New class KWidgetBlendAnimation

Matthias Kretz kretz at
Wed Feb 20 17:31:27 GMT 2008


sorry to answer only now. I had to be away for a bit.

On Saturday 09 February 2008, Rafael Fernández López wrote:
> Hi,
> When I was going to adapt KWidgetBlendAnimation to the KDE global animation
> settings I suddenly saw that it is in kdelibs.
> Nothing against this class, but there is a really important regression in
> the optimization part.
> Try to maximize the phonon kcm, and make it switch. Or just try to apply
> the patch Urs wrote for KPageWidget, and change pages on config dialogs
> with the dialog maximized => extremely slow and lots of frame loss.
> I had the same problem with previews on Open/Save dialogs, but those ones
> aren't expected to be that big, on the other hand I can maximize a dialog,
> what can be _really_ big.
> I think before shipping and using this class widespread we should think
> twice about it. My desktop at least when windows are big (not huge, just
> big) feels really, really slow.

First I'd like to note that all the animations that I ever mentioned (blog or 
here) really are smooth to my perception and on my computer. I wouldn't have 
considered them worth mentioning or even using otherwise.

Now I suspect there are
a) differences in perception
b) big differences in hardware and software (drivers)
(and for videos that I posted also issues with the screen capturing)

I have no good idea how to deal with that issue other than dumping animations 
altogether or waiting for things to magically work right for everybody.

Regarding the issue at hand:
1. I do think that Urs's original patch adds some nice eye-candy but doesn't 
add value and blends a potentially too big area.
2. For the Phonon KCM: I never actually maximized it (never occurred to me to 
make it 1400x1000 big...), but I can imagine the TreeView on the right 
getting way too big for the animation. Though OTOH it isn't too bad here as 
it just shows one blended frame and that's it. Looks like flicker but nothing 
worse (thanks to QTimeLine). Perhaps it would be good to add a maximum size 
for animation. Like when the widget to be animated get's bigger than a 
certain area the animation doesn't happen...

Matthias Kretz (Germany)                            <><
MatthiasKretz at, kretz at,
Matthias.Kretz at
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