Replace SwiftUI renderer with HTML/WKWebView

Gemini-iOS/BrowserNavigationController.swift

@@ -0,0 +1,97 @@
+//
+//  BrowserNavigationController.swift
+//  Gemini-iOS
+//
+//  Created by Shadowfacts on 12/16/20.
+//
+
+import UIKit
+import BrowserCore
+import Combine
+
+class BrowserNavigationController: UINavigationController {
+
+    let navigator: NavigationManager
+    
+    var poppedViewControllers = [UIViewController]()
+    var skipResetPoppedOnNextPush = false
+    
+    private var interactivePushTransition: InteractivePushTransition!
+    
+    private var cancellables = [AnyCancellable]()
+    
+    init(navigator: NavigationManager) {
+        self.navigator = navigator
+        
+        super.init(nibName: nil, bundle: nil)
+        
+        navigator.$currentURL
+            .sink { [weak self] (newURL) in
+                self?.pushViewController(BrowserWebViewController(navigator: navigator, url: newURL), animated: true)
+            }
+            .store(in: &cancellables)
+    }
+    
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        interactivePushTransition = InteractivePushTransition(navigationController: self)
+    }
+    
+    override func popViewController(animated: Bool) -> UIViewController? {
+        if let popped = super.popViewController(animated: animated) {
+            poppedViewControllers.insert(popped, at: 0)
+            return popped
+        } else {
+            return nil
+        }
+    }
+    
+    override func popToRootViewController(animated: Bool) -> [UIViewController]? {
+        if let popped = super.popToRootViewController(animated: animated) {
+            poppedViewControllers = popped
+            return popped
+        } else {
+            return nil
+        }
+    }
+    
+    override func popToViewController(_ viewController: UIViewController, animated: Bool) -> [UIViewController]? {
+        if let popped = super.popToViewController(viewController, animated: animated) {
+            poppedViewControllers.insert(contentsOf: popped, at: 0)
+            return popped
+        } else {
+            return nil
+        }
+    }
+    
+    override func pushViewController(_ viewController: UIViewController, animated: Bool) {
+        if skipResetPoppedOnNextPush {
+            skipResetPoppedOnNextPush = false
+        } else {
+            self.poppedViewControllers = []
+        }
+        super.pushViewController(viewController, animated: animated)
+    }
+    
+    func onWillShow() {
+        self.transitionCoordinator?.notifyWhenInteractionChanges({ (context) in
+            if context.isCancelled {
+                if self.interactivePushTransition.interactive {
+                    // when an interactive push gesture is cancelled, make sure to adding the VC that was being pushed back onto the popped stack so it doesn't disappear
+                    self.poppedViewControllers.insert(self.interactivePushTransition.pushingViewController!, at: 0)
+                } else {
+                    // when an interactive pop gesture is cancelled (i.e. the user lifts their finger before it triggers),
+                    // the popViewController(animated:) method has already been called so the VC has already been added to the popped stack
+                    // so we make sure to remove it, otherwise there could be duplicate VCs on the navigation stasck
+                    self.poppedViewControllers.remove(at: 0)
+                }
+            }
+        })
+    }
+    
+}

