SCROLLER(<N top row>, <N left col>, <N bottom row>, <N right col>, <N lines>, <C "up" or "down">)
 Scrolls within a specified area on the screen, or clears a window quickly.

 <lines> is the number of lines to scroll (0 clears the entire window)
 "U" or "u" = scroll up, "D" or "d" = scroll down.

 Zero <lines> clears the entire specified area, and other values "scroll"
 the screen to provide you with blank lines on which you may display the
 appropriate "next" entry or entries.

 The scrolling color attribute is determined by the current
 cursor position when SCROLLER() is called.

 * Example window displays eight records, and assumes there
 * are always at least eight records in the database file.
 * Scrolling is one record at a time.

 * Set up parameters.
 num_lines = 8       && number of lines in window
 t_row =  7          && top row of window
 b_row = 14          && bottom row of window
 l_col = 30          && left column of window
 r_col = 50          && right column of window
 direction = "D"     && initial direction to scroll is down

 * Open file.
 USE Datafile        && can be indexed or not

 * Paint window full of records.
 i = 1
 DO WHILE i <= num_lines .AND. .NOT. EOF()
    @ (t_row-1)+i, l_col SAY Field
    SKIP
    i = i+1
 ENDDO

 * Position pointer at first record.
 GO TOP

 * Loop for window display according to user keypress.
 DO WHILE .T.
    key  = INKEY()
    DO CASE
       CASE key = 18 .AND. .NOT. BOF()   && PgUp
          IF direction = "D"
             SKIP -1
             IF BOF()
                * Still at record one, no skip necessary.
                LOOP
             ENDIF
          ELSE
             SKIP -num_lines
          ENDIF
          direction = "D"
          row = t_row
       CASE key =  3 .AND. .NOT. EOF()   && PgDn
          IF direction = "U"
             SKIP 1
             IF EOF()
                SKIP -1    && recovery from EOF (not necessary with BOF)
                LOOP
             ENDIF
          ELSE
             SKIP num_lines
          ENDIF
          direction = "U"  && move down = scroll up
          row = b_row
       CASE key = 27       && Escape key to exit
          USE              && close files when done
          RETURN
       OTHERWISE
          LOOP
    ENDCASE

    * Scroll and repaint.
    SCROLLER( t_row, l_col, b_row, r_col, 1, direction )
    @ row, l_col SAY Field
 ENDDO


             Placed in the Public Domain by Tom Rettig Assoc.