[Development] Backporting QTextLayout Performance Improvements to Qt4

[Olivier Goffart]

On Monday 18 November 2013 11:06:57 Milian Wolff wrote:
> Hey all,
> 
> I'd like to ask again whether I could backport some performance improvements
> in QTextLayout/QTextEngine from Qt5 to Qt4.
> 
> Most notably there is https://codereview.qt-project.org/#change,34112 which
> effects us in Kate/KDE as outlined here:
> https://bugs.kde.org/show_bug.cgi?id=225228
> 
> The changeset above was merged in Qt5 and matured there, see
> https://codereview.qt-project.org/#change,34118
> 
> What I propose is to sync the current status of QTextLayout/QTextEngine from
> Qt5, put it into a patchset for Qt4 and get it into the next Qt4 release.
> 
> Would this be accepted? Or is there still a policy which forbids performance
> improvements to be merged into Qt4? Considering that the above makes the
> Kate editor practically useless for some files (freezes for multiple
> minutes), I personally see this as a bug fix anyways...

Don't forget that if you want to backport this patch, you also need at least 
to backport 

https://codereview.qt-project.org/31089
https://codereview.qt-project.org/31090
and
https://codereview.qt-project.org/34288


As a KDevelop/Kate user, i would be pleased to be able to open files with long 
lines without the current kate workaround to force a wrapping.

--
Olivier

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