Re: Layered display API

[Bo Lin <bo@dreamsphere.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Bo Lin <bo@dreamsphere.org>
>> Cc: rudalics@gmx.at,  emacs-devel@gnu.org,  dgutov@yandex.ru
>> Date: Thu, 14 Aug 2014 12:08:20 -0400
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> >> > What I meant is this: if you need to display below the last line of
>> >> >> > the buffer text, put the overlay at EOB, and include newlines in the
>> >> >> > overlay string when you need to move to the next screen line.  To
>> >> >> > align text horizontally you could use spaces or align-to display
>> >> >> > properties in the string.
>> >> >> 
>> >> >> Yes, I might try this, as soon as there's some suggestion how to handle 
>> >> >> the problem of `line-prefix' in this multi-overlay approach.
>> >> >
>> >> > Find the longest prefix and align everything so that the left edge
>> >> > keeps clear of that?
>> >> 
>> >> Zero length overlays don't get displayed so this won't work when the
>> >> buffer is empty.
>> >
>> > When a buffer is empty, there are no line prefixes, right?  Or did I
>> > misunderstand what you eman?
>> 
>> I thought this was about avoid padding the buffer text with
>> newlines?
>
> Sorry, it wasn't clear, as the previous citations talked about both.
>
> So turning to the padding the buffer: it's not about padding with
> newlines, it's about including newlines in overlay string.  After the
> newline, the overlay string would have the text to be displayed beyond
> the EOB.

Ah, I just realized the 'before/after-string properties does get
displayed even on zero length overlays. So yeah, this does work,
sorry for noise.

-Bo