fix: sync webview theme with window theme on Windows, closes #5802

.changes/webview-theme.md

@@ -0,0 +1,5 @@
+---
+"tauri": "patch"
+---
+
+On Windows, change webview theme based on Window theme for more accurate `prefers-color-scheme` support.

core/tauri-runtime-wry/Cargo.toml

@@ -13,7 +13,7 @@ exclude = [ "CHANGELOG.md", "/target" ]
 readme = "README.md"
 
 [dependencies]
-wry = { version = "0.23", default-features = false, features = [ "file-drop", "protocol" ] }
+wry = { git = "https://github.com/tauri-apps/wry", default-features = false, features = [ "file-drop", "protocol" ] }
 tauri-runtime = { version = "0.12.1", path = "../tauri-runtime" }
 tauri-utils = { version = "1.2.1", path = "../tauri-utils" }
 uuid = { version = "1", features = [ "v4" ] }

core/tauri-runtime-wry/src/lib.rs

@@ -81,6 +81,7 @@ pub use wry::application::platform::macos::{
 };
 
 use std::{
+  borrow::Cow,
   cell::RefCell,
   collections::{
     hash_map::Entry::{Occupied, Vacant},
@@ -286,7 +287,7 @@ impl From<&WryRequest<Vec<u8>>> for HttpRequestWrapper {
 }
 
 // response
-struct HttpResponseWrapper(WryResponse<Vec<u8>>);
+struct HttpResponseWrapper(WryResponse<Cow<'static, [u8]>>);
 impl From<HttpResponse> for HttpResponseWrapper {
   fn from(response: HttpResponse) -> Self {
     let (parts, body) = response.into_parts();
@@ -300,7 +301,7 @@ impl From<HttpResponse> for HttpResponseWrapper {
       res_builder = res_builder.header(name, val);
     }
 
-    let res = res_builder.body(body).unwrap();
+    let res = res_builder.body(body.into()).unwrap();
     Self(res)
   }
 }
@@ -2840,6 +2841,18 @@ fn handle_event_loop<T: UserEvent>(
         }
 
         match event {
+          #[cfg(windows)]
+          WryWindowEvent::ThemeChanged(theme) => {
+            if let Some(window) = windows.borrow().get(&window_id) {
+              if let Some(WindowHandle::Webview { inner, .. }) = &window.inner {
+                let theme = match theme {
+                  WryTheme::Dark => wry::webview::Theme::Dark,
+                  _ => wry::webview::Theme::Light,
+                };
+                inner.set_theme(theme);
+              }
+            }
+          }
           WryWindowEvent::CloseRequested => {
             on_close_requested(callback, window_id, windows.clone());
           }
@@ -3059,6 +3072,14 @@ fn create_webview<T: UserEvent>(
     webview_builder = webview_builder.with_additional_browser_args(&additional_browser_args);
   }
 
+  #[cfg(windows)]
+  if let Some(theme) = webview_attributes.theme {
+    webview_builder = webview_builder.with_theme(match theme {
+      Theme::Dark => wry::webview::Theme::Dark,
+      _ => wry::webview::Theme::Light,
+    });
+  }
+
   if let Some(handler) = ipc_handler {
     webview_builder = webview_builder.with_ipc_handler(create_ipc_handler(
       context,

core/tauri-runtime/src/webview.rs

@@ -29,6 +29,7 @@ pub struct WebviewAttributes {
   pub clipboard: bool,
   pub accept_first_mouse: bool,
   pub additional_browser_args: Option<String>,
+  pub theme: Option<Theme>,
 }
 
 impl WebviewAttributes {
@@ -43,6 +44,7 @@ impl WebviewAttributes {
       clipboard: false,
       accept_first_mouse: false,
       additional_browser_args: None,
+      theme: None,
     }
   }
 

core/tauri/src/window.rs

@@ -367,6 +367,7 @@ impl<'a, R: Runtime> WindowBuilder<'a, R> {
   /// - **macOS**: Only supported on macOS 10.14+.
   #[must_use]
   pub fn theme(mut self, theme: Option<Theme>) -> Self {
+    self.webview_attributes.theme = theme;
     self.window_builder = self.window_builder.theme(theme);
     self
   }