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@nicklockwood
nicklockwood / Hacking UIView Animation Blocks.md
Last active June 18, 2024 15:35
This article was originally written for objc.io issue 12, but didn't make the cut. It was intended to be read in the context of the other articles, so if you aren't familiar with concepts such as CALayer property animations and the role of actionForKey:, read the articles in that issue first.

Hacking UIView animation blocks for fun and profit

In this article, I'm going to explore a way that we can create views that implement custom Core Animation property animations in a natural way.

As we know, layers in iOS come in two flavours: Backing layers and hosted layers. The only difference between them is that the view acts as the layer delegate for its backing layer, but not for any hosted sublayers.

In order to implement the UIView transactional animation blocks, UIView disables all animations by default and then re-enables them individually as required. It does this using the actionForLayer:forKey: method.

Somewhat strangely, UIView doesn't enable animations for every property that CALayer does by default. A notable example is the layer.contents property, which is animatable by default for a hosted layer, but cannot be animated using a UIView animation block.

@seberg
seberg / rolling_window.py
Created October 10, 2012 14:38
Multidimensional rolling_window for numpy
def rolling_window(array, window=(0,), asteps=None, wsteps=None, axes=None, toend=True):
"""Create a view of `array` which for every point gives the n-dimensional
neighbourhood of size window. New dimensions are added at the end of
`array` or after the corresponding original dimension.
Parameters
----------
array : array_like
Array to which the rolling window is applied.
window : int or tuple
@deeplycloudy
deeplycloudy / audioplayer.py
Created March 21, 2012 20:37
Simple Python audio player with matplotlib and pyaudio
""" Play an audio file with pyaudio while concurrently showing audio playhead
on a matplotlib plot of the audio time series and spectrogram.
Adjust duration and filename in the script below to reflect your audio file.
v. 0.1
21 Mar 2012
Eric Bruning
"""
@RichardBronosky
RichardBronosky / git-flatten
Created November 19, 2011 07:27
How to flatten/squash a gist
git reset --soft $(/usr/local/bin/git log --format=%H | tail -1); git commit --amend --reset-author -m 'initial'