Gemini-iOS/BrowserWebViewController.swift

@@ -0,0 +1,188 @@
+//
+//  BrowserWebViewController.swift
+//  Gemini-iOS
+//
+//  Created by Shadowfacts on 12/16/20.
+//
+
+import UIKit
+import BrowserCore
+import WebKit
+import GeminiProtocol
+import GeminiFormat
+import GeminiRenderer
+
+class BrowserWebViewController: UIViewController {
+
+    let navigator: NavigationManager
+    let url: URL
+    private var task: GeminiDataTask?
+    private let renderer = GeminiHTMLRenderer()
+    
+    private var loaded = false
+    
+    private var errorStack: UIStackView!
+    private var errorMessageLabel: UILabel!
+    private var activityIndicator: UIActivityIndicatorView!
+    private var webView: WKWebView!
+    
+    init(navigator: NavigationManager, url: URL) {
+        self.navigator = navigator
+        self.url = url
+        
+        super.init(nibName: nil, bundle: nil)
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        
+        view.backgroundColor = .systemBackground        
+        
+        webView = WKWebView()
+        webView.navigationDelegate = self
+        webView.translatesAutoresizingMaskIntoConstraints = false
+        view.addSubview(webView)
+        NSLayoutConstraint.activate([
+            webView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            webView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            webView.topAnchor.constraint(equalTo: view.topAnchor),
+            webView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+        ])
+        
+        let errorTitle = UILabel()
+        errorTitle.text = "An error occurred"
+        errorTitle.font = UIFont(descriptor: UIFontDescriptor.preferredFontDescriptor(withTextStyle: .headline).withDesign(.serif)!, size: 0)
+        errorTitle.numberOfLines = 0
+        errorMessageLabel = UILabel()
+        errorMessageLabel.font = UIFont(descriptor: UIFontDescriptor.preferredFontDescriptor(withTextStyle: .body).withDesign(.serif)!, size: 0)
+        errorMessageLabel.numberOfLines = 0
+        errorStack = UIStackView(arrangedSubviews: [
+            errorTitle,
+            errorMessageLabel,
+        ])
+        errorStack.translatesAutoresizingMaskIntoConstraints = false
+        errorStack.axis = .vertical
+        errorStack.alignment = .center
+        errorStack.isHidden = true
+        view.addSubview(errorStack)
+        NSLayoutConstraint.activate([
+            errorStack.centerYAnchor.constraint(equalTo: view.centerYAnchor),
+            errorStack.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            errorStack.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+        ])
+        
+        activityIndicator = UIActivityIndicatorView(style: .large)
+        activityIndicator.translatesAutoresizingMaskIntoConstraints = false
+        activityIndicator.isHidden = true
+        view.addSubview(activityIndicator)
+        NSLayoutConstraint.activate([
+            activityIndicator.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+            activityIndicator.centerYAnchor.constraint(equalTo: view.centerYAnchor),
+        ])
+    }
+    
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        
+        loadDocument()
+    }
+    
+    private func loadDocument() {
+        guard !loaded else { return }
+        
+        webView.isHidden = true
+        errorStack.isHidden = true
+        activityIndicator.isHidden = false
+        activityIndicator.startAnimating()
+        
+        let url = self.url
+        task = try! GeminiDataTask(url: url) { (response) in
+            self.task = nil
+            self.loaded = true
+            
+            switch response {
+            case let .failure(error):
+                DispatchQueue.main.async {
+                    self.showError(message: error.localizedDescription)
+                }
+            case let .success(response):
+                if response.status.isRedirect {
+                    if let redirect = URL(string: response.meta) {
+                        self.navigator.changeURL(redirect)
+                    } else {
+                        DispatchQueue.main.async {
+                            self.showError(message: "Invalid redirect URL: '\(response.meta)'")
+                        }
+                    }
+                } else if response.status.isSuccess,
+                          let text = response.bodyText {
+                    self.renderDocument(GeminiParser.parse(text: text, baseURL: url))
+                } else {
+                    DispatchQueue.main.async {
+                        self.showError(message: "Unknown error: \(response.header)")
+                    }
+                }
+            }
+        }
+        task!.resume()
+    }
+    
+    private func showError(message: String) {
+        webView.isHidden = true
+        errorStack.isHidden = false
+        activityIndicator.isHidden = true
+        activityIndicator.stopAnimating()
+        
+        errorMessageLabel.text = message
+    }
+    
+    private func renderDocument(_ doc: Document) {
+        let html = BrowserWebViewController.preamble + renderer.renderDocumentToHTML(doc) + BrowserWebViewController.postamble
+        DispatchQueue.main.async {
+            self.webView.isHidden = false
+            self.errorStack.isHidden = true
+            self.activityIndicator.isHidden = true
+            self.activityIndicator.stopAnimating()
+            
+            if let title = doc.title {
+                self.navigationItem.title = title
+            }
+            
+            self.webView.loadHTMLString(html, baseURL: Bundle.main.bundleURL)
+        }
+    }
+    
+    private static let preamble = """
+    <!doctype html>
+    <html>
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
+        <link rel="stylesheet" href="\(Bundle.main.url(forResource: "browser", withExtension: "css")!.absoluteString)">
+    </head>
+    <body>
+    """
+    
+    private static let postamble = """
+    </body>
+    </html>
+    """
+
+}
+
+extension BrowserWebViewController: WKNavigationDelegate {
+    func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
+        let url = navigationAction.request.url!
+        if url.scheme == "file" {
+            decisionHandler(.allow)
+        } else {
+            decisionHandler(.cancel)
+            navigator.changeURL(url)
+            loadDocument()
+        }
+    }
+}

