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- ________________________________
- | |
- | Section 5: PRINTHEAD CONTROL |
- |________________________________|
-
-
- CONTENTS
-
- 5.1 Baseline Motion
- 5.2 Kerning, Tracking and Expansion
- 5.3 Diphthongs
- 5.4 Ligatures
-
-
- 5.1 BASELINE MOTION
-
- In a normal line of type, all characters (regardless of point size or
- typeface) are aligned with reference to an imaginary horizontal
- reference line, called the "baseline", which is essentially the location
- of the bottoms of most characters of the alphabet, excluding lowercase
- g, j, p, q and y and (in some fonts) uppercase J, which have
- "descenders" projecting below the baseline. To produce some special
- effects, it is necessary to change the level of the baseline. EXAMPLE:
- printing superscripts or subscripts.
-
- <BUd> Move Baseline Up distance d
-
- <BDd> Move Baseline Down distance d
-
- <BMd> Move Baseline distance d (+ is up, - is down)
-
- <BJd> Jump Baseline distance d (Next character only; + is up)
-
- NOTE: These baseline movement tags are primarily intended to make
- TEMPORARY changes of baseline within a single line of print, and the
- original baseline should normally be restored before the line ends. If
- youy wish to make a permanent change of baseline, i.e. one that will
- affect all subsequent lines, you should specify the desired downward (or
- upward) baseline movement by the use of a "Quad" tag with a distance
- value specified. For example, the tag <QL2in> will end, left-justify and
- print the current line, then move the baseline down 2 inches. (A
- negative value, for example <QL-1.5in>, specifies upward movement.) See
- Section 4.1.
-
-
- 5.2 KERNING, TRACKING AND EXPANSION
-
- Kerning refers to reductions in the spaces between certain pairs of
- letters, as compared with geometrically equal spacing, normally for the
- purpose of producing the visual appearance of even, uniform
- letterspacing.
-
- <Kd> Kern surrounding character pair d kerning units (54ths of an em)
-
- <Track=d> Reduce all letter & word spaces by d dots (300ths of an inch)
-
- <Expand=d> Expand all letter & word spaces by d dots (300ths of an inch)
-
- 5.3 DIPHTHONGS
-
- A diphthong is a pair of letters written as a single character (zero
- space between the letters) and pronounced in a specific manner. The
- diphthongs most commonly encountered in English-language text are "ae"
- and "oe", both usually pronounced "ee". They are found in some names or
- words of Latin or Greek origin, such as the names of classical
- characters like "Aesop", and arcane scientific words, such as
- "coelacanth".
-
- A diphthong may be produced by kerning the two letters by a suitable
- amount, normally 1/6th of an em, that is, 9 kerning units. For uppercase
- diphthongs, more kerning may be needed. EXAMPLES: "A<K15>Esop",
- "co<K9>elacanth".
-
- [NOTE: The Rubicon soft fonts supplied with the
- Commercial/Registered Edition of the Publisher contain these
- dipthongs in the "Pi font". They are also found in the Adobe
- PostScript and Hewlett-Packard Pi fonts.]
-
- 5.4 LIGATURES
-
- A "ligature" is a single unit or symbol representing two or more
- characters. In English, there are only five ligatures in common use, for
- the letter combinations ff, fi, fl, ffi and ffl.
-
- The ff, fl and ffl ligatures may be approximated by kerning the letters
- by a suitable amount, normally 1/6th of an em, that is, 9 kerning units:
- f<K9>f, f<K9>l, f<K9>f<K9>l. This method is less successful with the
- "fi" combination, since the dot over the "i" tends to interfere with the
- top of the "f".
-
- [NOTE: The Rubicon soft fonts supplied with the
- Commercial/Registered Edition of the Publisher contain these
- ligatures in the "Pi font", and many other commercial Pi fonts
- include some or all of them.]
-