feat(windows): add WebViewBuilderExtWindows::with_scroll_bar_style (#…

…1344)

* Windows: Use `CoreWebView2EnvironmentOptions` API.

Use the CoreWebView2EnvironmentOptions API wrapper when creating a
WebView2 environment on Windows, as opposed to using the
ICoreWebView2EnvironmentOptions* COM interfaces. The wrapper exposes
the interface methods with a more Rust-like API.

It may be possible to do this with ICoreWebView2Controller as well, but
I don't feel like experimenting with that right now. This is just an
improvement I realised I could make while implementing #1339.

Signed-off-by: Jamie Ridding <[email protected]>

* Add with_scroll_bar_style to WebViewBuilderExtWindows

Signed-off-by: Jamie Ridding <[email protected]>

* Add change file.

Signed-off-by: Jamie Ridding <[email protected]>

* Adjust change type in change file.

I used the wrong change type for wry in 1344-with_scroll_bar_style.
This commit upgrades the change type from a patch to a minor change.

Signed-off-by: Jamie Ridding <[email protected]>

* I forgot to run cargo fmt -_-

Signed-off-by: Jamie Ridding <[email protected]>

---------

Signed-off-by: Jamie Ridding <[email protected]>

.changes/1344-with_scroll_bar_style.md

@@ -0,0 +1,5 @@
+---
+"wry": minor
+---
+
+Windows: Implement `WebViewBuilderExtWindows::with_scroll_bar_style` to allow opting into Fluent Overlay style scrollbars.

src/lib.rs

@@ -238,6 +238,8 @@ pub use wkwebview::{PrintMargin, PrintOptions};
 #[cfg(target_os = "windows")]
 pub(crate) mod webview2;
 #[cfg(target_os = "windows")]
+pub use self::webview2::ScrollBarStyle;
+#[cfg(target_os = "windows")]
 use self::webview2::*;
 #[cfg(target_os = "windows")]
 use webview2_com::Microsoft::Web::WebView2::Win32::ICoreWebView2Controller;
@@ -1088,6 +1090,7 @@ pub(crate) struct PlatformSpecificWebViewAttributes {
   browser_accelerator_keys: bool,
   theme: Option<Theme>,
   use_https: bool,
+  scroll_bar_style: ScrollBarStyle,
 }
 
 #[cfg(windows)]
@@ -1098,6 +1101,7 @@ impl Default for PlatformSpecificWebViewAttributes {
       browser_accelerator_keys: true, // This is WebView2's default behavior
       theme: None,
       use_https: false, // To match macOS & Linux behavior in the context of mixed content.
+      scroll_bar_style: ScrollBarStyle::default(),
     }
   }
 }
@@ -1140,6 +1144,15 @@ pub trait WebViewBuilderExtWindows {
   ///
   /// The default value is `false`.
   fn with_https_scheme(self, enabled: bool) -> Self;
+
+  /// Specifies the native scrollbar style to use with webview2.
+  /// CSS styles that modify the scrollbar are applied on top of the native appearance configured here.
+  ///
+  /// Defaults to [`ScrollbarStyle::Default`] which is the browser default used by Microsoft Edge.
+  ///
+  /// Requires WebView2 Runtime version 125.0.2535.41 or higher, does nothing on older versions,
+  /// see https://learn.microsoft.com/en-us/microsoft-edge/webview2/release-notes/?tabs=dotnetcsharp#10253541
+  fn with_scroll_bar_style(self, style: ScrollBarStyle) -> Self;
 }
 
 #[cfg(windows)]
@@ -1163,6 +1176,11 @@ impl WebViewBuilderExtWindows for WebViewBuilder<'_> {
     self.platform_specific.use_https = enabled;
     self
   }
+
+  fn with_scroll_bar_style(mut self, style: ScrollBarStyle) -> Self {
+    self.platform_specific.scroll_bar_style = style;
+    self
+  }
 }
 
 #[cfg(target_os = "android")]

src/webview2/mod.rs

@@ -287,26 +287,30 @@ impl InnerWebView {
       arguments
     });
 
-    let additional_browser_args = HSTRING::from(additional_browser_args);
-
     let (tx, rx) = mpsc::channel();
     CreateCoreWebView2EnvironmentCompletedHandler::wait_for_async_operation(
       Box::new(move |environmentcreatedhandler| unsafe {
-        let options: ICoreWebView2EnvironmentOptions =
-          CoreWebView2EnvironmentOptions::default().into();
+        let options = CoreWebView2EnvironmentOptions::default();
 
-        let _ = options.SetAdditionalBrowserArguments(&additional_browser_args);
+        options.set_additional_browser_arguments(additional_browser_args);
 
         // Get user's system language
         let lcid = GetUserDefaultUILanguage();
         let mut lang = [0; MAX_LOCALE_NAME as usize];
         LCIDToLocaleName(lcid as u32, Some(&mut lang), LOCALE_ALLOW_NEUTRAL_NAMES);
-        options.SetLanguage(PCWSTR::from_raw(lang.as_ptr()))?;
+        options.set_language(String::from_utf16_lossy(&lang));
+
+        let scroll_bar_style = match pl_attrs.scroll_bar_style {
+          ScrollBarStyle::Default => COREWEBVIEW2_SCROLLBAR_STYLE_DEFAULT,
+          ScrollBarStyle::FluentOverlay => COREWEBVIEW2_SCROLLBAR_STYLE_FLUENT_OVERLAY,
+        };
+
+        options.set_scroll_bar_style(scroll_bar_style);
 
         CreateCoreWebView2EnvironmentWithOptions(
           PCWSTR::null(),
           &data_directory.unwrap_or_default(),
-          &options,
+          &ICoreWebView2EnvironmentOptions::from(options),
           &environmentcreatedhandler,
         )
         .map_err(Into::into)
@@ -1371,6 +1375,17 @@ impl InnerWebView {
   }
 }
 
+/// The scrollbar style to use in the webview.
+#[derive(Clone, Copy, Default)]
+pub enum ScrollBarStyle {
+  #[default]
+  /// The browser default scrollbar style.
+  Default,
+
+  /// Fluent UI style overlay scrollbars.
+  FluentOverlay,
+}
+
 #[inline]
 fn load_url_with_headers(
   webview: &ICoreWebView2,