Gemini-iOS/InteractivePushTransition.swift

@@ -0,0 +1,142 @@
+//
+//  InteractivePushTransition.swift
+//  Gemini-iOS
+//
+//  Created by Shadowfacts on 12/16/20.
+//
+
+import UIKit
+
+/// Allows interactively moving forward through the navigation stack after popping
+/// Based on https://github.com/NSExceptional/TBInteractivePushTransition
+class InteractivePushTransition: UIPercentDrivenInteractiveTransition {
+    
+    fileprivate let minimumPushVelocityThreshold: CGFloat = 700
+    fileprivate let minimumPushDistanceThreshold: CGFloat = 0.5
+    fileprivate let pushAnimationDuration: TimeInterval = 0.35
+    
+    private(set) weak var navigationController: BrowserNavigationController!
+
+    private(set) weak var interactivePushGestureRecognizer: UIScreenEdgePanGestureRecognizer!
+    
+    private(set) var interactive = false
+    private(set) weak var pushingViewController: UIViewController?
+    
+    init(navigationController: BrowserNavigationController) {
+        super.init()
+        
+        self.navigationController = navigationController
+
+        let interactivePushGestureRecognizer = UIScreenEdgePanGestureRecognizer(target: self, action: #selector(handleSwipeForward(_:)))
+        self.interactivePushGestureRecognizer = interactivePushGestureRecognizer
+        
+        navigationController.delegate = self
+        interactivePushGestureRecognizer.edges = .right
+        interactivePushGestureRecognizer.require(toFail: navigationController.interactivePopGestureRecognizer!)
+        navigationController.view.addGestureRecognizer(interactivePushGestureRecognizer)
+        
+        let trackpadGestureRecognizer = TrackpadScrollGestureRecognizer(target: self, action: #selector(handleSwipeForward(_:)))
+        trackpadGestureRecognizer.require(toFail: navigationController.interactivePopGestureRecognizer!)
+        navigationController.view.addGestureRecognizer(trackpadGestureRecognizer)
+    }
+
+    @objc func handleSwipeForward(_ recognizer: UIPanGestureRecognizer) {
+        interactive = true
+        
+        let velocity = recognizer.velocity(in: recognizer.view)
+        let translation = recognizer.translation(in: recognizer.view)
+        let dx = -translation.x / navigationController.view.bounds.width
+        let vx = -velocity.x
+        
+        switch recognizer.state {
+        case .began:
+            if let viewController = navigationController.poppedViewControllers.first {
+                pushingViewController = viewController
+                navigationController.poppedViewControllers.removeFirst()
+                navigationController.skipResetPoppedOnNextPush = true
+                navigationController.pushViewController(viewController, animated: true)
+            } else {
+                interactive = false
+            }
+            
+        case .changed:
+            update(dx)
+
+        case .ended:
+            if (dx > minimumPushDistanceThreshold || vx > minimumPushVelocityThreshold) {
+                finish()
+            } else {
+                cancel()
+            }
+            interactive = false
+            
+        default:
+            cancel()
+            interactive = false
+        }
+    }
+
+}
+
+extension InteractivePushTransition: UINavigationControllerDelegate {
+    func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
+        self.navigationController.onWillShow()
+    }
+    
+    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
+        if operation == .push, interactive {
+            return self
+        }
+        
+        return nil
+    }
+    
+    func navigationController(_ navigationController: UINavigationController, interactionControllerFor animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
+        if interactive {
+            return self
+        }
+        return nil
+    }
+}
+
+extension InteractivePushTransition: UIViewControllerAnimatedTransitioning {
+    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
+        return pushAnimationDuration
+    }
+    
+    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
+        let toView = transitionContext.view(forKey: .to)!
+        let fromView = transitionContext.view(forKey: .from)!
+
+        let dimmingView = UIView()
+        dimmingView.backgroundColor = .black
+        dimmingView.alpha = 0
+        dimmingView.frame = fromView.frame
+
+        transitionContext.containerView.addSubview(dimmingView)
+        transitionContext.containerView.addSubview(toView)
+        
+        // modify frame of presented view to go from x = <screen width> to x = 0
+        var frame = fromView.frame
+        frame.origin.x = frame.width
+        toView.frame = frame
+        frame.origin.x = 0
+        
+        // we want it linear while interactive, but we want the "ease out" animation
+        // if the user flicks the screen ahrd enough to finish the transition without interaction
+        let options = interactive ? UIView.AnimationOptions.curveLinear : .curveEaseOut
+        
+        let duration = transitionDuration(using: transitionContext)
+        UIView.animate(withDuration: duration, delay: 0, options: options, animations: {
+            // these magic numbers scientifically determined by repeatedly adjusting and comparing to the system animation
+            let translationDistance = -frame.size.width * 0.3
+            fromView.transform = CGAffineTransform(translationX: translationDistance, y: 0)
+            toView.frame = frame
+            dimmingView.alpha = 0.075
+        }) { (finished) in
+            fromView.transform = .identity
+            dimmingView.removeFromSuperview()
+            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
+        }
+    }
+}

