Systems Reference Library IBM 1130/1800 Plotter Subroutines

Y
number s of inches per user's unit to be used along
the
i
Y axis.
Xs
specifies 0 a the X value of the present position of the
pen ir
relat iv e to the desired origin, meas ured in the
user's s units.
e
a
Y
specifies sl
o the Y value of the present position of the
pen ici
relat iv e to the desired origin, meas ured in
the
go
s user's units.
n
a
e s
ASSEMBLER
d ti
rag
Standard
e n precision:
at
e
CALL S C A L F
l od
DC A
c r
DC
ov
e
DC
n a
DC
sr
l
tic
Extended precision:
a
o
nb
n
CALL S C A L E
t ls
DC A
oe
tDC
r ta
DC
vh
nDC
a
t
A, rt
oB
, C, and D are the addresses of constants or
idr
variables whose values correspond to X
ae
v
sand
Y
bf
a
,
calls. o Y
lir
s,
Fo r the standard precision c alling sequence,
e ni
, reach e Xconstant
or variable designated by A, B , C,
tea
os
and p D must be two words. T h i s is accomplished
hs
b
, ebest c by using the DEC statement. F o r extended
tprecision, iat l
v eac h constant or variable must be t hree
words. e the
l T h i s is accomplished best by using the
X FL
y et
C statement.
,
a
h
s
a
d
t
GRID e
s
cThe
grid subroutine plots a s t raight line parallel
rto
eit her the X or the Y axis in a positive o r a
inegative
direc t ion with tick marks at regularly
bspaced
intervals. T h e tick marks are 0.10 inch
elong,
wit h one half of the mark on each side of, and
d perpendicular to, t he grid line. T h e programmer
i
n
t
h
e
4
F
O
R
must specify the starting point, t he direction to be
plotted, how f ar to go, and the distance between
tick marks.
It is not required to know eit her the location of
the pen or whether it is up or down when this subroutine
is called. A t the end of the subroutine, t he
pen is lef t in the up position.
— 2 /
Starting
Point 1 1
FORTRAN
Standard precision:
Tick Marks
CA L L F G R I D (I, X, Y, U, N)
Extended precision:
CA L L E G R I D (I, X, Y, U, N)
I is an integer constant or v ariable that specifies
the direc t ion the grid line is to be generated, as
follows:
I = 0 specifies the +X direction
I = 1 specifies the +Y direction
I - 2 specifies the - X direction
I = 3 specifies the - Y direction
Only the last two bits of I are used to det ermine
the direction; therefore, us e of larger numbers
would repeat the instructions. F o r example,
24 or 4 plot the same as 0 (+X direction).
X is a signed real constant or v ariable that
specifies the X value of the grid line starting point,
measured in the us er's units.
Y is a signed real constant or variable that
specifies the Y value of the grid line starting point,
measured in the user's units.
U is a real constant or variable that specifies
the distance between tick marks, measured in the
user's units.
N is an integer constant or v ariable that defines
the length of the gr i d line. N is equal to the number
of tick marks minus one, and must be less than
32768.