Re: LYNX-DEV ac-0.24 and clearok

[Klaus Weide]

On Sat, 17 May 1997, Foteos Macrides wrote:

> "John E. Davis" <address@hidden> wrote:
> >   According to the curses man page, clearok is to be used when the
> >status of the display is unknown and it will cause the screen to be
> >completely redrawn upon refresh.  

Since you mention the man page.. . the one for clear() says

       The erase and werase routines copy blanks to  every  posi-
       tion in the window, clearing the screen.

       The  clear  and wclear routines are like erase and werase,
       but they also call clearok, so that the screen is  cleared
                                                          ^^^^^^^
       completely  on  the  next call to wrefresh for that window
       ^^^^^^^^^^
       and repainted from scratch.

Your recent change for slang-lynx's clear() already makes it behave
quite differently.  Does that make sense?  If it does something different
from what a read clear() does, it probably should have a different name.
It would be better to look at all the occurences of clear() (not *that*
many) and replace them with erase() if appropriate, right?  That would
then avoid unnecessary refreshes not only for slang users, but also
(n)curses users.

> >Unfortunately, this is happening in
> >situations where I see no reason for it and its use is defeating the
> >screen management optimization routines.  [...]
> 
>       That change would again make clearok(curscr, TRUE) disfunctional
> with slang.  I'm not sure what you mean by "if the display is properly
> managed".  Things can be written to the screen which slang didn't write,
> and thus doesn't know about.  If you make clearok(curscr, TRUE)
> disfunctional again, you won't be able to get rid of them.

That "quick fix" isn't really a fix, but probably proof that many of the
clearok's are unnecessary - as long as nothing goes wrong and as long as
nothing else is writing to the terminal.

So maybe those clearok's should be
1) removed completely, or
2) not used if USE_SLANG, or
3) (some) only uses if enable_scrollback is set?

   Klaus

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