Ladybird: Inform WebContent whether the AppKit chrome is in dark mode

Ladybird/AppKit/UI/LadybirdWebView.mm

@@ -872,6 +872,11 @@ static void copy_text_to_clipboard(StringView text)
     [self handleResize];
 }
 
+- (void)viewDidChangeEffectiveAppearance
+{
+    m_web_view_bridge->update_palette();
+}
+
 - (BOOL)isFlipped
 {
     // The origin of a NSScrollView is the lower-left corner, with the y-axis extending upwards. Instead,

Ladybird/AppKit/UI/LadybirdWebViewBridge.cpp

@@ -13,6 +13,8 @@
 #include <LibWeb/Crypto/Crypto.h>
 #include <UI/LadybirdWebViewBridge.h>
 
+#import <UI/Palette.h>
+
 namespace Ladybird {
 
 template<typename T>
@@ -85,6 +87,12 @@ void WebViewBridge::set_viewport_rect(Gfx::IntRect viewport_rect, ForResize for_
     }
 }
 
+void WebViewBridge::update_palette()
+{
+    auto theme = create_system_palette();
+    client().async_update_system_theme(move(theme));
+}
+
 void WebViewBridge::mouse_down_event(Gfx::IntPoint position, GUI::MouseButton button, KeyModifier modifiers)
 {
     client().async_mouse_down(to_content_position(position), to_underlying(button), to_underlying(button), modifiers);
@@ -183,13 +191,4 @@ void WebViewBridge::create_client(WebView::EnableCallgrindProfiling enable_callg
     }
 }
 
-void WebViewBridge::update_palette()
-{
-    auto theme = MUST(Gfx::load_system_theme(DeprecatedString::formatted("{}/res/themes/Default.ini", s_serenity_resource_root)));
-    auto palette_impl = Gfx::PaletteImpl::create_with_anonymous_buffer(theme);
-    auto palette = Gfx::Palette(move(palette_impl));
-
-    client().async_update_system_theme(move(theme));
-}
-
 }

Ladybird/AppKit/UI/LadybirdWebViewBridge.h

@@ -35,6 +35,8 @@ public:
     };
     void set_viewport_rect(Gfx::IntRect, ForResize = ForResize::No);
 
+    void update_palette();
+
     void mouse_down_event(Gfx::IntPoint, GUI::MouseButton, KeyModifier);
     void mouse_up_event(Gfx::IntPoint, GUI::MouseButton, KeyModifier);
     void mouse_move_event(Gfx::IntPoint, GUI::MouseButton, KeyModifier);
@@ -59,8 +61,6 @@ private:
 
     virtual void create_client(WebView::EnableCallgrindProfiling) override;
 
-    void update_palette();
-
     Vector<Gfx::IntRect> m_screen_rects;
     Gfx::IntRect m_viewport_rect;
 

Ladybird/AppKit/UI/Palette.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibCore/AnonymousBuffer.h>
+
+namespace Ladybird {
+
+bool is_using_dark_system_theme();
+Core::AnonymousBuffer create_system_palette();
+
+}

Ladybird/AppKit/UI/Palette.mm

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/DeprecatedString.h>
+#include <Ladybird/Utilities.h>
+#include <LibGfx/Palette.h>
+#include <LibGfx/SystemTheme.h>
+
+#import <System/Cocoa.h>
+#import <UI/Palette.h>
+
+namespace Ladybird {
+
+bool is_using_dark_system_theme()
+{
+    auto* appearance = [NSApp effectiveAppearance];
+
+    auto* matched_appearance = [appearance bestMatchFromAppearancesWithNames:@[
+        NSAppearanceNameAqua,
+        NSAppearanceNameDarkAqua,
+    ]];
+
+    return [matched_appearance isEqualToString:NSAppearanceNameDarkAqua];
+}
+
+Core::AnonymousBuffer create_system_palette()
+{
+    auto is_dark = is_using_dark_system_theme();
+
+    auto theme_file = is_dark ? "Default"sv : "Dark"sv;
+    auto theme_path = DeprecatedString::formatted("{}/res/themes/{}.ini", s_serenity_resource_root, theme_file);
+
+    auto theme = MUST(Gfx::load_system_theme(theme_path));
+    auto palette_impl = Gfx::PaletteImpl::create_with_anonymous_buffer(theme);
+    auto palette = Gfx::Palette(move(palette_impl));
+
+    palette.set_flag(Gfx::FlagRole::IsDark, is_dark);
+
+    return theme;
+}
+
+}

Ladybird/CMakeLists.txt

@@ -136,6 +136,7 @@ elseif (APPLE)
         AppKit/UI/Event.mm
         AppKit/UI/LadybirdWebView.mm
         AppKit/UI/LadybirdWebViewBridge.cpp
+        AppKit/UI/Palette.mm
         AppKit/UI/Tab.mm
         AppKit/UI/TabController.mm
         AppKit/Utilities/Conversions.mm