2B4
User's
Handbook
to the Atari 400/800 Computers
command
specifies the type
of
XIO
command
to
be executed.
The
XIO
commands are listed in Table 5-4.
Thecommand
for
XIO
fill
area
is
18.
The channe/# specified must be
opened
for
input
or
output.
In graphics, channel 6
is
used.
numexpl
and
numexp
2
are given
dummy
values
(0)
unless XIO
is
used in
conjunction
with
an
RS
-2
32
operation
or
to
open a channel. device refers
to
the
input
or
output
device used with
the
XIO command. The
device specified
for
XIO when used
as
a fill area command in
graphics
will
be "S:".
The
following
example illustrates the
use
of
the XIO command
to
fill
an
area in graphics.
XIO
Example Program
100
GRAPHICS 5
200
COLOR 1
300
PLOT
50
,2
0
400
DRAWTO
50
,
10
500
DRAWTO
10
,
10
600
POSITION
20,20
700
POKE
765,1
800
XIO
18
,#6,
0,0,"S:"
The
following
steps must be
followed
in
the
order
specified in
order
to
fill
an
area on the graphics display.
1.
PLOT the
point
at
the
bottom
right-hand
corner
of
the
figure
to
be filled. (Reference line
300
in
the
XIO Example
Program).
2. Execute a DRAWTO
to
the
upper
right-hand corner
of
the
figure. (Reference
line
400
in the
XIO
Example Program).
3.
Execute a DRAWTO to the
upper
left-hand
corner
of
the
figure (Reference
line
500
in the XIO Example Program).
4. Execute a POSITION statement
to
move the cursor
to
the
lower
left-hand
corner
of
the figure (Reference
line
600
in
XIO Example Program).
To Next Page
Loading...
