Rohan Dilip Sanap therohansanap

1. The Layer Tree

Core Animation's original name is Layer Kit

Core Animation is a compositing engine; its job is to compose different pieces of visual content on the screen, and to do so as fast as possible. The content in question is divided into individual layers stored in a hierarchy known as the layer tree. This tree forms the underpinning for all of UIKit, and for everything that you see on the screen in an iOS application.

In UIView, tasks such as rendering, layout and animation are all managed by a Core Animation class called CALayer. The only major feature of UIView that isn’t handled by CALayer is user interaction.

There are four hierarchies, each performing a different role:

view hierarchy
layer tree

	let safeSequence = xs
	.observeOn(MainScheduler.instance) // observe events on main scheduler
	.catchErrorJustReturn(onErrorJustReturn) // can't error out
	.share(replay: 1, scope: .whileConnected) // side effects sharing
	return Driver(raw: safeSequence) // wrap it up

	let results = query.rx.text.asDriver() // This converts a normal sequence into a `Driver` sequence.
	.throttle(.milliseconds(300), scheduler: MainScheduler.instance)
	.flatMapLatest { query in
	fetchAutoCompleteItems(query)
	.asDriver(onErrorJustReturn: []) // Builder just needs info about what to return in case of error.
	}

	results
	.map { "\($0.count)" }
	.drive(resultCount.rx.text)

	let results = query.rx.text
	.throttle(.milliseconds(300), scheduler: MainScheduler.instance)
	.flatMapLatest { query in
	fetchAutoCompleteItems(query)
	.observeOn(MainScheduler.instance) // results are returned on MainScheduler
	.catchErrorJustReturn([]) //in the worst case, errors are handled
	}
	.share(replay: 1) // HTTP requests are shared and results replayed to all UI elements

	results

	let results = query.rx.text
	.throttle(.milliseconds(300), scheduler: MainScheduler.instance)
	.flatMapLatest { query in
	fetchAutoCompleteItems(query)
	}

	results
	.map { "\($0.count)" }
	.bind(to: resultCount.rx.text)
	.disposed(by: disposeBag)

	@interface YourViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {
	UIImageOrientation scrollOrientation;
	CGPoint lastPos;
	}

	- (void) tableView:(UITableView )tableView willDisplayCell:(UITableViewCell )cell forRowAtIndexPath:(NSIndexPath *)indexPath {
	if (tableView.isDragging) {
	UIView *myView = cell.contentView;
	CALayer *layer = myView.layer;
	CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;