Commodore 16 User Manual page 38

When
you
RUN
this
program.
(he
screen
background changes
to a
lighl
blue,
and
ihe spectrum
ol
Commodore
1
6 colours
is
shown
al
each
luminance
level. You'fl
notice
Ihat
black
is
Ihe
same
al all
luminance
levels.
NOTE:
Like
most
ol
the
BASIC
graphic lerms
reviewed
in this
chapter.
COLOR
may
be
referred to as
a statement
or
command
interchangeably.
THE GRAPHIC
COMMAND
The
graphics you've seen so
tar
use
only the
keyboard
without really
taking advantage
of
your computer's
capabilities.
The BASIC
language
of your
Commodore
1
6 contains
commands
to
draw shapes and forms
through programs. To use
the graphics-related
commands
of
you'
computer,
you must
enter a
new
mode, the
GRAPHIC
mode. Graphic
mode
can be
considered the
drawing
mode,
since
all
the
drawing
commands
are
"activated".
You
can't
use these
commands
until
you
specify exactly
what
graphics
mode
you want
to use;
you
specify
which type
ot
graphics
mode
you want by
using the
GRAPHIC
command.
There
are
three different
modes:
normal
text,
high-
resolution graphic
and
multi-colour graphic
modes.
Wllh
the
GRAPHIC
command,
you can even have
part-text,
part-graphic
screens
that
'ol
you can
write
on one
pari ol Ihe
screen
and draw on
the
rest.
The
command
to enter
this
new mode
is
GRAPHIC
In
general the
GRAPHIC
command
looks
like this
GRAPHIC
mode,
clear
-*
—
this part
is
optional
Mode number
Effect
1
2
Texl
High-resolution
graphics
High-resolution
graphics
+
text
Multi-colour
graphics
Multi-colour graphics
+
text
Clwr number
Effect
1
Don't
clear
screen
Clear screen
72
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I
I
I
I
1
1
1
1
1
(
(
1
I
(
I
1 1
1
1
1
1
I
1
f '
(
1 (
(
!
1
1
I
1
'
'
!
1
'
f
1
1
1
(
1
1
I
f
i 1
To
switch from the normal graphics
(of text
mode)
to high-resolution,
just
type the
command GRAPHIC
2,1
and press HETORH
The screen
goes blank and
Ihe cursor reappears near
the
bottom
of
the
screen
Your
Commodore
1
6 screen
is
divided
into
2 separale
sections: Ihe top
for
graphics and
Ihe
bottom
live lines lor text.
It
you
don't
wanl
the
bottom
five lines
for text,
you can
use
the
command GRAPHIC
1,1,
but
you
won't
be
able
to
see
any
commands
you
type.
You
can switch
back and
forth
from
graphics
to text
using the
GRAPHIC
command
The command
GRAPHIC
switches the screen back
to text,
while
GRAPHIC
2 switches back
to
hign-res without erasing Ihe
screen
Adding
,1
after
the
command
erases the screen
There
is
another
way
to clear the high-resotulton screen.
The
command SCNCLR
erases the
screen
without
changing
the graphic
mode
Once
you
use
high-resolution graphics,
Ihe
computer
sots aside
1
0K
of
memory
for
your
high-res
screen. This memory
is
taken trom
the
BASIC
program
area.
When
you
are through using graphics, you
can
reclaim
this
memory
by using ihe
command
GRAPHIC
CLR.
HIGH RESOLUTION GRAPHICS
Your
Commodore
1
6 screen
contains 25 rows of
40
characters each.
or
1
000
total
character positions
on
the screen. Each character
is
formed
out ol single dots, with
8 rows
of
8 dots each
making
an
entire
character.
Your screen has a
total
of
320
dots
on each
row,
and 200
rows
of dots, or
64.000
dots
all together.
The
high resolution
graphics
on
your
Commodore
1
6
give you control
over every
single dol
Using normal graphics, you have
limited control over
me
Individual
dots Drawing a racing
stripe or a
playing card
is
a
nice
little
exercise,
bul
your creation
is
limited
to
using the characters
(letters,
graphic
symbols,
etc.)
on
your
computer
keyboard.
You can
slill
create
all
kinds
of
shapes and
figures but
just
a fraction of
what you could
do
if
you
could control
each
dot
by
itself
The
high resolution graphics
capability of
your
Commodore
16
lets
you do
|ust that
Resolution
73