ilyapuchka

// The issue with sectionHeadersPinToVisibleBounds and sectionFootersPinToVisibleBounds is that they do not pin 
// first header and last footer when bouncing. This layout subclass fixes that.

class StickyLayout: UICollectionViewFlowLayout {
    
    override init() {
        super.init()
        self.sectionFootersPinToVisibleBounds = true
        self.sectionHeadersPinToVisibleBounds = true
    }

natecook1000

Greetings and salutations, NSHipsters!

As the year winds down, it's a tradition here at NSHipster to ask you, dear readers, to offer up your favorite tricks and tips from the past year as gifts to your fellow hipsters. With iOS 9, El Capitan, brand new watch- and tvOS's, and the open-sourcing of some minor Apple-related tech, there's bound to be lots to share.

Submit your favorite piece of Swift or @objc trivia, helpful hints, unexpected discoveries, useful workarounds, useless fascinations, or anything else you found cool this year. Just comment below!

If you need inspiration, try [the list from last year][2015], or [from the year before][2014], or [from the year before that][2013].

natecook1000

// CalculatorView.swift		
// as seen in http://nshipster.com/ibinspectable-ibdesignable/		
//		
// (c) 2015 Nate Cook, licensed under the MIT license		

/// The alignment for drawing an String inside a bounding rectangle.
enum NCStringAlignment {
    case LeftTop
    case CenterTop
    case RightTop

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD