC Lowercase Greek nu 0 Lowercase Greek nu
111 215 TEC Capital Greek Omega 2 Lowercase Greek omicron
112 123 SGS Lowercase Greek pi 0 Lowercase Greek pi
112 240 TEC Lowercase Greek pi 0 Lowercase Greek pi
113 234 TEC Lowercase Greek theta 0 Lowercase Greek theta
114 242 TEC Lowercase Greek rho 0 Lowercase Greek rho
115 243 TEC Lowercase Greek sigma 0 Lowercase Greek sigma
116 244 TEC Lowercase Greek tau 0 Lowercase Greek tau
117 249 TEC Lowercase Greek upsilon 0 Lowercase Greek upsilon
118 196 TEC Capital Greek Delta 2 Alternate lowercase omega
119 247 TEC Lowercase Greek omega 0 Lowercase Greek omega
120 248 TEC Lowercase Greek xi 0 Lowercase Greek xi
121 241 TEC Lowercase Greek psi 0 Lowercase Greek psi
122 250 TEC Lowercase Greek zeta 0 Lowercase Greek zeta
123 117 SGS Box-Drawing T Right 1 Left brace
124 198 TEC Capital Greek Fi 2 Vertical bar
125 116 SGS Box-Drawing T Left 1 Right brace
126 200 TEC Similar to, Centered tilde 0 Similar to, Centered tilde
127 127 DC0 Display Ctrl DT (DEL) 2 UNDEFINED
128 128 DC1 Display Ctrl 80 2 UNDEFINED
129 129 DC1 Display Ctrl 81 2 UNDEFINED
130 130 DC1 Display Ctrl 82 2 UNDEFINED
131 131 DC1 Display Ctrl 83 2 UNDEFINED
132 132 DC1 Display Ctrl 84 (IND) 2 UNDEFINED
133 133 DC1 Display Ctrl 85 (NEL) 2 UNDEFINED
134 134 DC1 Display Ctrl 86 2 UNDEFINED
135 135 DC1 Display Ctrl 87 2 UNDEFINED
136 136 DC1 Display Ctrl 88 (HTS) 2 UNDEFINED
137 137 DC1 Display Ctrl 89 2 UNDEFINED
138 138 DC1 Display Ctrl 8A 2 UNDEFINED
139 139 DC1 Display Ctrl 8B 2 UNDEFINED
140 140 DC1 Display Ctrl 8C 2 UNDEFINED
141 141 DC1 Display Ctrl 8D (RI) 2 UNDEFINED
142 142 DC1 Display Ctrl 8E (SS2) 2 UNDEFINED
143 143 DC1 Display Ctrl 8F (SS3) 2 UNDEFINED
144 144 DC1 Display Ctrl 90 (DCS) 2 UNDEFINED
145 145 DC1 Display Ctrl 91 2 UNDEFINED
146 146 DC1 Display Ctrl 92 2 UNDEFINED
147 147 DC1 Display Ctrl 93 2 UNDEFINED
148 148 DC1 Display Ctrl 94 2 UNDEFINED
149 149 DC1 Display Ctrl 95 2 UNDEFINED
150 150 DC1 Display Ctrl 96 2 UNDEFINED
151 151 DC1 Display Ctrl 97 2 UNDEFINED
152 152 DC1 Display Ctrl 98 2 UNDEFINED
153 153 DC1 Display Ctrl 99 2 UNDEFINED
154 154 DC1 Display Ctrl 9A 2 UNDEFINED
155 155 DC1 Display Ctrl 9B (CSI) 2 UNDEFINED
156 156 DC1 Display Ctrl 9C (ST) 2 UNDEFINED
157 157 DC1 Display Ctrl 9D (OSC) 2 UNDEFINED
158 158 DC1 Display Ctrl 9E (PM) 2 UNDEFINED
159 159 DC1 Display Ctrl 9F (APC) 2 UNDEFINED
160 160 TEC UNDEFINED 2 Double down arrow
161 217 TEC Capital Greek Upsilon 0 Capital Greek Upsilon
162 039 SGA Apostrophe 0 Foot/Minute/Prime
163 121 SGS Less-Equal 0 Less-Equal
163 188 TEC Less-Equal 0 Less-Equal
164 179 TEC Upper L to lower R diagonal 1 Fraction slash
165 194 TEC Infinity 0 Infinity
166 246 TEC Function-of sign, Script f 0 Script f
167 180 TEC Upper R to lower L diagonal 2 Club suit
168 096 SGS Diamond (solid) 0 Diamond (solid)
169 182 TEC Inverted Not sign 2 Heart suit
170 199 TEC Capital Greek Gamma 2 Spade suit
171 204 TEC Capital Greek Lambda 2 Left-and-right arrow
172 251 TEC Left arrow 0 Left arrow
173 094 SGA Circumflex Accent 1 Up arrow
174 253 TEC Right arrow 0 Right arrow
175 254 TEC Down Arrow 0 Down Arrow
176 102 SGS Degree Symbol 0 Degree Symbol
177 103 SGS Plus or Minus 0 Plus or Minus
178 034 SGA Double Quote 1 Double prime
179 122 SGS Greater-Equal 0 Greater-Equal
179 190 TEC Greater-Equal 0 Greater-Equal
180 203 TEC Multiplication symbol 0 Multiplication symbol
181 193 TEC Proportional-to 0 Proportional-to
182 239 TEC Partial differential sign 0 Partial differential sign
183 UNDEFINED 2 Large center dot
184 195 TEC Division 0 Division
185 124 SGS Not-Equal 0 Not-Equal
185 189 TEC Not-Equal 0 Not-Equal
186 207 TEC Identical-to sign 0 Identical-to sign
187 201 TEC Asymptotically equals 1 Approximately equal
188 114 SGS Horizontal Line - Scan 7 1 Ellipsis
189 120 SGS Vertical Line Centered 0 Up/Down arrow extension
189 166 TEC Vertical Line Centered 0 Up/Down Arrow extension
190 113 SGS Horizontal Line - Scan 5 0 Horizontal arrow extension
