CrossPlatformDefines.swift

/*
 
 Erica Sadun, http://ericasadun.com
 Cross Platform Defines
 
 Apple Platforms Only
 Will update to #if canImport() when available
 
 */

import Foundation

// Frameworks
#if os(OSX)
    import Cocoa
#else
    import UIKit
#endif

// UIKit/Cocoa Classes
#if os(OSX)
    public typealias View = NSView
    public typealias Font = NSFont
    public typealias Color = NSColor
    public typealias Image = NSImage
    public typealias BezierPath = NSBezierPath
    public typealias ViewController = NSViewController
#else
    public typealias View = UIView
    public typealias Font = UIFont
    public typealias Color = UIColor
    public typealias Image = UIImage
    public typealias BezierPath = UIBezierPath
    public typealias ViewController = UIViewController
#endif

CrossPlatformRenderer.swift

/*
 
 Erica Sadun, http://ericasadun.com
 Cross Platform Defines: Image Renderer
 
 Apple Platforms Only
 Will update to #if canImport() when available
 
 */

import Foundation

// Frameworks
#if os(OSX)
    import Cocoa
#else
    import UIKit
#endif

#if os(OSX)
    public class MacGraphicsImageRendererFormat: NSObject {
        public var opaque: Bool = false
        public var prefersExtendedRange: Bool = false
        public var scale: CGFloat = 2.0
        public var bounds: CGRect = .zero
    }
    
    public typealias GraphicsImageRendererFormat = MacGraphicsImageRendererFormat
#else
    public typealias GraphicsImageRendererFormat = UIGraphicsImageRendererFormat
#endif

#if os(OSX)
    public class MacGraphicsImageRendererContext: NSObject {
        
        public var format: GraphicsImageRendererFormat
        
        public var cgContext: CGContext {
            guard let context = NSGraphicsContext.current()?.cgContext
                else { fatalError("Unavailable cgContext while drawing") }
            return context
        }
        
        public func clip(to rect: CGRect) {
            cgContext.clip(to: rect)
        }
        
        public func fill(_ rect: CGRect) {
            cgContext.fill(rect)
        }
        
        public func fill(_ rect: CGRect, blendMode: CGBlendMode) {
            NSGraphicsContext.saveGraphicsState()
            cgContext.setBlendMode(blendMode)
            cgContext.fill(rect)
            NSGraphicsContext.restoreGraphicsState()
        }
        
        public func stroke(_ rect: CGRect) {
            cgContext.stroke(rect)
        }
        
        public func stroke(_ rect: CGRect, blendMode: CGBlendMode) {
            NSGraphicsContext.saveGraphicsState()
            cgContext.setBlendMode(blendMode)
            cgContext.stroke(rect)
            NSGraphicsContext.restoreGraphicsState()
        }
        
        public override init() {
            self.format = GraphicsImageRendererFormat()
            super.init()
        }
        
        public var currentImage: NSImage {
            guard let cgImage = cgContext.makeImage()
                else { fatalError("Cannot retrieve cgImage from current context") }
            return NSImage(cgImage: cgImage, size: format.bounds.size)
        }
    }
    
    public typealias GraphicsImageRendererContext = MacGraphicsImageRendererContext
#else
    public typealias GraphicsImageRendererContext = UIGraphicsImageRendererContext
#endif

#if os(OSX)
    public class MacGraphicsImageRenderer: NSObject {
        
        public class func context(with format: GraphicsImageRendererFormat) -> CGContext? {
            fatalError("Not implemented")
        }
        
        public class func prepare(_ context: CGContext, with: GraphicsImageRendererContext) {
            fatalError("Not implemented")
        }
        
        public class func rendererContextClass() {
            fatalError("Not implemented")
        }
        
        public var allowsImageOutput: Bool = true
        
        public let format: GraphicsImageRendererFormat
        
        public let bounds: CGRect
        
        public init(bounds: CGRect, format: GraphicsImageRendererFormat) {
            (self.bounds, self.format) = (bounds, format)
            self.format.bounds = self.bounds
            super.init()
        }
        
        public convenience init(size: CGSize, format: GraphicsImageRendererFormat) {
            self.init(bounds: CGRect(origin: .zero, size: size), format: format)
        }
        
        public convenience init(size: CGSize) {
            self.init(bounds: CGRect(origin: .zero, size: size), format: GraphicsImageRendererFormat())
        }
        
        public func image(actions: @escaping (GraphicsImageRendererContext) -> Void) -> NSImage {
            let image = NSImage(size: format.bounds.size, flipped: false) {
                (drawRect: NSRect) -> Bool in
                
                let imageContext = GraphicsImageRendererContext()
                imageContext.format = self.format
                actions(imageContext)
                
                return true
            }
            return image
        }
        
        public func pngData(actions: @escaping (GraphicsImageRendererContext) -> Void) -> Data {
            let image = self.image(actions: actions)
            var imageRect = CGRect(origin: .zero, size: image.size)
            guard let cgImage = image.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
                else { fatalError("Could not construct PNG data from drawing request") }
            let bitmapRep = NSBitmapImageRep(cgImage: cgImage)
            bitmapRep.size = image.size
            guard let data = bitmapRep.representation(using: .PNG, properties: [:])
                else { fatalError("Could not retrieve data from drawing request") }
            return data
        }
        
        public func jpegData(withCompressionQuality compressionQuality: CGFloat, actions: @escaping (GraphicsImageRendererContext) -> Void) -> Data {
            let image = self.image(actions: actions)
            var imageRect = CGRect(origin: .zero, size: image.size)
            guard let cgImage = image.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
                else { fatalError("Could not construct PNG data from drawing request") }
            let bitmapRep = NSBitmapImageRep(cgImage: cgImage)
            bitmapRep.size = image.size
            guard let data = bitmapRep.representation(using: .JPEG, properties: [NSImageCompressionFactor: compressionQuality])
                else { fatalError("Could not retrieve data from drawing request") }
            return data
        }
        
        public func runDrawingActions(_ drawingActions: (GraphicsImageRendererContext) -> Void, completionActions: ((GraphicsImageRendererContext) -> Void)? = nil) throws {
            fatalError("Not implemented")
        }
    }
#endif

#if os(OSX)
    public typealias GraphicsImageRenderer = MacGraphicsImageRenderer
#else
    public typealias GraphicsImageRenderer = UIGraphicsImageRenderer
#endif

ImageFormatUtility.swift

#if os(OSX)
    import Cocoa
#else
    import UIKit
#endif

#if os(OSX)
    extension NSImage {
        /// Return PNG representation data for image
        var pngData: Data? {
            var imageRect = CGRect(origin: .zero, size: size)
            guard let cgImage = cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
                else { return nil }
            let bitmapRep = NSBitmapImageRep(cgImage: cgImage)
            bitmapRep.size = size
            return bitmapRep.representation(using: .PNG, properties: [:])
        }
    }
#else
    extension UIImage {
        /// Return PNG representation data for image
        var pngData: Data? {
            return UIImagePNGRepresentation(self)
        }
    }
#endif

PushDraw.swift

#if os(macOS)
    import Cocoa
    
    public func pushDraw(in context: Any? = nil,
                         applying actions: () -> Void)
    {
        NSGraphicsContext.saveGraphicsState()
        actions()
        NSGraphicsContext.restoreGraphicsState()
    }
#else
    import UIKit
    
    public func pushDraw(in context: UIGraphicsImageRendererContext,
                         applying actions: () -> Void)
    {
        context.cgContext.saveGState()
        actions()
        context.cgContext.restoreGState()
    }
#endif

Awesome