CODEWITHSUNDEEP
iphoneobjective-ccore-animation
Vsevolod Sauta
Vsevolod Sauta

Reputation: 33

CoreAnimation gets jerking

I've created an UIView and some layers. I've organized those layers into superview-subview hierarchy with the root in UIView's layer, added some gesture recognizers and I am trying to manipulate layers' geometry on events from gesture recognizers (setting bounds and position for sure). I use implicit animations and CATransactions. No explicit animations are used.

The actual result is good enough if I create CATransaction with duration = 0. But if I set the duration to 0.2 I get some strange results: as event come not rapidly and previous transaction have time to be completed before the next starts everything is OK (for example on tapping), but if there is not enough time (for example on pinch or pan) the layer being resized starts jerking. Visually it looks like animation rolls back to the initial point and starts again to the new value.

I do not see any reason for this. I've tried to perform the layout in -[UIView layoutSubviews] and invoke setNeedsDisplay in gesture recognizers handlers. I've also tried to separate this logic into separate method but it does not help.

I repeat once more that I use only implicit animations. And what I want to know is why does it happen (but not how to work around).

Any clues?

Upvotes: 0

Views: 167

Answers (1)

Padavan
Padavan

Reputation: 1074

I think, it's because you start new animation when previous not finished. Maybe, you need to stop it like

[yourView.layer removeAnimationForKey:@"yourAnimationKey"];

and you need to implement animation delegate method

-(void)stopAnimation:(id)sender
{
    yourView.frame = [[yourView.layer presentationLayer] frame]; // that set frame of your view to it's animation position
}

Upvotes: 1

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