Display Control
Combining Addressing Methods
You
may
use
a combination of screen, workspace,
and
cursor-relative coordinates
within
a
single escape sequence.
Example:
Move
the
cursor (and roll
the
text
if
necessary) so
that
it
is positioned
at
the
character
in
the
70th
column of
the
18th
row below
the
current
cursor
position.
Ec&a69c+18R
Example:
Move
the
cursor
so
that
it
is positioned
at
the
character
15 columns
to
the
left
of
the
current
cursor
position
in
the
4th
row
currently
visible on
the
screen.
Ec&a-1Sc3Y
Example:
Move
the
cursor
(and roll
the
text
up or down,
if
necessary) so
that
it
is
positioned
at
the
character
in°
the
10th
column of row 65
in
the
workspace.
Ec&a9c64R
Cursor Position Sensing
The
current
cursor position can be sensed by a program
in
either
workspace-relative
or
screen-relative coordinates.
The
procedure
is
for
the
program to
send
the
appropriate
escape
sequence, followed
by
a
request
for
input
from
the
terminal
(INPUT command,
in
BASIC).
The
terminal
responds
with
the
cursor position.
WORKSPACE-RELATIVE
CURSOR
SENSING. The following example
illustrates
sens-
ing
the
cursor position,
in
workspace-relative coordinates,
when
the
cursor is
at
column 20,
row 40
in
the
workspace.
computer:
Ec
a
terminal:
Ec&a020c040R
SCREEN-RELATIVE
CURSOR
SENSING.
The
following example
illustrates
sensing
the
cursor position,
in
screen-relative coordinates.
The
cursor is
at
column 20, row 40
in
the
workspace,
but
screen row 0 begins
at
workspace row 35.
computer:
Ec
'
terminal: Ec&a020cOOSY
WINDOW
CONTROL
The
window can
be
positioned
in
the
workspace to display selected 24-row (one page) seg-
ments
of
the
workspace. Movement
is
in
row
or
page increments.
4-8
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