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POCALayer transform different when animated
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copied!<p>This has been driving me crazy. I am using s <code>CATransform3D</code> to animate the main layer of my view (to apply a perspective effect). I have a function called <code>ApplyPerspective</code> that sets it up, and <code>ClearPerspective</code> which resets the layer's transform property to <code>CATransform3DIdentity</code>.</p> <p>Here's my code:</p> <pre><code> ApplyPerspective(self.mainContentView); [UIView animateWithDuration:self.animationDuration delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{ ClearPerspective(self.mainContentView); } completion:nil]; </code></pre> <p>The issue I am having is that the perspective transform applied by <code>ApplyPerspective</code> is incorrect. If I remove the -<code>animateWithDuration</code> call, but leave the <code>ApplyPerspective</code> call, the layer is rendered as expected. I am not sure why the behavior is changing when animated.</p> <p>I have tried changing the duration, animation curve, flattening the function calls, but I am unable to trace the source of this error.</p> <p>Update to add bodies of ApplyPerspective() and ClearPerspective():</p> <pre><code>void ApplyPerspective(UIView *aView) { // Magic numbers derived using debug sliders CGFloat zDist, rotRads, xOffset, yOffset, scale, shift; if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) { zDist = 172.5378; rotRads = 2.6531; xOffset = -13.0; yOffset = 402; shift = -241; } else { zDist = 513.4995; rotRads = 1.0007; xOffset = 0.0; yOffset = -100.0; scale = 1.0; shift = 0.0; } CATransform3D p = CATransform3DIdentity; p = CATransform3DTranslate(p, xOffset, yOffset, 0.0); p.m34 = 1.0 / -zDist; p = CATransform3DRotate(p, rotRads, 1.0, 0.0, 0); p = CATransform3DTranslate(p, 0, shift, 0.0); aView.layer.transform = p; } void ClearPerspective(UIView *aView, UIView *parentView) { aView.layer.transform = CATransform3DIdentity; } </code></pre> <p>Here's the view hierarchy: mainContentView is a child of the ViewController's root view, which uses auto layout. The constraints are such that mainContentView fills the root view. mainContentView has a sibling image view which is used as a background during the animation.</p>

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