The ESCape”A”CHR$(n command sets the line spacing to n/72-
)
inch if the n is any number from 0 through 85. If n is between 85 and
128, the line spacing is 85/72-inch. At 128 the sequence starts again,
with 128 giving the same result as 0, 129 the same as 1, and so on.
Therefore, the X+128 in line 30 produces a change in line spacing
from 0 to 24/72-inch.
In summary, ESCape “A ” CHR$( n) selects line spacing in 72nds of a
inch, where:
n= 0-
85
line
spacing
=
0 - 85/72-inch
85 - 127
85/72-inch
128 -
213 0 - 85/72-inch
214 -
255
85 /72-inch
Since the ESCape “A” sequence lets you specify any 72nd of an inch
(from 0 - 85) and since each dot of a dot matrix fills l/72-inch, you can
use this command instead of the preset commands that we covered
above. You can set U-dot line spacing either by specifying 12 to the
“A” sequence or by using the preset command:
CHR!$(27)“A”CHR$(12) or CHR!$(27)“2”
Notice the position of the ESCape “A” sequence in line 30-right
between the strings STAIR and STEPS. We placed it there to demon-
strate that the FX doesn’t execute the line-feed command until the end
of the print line. Otherwise it would print the two strings on different
lines.
Also notice that the lowest valid line spacing is zero dots. You can
use this when you want to make multiple overstrikes on one line. To
see an example, make these changes to your program:
20
FOR X=0 TO 4
30 LPRINT TAB(6*X)"STAIR"CHR$(27)"A"CHR$(0)
STEPS"
The reason for emphasizing 72nds of an inch is that the distance
between the centers of any two pins on the print head is l/72-inch. So
these line spacing commands are simply telling the printer just how
many dots to space between the lines.
97
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