Re: [Bug-AUCTeX] Re: preview oddity when "merging" inline formulas...

[David Kastrup]

Evil Boris <address@hidden> writes:

> David Kastrup <address@hidden> writes:
>
>> Evil Boris <address@hidden> writes:
>
>>>    and this depends on $x$ and $y$ MORE TEXT MORE TEXT MORE TEXT
>>>    MORE TEXT MORE TEXT MORE TEXT MORE TEXT MORE TEXT
>
>>> [...]
>
>>>    and this depends on $x, y$ MORE TEXT MORE TEXT MORE TEXT MORE
>>>    TEXT MORE TEXT MORE TEXT MORE TEXT MORE TEXT
>
>>> with the cursor someplace around the comma.  Notice that there are
>>> two preview-generated pictures around [can't really tell what they
>>> are supposed to represent, too small for my eye sight], which is
>>> annoying but understandable.  If I type C-c C-p C-p now,
>>> everything after the $x,y$ disappears from the display!  Very
>>> disconcerting, especially the first time it happens.  C-c C-p C-d
>>> makes everything peachy again.
>
>> "Merging" previews is not really a sensible operation.  What you
>> end up with is regenerating the only one, crippled preview.  The
>> results are that the math environment is incomplete, and TeX looks
>> beyond the actually cut region for fixing it.
>
> I do not know if I explained myself properly.  What I do is have
> "$x$ and $y$" in my text, previewing fine.  Then I edit it to say
> "$x,y$" and try to force preview to update the picture at the point.

Yes.  But you then have _two_ modified previews, each of them starting
with a preview icon (the options you can use on those icons are shown
if you move mouse over them).

The first one is something like '$x,' and the second one something
like 'y$'.  Now if you regenerate either of those two previews, you
basically get a mess.

> At this point all hell breaks loose---all or some part of the
> containing math expression gets a proper preview image, but the rest
> of the file (and I had this experience with a 20 page paper)
> **appears** to disappear.  I thought that it was unnecessarily
> brutal for an unsuspecting user. :)

As I said: localization of errors at the edges and particularly
_beyond_ the edges of the current region is flaky right now, and those
half-previews tend to throw LaTeX for a loop at a point where
preview-latex does not expect it.

> A secondary issue is that there are those slightly annoying pictures
> attached to "opened" math expressions --- in this case the second
> one, that was attached to $y$ refuses to go away, even though it
> looks to me like I have have deleted character (namely the $ in
> front of "y") to which it seems to be attached.

Well, you can use C-c C-p C-c C-p to remove the preview, or you can
use mouse-3 on the "annoying picture" to remove it.

>> However, it might be a useful idea to regenerate butting edited
>> previews together.  Does the following patch lead to more
>> satisfactory behavior for you?
>
> Thanks.  Will take a look a bit later.  

I already checked an extended version (with a modified doc string)
into CVS.  It is probably more likely what people would expect after
editing.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum