[Okular-devel] Dt. 6th August - status

[Albert Astals Cid]

El Dijous, 8 d'agost de 2013, a les 00:37:42, Jaydeep Solanki va escriure:
> I tried a lot of approaches for TextDocument threading and finally I
> settled to a really simple approach (as it makes generator threaded as well
> as gives best performance), diff attached.
> I just want to ask, how to know when the document is closed and delete that
> pointer, because now if I close a document and open another document images
> displayed are of the previous document.

How does this fix the incorrect loadResource being called?

Cheers,
  Albert

> 
> On Wed, Aug 7, 2013 at 6:11 AM, Fabio D'Urso <fabiodurso at hotmail.it> wrote:
> > Hi,
> > 
> > On Wednesday, August 07, 2013 12:31:41 AM Albert Astals Cid wrote:
> > > El Dimarts, 6 d'agost de 2013, a les 20:52:25, Jaydeep Solanki va
> > 
> > escriure:
> > > > Hi,
> > > > 
> > > > I have implemented a simple Qt Visibility support, which hides text,
> > 
> > it's
> > 
> > > > doesn't hide the exact area of the text, because the way QTextDocument
> > 
> > is
> > 
> > > > developed it is impossible to implement an approach that hides only a
> > 
> > part
> > 
> > > > of line. Either we can hide a line or not hide it.
> > > > And implementing an approach in which incrementing the cursor and not
> > > > inserting the text was my idea, but it seems they are using the text
> > > > so
> > > > much that, I'm not able to get a way to exclude the text and implement
> > > > visibility.
> > > 
> > > Before continuing to work on that, i think you should explore with the
> > > Qt
> > > guys how feasible is this work to be accepted upstream with the known
> > > limitations you mention, because if it's not going to be accepted, it's
> > 
> > not
> > 
> > > really useful for us since we can't expect people to patch their Qt for
> > 
> > us.
> > 
> > > > Regarding the threaded QTextDocument, I tried the approach you said,
> > 
> > and
> > 
> > > > it
> > > > seems that it is also blocking UI, even more then single threaded.
> > 
> > Suppose
> > 
> > > > I'm on a page and the next page is loading in other thread, the UI
> > 
> > thread
> > 
> > > > will have to wait till the other thread finishes it's job (because of
> > > > locking), which takes a bit more time than usual because it is
> > 
> > generated
> > 
> > > > from a cloned QTextDocument.
> > > 
> > > Why would the UI thread have to wait?
> > 
> > Disclaimer: I haven't read the whole discussion, so this idea might not be
> > applicable. If I understood correctly, there's some object that needs to
> > be
> > cloned because its methods are not reentrant, but cloning is expensive.
> > 
> > I was thinking about keeping a pool of clones, initially containing only
> > one
> > instance, and adding a new clone to the pool when an instance is requested
> > and
> > there are no readily available ones.
> > 
> > Of course this approach, if feasible at all, will waste memory. Depending
> > on
> > the size of the object it might pay or not.
> > 
> > > > Regarding the clone method overriding in EpubDocument, I'm using a
> > 
> > dynamic
> > 
> > > > property, to store the name of the generator, and using it I decide
> > 
> > which
> > 
> > > > method to call EpubDocument::myClone() or QTextDocument::clone() in
> > > > TextDocumentGenerator.
> > > 
> > > You can't call EpubDocument::myClone in TextDocumentGenerator, that
> > > introduces a circular dependency.
> > > 
> > > > One more thing I noticed about Okular is it doesn't free up memory,
> > 
> > after
> > 
> > > > the document is closed, it frees after Okular quits, so my question is
> > > > does
> > > > it use the memory (cached pixmaps) when I load the same document again
> > 
> > ?
> > 
> > > Nope, it should free it, if it doesn't it's a bug that has to be fixed.
> > 
> > I remember reading somewhere that most free() implementations don't
> > actually
> > return the memory back to the OS, instead they keep free'd blocks in a
> > internal pool for future reuse. Eventually, when the process dies, all of
> > its
> > memory is reclaimed back by the OS.
> > 
> > As Albert said, Okular does "free" pixmaps, but maybe you see that
> > behavior
> > for this reason.
> 
> Makes sense.
> 
> > > Cheers,
> > > 
> > >   Albert
> > >   
> > > > Cheers,
> > > > Jaydeep
> > > 
> > > _______________________________________________
> > > Okular-devel mailing list
> > > Okular-devel at kde.org
> > > https://mail.kde.org/mailman/listinfo/okular-devel
> > 
> > --
> > Fabio
> > 
> > _______________________________________________
> > Okular-devel mailing list
> > Okular-devel at kde.org
> > https://mail.kde.org/mailman/listinfo/okular-devel