Graphics
Programming Considerations
When SCALED
or
SCL
401 4 mode is selected
via
the
Terminal Configuration
menu,
applying
power to
the
terminal
or
executinga
hard
reset
turns
on
the
graphics
cursor
and
positions
it
in
the
upper
left-hand
corner
of
the
screendisplay,
emulating
the
4014 function. When4014 mode
is
selected programmatically,
the
state
of
the
cursor
and
pen
is
not
changed.
8-BIT
MODE.
Characters
sent
to
the
terminal
in
4014 mode
have
their
parity
bit
cleared
automatically.
Thus
the
ROMAN extension
character
set
is
not
accessible
in
8-Bit
and
Tektronix-modes. 7-bit
mute
processing
retains
its
normal function.
GRAPHICS STATUS
You
can
request
graphics
status
information
in
addition to
normal
terminal
status
data.
All
graphics
status
requests
are
initiated
by sending
an
Ec * 5 followed by a single
parameter
(1
through
1
2)
and
terminated
by a .
The
single
parameter
selects
the
desired
status
block.
If
an
invalid
parameter
is
used,
the
terminal
responds
with
its
ID (see Device ID Request,
parame-
ter=l).
Graphics
Status
request: Ec * 5
<parameter>
"
where
Ec * 5
is
the
graphics
status
escape sequence.
<parameter>
is
1-12
and
selects one of twelve blocks of graphics
status
data.
The graphics
status
blocks
that
can
be requested
are
listed
in
Table D-15
together
with
the
format of
their
terminal's
response. Detailed descriptions ofeach
status
request
are
found
in
the
following
paragraphs.
The
terminal
responds
with
one or more bytes of
status
information followed by a block
terminator.All
status
information is'inASCII format,
with
commas
as
separators.
Coordinates
are
returned
in
a fixed
format
consisting of a sign
and
five digits.
Leading
zeros
are
used
as
required
to provide a fixed
number
ofdigits (ie +00100,
-01234).
This
allowsyou to
use
simple
input
statements
without
needing
to
mask
or
shift
bits.
If
DC1
handshake
protocol
is
enabled
(ie,
ttNO"
is
entered
in
the
ttInhHndShk(G)"
and
tt
InhDC2
(H)"
fields
of
the
Terminal
Configuration menu),
the
status
block is
not
actually
sent
until
receipt
of
a DC1 character.
If
the
DC1
character
is used, only one
graphics
status
request
can
be enabled while
the
terminal
is
waiting
for a DC1. When
the
DC1
is
received,
the
last
graphics
status
block
requested
is
sent
to
the
terminal.
While
the
terminal
is
waiting
for
the
DC1,
the
Device
Status
Pending
bit
is set.
D-53
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