tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

insidegui

https://statici.icloud.com/fmipmobile/deviceImages-9.0/iPhone/iPhone9,4-2-3-0/online-infobox__3x.png
                                                   A   B      C         D E F G

A: deviceImages version seems to determine the format of the image specifier (C, D, E, F)
B: device marketing name
C: device model identifier
D: color cover glass (front color)
   1 - Black
   2 - White
E: device enclosure color (back color)

smileyborg

// UICollectionView Objective-C example

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
        
    NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] firstObject];
    if (selectedIndexPath != nil) {
        id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator;
        if (coordinator != nil) {
            [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {

bgayman

//
//  ViewController.swift
//  CameraFilter
//

import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {
    

leilee

public extension UIView {
    
    private static let kLayerNameGradientBorder = "GradientBorderLayer"
    
    public func setGradientBorder(
        width: CGFloat,
        colors: [UIColor],
        startPoint: CGPoint = CGPoint(x: 0.5, y: 0),
        endPoint: CGPoint = CGPoint(x: 0.5, y: 1)
    ) {

domingogallardo

func minMax(array: [Int]) -> (min: Int, max: Int) {
    var minActual = array[0]
    var maxActual = array[0]
    for valor in array[1..<array.count] {
        if valor < minActual {
            minActual = valor
        } else if valor > maxActual {
            maxActual = valor
        }
    }

levantAJ

import ImageIO
import AVFoundation

var cvPixelBuffer: CVPixelBuffer? {
    var pixelBuffer: CVPixelBuffer? = nil
    let options: [NSObject: Any] = [
        kCVPixelBufferCGImageCompatibilityKey: false,
        kCVPixelBufferCGBitmapContextCompatibilityKey: false,
        ]
    let status = CVPixelBufferCreate(kCFAllocatorDefault, Int(size.width), Int(size.height), kCVPixelFormatType_32BGRA, options as CFDictionary, &pixelBuffer)

hborders

#!/bin/bash -euo pipefail

if [ ${#} -eq 0 ]
then
# read from STDIN
MAYBE_CFBUNDLEVERSION=$( cat )
else
MAYBE_CFBUNDLEVERSION="${1}"
fi

ashfurrow

Apps to install from macOS App Store:

• Pastebot
• GIF Brewery
• Slack
• Keynote/Pages/Numbers
• 1Password
• OmniFocus 3
• Airmail 3
• iA Writer

czwen

xcrun simctl spawn booted launchctl debug system/com.apple.SpringBoard --environment DYLD_INSERT_LIBRARIES=/Applications/Reveal.app/Contents/SharedSupport/iOS-Libraries/libReveal.dylib

xcrun simctl spawn booted launchctl stop com.apple.SpringBoard