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I'm trying to animate a UIVisualEffectsView with a blur effect on top of a UIImageView. Animating the effects view 'in' seems to work, however when animating it 'out' on the first animation frame the effect vanishes to what looks like a 0.5 alpha view.

Is this a bug in iOS8 or am I doing it wrong?

You can play with the example project at https://github.com/mickeyl/iOS-Bug-Example-Projects/tree/master/Animating-UIVisualEffectsView

Here is a preview of what I'm seeing:

Animating UIVisualEffectsView bug

Update: Obviously the problem is the height parameter in the new rect. Keeping it works around it. If you then add the effect as subview to the image and clipToBounds, I can get the intended effect. Still I view this as a bug.

DrMickeyLauer
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1 Answers1

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This is the response from Apple Developer Relations:

This issue behaves as intended based on the following:

When animating the height 0 -> 300, the presentation layer in the render server knows its full size so the render server can properly sample for blur. When returning back to zero height, the presentation layer now has a height of zero, to which the render server has no way to sample correctly. So the effect drops but the remaining layers still animate properly.

Your solution is the correct one. The render server simply cannot accommodate blur in this scenario.

Please update your bug report to let us know if this is still an issue for you.

DrMickeyLauer
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