Re: Upgrading deprecations

[phantomjinx <p g richardson phantomjinx co uk>]

On 05/13/2013 12:12 PM, Lionel Landwerlin wrote:
> On 13/05/13 10:36, phantomjinx wrote:
> > Hi,
> >
> > I am trying to bring the coverflow CD animation in gtkpod up to version 1.12 by removing the
> > deprecations.
> >
> > Having replaced ClutterBehaviour and ClutterAnimation with use of the easing state as described here
> > [1], I have
> > run into a problem.
> >
> > Clicking the right button scrolls the set of CD covers to the left and likewise clicking the left
> > button scrolls to the right.
> >
> > With an easing duration of 1600ms, this works nicely except that the rotation is always clockwise
> > whereas with ClutterBehaviour I was
> > able to set it to counter-clockwise ensuring that a CD cover would rotate the shortest way around,
> > rather than spinning needlessly.
>
> You will have to implement this behavior yourself :(
>
> > Secondly and more importantly, if I click the right button quickly, the animation may still be in
> > the middle hence the covers end up out of
> > position to the point that some even end up on the wrong side of the screen. I originally got around
> > this by calling clutter_timeline_stop
> > and clearing all clutter behaviours before starting a new animation. How would I achieve the same
> > kind of thing with the easing state please?
>
> When doing an implicit animation on an actor, you can get a ClutterTransition object (subclass of
> ClutterTimeline) by calling clutter_actor_get_transition() (might return NULL if no implicit
> animations are running). You can use the returned object to stop the implicit animation and trigger
> a new implicit animation.

<snip>

> > [1] https://developer.gnome.org/clutter/stable/migrating-ClutterAnimation.html
> > [2] 
> > https://gitorious.org/~phantomjinx/gtkpod/phantomjinx-gtkpod-plugin/blobs/updating-clarity/plugins/clarity/clarity_canvas.c

Hi,

So, with the help of Lionel (thx!), I have successfully solved the second problem. By removing all
transitions before kicking off
a new transition ensures I can click buttons as fast as I like with no ill-effects. Thanks for the info.

However, the first problem (outlined above) is still an issue but I am starting to understand it a
little better. When a cover is moved
from the right of the screen to the centre, it changes from a rotation angle of 290 to an angle of
0. Likewise, a cover moving from the
centre to the left of the screen rotates from an angle of 0 to 70 (all on the Y-axis).

The problem seems to be excessive rotation when the angle is large. In this case going from 290 -> 0
seems to add an extra 360 degree rotation,
giving the animation of the cover a complete full spin before landing in position. For the 0 -> 70,
this spin does not take place and the cover
simply slides into place. Can somebody explain what would be causing this and how I would go about
implementing something to stop it?

Many thanks

PGR

-- 
Paul Richardson

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