Review Request: Improve Style KCM loading time by delaying the Desktop (Plasma) Themes load

[Ben Cooksley]

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Ship it!


Excellent, solves bug #222745

- Ben


On 2010-03-20 13:16:11, Darío Andrés wrote:
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> (Updated 2010-03-20 13:16:11)
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> 
> Review request for kdelibs and Plasma.
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> Summary
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> Currently the Style KCM takes a few seconds to be started because it loads (from start, and twice) the Workspace (Plasma Themes)
> As I sometimes want to only change the Application Widget Style, this load doesn't seem necessary and it consumes time. (it also causes a delay when loading "Appearance" on SystemSettings)
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> In order to avoid that I propose to load the desktop themes only after the "Workspace" tab is clicked.
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> I have tested different approaches to not block the UI, but they don't seem to be nice code.
> So, the GUI will be blocked for a while, but as we are using QTimer::singleShot(100, ..., loadDesktopTheme), the GUI will be draw a first time, and then the themes will be loaded.
> To improve the situation a bit more, I also set the cursor to "waiting" until the themes are loaded and appear on the list
> (I was wondering if we could add a label or something saying "Loading themes" .. or if the whole situation is self-explanatory (busy cursor))
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> I also removed a call which loaded the themes when ThemeModel was created, because that will cause the themes to be loaded twice (taking 1.5~2x time)
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> [[In our future plans we wanted to split the Workspace theme to its own KCM, but until we do this (and if we ever do it), this seems like a nice improvement]]
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> Diffs
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>   svn://anonsvn.kde.org/home/kde/trunk/KDE/kdebase/workspace/kcontrol/style/kcmstyle.h 1105269 
>   svn://anonsvn.kde.org/home/kde/trunk/KDE/kdebase/workspace/kcontrol/style/kcmstyle.cpp 1105269 
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> Diff: http://reviewboard.kde.org/r/3322/diff
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> Testing
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> No regressions so far
> The overall KCM startup time decreased a lot
> The blocked UI doesn't seem "blocked" as it is properly drawn a first time, and the busy cursor is shown
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> Was there an alternative to "QTimer::singleShot" just to perform a queued slot call ?
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> Thanks,
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> Darío
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