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SCROLL()
Scroll a screen region up or down, right or left
------------------------------------------------------------------------------
Syntax
SCROLL([<nTop>], [<nLeft>],[<nBottom>], [<nRight>],
[<nVert>] [<nHoriz>]) --> NIL
Arguments
<nTop>, <nLeft>, <nBottom>, and <nRight> define the
scroll region coordinates. Row and column values can range from 0, 0 to
MAXROW(), MAXCOL(). If you do not specify coordinate arguments, the
dimensions of the visible display are used.
<nVert> defines the number of rows to scroll vertically. A positive
value scrolls up the specified number of rows. A negative value scrolls
down the specified number of rows. A value of zero disables vertical
scrolling. If <nVert> is not specified, zero is assumed.
<nHoriz> defines the number of rows to scroll horizontally. A
positive value scrolls left the specified number of columns. A negative
value scrolls right the specified number of columns. A value of zero
disables horizontal scrolling. If <nHoriz> is not specified, zero is
assumed.
If you supply neither the <nVert> nor <nHoriz> parameters to SCROLL(),
the area specified by the first four parameters will be blanked.
Warning! Horizontal scrolling is not supported on all of the
alternate terminal drivers (i.e., ANSITERM, NOVTERM, PCBIOS).
Returns
SCROLL() always returns NIL.
Description
SCROLL() is a screen function that scrolls a screen region up or down a
specified number of rows. When a screen scrolls up, the first line of
the region is erased, all other lines are moved up, and a blank line is
displayed in the current standard color on the bottom line of the
specified region. If the region scrolls down, the operation is
reversed. If the screen region is scrolled more than one line, this
process is repeated.
SCROLL() is used primarily to display status information into a defined
screen region. Each time a new message is displayed, the screen region
scrolls up one line and a new line displays at the bottom.
Examples
. This user-defined function displays a message string at the
bottom of a screen region after scrolling the region up one line:
FUNCTION ScrollUp( nTop, nLeft, nBottom, nRight, ;
expDisplay )
//
SCROLL(nTop, nLeft, nBottom, nRight, 1)
@ nBottom, nLeft SAY expDisplay
//
RETURN NIL
Files Library is CLIPPER.LIB.
See Also:
@...BOX
@...CLEAR
@...TO
CLEAR SCREEN
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