Question

I have a CAGradientLayer that I want to scale as the user drags there finger. However, when I set the frame, the layer animates to the new size. This happens with other properties, too, including start/endPoint.

Here’s an example:

_gradient.frame = CGRectMake(0, 480-toHeight, 320, toHeight);

Yet, if I only call this when the user has dragged 10 or so pixels, the layer doesn’t simply jump to the new size, it animates in a smooth but quick eased animation. I’m positive this isn’t called in an animation block. To further debug, I also animate the frame of a UIView in the same scope and that doesn’t animate.

I’m new to CALayers, so maybe I’m doing something way wrong.

Answer 1

Most of CALayer’s properties are animated by default. You need to disable these implicit animations:

[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
// change layer's properties
_gradient.frame = newFrame;
[CATransaction commit];

Here is a good sample to help you with learning Core Animation.