Graphics
Type and run the following program; be especially careful to
include all semicolons. The program produces the printout you see
below.
10
WIDTH"LPT1:".255
20
LPRINTCIiR$(27):"*":CHR$(O):CHR$(4O):CRR$(0);
30
FOR
Xtl
TO
40
40
LPRINTCHR$(170):
50
NEXT
X
:.-
--“..-
Line
20
specifies single-density graphics mode and also reserves
40
columns for graphics. Line
30
begins a loop to supply
40
bytes of
data. Line
40
contains the number
170,
which produces the first pin
pattern shown in the section on pin labels, and line
50
finishes the
loop.
Note: Some software programs (including most versions of
BASIC) automatically insert carriage return and line feed codes
after every
80
or
130
characters. This is usually no problem with
text, but it can spoil your graphics. Two extra-cohnnns of
graphics are printed in the middle of the ones you send, and two
data numbers are left over and printed as text.
In some versions of BASIC, you can prevent unwanted
,co$rol
codes in graphics by putting a WIDTH statement ‘at thebeginning
of all graphics programs. The format in many BASK versions is
either WIDTH
ZPTl:“,
255
or
WIDTH
LPRINT
255.
Check your
software manual for the proper format.
Software and Graphics
4-15
