Appendix E. Data Explorer Fonts

All fonts used by Data Explorer are stored as files in the /usr/local/dx/fonts directory. Users can add their own fonts by creating a file in the correct format and using the DXFONTS environment variable to list the directory or directories where the additional font files are stored.

Fonts are stored in the standard Data Explorer file format. A font file must contain the following information (for more information on the Data Explorer file format, see Appendix B. "Importing Data: File Formats").

The font is a group that contains 256 fields, one for each ASCII character value, and two attributes describing the height of the font. For example:

 object "myfont" class group
    member 0 value "empty"
    member 1 value "control-a"
   .
   ∶
    member 65 value "A"
    member 66 value "B"
   .
   ∶
    member 255 value "empty"
    attribute "font ascent" number 0.75
    attribute "font descent" number 0.25

The attributes describe the maximum height above and below the baseline for all characters in this font. The values should be positive floating point numbers and they should add to 1.0.

Each member of the group must be a field.

Each field must contain a 2-D or 3-D "positions" component, and a "connections" component with element type "lines" or "triangles".

 object "positions1" class array type float rank 1 shape 3  items 3
   data follows  0.1 0.5 0.0   0.3 0.6 0.0    0.5 0.5 0.0
 object "connections1" class array type int rank 1 shape 2 items 2
   data follows  0 1   1 2
   attribute "element type" string "lines"
   attribute "ref" string "positions"

The character positions are assumed to have their horizontal (X) origin at the left edge and their vertical (Y) origin at the baseline.

Each field must have a "char width" attribute describing the character width for spacing when combining characters into strings.

 object "circumflex" class field
   component "positions" value "positions1"
   component "connections1" value "connections1"
   attribute "char width" number 0.55

The fields can contain other components (such as "colors" or "normals" ), although the standard Data Explorer modules will not process this information.

Those ASCII codes for which there is no representation should be empty fields:

object "empty" class field

A space character can be generated by making an empty field with a positive width:

 object "wide" class field
   attribute "char width" number 0.3
 object "myfont" class group
  .
  ∶
   member 32 value "wide"
  .
  ∶

 object "umlaut" class field
   component "connections" value "con1"
   component "positions"   value "pos1"
   component "char width"  number 0.0

The following fonts are supplied with Data Explorer, and may be found in this directory /usr/local/dx/fonts. Each one is a Data Explorer format file. If you would like to look at the structure of a font file, simply Import the data using the Import module, and Export it in text format.

default fonts	area	an area font (same as pitman)
	fixed	a fixed width font (same as roman_sfix)
	variable	a variable width font (same as roman_s)
cyrilic font	cyril_d	a cyrilic double-line font
Gothic fonts	gothiceng_t	an English gothic triple-line font
	gothicger_t	a German gothic triple-line font
	gothicit_t	an Italian gothic triple-line font
Greek fonts	greek_s	a Greek single-line font
	greek_d	a Greek double-line font
italic fonts	italic_d	an italic double-line font
	italic_t	an italic triple-line font
area (filled) font	pitman	an area typewriter style font that includes European National Language characters
Roman fonts	roman_s	a Roman single-line sans serif font
	roman_d	a Roman double-line sans serif font
	roman_dser	a Roman double-line serif font
	roman_tser	a Roman triple-line serif font
	roman_ext	an extended character set Roman single-line sans-serif font that includes European National Language characters
script fonts	script_s	a script single-line font
	script_d	a script double-line font

The default font directory is /usr/local/dx/fonts. For user-added fonts, the DXFONTS variable can contain a colon-separated list of directories to search for fonts before searching the default directory. A font file name must be the same as the font name. For example, the font "cursive" should be stored in the "cursive.dx" file, and the font parameter to the Caption module should be "cursive" to use this font. The names of user-supplied fonts should be all lowercase.

Since font files are in the standard Data Explorer file format, in addition to being used by Caption, Plot, AutoAxes, and ColorBar, they can be read into Data Explorer with Import and processed like any other group. Individual characters can be selected with Select, colored with Color, and displayed with ShowConnections. Newly constructed fonts can be exported with Export.

Table 8 and Table 9 illustrate those characters that are part of the roman_ext font. The appearance of a character may differ from that illustrated in the tables.

