Commit | Line | Data |
---|---|---|
8340f87c BJ |
1 | .NH |
2 | Point Sizes; Line Spacing | |
3 | .PP | |
4 | As mentioned above, | |
5 | the command | |
6 | .BD .ps | |
7 | sets the point size. | |
8 | One point is 1/72 inch, | |
9 | so 6-point characters are at most 1/12 inch high, | |
10 | and 36-point characters are \(12 inch. | |
11 | There are 15 point sizes, listed below. | |
12 | .P1 1 | |
13 | .ps 6 | |
14 | 6 point: Pack my box with five dozen liquor jugs. | |
15 | .ps 7 | |
16 | .vs 8p | |
17 | 7 point: Pack my box with five dozen liquor jugs. | |
18 | .vs 9p | |
19 | .ps 8 | |
20 | 8 point: Pack my box with five dozen liquor jugs. | |
21 | .vs 10p | |
22 | .ps 9 | |
23 | 9 point: Pack my box with five dozen liquor jugs. | |
24 | .vs 11p | |
25 | .ps 10 | |
26 | 10 point: Pack my box with five dozen liquor | |
27 | .vs 12p | |
28 | .ps 11 | |
29 | 11 point: Pack my box with five dozen | |
30 | .vs 14p | |
31 | .ps 12 | |
32 | 12 point: Pack my box with five dozen | |
33 | .vs 16p | |
34 | .ps 14 | |
35 | 14 point: Pack my box with five | |
36 | .vs 24p | |
37 | \s1616 point\s18 18 point\s20 20 point | |
38 | .vs 40p | |
39 | \s2222\s24 24\s28 28\s36 36 | |
40 | .ps 10 | |
41 | .vs 12p | |
42 | .P2 | |
43 | .PP | |
44 | If the number after | |
45 | .BD .ps | |
46 | is not one of these | |
47 | legal sizes, | |
48 | it is rounded up to the next valid value, | |
49 | with a maximum of 36. | |
50 | If no number follows | |
51 | .BD .ps , | |
52 | .UL troff | |
53 | reverts to the previous size, whatever it was. | |
54 | .UL troff | |
55 | begins with point size 10, | |
56 | which is usually fine. | |
57 | This document is in 9 point. | |
58 | .PP | |
59 | The point size can also be changed in the middle of a line | |
60 | or even a word | |
61 | with the in-line command | |
62 | .BD \es . | |
63 | To produce | |
64 | .P1 | |
65 | \s8UNIX\s10 runs on a \s8PDP-\s1011/45 | |
66 | .P2 | |
67 | type | |
68 | .P1 | |
69 | \es8UNIX\es10 runs on a \es8PDP-\es1011/45 | |
70 | .P2 | |
71 | As above, | |
72 | .BD \es | |
73 | should be followed by a legal point size, | |
74 | except that | |
75 | .BD \es0 | |
76 | causes the size to revert to | |
77 | its previous value. | |
78 | Notice that | |
79 | .BD \es1011 | |
80 | can be understood correctly as `size 10, followed by an 11', if the size is legal, | |
81 | but not otherwise. | |
82 | Be cautious with similar constructions. | |
83 | .PP | |
84 | Relative size changes are also legal and useful: | |
85 | .P1 | |
86 | \es\-2UNIX\es+2 | |
87 | .P2 | |
88 | temporarily decreases the size, whatever it is, by two points, then | |
89 | restores it. | |
90 | Relative size changes have the advantage that the size difference | |
91 | is independent of the starting size of the document. | |
92 | The amount of the relative change is restricted | |
93 | to a single digit. | |
94 | .WS | |
95 | .PP | |
96 | The other parameter that determines what the type looks like | |
97 | is the spacing between lines, | |
98 | which is set independently of the point size. | |
99 | Vertical spacing is measured from the bottom of one line to | |
100 | the bottom of the next. | |
101 | The command to control vertical spacing is | |
102 | .BD .vs . | |
103 | For running text, it is usually best to set the vertical spacing | |
104 | about 20% bigger than the character size. | |
105 | For example, so far in this document, we have used | |
106 | ``9 on 11'', that is, | |
107 | .P1 | |
108 | ^ps 9 | |
109 | ^vs 11p | |
110 | .P2 | |
111 | If we changed to | |
112 | .P1 | |
113 | ^ps 9 | |
114 | ^vs 9p | |
115 | .P2 | |
116 | .vs 9p | |
117 | .ne 3 | |
118 | the running text would look like this. | |
119 | After a few lines, you will agree it looks a little cramped. | |
120 | The right vertical spacing is partly a matter of taste, depending on how | |
121 | much text you want to squeeze into a given space, | |
122 | and partly a matter of traditional printing style. | |
123 | By default, | |
124 | .UL troff | |
125 | uses 10 on 12. | |
126 | .PP | |
127 | .vs 14p | |
128 | .ps 12 | |
129 | Point size and vertical spacing make a substantial difference in the amount of text | |
130 | per square inch. | |
131 | This is 12 on 14. | |
132 | .ne 2 | |
133 | .PP | |
134 | .ne 2 | |
135 | .ps 6 | |
136 | .vs 7p | |
137 | Point size and vertical spacing make a substantial difference in the amount of text | |
138 | per square inch. | |
139 | For example, | |
140 | 10 on 12 uses about twice as much space as 7 on 8. | |
141 | This is 6 on 7, which is even smaller. | |
142 | It packs a lot more words per line, | |
143 | but you can go blind trying to read it. | |
144 | .PP | |
145 | When used without arguments, | |
146 | .BD .ps | |
147 | and | |
148 | .BD .vs | |
149 | revert to the previous size and vertical spacing | |
150 | respectively. | |
151 | .WS | |
152 | .PP | |
153 | The command | |
154 | .BD .sp | |
155 | is used to get extra vertical space. | |
156 | Unadorned, | |
157 | it gives you one extra blank line (one | |
158 | .BD .vs , | |
159 | whatever that has been set to). | |
160 | Typically, that's more or less than you want, | |
161 | so | |
162 | .BD .sp | |
163 | can be followed by | |
164 | information about how much space you want _ | |
165 | .P1 | |
166 | ^sp 2i | |
167 | .P2 | |
168 | means `two inches of vertical space'. | |
169 | .P1 | |
170 | ^sp 2p | |
171 | .P2 | |
172 | means `two points of vertical space'; | |
173 | and | |
174 | .P1 | |
175 | ^sp 2 | |
176 | .P2 | |
177 | means `two vertical spaces' _ two of whatever | |
178 | .BD .vs | |
179 | is set to | |
180 | (this can also be made explicit with | |
181 | .BD .sp\ 2v ); | |
182 | .UL troff | |
183 | also understands decimal fractions in most places, | |
184 | so | |
185 | .P1 | |
186 | ^sp 1.5i | |
187 | .P2 | |
188 | is a space of 1.5 inches. | |
189 | These same scale factors can be used after | |
190 | .BD .vs | |
191 | to define line spacing, and in fact after most commands | |
192 | that deal with physical dimensions. | |
193 | .PP | |
194 | It should be noted that all size numbers are converted internally | |
195 | to `machine units', which are 1/432 inch | |
196 | (1/6 point). | |
197 | For most purposes, this is enough resolution | |
198 | that you don't have to worry about the accuracy of the representation. | |
199 | The situation is not quite so good vertically, | |
200 | where resolution is 1/144 inch | |
201 | (1/2 point). |