Gemini-iOS/Resources/browser.css

@@ -0,0 +1,40 @@
+body {
+    font-family: ui-serif;
+    overflow-wrap: break-word;
+}
+
+pre {
+    font-family: ui-monospace;
+    overflow-wrap: normal;
+    overflow-x: auto;
+    tab-size: 4;
+}
+
+h1, h2, h3 {
+    line-height: 1;
+    font-weight: normal;
+}
+
+p.link {
+    display: block;
+    margin: 8px 0; 
+}
+
+a {
+    color: rgb(0, 122, 255);
+}
+
+ul {
+    padding-left: 20px;
+}
+
+@media (prefers-color-scheme: dark) {
+    body {
+        background-color: black;
+        color: white;
+    }
+    
+    a {
+        color: rgb(10, 132, 255);
+    }
+}

Gemini-iOS/SceneDelegate.swift

@@ -40,13 +40,14 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
         navigationManager.delegate = self
         
         // Create the SwiftUI view that provides the window contents.
-        let contentView = ContentView(navigator: navigationManager)
+//        let contentView = ContentView(navigator: navigationManager)
 
         // Use a UIHostingController as window root view controller.
         if let windowScene = scene as? UIWindowScene {
             let window = UIWindow(windowScene: windowScene)
             window.overrideUserInterfaceStyle = Preferences.shared.theme
-            window.rootViewController = UIHostingController(rootView: contentView)
+            window.rootViewController = BrowserNavigationController(navigator: navigationManager)
+//            window.rootViewController = UIHostingController(rootView: contentView)
 //            window.rootViewController = BrowserViewController(navigator: navigationManager)
             self.window = window
             window.makeKeyAndVisible()

Gemini-iOS/TrackpadScrollGestureRecognizer.swift

@@ -0,0 +1,22 @@
+//
+//  TrackpadScrollGestureRecognizer.swift
+//  Gemini-iOS
+//
+//  Created by Shadowfacts on 12/16/20.
+//
+
+import UIKit
+
+class TrackpadScrollGestureRecognizer: UIPanGestureRecognizer {
+
+    override init(target: Any?, action: Selector?) {
+        super.init(target: target, action: action)
+        
+        self.allowedScrollTypesMask = .all
+    }
+    
+    override func shouldReceive(_ event: UIEvent) -> Bool {
+        return event.type == .scroll
+    }
+    
+}