Table 8. roman_ext Font Characters (Part 1)

Octal Value	40	60	100	120	140	160	200
0	Blank	0	@	P	'	p	Ç
1	!	1	A	Q	a	q	ü
2	"	2	B	R	b	r	é
3	#	3	C	S	c	s	â
4	$	4	D	T	d	t	ä
5	%	5	E	U	e	u	à
6	&	6	F	V	f	v	å
7	'	7	G	W	g	w	ç
10	(	8	H	X	h	x	ê
11	)	9	I	Y	i	y	ë
12	*	:	J	Z	j	z	è
13	+	;	K	[	k	{	ï
14	,	<	L	\	l	&splitvbar;	î
15	-	=	M	]	m	}	ì
16	.	>	N	-^	n	~	Ä
17	/	?	O	_	o	&ballot;	&angstrom;

Table 9. roman_ext Font Characters (Part 2)

Octal Value	220	240	260	300	320	340	360
0	É	á		α	ρ	ι
1	æ	í		B	σ	κ
2	Æ	ó		γ	τ	λ
3	ô	ú		δ	υ	μ
4	ö	ñ		ε	φ	ν
5	ò	ñ		ζ	χ	ξ
6	û	a		η	ψ	ο
7	ù	o		θ	ω	π
8	ÿ	&invq;		Ι	α	ρ
9	Ö			&Kappa	β	σ
10	Ü			&Lambda	γ	τ
11	¢			Μ	δ	υ
12	£			Ν	ε	φ
13	¥	¡		Ξ	ζ	χ
14	&peseta;	"		Ο	η	ψ
15	&florin;	"	&integral;	Π	θ	ω

Table 10. Additional Symbols \001 - \035

1	apostrophe curly open	'
2	apostrophe curly close	'
3	backslash	\
4	bullet	*
5	cent	¢
6	copyright	©
7	cross product	×
10	degree	°
11	emdash	--
12	endash	-
13	exclamation	¡
14	franc	&florin;
15	guillemet open	"
16	guillemet close	"
17	guillemet single open
20	guillemet single close
21	infinity	&infinity;
22	integral	&integral;
23	interrogatory	&invq;
24	minus	-
25	notequal	<>
26	plusminus	±
27	pound	£
30	quote Open	"
31	quote close	"
32	registered	®
33	similar	&similar;
34	trademark	(TM)
35	yen	¥

The octal values for the English and Greek character sets in the pitman (or area) font are the same as those illustrated in Table 8 and Table 9. European National Languages characters are provided using single octal values or using a combination of values (see Table 11). For example, ä is produced using 252a, and î is produced using \221\237. Additional special symbols are provided with octal values 001 to 035 (see Table 10).

The following illustrates how you could produce a caption that contains the string "Jag är här på semester".

caption = Caption("Jag \252ar h\252ar p\213a semester"; font="pitman");
camera = AutoCamera (caption);
Display(caption,camera);

Table 11. European National Language Symbols and Characters \200 to \255

200	aBar
201	accentAcute	´	To type a acute, enter \201a. To type i acute, enter\201\237.
202	AccentAcute	´	(Uppercase except I)
203	IAccentAcute	Í	(Uppercase I Acute) To type A acute, enter \202A.
204	accentGrave	`	(lowercase)
205	AccentGrave	`	(Uppercase except I)
206	IAccentGrave	Ì	(Uppercase I)
207	accentHungarian		(Double quote accent over o and u)
210	AccentHungarian		(Double quote accent over O and U)
211	ae	æ	(Ligature)
212	AE	Æ	(Ligature)
213	angstrom		(Lowercase)
214	Angstrom		(Uppercase)
215	breve		(Lowercase)
216	Breve		(Uppercase)
217	c cedilla	ç	(Lowercase c cedilla)
220	C cedilla	Ç	(Uppercase C cedilla)
221	widecircumflex	^	(Looks better than ASCII Circumflex when used as a lowercase accent)
222	WideCircumflex	^	(Uppercase except for I and O)
223	WideCircumflex	Î	(Uppercase I)
224	WideCircumflex	Ô	(Uppercase O)
225	Clicka		(Used in Lithuanian over C, S, Z, c, s, and z; also called hacek or caron)
226	CommaRomanian		(Used in Romanian under S, T, s, and t)
227	enya		(Lowercase for Spanish n, and Portuguese a and o)
230	Enya		(Uppercase for Spanish N, and Portuguese A and O)
231	eth	ð	(Icelandic)
232	Eth	Ð	(Icelandic)
233	hookLithuanian		(Cedilla-like hook used under Lithuanian a, e, and u)
234	ihookLithuanian		(Cedilla-like hook used under Lithuanian i)
235	HookLithuanian		(Cedilla-like hook used under Lithuanian A, E, and U)
236	IHookLithuanian		(Cedilla-like hook used under Lithuanian I)
237	i dotless		(Dotless i to be accented with acute, grave, etc.)
240	l slash		(Slashed l used in Polish)
241	L slash		(Slashed L used in Polish)
242	macron		(Lowercase)
243	Macron		(Uppercase)
244	oBar
245	o slash	ø	(Danish slashed o)
246	O slash	Ø	(Danish slashed O)
247	Overdot	.	(Dot placed over Polish Z and z)
250	thorn	þ	(Icelandic)
251	Thorn	Þ	(Icelandic)
252	umlaut	¨aut;	(Lowercase, also called diaresis)
253	Umlaut	¨aut;	(Uppercase, except for I and O)
254	IUmlaut	¨aut;	(I umlaut)
255	OUmlaut	¨aut;	(O umlaut)