Background for login, splash, and lockscreen

[Jens Reuterberg]

(Im really really tired - please let me rephrase)

Ok so you have the default blurred wallpaper for the login, based on the 
default wallpaper. 
But then you pick a new wallpaper, and instead of having it get blurred during 
login (which would make it really heavy and annoying) the wallpaper picker 
blurs at the time of choosing, saving it (and the default one) in some folder 
to be used as background for the login. 
When you pick a new wallpaper the picker deletes the current one and replaces 
it with the blurred image of your current choice. The PNG of the blurred 
wallpaper can even be smaller in resolution (to save on space I guess) since, 
using gaussian blur removes all detail anyway and the resolution becomes 
almost meaningless.

(Granted I know close to nothing about the subject - just wondering why that 
wouldn't work)

On Monday 23 June 2014 08.42.27 Jens Reuterberg wrote:
> Ok so I have to ask (because my mum once told me as a child, slow people ask
> a lot of questions - but only complete idiots don't) :)
> 
> Place be nice.
> 
> Wouldn't it be possible to have the wallpaper picker pick the login
> wallpaper as well? I mean say I choose a wallpaper with a photo of a dog or
> something - can't the wallpaper picker, blur it with gaussian blur at the
> time of picking, saving it in a special folder and at the same time
> deleting the past blurred wallpaper?
> 
> So that when you log in you have your current wallpaper, blured as
> background?
> 
> /Jens
> 
> On Sunday 22 June 2014 20.57.11 Martin Graesslin wrote:
> > On Saturday 21 June 2014 16:18:10 Kai Uwe Broulik wrote:
> > > Can't we just use QtGraphicalEffects and just blur (and/or desaturate
> > > and/or darken) whatever picture the user has chosen?
> > > 
> > > The overall performance of these is great (at least on Android which is
> > > slow in any other QtQuick respect) but their instantiation takes ages,
> > > so
> > > might not be suitable for lockscreen which needs to start quickly or
> > > splash which shouldn't unnecessarily delay startup.
> > > 
> > > So, umm, while writing this I figured it's not that good of an idea as I
> > > initially thought :-)
> > 
> > so you suggest that on millions of devices we blur the window fullscreen
> > every time the user logs in (lots of more important stuff to do) and locks
> > the screen? Compared to preparing it once and just installing it? That
> > sounds like a very bad memory-time tradeoff [1].
> > 
> > Cheers
> > Martin
> > 
> > [1] https://en.wikipedia.org/wiki/Time-memory_tradeoff
> 
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