Gemini.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 50;
+	objectVersion = 52;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -40,6 +40,13 @@
 		D664673624BD07F700B0B741 /* RenderingBlock.swift in Sources */ = {isa = PBXBuildFile; fileRef = D664673524BD07F700B0B741 /* RenderingBlock.swift */; };
 		D664673824BD086F00B0B741 /* RenderingBlockView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D664673724BD086F00B0B741 /* RenderingBlockView.swift */; };
 		D664673A24BD0B8E00B0B741 /* Fonts.swift in Sources */ = {isa = PBXBuildFile; fileRef = D664673924BD0B8E00B0B741 /* Fonts.swift */; };
+		D688F586258AC738003A0A73 /* GeminiHTMLRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D688F585258AC738003A0A73 /* GeminiHTMLRenderer.swift */; };
+		D688F590258AC814003A0A73 /* HTMLEntities in Frameworks */ = {isa = PBXBuildFile; productRef = D688F58F258AC814003A0A73 /* HTMLEntities */; };
+		D688F599258ACAAE003A0A73 /* BrowserWebViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D688F598258ACAAE003A0A73 /* BrowserWebViewController.swift */; };
+		D688F5FF258ACE6B003A0A73 /* browser.css in Resources */ = {isa = PBXBuildFile; fileRef = D688F5FE258ACE6B003A0A73 /* browser.css */; };
+		D688F621258B0811003A0A73 /* BrowserNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D688F620258B0811003A0A73 /* BrowserNavigationController.swift */; };
+		D688F62A258B0833003A0A73 /* InteractivePushTransition.swift in Sources */ = {isa = PBXBuildFile; fileRef = D688F629258B0833003A0A73 /* InteractivePushTransition.swift */; };
+		D688F633258B09BB003A0A73 /* TrackpadScrollGestureRecognizer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D688F632258B09BB003A0A73 /* TrackpadScrollGestureRecognizer.swift */; };
 		D691A64E25217C6F00348C4B /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D691A64D25217C6F00348C4B /* Preferences.swift */; };
 		D691A66725217FD800348C4B /* PreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D691A66625217FD800348C4B /* PreferencesView.swift */; };
 		D691A68725223A4700348C4B /* NavigationBar.swift in Sources */ = {isa = PBXBuildFile; fileRef = D691A68625223A4600348C4B /* NavigationBar.swift */; };
@@ -298,6 +305,12 @@
 		D664673524BD07F700B0B741 /* RenderingBlock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RenderingBlock.swift; sourceTree = "<group>"; };
 		D664673724BD086F00B0B741 /* RenderingBlockView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RenderingBlockView.swift; sourceTree = "<group>"; };
 		D664673924BD0B8E00B0B741 /* Fonts.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Fonts.swift; sourceTree = "<group>"; };
+		D688F585258AC738003A0A73 /* GeminiHTMLRenderer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GeminiHTMLRenderer.swift; sourceTree = "<group>"; };
+		D688F598258ACAAE003A0A73 /* BrowserWebViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrowserWebViewController.swift; sourceTree = "<group>"; };
+		D688F5FE258ACE6B003A0A73 /* browser.css */ = {isa = PBXFileReference; lastKnownFileType = text.css; path = browser.css; sourceTree = "<group>"; };
+		D688F620258B0811003A0A73 /* BrowserNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrowserNavigationController.swift; sourceTree = "<group>"; };
+		D688F629258B0833003A0A73 /* InteractivePushTransition.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InteractivePushTransition.swift; sourceTree = "<group>"; };
+		D688F632258B09BB003A0A73 /* TrackpadScrollGestureRecognizer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TrackpadScrollGestureRecognizer.swift; sourceTree = "<group>"; };
 		D691A64D25217C6F00348C4B /* Preferences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Preferences.swift; sourceTree = "<group>"; };
 		D691A66625217FD800348C4B /* PreferencesView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesView.swift; sourceTree = "<group>"; };
 		D691A6762522382E00348C4B /* BrowserViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BrowserViewController.swift; sourceTree = "<group>"; };
@@ -373,6 +386,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D688F590258AC814003A0A73 /* HTMLEntities in Frameworks */,
 				D62664F024BC0D7700DF9B88 /* GeminiFormat.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -530,6 +544,7 @@
 				D62664EB24BC0B4D00DF9B88 /* DocumentView.swift */,
 				D664673724BD086F00B0B741 /* RenderingBlockView.swift */,
