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From: adb@cs.bu.edu (Adam Bryant)
Newsgroups: comp.unix.programmer
Subject: Re: Can CURSES do a simple scroll?
Message-ID: <ADB.90Sep12121809@cs.bu.edu>
Date: 12 Sep 90 16:18:09 GMT
References: <1990Sep12.051641.11113@rodan.acs.syr.edu>
Sender: news@bu.edu.bu.edu
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Organization: Boston University
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In-reply-to: nicktrou@rodan.acs.syr.edu's message of 12 Sep 90 05:16:41 GMT

In article <1990Sep12.051641.11113@rodan.acs.syr.edu> nicktrou@rodan.acs.syr.edu (Nikos B. Troullinos) writes:
+
+  Path: bu.edu!rpi!uupsi!rodan.acs.syr.edu!nicktrou
+  From: nicktrou@rodan.acs.syr.edu (Nikos B. Troullinos)
+  Newsgroups: comp.unix.programmer
+  Keywords: curses
+  Date: 12 Sep 90 05:16:41 GMT
+  Organization: Syracuse University, Syracuse, NY
+  Lines: 49
+
+  I am trying to use CURSES in a program where decent scrolling off the 
+  screen is required when the cursor is in the last line and a newline
+  is echoed (how unusual!)
+
+   void main()
+   {
+   int c;
+
+     initscr();
+     cbreak();
+     noecho();
+     nl(); 
+     idlok(stdscr, TRUE);
+     scrollok(stdscr, TRUE);  
+     refresh();
+
+     while ((c=getch()) != EOT) 
+     {addch(c);refresh();}
+      refresh();
+     endwin();
+  }

Try changing the line:

      {addch(c); refresh(); }

to
      {
        if ((c == '\n') || (c == '\r'))
          scroll(stdscr);
        else
          addch(c);
        refresh();
      }

I have only made a little use of the scrolling functionality of curses
myself, and have found that it often makes mistakes, such as when you
scroll up a line that has the same characters on the line about, it
forgets to redraw those characters during the scroll.

[I get around that by redrawing the entire screen all over again in
 memory and then issuing a refresh().  The way to do that is to use:

   move(0, 0);
   clrtobot();

in place of 'clear()'.  Only use 'clear()' when you absolutely know
that the screen will be greatly changed, since this tremendously
increased display speed]

Hope this correctly answers your question.

adam
ps.  Now, if only curses would implement backward scrolling, my built
in pager would be really efficient.
--
Adam Bryant                               INTERNET: adb@cs.bu.edu
Conquer Hack'n'Slasher                    BITNET:   adb@buenga
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