Re: [Denemo-devel] Export .png is broken

[Richard Shann]

On Sat, 2011-01-08 at 08:47 -0600, Jeremiah Benham wrote:
> 
> On Jan 7, 2011, at 4:10 PM, Richard Shann <address@hidden>  
> wrote:
> 
> > On Fri, 2011-01-07 at 14:18 -0600, Jeremiah Benham wrote:
> >>
> >> I am going to use waitpid().
> >>
> > I think there is a glib version of this (so that it'll work
> > cross-platform)
> 
> Yes. That is g_child_watch_add(). I looked at the code and saw that  
> the viewer is launched when lilypond is done.
right - it let's you get on with working in Denemo while lilypond is
running. For an export I guess you would want to put up some sort of
progress dialog, refreshed at intervals, to be taken down when LilyPond
has finished.

>  If this is an export  
> then why would we need to run anything after lilypond for a png or PDF  
> except deleting the mess of files that are created in order to render  
> a png. This used to be created in the .denemo directory and moved and  
> renamed into the destination diretory.
I would guess it still is being created there - I am fairly sure I
haven't done anything in this export code.

>  The behavior I am observing on  
> my system is that it creates a lily file with a filename.png.ly kind  
> of name in the destination directory. The png is created via lilypond  
> with a name like filename.png_.png. Then denemo is trying to do  
> something else with it (I have not found this portion of the code).  
> Then I see an error message on the terminal saying that file \blah 
> \blah.png can't be found. Replace blah with hex.
this is a clear sign that the code has gone wrong - some unintended
memory is being accessed - typical is one of these g_strconcat with no
NULL at the end.

>  Is denemo still  
> trying to rename the png.
I would expect so, unless you wrote something else. (It is my fault this
is messed up, I changed to async running of LilyPond (good) but didn't
look at the export code (bad)).
Much better though than trying to do moving the file after creation
(tricky in unknown filesystems) is to create the right filename in the
first place. So I suggest you start from the call to export pdf or png
and once the user has chosen a filename pass this (with an indicator
png/pdf if needed) to some modified version of the current code -
modified to tell LilyPond to output directly to the right place and not
to call a viewer but to call the progress-indicator widget.
Richard


>  It also leaves a mess with all the temporary  
> in the destination diretory. The png is actually being produced though  
> but with an incorrect name.
> 
> Jeremiah
> 
> > Richard
> >
> >