 				D6DA5782252396030048B65A /* View+Extensions.swift */,
+				D688F585258AC738003A0A73 /* GeminiHTMLRenderer.swift */,
 			);
 			path = GeminiRenderer;
 			sourceTree = "<group>";
@@ -550,11 +565,23 @@
 			name = Frameworks;
 			sourceTree = "<group>";
 		};
+		D688F618258AD231003A0A73 /* Resources */ = {
+			isa = PBXGroup;
+			children = (
+				D688F5FE258ACE6B003A0A73 /* browser.css */,
+			);
+			path = Resources;
+			sourceTree = "<group>";
+		};
 		D6E152A324BFFDF500FDF9D3 /* Gemini-iOS */ = {
 			isa = PBXGroup;
 			children = (
 				D6E152A424BFFDF500FDF9D3 /* AppDelegate.swift */,
 				D6E152A624BFFDF500FDF9D3 /* SceneDelegate.swift */,
+				D688F620258B0811003A0A73 /* BrowserNavigationController.swift */,
+				D688F629258B0833003A0A73 /* InteractivePushTransition.swift */,
+				D688F632258B09BB003A0A73 /* TrackpadScrollGestureRecognizer.swift */,
+				D688F598258ACAAE003A0A73 /* BrowserWebViewController.swift */,
 				D691A6762522382E00348C4B /* BrowserViewController.swift */,
 				D6E152A824BFFDF500FDF9D3 /* ContentView.swift */,
 				D691A68625223A4600348C4B /* NavigationBar.swift */,
@@ -562,6 +589,7 @@
 				D691A64D25217C6F00348C4B /* Preferences.swift */,
 				D691A66625217FD800348C4B /* PreferencesView.swift */,
 				D62BCEE1252553620031D894 /* ActivityView.swift */,
+				D688F618258AD231003A0A73 /* Resources */,
 				D6E152AA24BFFDF600FDF9D3 /* Assets.xcassets */,
 				D6E152AF24BFFDF600FDF9D3 /* LaunchScreen.storyboard */,
 				D6E152B224BFFDF600FDF9D3 /* Info.plist */,
@@ -748,6 +776,9 @@
 				D68544302522E10F004C4AE0 /* PBXTargetDependency */,
 			);
 			name = GeminiRenderer;
+			packageProductDependencies = (
+				D688F58F258AC814003A0A73 /* HTMLEntities */,
+			);
 			productName = GeminiRenderer;
 			productReference = D62664CE24BC081B00DF9B88 /* GeminiRenderer.framework */;
 			productType = "com.apple.product-type.framework";
@@ -890,6 +921,9 @@
 				Base,
 			);
 			mainGroup = D626645224BBF1C200DF9B88;
+			packageReferences = (
+				D688F58E258AC814003A0A73 /* XCRemoteSwiftPackageReference "swift-html-entities" */,
+			);
 			productRefGroup = D626645C24BBF1C200DF9B88 /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
@@ -968,6 +1002,7 @@
 			files = (
 				D6E152B124BFFDF600FDF9D3 /* LaunchScreen.storyboard in Resources */,
 				D6E152AE24BFFDF600FDF9D3 /* Preview Assets.xcassets in Resources */,
+				D688F5FF258ACE6B003A0A73 /* browser.css in Resources */,
 				D6E152AB24BFFDF600FDF9D3 /* Assets.xcassets in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1048,6 +1083,7 @@
 				D62664EE24BC0BCE00DF9B88 /* MaybeLazyVStack.swift in Sources */,
 				D62664EC24BC0B4D00DF9B88 /* DocumentView.swift in Sources */,
 				D6DA5783252396030048B65A /* View+Extensions.swift in Sources */,
+				D688F586258AC738003A0A73 /* GeminiHTMLRenderer.swift in Sources */,
 				D664673824BD086F00B0B741 /* RenderingBlockView.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1064,7 +1100,11 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D688F621258B0811003A0A73 /* BrowserNavigationController.swift in Sources */,
 				D691A66725217FD800348C4B /* PreferencesView.swift in Sources */,
+				D688F62A258B0833003A0A73 /* InteractivePushTransition.swift in Sources */,
+				D688F599258ACAAE003A0A73 /* BrowserWebViewController.swift in Sources */,
+				D688F633258B09BB003A0A73 /* TrackpadScrollGestureRecognizer.swift in Sources */,
 				D6E152A524BFFDF500FDF9D3 /* AppDelegate.swift in Sources */,
 				D691A6A0252242FC00348C4B /* ToolBar.swift in Sources */,
 				D6E152A724BFFDF500FDF9D3 /* SceneDelegate.swift in Sources */,
@@ -1949,6 +1989,25 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCRemoteSwiftPackageReference section */
+		D688F58E258AC814003A0A73 /* XCRemoteSwiftPackageReference "swift-html-entities" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/Kitura/swift-html-entities";
+			requirement = {
+				kind = upToNextMajorVersion;
+				minimumVersion = 3.0.200;
+			};
+		};
+/* End XCRemoteSwiftPackageReference section */
+
+/* Begin XCSwiftPackageProductDependency section */
+		D688F58F258AC814003A0A73 /* HTMLEntities */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = D688F58E258AC814003A0A73 /* XCRemoteSwiftPackageReference "swift-html-entities" */;
+			productName = HTMLEntities;
+		};
+/* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = D626645324BBF1C200DF9B88 /* Project object */;
 }

