nicklockwood

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.

nicktoumpelis

git clean -xfd
git submodule foreach --recursive git clean -xfd
git reset --hard
git submodule foreach --recursive git reset --hard
git submodule update --init --recursive

eladb

- (void)setupCamera
{
    self.coreImageContext = [CIContext contextWithOptions:nil];

    // session
    self.cameraSession = [[AVCaptureSession alloc] init];
    [self.cameraSession setSessionPreset:AVCaptureSessionPresetPhoto];
    [self.cameraSession commitConfiguration];
    
    // input

carlosefonseca

#!/usr/bin/env bash

# obtains all data tables from database
TS=`sqlite3 $1 "SELECT tbl_name FROM sqlite_master WHERE type='table' and tbl_name not like 'sqlite_%';"`

# exports each table to csv
for T in $TS; do

sqlite3 $1 <<!
.headers on

originell

Analysis of Apple’s rubber band scrolling

January 6, 2013

I recently saw a post on Twitter from @chpwn that described the alogorithm that Apple uses for its “rubber band” or “bungee” scrolling.

b = (1.0 – (1.0 / ((x * c / d) + 1.0))) * d

paul-delange

/*
 *  TGDFileHash.c
 *  TagAdA: Tagging Advanced Application
 *  
 *  Copyright © 2008-2010 The TagAdA Team. All rights reserved.
 * 
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  

steipete

// Taken from http://PSPDFKit.com. This snippet is under public domain.
#define UIKitVersionNumber_iOS_7_0 0xB57
BOOL PSPDFIsUIKitFlatMode(void) {
    static BOOL isUIKitFlatMode = NO;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        // We get the modern UIKit if system is running >= iOS 7 and we were linked with >= SDK 7.
        if (kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber_iOS_7_0) {
            isUIKitFlatMode = (NSVersionOfLinkTimeLibrary("UIKit") >> 16) >= UIKitVersionNumber_iOS_7_0;
        }

aras-p

// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,

ashfurrow

1.3MB png 640x1136

• Accelerate 179ms every time
• CoreImage 298ms first time 147ms subsequent times @1x scale
• CoreImage 262ms first time 126ms subsequent times @0.5x scale
• CoreImage 260ms first time 118ms subsequent times @0.25x scale

(Lower on 0.5x probably because of whole number for blur radius)

niw

/*
 * A simple libpng example program
 * http://zarb.org/~gc/html/libpng.html
 *
 * Modified by Yoshimasa Niwa to make it much simpler
 * and support all defined color_type.
 *
 * To build, use the next instruction on OS X.
 * $ brew install libpng
 * $ clang -lz -lpng16 libpng_test.c