[Experimental Feature] Game Screenshots (#242)

* Adds extension to handle interactions with Photos app
- isAuthorized to check/ask for authorization
- saveUIImage to save a UIImage to Photos

* Adds a Pause Menu button for taking game screenshots

* Adds @Feature and @Options for Game Screenshots

* Implements Game Screenshots feature in GameViewController

* Updates project settings

* Passes call to save to Photos as a closure into authorization prompt
- Ensures that the screenshot is saved when the user is first prompted for access to Photos
- More elegant extension code

---------

Co-authored-by: Riley Testut <riley@rileytestut.com>

Delta.xcodeproj/project.pbxproj

@@ -34,6 +34,8 @@
 /* Begin PBXBuildFile section */
 		1FA4ABA79AB72914FE414A61 /* libPods-Delta.a in Frameworks */ = {isa = PBXBuildFile; fileRef = DC866E433B3BA9AE18ABA1EC /* libPods-Delta.a */; };
 		87343D7B985519A5890A61C6 /* libPods-DeltaPreviews.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 7E3E5A45AB20C8A87754453B /* libPods-DeltaPreviews.a */; };
+		ACF7E30D29F73D03000FE071 /* GameScreenshots.swift in Sources */ = {isa = PBXBuildFile; fileRef = ACF7E30C29F73D03000FE071 /* GameScreenshots.swift */; };
+		ACF7E30F29F743A3000FE071 /* PHPhotoLibrary+Authorization.swift in Sources */ = {isa = PBXBuildFile; fileRef = ACF7E30E29F743A3000FE071 /* PHPhotoLibrary+Authorization.swift */; };
 		BF00BEA625B758AA00C8607D /* SystemBIOS.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF00BEA525B758AA00C8607D /* SystemBIOS.swift */; };
 		BF02D5DA1DDEBB3000A5E131 /* openvgdb.sqlite in Resources */ = {isa = PBXBuildFile; fileRef = BF02D5D91DDEBB3000A5E131 /* openvgdb.sqlite */; };
 		BF04E6FF1DB8625C000F35D3 /* ControllerSkinsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF04E6FE1DB8625C000F35D3 /* ControllerSkinsViewController.swift */; };
@@ -257,6 +259,8 @@
 		8ECE6641DE30D01EA30FE7F6 /* Pods-DeltaPreviews.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-DeltaPreviews.release.xcconfig"; path = "Pods/Target Support Files/Pods-DeltaPreviews/Pods-DeltaPreviews.release.xcconfig"; sourceTree = "<group>"; };
 		A01281C7023C0041B25963BE /* Pods-DeltaPreviews.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-DeltaPreviews.debug.xcconfig"; path = "Pods/Target Support Files/Pods-DeltaPreviews/Pods-DeltaPreviews.debug.xcconfig"; sourceTree = "<group>"; };
 		A19FF50F55441BC2B2248241 /* Pods-Delta.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Delta.release.xcconfig"; path = "Pods/Target Support Files/Pods-Delta/Pods-Delta.release.xcconfig"; sourceTree = "<group>"; };
+		ACF7E30C29F73D03000FE071 /* GameScreenshots.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GameScreenshots.swift; sourceTree = "<group>"; };
+		ACF7E30E29F743A3000FE071 /* PHPhotoLibrary+Authorization.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "PHPhotoLibrary+Authorization.swift"; sourceTree = "<group>"; };
 		BF00BEA525B758AA00C8607D /* SystemBIOS.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SystemBIOS.swift; sourceTree = "<group>"; };
 		BF02D5D91DDEBB3000A5E131 /* openvgdb.sqlite */ = {isa = PBXFileReference; lastKnownFileType = file; path = openvgdb.sqlite; sourceTree = "<group>"; };
 		BF0418131D01E93400E85BCF /* GBADeltaCore.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = GBADeltaCore.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -526,6 +530,7 @@
 				D524F4A2273DE9C000D500B2 /* ProcessInfo+JIT.swift */,
 				D524F4A4273DEBB400D500B2 /* ServerManager+Delta.swift */,
 				D5011C47281B6E8B00A0760B /* CharacterSet+Filename.swift */,
+				ACF7E30E29F743A3000FE071 /* PHPhotoLibrary+Authorization.swift */,
 			);
 			path = Extensions;
 			sourceTree = "<group>";
@@ -1068,6 +1073,7 @@
 			isa = PBXGroup;
 			children = (
 				D5A9C01C29DE058C00A8D610 /* VariableFastForward.swift */,
+				ACF7E30C29F73D03000FE071 /* GameScreenshots.swift */,
 			);
 			path = Features;
 			sourceTree = "<group>";
@@ -1554,6 +1560,8 @@
 				D5A9C00329DDED6D00A8D610 /* ExperimentalFeaturesView.swift in Sources */,
 				BF1F45BF21AF676F00EF9895 /* Box.swift in Sources */,
 				BF7AE80A1C2E8C7600B1B5BC /* UIColor+Delta.swift in Sources */,
+				ACF7E30F29F743A3000FE071 /* PHPhotoLibrary+Authorization.swift in Sources */,
+				ACF7E30D29F73D03000FE071 /* GameScreenshots.swift in Sources */,
 				BF797A2D1C2D339F00F1A000 /* UILabel+FontSize.swift in Sources */,
 				BF80E1D21F13117000847008 /* ControllerInputsViewController.swift in Sources */,
 				BF5942641E09BBB10051894B /* LoadControllerSkinImageOperation.swift in Sources */,

