Add the ability to navigate with swipe gesture

This switch is for WebView on macOS,
enabling us to swipe horizontally to
trigger backward and forward page navigation.

This commit also includes a worked example for it.

For details, see <https://developer.apple.com/documentation/webkit/wkwebview/1414995-allowsbackforwardnavigationgestu>

Signed-off-by: pan93412 <pan93412@gmail.com>

.changes/allow-back-forward-gesture.md

@@ -0,0 +1,11 @@
+---
+"wry": minor
+---
+
+Add the ability to navigate with swipe gesture
+
+This switch is for WebView on macOS, enabling us to swipe horizontally to trigger backward and forward page navigation.
+
+This commit also includes a worked example for it.
+
+For details, see <https://developer.apple.com/documentation/webkit/wkwebview/1414995-allowsbackforwardnavigationgestu>

examples/with_forward_gesture.rs

@@ -0,0 +1,36 @@
+// Copyright 2020-2022 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+fn main() -> wry::Result<()> {
+  use wry::{
+    application::{
+      event::{Event, StartCause, WindowEvent},
+      event_loop::{ControlFlow, EventLoop},
+      window::WindowBuilder,
+    },
+    webview::WebViewBuilder,
+  };
+
+  let event_loop = EventLoop::new();
+  let window = WindowBuilder::new()
+    .with_title("Hello World")
+    .build(&event_loop)?;
+  let _webview = WebViewBuilder::new(window)?
+    .with_back_forward_navigation_gestures(true)
+    .with_url("https://html5test.com")?
+    .build()?;
+
+  event_loop.run(move |event, _, control_flow| {
+    *control_flow = ControlFlow::Wait;
+
+    match event {
+      Event::NewEvents(StartCause::Init) => println!("Wry has started!"),
+      Event::WindowEvent {
+        event: WindowEvent::CloseRequested,
+        ..
+      } => *control_flow = ControlFlow::Exit,
+      _ => (),
+    }
+  });
+}

src/webview/mod.rs

@@ -215,6 +215,14 @@ pub struct WebViewAttributes {
   ///
   /// This configuration only impacts macOS.
   pub accept_first_mouse: bool,
+
+  /// Indicates whether horizontal swipe gestures trigger backward and forward page navigation.
+  ///
+  /// ## Platform-specific
+  ///
+  /// This configuration only impacts macOS.
+  /// [Documentation](https://developer.apple.com/documentation/webkit/wkwebview/1414995-allowsbackforwardnavigationgestu).
+  pub back_forward_navigation_gestures: bool,
 }
 
 impl Default for WebViewAttributes {
@@ -241,6 +249,7 @@ impl Default for WebViewAttributes {
       devtools: false,
       zoom_hotkeys_enabled: false,
       accept_first_mouse: false,
+      back_forward_navigation_gestures: false,
     }
   }
 }
@@ -295,6 +304,17 @@ impl<'a> WebViewBuilder<'a> {
     })
   }
 
+  /// Indicates whether horizontal swipe gestures trigger backward and forward page navigation.
+  ///
+  /// ## Platform-specific
+  ///
+  /// This configuration only impacts macOS.
+  /// [Documentation](https://developer.apple.com/documentation/webkit/wkwebview/1414995-allowsbackforwardnavigationgestu).
+  pub fn with_back_forward_navigation_gestures(mut self, gesture: bool) -> Self {
+    self.webview.back_forward_navigation_gestures = gesture;
+    self
+  }
+
   /// Sets whether the WebView should be transparent.
   ///
   /// ## Platform-specific:

src/webview/wkwebview/mod.rs

@@ -343,6 +343,13 @@ impl InnerWebView {
         let _: () = msg_send![webview, initWithFrame:frame configuration:config];
       }
 
+      // allowsBackForwardNavigation
+      #[cfg(target_os = "macos")]
+      {
+        let value = attributes.back_forward_navigation_gestures;
+        let _: () = msg_send![webview, setAllowsBackForwardNavigationGestures:value];
+      }
+
       // Message handler
       let ipc_handler_ptr = if let Some(ipc_handler) = attributes.ipc_handler {
         let cls = ClassDecl::new("WebViewDelegate", class!(NSObject));