Re: Avoiding clearing the screen

[Thomas Dickey]

On Thu, Dec 20, 2007 at 09:03:01AM +0100, Christer Enfors wrote:
> Now, my problem is that the entire screen is cleared when I press a key to 
> go up or down in the menu, which causes some terminals to flicker terribly. 
> I was expecting ncurses to only redraw a subsection of the menu - the menu 
> item that was previously selected, and the new one. That the entire screen 
> is cleared is strange to me, because I don't clear the entire screen - I 
> only clear one of my windows (which takes up the bottom fifth of the 
> screen).

> The function that causes the screen to be cleared is doupdate().
...
>  while (done == 0)
>    {
>      switch (getch()) /* User presses j or KEY_DOWN here. */

By the way, getch does a refresh, which in turn calls doupdate().

>  wclear(win); /* Clear the bottom fifth of the screen. This is the
>               * only part of the relevant code where any type of
>               * clear function is called.
>               */

Looking at the code for 'refresh', I see the problem:

    if (win->_clear) {
        win->_clear = FALSE;
        newscr->_clear = TRUE;
    }

...which is telling it that if any window does wclear(), then the working
window 'newscr' is cleared.  If you use werase() you should get the
expected result.

-- 
Thomas E. Dickey <address@hidden>
http://invisible-island.net
ftp://invisible-island.net

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