Delta/Emulation/GameViewController.swift

@@ -7,6 +7,7 @@
 //
 
 import UIKit
+import Photos
 
 import DeltaCore
 import GBADeltaCore
@@ -412,6 +413,9 @@ extension GameViewController
             pauseViewController.fastForwardItem?.action = { [unowned self] item in
                 self.performFastForwardAction(activate: item.isSelected)
             }
+            pauseViewController.screenshotItem?.action = { [unowned self] item in
+                self.performScreenshotAction()
+            }
             
             pauseViewController.sustainButtonsItem?.isSelected = gameController.sustainedInputs.count > 0
             pauseViewController.sustainButtonsItem?.action = { [unowned self, unowned pauseViewController] item in
@@ -1078,6 +1082,73 @@ extension GameViewController
             emulatorCore.rate = emulatorCore.deltaCore.supportedRates.lowerBound
         }
     }
+    
+    func performScreenshotAction()
+    {
+        guard let snapshot = self.emulatorCore?.videoManager.snapshot() else { return }
+
+        let imageScale = ExperimentalFeatures.shared.gameScreenshots.size?.rawValue ?? 1.0
+        let imageSize = CGSize(width: snapshot.size.width * imageScale, height: snapshot.size.height * imageScale)
+        
+        let format = UIGraphicsImageRendererFormat()
+        format.scale = 1
+        let renderer = UIGraphicsImageRenderer(size: imageSize, format: format)
+
+        let scaledSnapshot = renderer.image { (context) in
+            context.cgContext.interpolationQuality = .none
+            snapshot.draw(in: CGRect(origin: .zero, size: imageSize))
+        }
+
+        if ExperimentalFeatures.shared.gameScreenshots.saveToPhotos
+        {
+            PHPhotoLibrary.runIfAuthorized
+            {
+                PHPhotoLibrary.saveUIImage(image: scaledSnapshot)
+            }
+        }
+        
+        if ExperimentalFeatures.shared.gameScreenshots.saveToFiles
+        {
+            guard let data = scaledSnapshot.pngData() else { return }
+            
+            let screenshotsDirectory = FileManager.default.documentsDirectory.appendingPathComponent("Screenshots")
+            
+            do
+            {
+                try FileManager.default.createDirectory(at: screenshotsDirectory, withIntermediateDirectories: true, attributes: nil)
+            }
+            catch
+            {
+                print(error)
+            }
+            
+            let date = Date()
+            let dateFormatter = DateFormatter()
+            dateFormatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
+            
+            let fileName: URL
+            if let game = self.game as? Game
+            {
+                let filename = game.name + "_" + dateFormatter.string(from: date) + ".png"
+                fileName = screenshotsDirectory.appendingPathComponent(filename)
+            }
+            else
+            {
+                fileName = screenshotsDirectory.appendingPathComponent(dateFormatter.string(from: date) + ".png")
+            }
+            
+            do
+            {
+                try data.write(to: fileName)
+            }
+            catch
+            {
+                print(error)
+            }
+        }
+        
+        self.pauseViewController?.screenshotItem?.isSelected = false
+    }
 }
 
 //MARK: - GameViewControllerDelegate -

Delta/Experimental Features/ExperimentalFeatures.swift

@@ -21,6 +21,11 @@ struct ExperimentalFeatures: FeatureContainer
              description: "Enable to show the Status Bar during gameplay.")
     var showStatusBar
     
+    @Feature(name: "Game Screenshots",
+             description: "When enabled, a Screenshot button will appear in the Pause Menu, allowing you to save a screenshot of your game. You can choose to save the screenshot to Photos or Files.",
+             options: GameScreenshotsOptions())
+    var gameScreenshots
+    
     private init()
     {
         self.prepareFeatures()

