Re: LYNX-DEV scrollok and lynx_force_repaint

[Klaus Weide]

On Thu, 6 Nov 1997, Nelson Henry Eric wrote:

> The entry to that thread is:
>       "http://www.flora.org/lynx-dev/html/month1097/msg00063.html";, but
> again, I was asking John for information only to help me try to get a better
> grasp of the `problem'.  Using exactly the same Lynx source and Slang library,
> I get four variations, Sun-Screen, Sun-prompt, Solaris-Screen, Solaris-prompt.
> I _think_ the Sun machine uses termcap, and the Solaris machine, terminfo.

I looked at the page you gave in that message again.  I dont have Japanese
display, but I think I could reproduce in what screen positions the
effects you have described occur.

It seems this problem is only with double-byte text.  When the box pops
up, its left margin border character will cover the second half of
Japanese characters; and the right margin may overlay the first half of
other characters.  So you probably end up with a screen having invalid
double-byte combinations that don't mean any displayable character to
your system..  I am surprised the effect isn't more disastrous than just
the shifting you get.

I don't know a solution for this (if this is indeed the reason).  The
double-byte characters can start on even or odd character positions,
so shifting the popup box by one position to avoid partial overwriting
isn't in general possible.  If the display library (slang or ncurses)
were more Kanji-savvy, it could blank out the other half of partially
overwritten characters.  But for this, it would have to keep track of
where each character starts, or analyze all lines of the screen image
that may be covered by the popup box from the start.  I don't know
what the "Kanji support" in slang actually does, but I suppose that's
not part of it.

I could also be wrong and not understand very well how this Kanji thing
works at all.

   Klaus

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