Gemini.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -0,0 +1,16 @@
+{
+  "object": {
+    "pins": [
+      {
+        "package": "HTMLEntities",
+        "repositoryURL": "https://github.com/Kitura/swift-html-entities",
+        "state": {
+          "branch": null,
+          "revision": "2b14531d0c36dbb7c1c45a4d38db9c2e7898a307",
+          "version": "3.0.200"
+        }
+      }
+    ]
+  },
+  "version": 1
+}

GeminiFormat/Document.swift

@@ -21,6 +21,13 @@ public struct Document {
         // todo: should this be \r\n
         return lines.map { $0.geminiText() }.joined(separator: "\n")
     }
+    
+    public var title: String? {
+        for case let .heading(text, level: _) in lines {
+            return text
+        }
+        return nil
+    }
 }
 
 public extension Document {

GeminiRenderer/GeminiHTMLRenderer.swift

@@ -0,0 +1,78 @@
+//
+//  GeminiHTMLRenderer.swift
+//  GeminiRenderer
+//
+//  Created by Shadowfacts on 12/16/20.
+//
+
+import Foundation
+import GeminiFormat
+import HTMLEntities
+
+public protocol GeminiHTMLRendererDelegate: class {
+    
+}
+
+public class GeminiHTMLRenderer {
+    
+    public weak var delegate: GeminiHTMLRendererDelegate?
+    
+    public init() {
+    }
+    
+    public func renderDocumentToHTML(_ doc: Document) -> String {
+        var str = ""
+        
+        var inPreformatting = false
+        var inList = false
+        
+        for line in doc.lines {
+            if inList && !line.isListItem {
+                str += "</ul>"
+            }
+            
+            switch line {
+            case let .text(text):
+                str += "<p>\(text.htmlEscape())</p>"
+            case let .link(url, text: maybeText):
+                let text = maybeText ?? url.absoluteString
+                str += "<p class=\"link\"><a href=\"\(url.absoluteString)\">\(text.htmlEscape())</a></p>"
+            case .preformattedToggle(alt: _):
+                inPreformatting = !inPreformatting
+                if inPreformatting {
+                    str += "<pre>"
+                } else {
+                    str += "</pre>"
+                }
+            case let .preformattedText(text):
+                str += text.htmlEscape()
+                str += "\n"
+            case let .heading(text, level: level):
+                let tag = "h\(level.rawValue)"
+                str += "<\(tag)>\(text.htmlEscape())</\(tag)>"
+            case let .unorderedListItem(text):
+                if !inList {
+                    inList = true
+                    str += "<ul>"
+                }
+                str += "<li>\(text.htmlEscape())</li>"
+            case let .quote(text):
+                str += "<blockquote>\(text.htmlEscape())</blockquote>"
+            }
+        }
+        
+        return str
+    }
+    
+}
+
+fileprivate extension Document.Line {
+    var isListItem: Bool {
+        switch self {
+        case .unorderedListItem(_):
+            return true
+        default:
+            return false
+        }
+    }
+}