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• If the specified cursor relative row follows the bottom
line currently visible on the screen, the cursor moves to
the specified column in the bottom row of the screen and
the text rolls upward until the specified row appears in
the. bottom line of the screen.
If you specify only
Ii
<column number)
the cursor remains
in the current row. Similarly, if you specify only a
<row
number)
the cursor remains in the current column.
Example: The following escape sequence moves the cursor
(and rolls the text if necessary) so that it is
positioned at the character residing 15 columns
to the right,and 25 rows above the current cur-
sor position within display memory:
<ESCHa+15c-25R
Combining Absolute
and Relative Addressing
You may use a combination of screen relative, absolute,
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 residing
in the 70th column of the 18th row below the
current cursor position.
<ESCHa69c+18R
Example: Move the cursor so that it is positioned at the
character residing 15 columns to the left of the
current cursor position in the 4th row currently
visible on the screen.
<ESCHa-15c3Y
Example: Move the cursor (and roll the text up or down if
necessary) so that it is positioned at the char-
acter residing in the 10th column of absolute
row 65 in display memory.
<ESC)"a9c64R
EDIT OPERATIONS
You can edit data displayed on the screen by simply
overstriking the old data. In addition, the terminal
provides the following edit functions which can be enabled
and disabled either manually by using the edit control keys
or programmatically by using escape sequences:
• Insert Line
• Delete Line
• Insert Character
• Delete Character
• Clear Display
• Clear Line
Display Control
Insert Line
When you use the insert line edit function, the text line
containing the cursor and all text lines below it roll
downward one line, a blank line is inserted in the screen
row containing the cursor, and the cursor moves to the left
margin of the blank line.
From the keyboard, each time you press the. key the
terminal inserts one blank line. If you hold the key down,
the terminal continues to insert blank lines until the key is
released.
From a program executing in a host computer, you insert a
blank line at the current cursor position using the follow-
ing escape sequence:
<ESC)L
Delete Line
When you use the delete line edit function, the text line
containing the cursor is deleted from display memory, all
text lines below it roll upward one row, and the cursor
moves to the left margin.
From the keyboard, each time you press the
III
key the
terminal deletes one line of text.
If
you hold the key down,
the terminal continues to delete text lines until the key is
released or until there are no subsequent text lines remain-
ing in display memory. In the latter case, pressing or
continuing to hold down this key has no further effect.
From a program executing in a host computer, you delete
the text line at the current cursor position using the follow-
ing escape sequence:
<ESC)M
Insert Character
When the insert character editing function is enabled,
characters entered through the keyboard or received from
the host computer are inserte4 into display memory at the
cursor position. Each time a character is inserted, the
cursor and all characters from the current cursor position
through the right margin move one column to the right.
Characters that are forced over the right margin are lost.
When the cursor reaches the right margin, it moves to the
left margin in the next lower line and the insert character
function continues from that point.
This edit function is meant to be used within that portion of
the screen delineated by the left and right margins.
If
you
position the cursor to the left of the left margin, the insert
character function works as described above.
If
you po-
sition the cursor beyond the right margin, however, the
insert character function affects those characters between
the current cursor position and the right boundary of the
screen. In such a case, when the cursor reaches the right
boundary of the screen, it moves to the left margin in the
next lower line and the insert character function continues
from that point as described in the first paragraph above.
4-5
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