silica-viewer/SilicaViewer/AppDelegate.swift

import Cocoa
import ZIPFoundation
import AVFoundation

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations {
    var exporter: AVAssetExportSession?
    
    @IBAction func showInfoAction(_ sender: Any) {
        NSApplication.shared.keyWindow?.contentViewController?.performSegue(withIdentifier: "showInfo", sender: self)
    }
    
    @IBAction func showTimelapseAction(_ sender: Any) {
        NSApplication.shared.keyWindow?.contentViewController?.performSegue(withIdentifier: "showTimelapse", sender: self)
    }
    
    func validateUserInterfaceItem(_ item: NSValidatedUserInterfaceItem) -> Bool {
        // Show timelapse and show info buttons
        if(item.tag == 67 || item.tag == 68) {
            return NSApplication.shared.keyWindow != nil
        }
        
        return true
    }
    
    @IBAction func exportAction(_ sender: Any) {
        let document = NSApplication.shared.keyWindow?.windowController?.document as? Document;
        
        let savePanel = NSSavePanel()
        savePanel.title = "Save"
        savePanel.allowedFileTypes = ["public.png", "public.jpeg"]
        savePanel.accessoryView = ExportAccessoryView.fromNib()
        
        savePanel.begin { (result) in
            if result.rawValue == NSApplication.ModalResponse.OK.rawValue {
                let canvas = document?.makeComposite()
                let canvasTiff = canvas?.tiffRepresentation
                let bitmapImage = NSBitmapImageRep(data: canvasTiff!)
                let canvasPng = bitmapImage!.representation(using: .png, properties: [:])
             
                try? canvasPng?.write(to: savePanel.url!)
            }
        }
    }
    
    @IBAction func exportThumbnailAction(_ sender: Any) {
        let document = NSApplication.shared.keyWindow?.windowController?.document as? Document;
        
        let savePanel = NSSavePanel()
        savePanel.title = "Save Thumbnail"
        savePanel.allowedFileTypes = ["public.png"]
        savePanel.begin { (result) in
            if result.rawValue == NSApplication.ModalResponse.OK.rawValue {
                let canvas = document?.makeThumbnail()
                let canvasTiff = canvas?.tiffRepresentation
                let bitmapImage = NSBitmapImageRep(data: canvasTiff!)
                let canvasPng = bitmapImage!.representation(using: .png, properties: [:])
             
                try? canvasPng?.write(to: savePanel.url!)
            }
        }
    }
    
    @IBAction func exportTimelapseAction(_ sender: Any) {
        guard let originalWindow = NSApplication.shared.keyWindow else {
            return
        }
        
        let document = originalWindow.windowController?.document as? Document;

        let savePanel = NSSavePanel()
        savePanel.title = "Save Timelapse"
        savePanel.allowedFileTypes = ["public.mpeg-4"]
        savePanel.begin { (result) in
            if result.rawValue == NSApplication.ModalResponse.OK.rawValue {
                guard let archive = Archive(data: (document?.data)!, accessMode: Archive.AccessMode.read) else  {
                    return
                }
                
                let directory = NSTemporaryDirectory()
                
                let mixComposition = AVMutableComposition()
                var instructions: [AVMutableVideoCompositionLayerInstruction] = []
                var duration = CMTime.zero
                
                for entry in archive.makeIterator() {
                    if entry.path.contains(VideoPath) {
                        let fileName = NSUUID().uuidString + ".mp4"
                        
                        // This returns a URL? even though it is an NSURL class method
                        let fullURL = NSURL.fileURL(withPathComponents: [directory, fileName])!
                        
                        let _ = try? archive.extract(entry, to: fullURL)
                        
                        let asset = AVAsset(url: fullURL)
                        
                        guard let track = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else {
                            return
                        }
                            
                        try? track.insertTimeRange(CMTimeRangeMake(start: .zero, duration: asset.duration),
                                                        of: asset.tracks(withMediaType: .video)[0],
                                                        at: duration)
                        
                        duration = CMTimeAdd(duration, asset.duration)
                        
                        let opacityInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
                        opacityInstruction.setOpacity(0.0, at: duration + asset.duration)
                        
                        instructions.append(opacityInstruction)
                    }
                }
                
                let mainInstruction = AVMutableVideoCompositionInstruction()
                mainInstruction.timeRange = CMTimeRangeMake(start: .zero, duration: duration)
                mainInstruction.layerInstructions = instructions
                
                let mainComposition = AVMutableVideoComposition()
                mainComposition.instructions = [mainInstruction]
                mainComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)
                mainComposition.renderSize = CGSize(width: document!.info.videoFrame.0, height: document!.info.videoFrame.1)
                
                self.exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
                self.exporter?.outputURL = savePanel.url!
                self.exporter?.outputFileType = AVFileType.mp4
                self.exporter?.videoComposition = mainComposition
                
                let alert = NSAlert()
                alert.messageText = "Exporting timelapse..."
                alert.addButton(withTitle: "Cancel")
                alert.beginSheetModal(for: originalWindow) { (resonse) in
                    self.exporter?.cancelExport()
                    alert.window.close()
                }
                
                self.exporter?.exportAsynchronously {
                    if self.exporter?.status != .cancelled {
                        DispatchQueue.main.sync {
                            alert.window.close()
                        }
                    }
                }
            }
        }
    }
    
}