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4.4.3 Defining the space and column
Beforeyou useprint positioningcommands,you firstmay want tochange the
definitions of the line or space (sometimes called “vertical and horizontal
motionindexes”, VMI and HMI). These definitions don’t actually move the
print position. Instead, they define two basic units you can use in print
position commands.
What’simportant about the space is that itdefines how far the print position
travelsfor every character you print (except for proportionally spaced text).
The spacecan also be thought ofas the width of avertical print column. One
columnwidth is thewidth of thespace characterin thecurrent font, nomatter
whether it ismonospaced or proportionally spaced.
Occasionally you may want to change space width to override the current
pitch setting. Let’s look at an example. The space width comes in units of
l/120thof an inch,and the Courierfont canprint 10characters per inch.Each
character covers atenth —12/120ths—of an inch, so that font’s default
space width is 12units. If we change its space width to 6, each character
would half-overlap the one before it.
If you are using <S1>and <SO> to shift between aprimary and secondary
font, it’sagood idea to change the space width after every shift.
To change the space width you send this command:
,<ESC>&k nH
inwhich for nyou can enter anumber from O(zero) to 840. Awidth of Owill
print characters on top of each other; awidth of 840 will print them seven
inches apart.
4.4.5 Defining line depth
The linedep[h(sometimes called the “vertical motion index”) specifies how
fardown apage theprint positionwill movefor eachline feed.You probably
won’t usethe line depth as much as lines-per-inch. Line depth can be more
precisebut it isn’t as easy to calculate. The line depth comes in multiples of
l/48th of an inch.
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