Re: frescobaldi destination temp folder

[David Wright]

On Sat 21 Apr 2018 at 23:33:44 (-0400), Kieren MacMillan wrote:

> I'm running Frescobaldi 2.20.0 on Mac OS X 10.12.6.
> 
> 1. I open the Lilypond file(s) in Frescobaldi, and once the first PDF is 
> generated, I open that in an external PDF viewer (usually Skim; sometimes 
> Preview), because I find Frescobaldi’s built-in viewer to be of lesser 
> quality.
> 
> 2. As I recompile, the external application shows the changes (on my second 
> monitor, which is very nice to have!). If I work long enough on a file, it 
> eventually happens that the external application stops updating on 
> compilation. At that point, I can look in the log to find the temp path that 
> Frescobaldi is using, e.g.,
> 
>    Layout output to 
> `/var/folders/l3/8qtf8wts5kj93q4w13f4qdfc0000gn/T//lilypond-4TMu7P'
> 
> and open the newly-compiled PDF in that folder. Beyond that point, no amount 
> of recompiling "jump-starts" the non-temp version of the PDF.
> 
> 3. Quitting and restarting Frescobaldi always "jump-starts" the non-temp 
> version of the PDF — but after working on the file a certain 
> [indeterminate!?] period of time, the problem appears again.

I'm not a Mac user, so this is just a guess based on zero evidence.

On linux, I'm used to running LP in one xterm and viewing the PDF with
xpdf in mc in another one. I have to press r in the PDF to refresh it
(though changing page, or resizing the PDF, will have the same
refreshing effect). If I press r at the moment that LP is converting
PS→PDF, the effect can be bizarre (eg staves, stems and beams but
nothing else) because xpdf is reading a file that LP is still writing.
IOW there's no file-locking to protect the processes from each other.

Now imagine that there IS file-locking. LP would lock the PDF file
each time it revised it. If I pressed r at that time, I expect xpdf
might silently ignore the request and continue to display the old
contents.

But what if xpdf locked the PDF file each time I pressed r until it
had read the file—what would LP do if it hit a lock? One reaction
might be to write to a nonce file instead, so that it can return
control to the user (and update its graphics panel).

Just an idea; no brickbats please. I have no idea whether Macs use
file-locking here, and I don't use Frescobaldi either.

Cheers,
David.