Delta/Experimental Features/Features/GameScreenshots.swift

@@ -0,0 +1,54 @@
+//
+//  GameScreenshots.swift
+//  Delta
+//
+//  Created by Chris Rittenhouse on 4/24/23.
+//  Copyright © 2023 Riley Testut. All rights reserved.
+//
+
+import SwiftUI
+
+import DeltaFeatures
+
+enum ScreenshotSize: Double, CaseIterable, CustomStringConvertible
+{
+    case x5 = 5
+    case x4 = 4
+    case x3 = 3
+    case x2 = 2
+    
+    var description: String {
+        if #available(iOS 15, *)
+        {
+            let formattedText = self.rawValue.formatted(.number.decimalSeparator(strategy: .automatic))
+            return "\(formattedText)x Size"
+        }
+        else
+        {
+            return "\(self.rawValue)x Size"
+        }
+    }
+}
+
+extension ScreenshotSize: LocalizedOptionValue
+{
+    var localizedDescription: Text {
+        Text(self.description)
+    }
+    
+    static var localizedNilDescription: Text {
+        Text("Original Size")
+    }
+}
+
+struct GameScreenshotsOptions
+{
+    @Option(name: "Save to Files", description: "Save the screenshot to the app's directory in Files.")
+    var saveToFiles: Bool = true
+
+    @Option(name: "Save to Photos", description: "Save the screenshot to the Photo Library.")
+    var saveToPhotos: Bool = false
+
+    @Option(name: "Image Size", description: "Choose the size of screenshots. This only increases the export size, it does not increase the quality.", values: ScreenshotSize.allCases)
+    var size: ScreenshotSize?
+}

Delta/Extensions/PHPhotoLibrary+Authorization.swift

@@ -0,0 +1,46 @@
+//
+//  PHPhotoLibrary+Authorization.swift
+//  Delta
+//
+//  Created by Chris Rittenhouse on 4/24/23.
+//  Copyright © 2023 Riley Testut. All rights reserved.
+//
+
+import UIKit
+import Photos
+
+extension PHPhotoLibrary
+{
+    static func runIfAuthorized(code: @escaping () -> Void)
+    {
+        PHPhotoLibrary.requestAuthorization(for: .addOnly, handler: { success in
+            switch success
+            {
+            case .authorized:
+                code()
+                
+            case .denied, .restricted, .notDetermined, .limited:
+                break
+            }
+        })
+    }
+    
+    static func saveUIImage(image: UIImage)
+    {
+        // Save the image to the Photos app
+        PHPhotoLibrary.shared().performChanges({
+            PHAssetChangeRequest.creationRequestForAsset(from: image)
+        }, completionHandler: { success, error in
+            if success
+            {
+                // Image saved successfully
+                print("Image saved to Photos app.")
+            }
+            else
+            {
+                // Error saving image
+                print("Error saving image: \(error?.localizedDescription ?? "Unknown error")")
+            }
+        })
+    }
+}

Delta/Pause Menu/PauseViewController.swift

@@ -19,7 +19,7 @@ class PauseViewController: UIViewController, PauseInfoProviding
     }
     
     var pauseItems: [MenuItem] {
-        return [self.saveStateItem, self.loadStateItem, self.cheatCodesItem, self.fastForwardItem, self.sustainButtonsItem].compactMap { $0 }
+        return [self.saveStateItem, self.loadStateItem, self.cheatCodesItem, self.fastForwardItem, self.sustainButtonsItem, self.screenshotItem].compactMap { $0 }
     }
     
     /// Pause Items
@@ -28,6 +28,7 @@ class PauseViewController: UIViewController, PauseInfoProviding
     var cheatCodesItem: MenuItem?
     var fastForwardItem: MenuItem?
     var sustainButtonsItem: MenuItem?
+    var screenshotItem: MenuItem?
     
     /// PauseInfoProviding
     var pauseText: String?
@@ -160,6 +161,7 @@ private extension PauseViewController
         self.cheatCodesItem = nil
         self.sustainButtonsItem = nil
         self.fastForwardItem = nil
+        self.screenshotItem = nil
         
         guard self.emulatorCore != nil else { return }
         
@@ -179,6 +181,11 @@ private extension PauseViewController
         
         self.fastForwardItem = MenuItem(text: NSLocalizedString("Fast Forward", comment: ""), image: #imageLiteral(resourceName: "FastForward"), action: { _ in })
         self.sustainButtonsItem = MenuItem(text: NSLocalizedString("Hold Buttons", comment: ""), image: #imageLiteral(resourceName: "SustainButtons"), action: { _ in })
+        
+        if ExperimentalFeatures.shared.gameScreenshots.isEnabled
+        {
+            self.screenshotItem = MenuItem(text: NSLocalizedString("Screenshot", comment: ""), image: #imageLiteral(resourceName: "Screenshot"), action: { _ in })
+        }
     }
     
     func updateSafeAreaInsets()

Resources/Assets.xcassets/Pause Icons/Screenshot.imageset/Contents.json

@@ -0,0 +1,26 @@
+{
+  "images" : [
+    {
+      "filename" : "screenshot.png",
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "screenshot@2x.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "screenshot@3x.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "properties" : {
+    "template-rendering-intent" : "template"
+  }
+}