190 163 TEC Centered box horizonal line 0 Right/Left Arrow extension
191 104 SGS Display Ctrl NL 0 CRLF symbol ( <_| )
192 UNDEFINED 2 Aleph
193 UNDEFINED 2 Fraktur I
194 UNDEFINED 2 Fraktur R
195 UNDEFINED 2 Script P
196 202 TEC Circled dot operator 2 Circled set/vector multiply
197 UNDEFINED 2 Circled set/vector summation
198 UNDEFINED 2 Null set, empty set
199 220 TEC Union 0 Union
200 221 TEC Intersection 0 Intersection
201 219 TEC Superset of 0 Superset of
202 UNDEFINED 2 Contains as subclass
203 UNDEFINED 2 Not contained as subclass
204 218 TEC Subset of 0 Subset of
205 UNDEFINED 2 Contained as subclass
206 UNDEFINED 2 Member of set
207 UNDEFINED 2 Not member of set
208 178 TEC Summation sign, lower half 1 Angle
209 197 TEC Nabla, Laplace operator 0 Nabla, Laplace operator
210 UNDEFINED 2 Registered, serif
211 216 TEC Capital Greek Xi 2 Copyright, serif
212 209 TEC Capital Greek Psi 2 Trademark, serif
213 208 TEC Capital Greek Pi 1 Product (big capital Pi)
214 161 TEC Radical sign 0 Radical sign
214 214 TEC Radical sign 0 Radical sign
215 126 SGS Centered Dot (small) 0 Centered Dot (small)
216 181 TEC Not sign 0 Not sign
216 224 TEC Not sign 0 Not sign
217 222 TEC Logical AND 0 Logical AND
218 223 TEC Logical OR 0 Logical OR
219 205 TEC If and only if sign (<=>) 0 If and only if sign (<=>)
220 UNDEFINED 2 Double left arrow
221 252 TEC Up arrow 2 Double up arrow
222 206 TEC Implies sign (=>) 0 Double right arrow
223 184 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 185 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 186 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 187 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 210 TEC Reverse question mark 2 Double down arrow
223 212 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 213 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 237 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
223 245 TEC Reverse question mark (UNDEFINED) 2 Double down arrow
224 097 SGS Checkerboard (Error) 2 Diamond (hollow)
225 177 TEC Summation sign, upper half 1 Bra (large left angle bracket)
226 UNDEFINED 2 Registered, sans-serif
227 UNDEFINED 2 Copyright, sans-serif
228 UNDEFINED 2 Trademark, sans-serif
229 211 TEC Capital Greek Sigma 1 Summation (big capital Sigma)
230 171 TEC Extensible Left parenthesis top 0 Extensible left paren top
231 UNDEFINED 2 Extension for left paren
232 172 TEC Extensible Left parenthesis bot 0 Extensible left paren bottom
233 108 SGS Upper-Left Box Corner Centered 1 Left Bracket extension top
233 162 TEC Upper-Left Box Corner Centered 1 Left Bracket extension top
234 092 SGA Reverse Solidus, Backslash 2 Extension for left bracket
235 109 SGS Lower-Left Box Corner Centered 1 Left bracket extension bottom
236 167 TEC Extensible left bracket top 1 Extensible left brace top
237 175 TEC Extensible Left brace middle 0 Extensible left brace middle
238 168 TEC Extensible Left bracket bottom 1 Extensible left brace bot
239 UNDEFINED 2 Extension for left/right brace
240 UNDEFINED 2 UNDEFINED
241 183 TEC Ket, large right angle bracket 0 Ket
242 191 TEC Integral sign 0 Integral sign
243 164 TEC Integral top 0 Integral top
244 UNDEFINED 2 Extension for integral
245 165 TEC Integral bottom 0 Integral bottom
246 173 TEC Extensible Right parenthesis top 0 Extensible Right paren top
247 UNDEFINED 2 Extension for right paren
248 174 TEC Extensible Right parenthesis bot 0 Extensible Right paren bottom
249 107 SGS Upper-Right Box Corner Centered 1 Right Bracket extension Top
250 UNDEFINED 2 Extension for right bracket
251 106 SGS Lower-Right Box Corner Centered 1 Right Bracket extension Bottom
252 169 TEC Extensible Right bracket top 1 Extensible Right brace top
253 176 TEC Extensible Right brace middle 0 Extensible Right brace middle
254 170 TEC Extensible Right bracket bottom 1 Extensible Right brace bot
255 255 TEC (NONDISPLAY) 0 (NONDISPLAY)
(the end)