Genie.swift

//
//  Genie.swift
//  iOrdning7
//
//  Created by Erik Aderstedt on 2016-07-11.
//  Copyright © 2016 Aderstedt Software AB. All rights reserved.
//

import Cocoa
import Quartz

let genieKernel: CIKernel = {
	guard
		let url = Bundle.main.urlForResource("ASGenieKernel", withExtension: "txt"),
		let str = try? String(contentsOf: url),
		let kernel = CIKernel(string: str) else { fatalError("Resource not accessible") }

	return kernel
}()

class GenieFilter: CIFilter {

	var inputTime: CGFloat = 2
	var inputDelta: CGFloat = 10
	var inputTarget: CGFloat = 200
	var inputScalingFactor: CGFloat = 1
	var inputImage: CIImage? = nil

	override func setDefaults() {
		super.setDefaults()

		inputTime = 2
		inputDelta = 10
		inputTarget = 200
		inputScalingFactor = 1
	}

	override var attributes: [String : AnyObject] {
		return ["inputTime": [kCIAttributeMin: 0.0,
			kCIAttributeMax: 2.0,
			kCIAttributeSliderMin: 0.0,
			kCIAttributeSliderMax: 2.0,
			kCIAttributeDefault: 0.0,
			kCIAttributeIdentity: 0.0,
			kCIAttributeClass: NSNumber.self,
			kCIAttributeType: kCIAttributeTypeScalar],
				"inputTarget": [kCIAttributeSliderMin: 0.0,
			kCIAttributeSliderMax: 500.0,
			kCIAttributeDefault: 0.0,
			kCIAttributeIdentity: 250.0,
			kCIAttributeClass: NSNumber.self,
			kCIAttributeType: kCIAttributeTypeScalar],
				"inputDelta": [kCIAttributeSliderMin: 0.0,
			kCIAttributeSliderMax: 40.0,
			kCIAttributeDefault: 20.0,
			kCIAttributeIdentity: 20.0,
			kCIAttributeClass: NSNumber.self,
			kCIAttributeType: kCIAttributeTypeScalar],
				"inputImage": [kCIAttributeClass: CIImage.self],
			"outputImage": [kCIAttributeClass: CIImage.self]]
	}

	override var outputImage: CIImage? {

		guard let image = inputImage else { print("No input image!"); return nil }
		let inputImageExtent = image.extent
		let extent = [inputImageExtent.origin.x, inputImageExtent.origin.y, inputImageExtent.size.width, inputImageExtent.size.height]
		let definition = [inputImageExtent.origin.x, inputImageExtent.origin.y, inputImageExtent.size.width * inputScalingFactor, inputImageExtent.size.height * inputScalingFactor]
		let sampler = CISampler(image: image)
		let o = apply(genieKernel, arguments: [sampler, inputTime, inputDelta, inputTarget, inputScalingFactor], options: [kCIApplyOptionExtent: extent, kCIApplyOptionDefinition: definition])

		return o
	}

}

extension NSView {

	var snapshot: CGImage? {
		guard let bir = self.bitmapImageRepForCachingDisplay(in: self.bounds) else {
			NSLog("No snapshot available.")
			return nil
		}
		self.cacheDisplay(in: self.bounds, to: bir)
		guard let inputImage = bir.cgImage else {
			NSLog("Could not get cgImage from cached image.")
			return nil
		}

		return inputImage
	}
}

func performGenieAnimationIn(_ view: NSView, toLeftSideAtY target: CGFloat, using snapshot: CGImage) {

	let didUseCoreImageFilters = view.layerUsesCoreImageFilters
	view.layerUsesCoreImageFilters = true

	// Configure the view to accept "our" layer.
	assert(view.wantsLayer == true)
	guard let rootLayer = view.layer else {
		NSLog("No root layer for target view.")
		view.layerUsesCoreImageFilters = didUseCoreImageFilters
		return
	}

	rootLayer.contents = nil

	let ourLayer = CALayer()
	ourLayer.backgroundColor = NSColor.controlColor().cgColor
	ourLayer.name = "contentsLayer"
	ourLayer.bounds = view.bounds
	ourLayer.anchorPoint = CGPoint(x: 0, y: 0)
	ourLayer.isOpaque = false
	ourLayer.contentsGravity = kCAGravityResize
	ourLayer.position = CGPoint(x: 0, y: 0)
	ourLayer.contents = snapshot

	rootLayer.addSublayer(ourLayer)

	let filter = GenieFilter()
	filter.setDefaults()
	filter.name = "genie"
	filter.inputTarget = target
	filter.inputTime = 2.0
	filter.inputDelta = 10
	filter.inputScalingFactor = view.window?.backingScaleFactor ?? 1

	ourLayer.filters = [filter]

	let animation = CABasicAnimation(keyPath: "filters.genie.inputTime")
	animation.fromValue = 0
	animation.toValue = 2
	animation.duration = NSEvent.modifierFlags() == NSEventModifierFlags.option ? 4.0 : 0.4
	animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)

	CATransaction.begin()

	CATransaction.setCompletionBlock {
		ourLayer.removeFromSuperlayer()
		if !didUseCoreImageFilters {
			view.layerUsesCoreImageFilters = false
		}
	}

	ourLayer.add(animation, forKey: "genie")

	CATransaction.commit()
}

any chance of porting this to iOS ?