Everywhere: Add an is_fullscreen parameter to set_viewport

This will be used by the UIs to notify WebContent when fullscreen for
content is entered or exited.

Libraries/LibWeb/Page/ViewportIsFullscreen.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2026-present, the Ladybird developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+namespace Web {
+
+enum class ViewportIsFullscreen : u8 {
+    Yes,
+    No,
+};
+
+}

Libraries/LibWebView/HeadlessWebView.cpp

@@ -60,7 +60,7 @@ HeadlessWebView::HeadlessWebView(Core::AnonymousBuffer theme, Web::DevicePixelSi
         m_viewport_size = size.template to_type<Web::DevicePixels>();
 
         client().async_set_window_size(m_client_state.page_index, m_viewport_size);
-        client().async_set_viewport(m_client_state.page_index, m_viewport_size, m_device_pixel_ratio);
+        client().async_set_viewport(m_client_state.page_index, m_viewport_size, m_device_pixel_ratio, Web::ViewportIsFullscreen::No);
 
         client().async_did_update_window_rect(m_client_state.page_index);
     };
@@ -79,7 +79,7 @@ HeadlessWebView::HeadlessWebView(Core::AnonymousBuffer theme, Web::DevicePixelSi
 
         client().async_set_window_position(m_client_state.page_index, screen_rect.location());
         client().async_set_window_size(m_client_state.page_index, screen_rect.size());
-        client().async_set_viewport(m_client_state.page_index, screen_rect.size(), m_device_pixel_ratio);
+        client().async_set_viewport(m_client_state.page_index, screen_rect.size(), m_device_pixel_ratio, m_is_fullscreen);
 
         client().async_did_update_window_rect(m_client_state.page_index);
     };
@@ -87,19 +87,22 @@ HeadlessWebView::HeadlessWebView(Core::AnonymousBuffer theme, Web::DevicePixelSi
     on_fullscreen_window = [this]() {
         m_previous_dimensions.set_size(m_viewport_size);
         m_viewport_size = screen_rect.size();
+        m_is_fullscreen = Web::ViewportIsFullscreen::Yes;
 
         client().async_set_window_position(m_client_state.page_index, screen_rect.location());
         client().async_set_window_size(m_client_state.page_index, screen_rect.size());
-        client().async_set_viewport(m_client_state.page_index, screen_rect.size(), m_device_pixel_ratio);
+        client().async_set_viewport(m_client_state.page_index, screen_rect.size(), m_device_pixel_ratio, Web::ViewportIsFullscreen::Yes);
 
         client().async_did_update_window_rect(m_client_state.page_index);
     };
 
     on_exit_fullscreen_window = [this]() {
         m_viewport_size = m_previous_dimensions.size();
+        m_is_fullscreen = Web::ViewportIsFullscreen::No;
+
         client().async_set_window_position(m_client_state.page_index, m_previous_dimensions.location());
         client().async_set_window_size(m_client_state.page_index, m_previous_dimensions.size());
-        client().async_set_viewport(m_client_state.page_index, m_previous_dimensions.size(), m_device_pixel_ratio);
+        client().async_set_viewport(m_client_state.page_index, m_previous_dimensions.size(), m_device_pixel_ratio, Web::ViewportIsFullscreen::No);
 
         client().async_did_update_window_rect(m_client_state.page_index);
     };
@@ -168,7 +171,7 @@ void HeadlessWebView::initialize_client(CreateNewClient create_new_client)
     ViewImplementation::initialize_client(create_new_client);
 
     client().async_update_system_theme(m_client_state.page_index, m_theme);
-    client().async_set_viewport(m_client_state.page_index, viewport_size(), m_device_pixel_ratio);
+    client().async_set_viewport(m_client_state.page_index, viewport_size(), m_device_pixel_ratio, m_is_fullscreen);
     client().async_set_window_size(m_client_state.page_index, viewport_size());
     client().async_update_screen_rects(m_client_state.page_index, { { screen_rect } }, 0);
 }
@@ -178,7 +181,7 @@ void HeadlessWebView::reset_viewport_size(Web::DevicePixelSize size)
     m_viewport_size = size;
 
     client().async_set_window_size(m_client_state.page_index, m_viewport_size);
-    client().async_set_viewport(m_client_state.page_index, m_viewport_size, m_device_pixel_ratio);
+    client().async_set_viewport(m_client_state.page_index, m_viewport_size, m_device_pixel_ratio, m_is_fullscreen);
 
     client().async_did_update_window_rect(m_client_state.page_index);
 }

Libraries/LibWebView/ViewImplementation.cpp

@@ -480,6 +480,15 @@ void ViewImplementation::exit_fullscreen()
     client().async_exit_fullscreen(page_id());
 }
 
+void ViewImplementation::set_is_fullscreen(Web::ViewportIsFullscreen is_fullscreen)
+{
+    if (m_is_fullscreen == is_fullscreen)
+        return;
+
+    handle_resize();
+    did_update_window_rect();
+}
+
 void ViewImplementation::alert_closed()
 {
     client().async_alert_closed(page_id());
@@ -618,7 +627,7 @@ void ViewImplementation::update_zoom()
 
 void ViewImplementation::handle_resize()
 {
-    client().async_set_viewport(page_id(), this->viewport_size(), m_device_pixel_ratio);
+    client().async_set_viewport(page_id(), viewport_size(), m_device_pixel_ratio, m_is_fullscreen);
 }
 
 void ViewImplementation::initialize_client(CreateNewClient create_new_client)
@@ -635,7 +644,7 @@ void ViewImplementation::initialize_client(CreateNewClient create_new_client)
     m_client_state.client_handle = MUST(Web::Crypto::generate_random_uuid());
     client().async_set_window_handle(m_client_state.page_index, m_client_state.client_handle);
     client().async_set_zoom_level(m_client_state.page_index, m_zoom_level);
-    client().async_set_viewport(m_client_state.page_index, viewport_size(), m_device_pixel_ratio);
+    client().async_set_viewport(m_client_state.page_index, viewport_size(), m_device_pixel_ratio, m_is_fullscreen);
     client().async_set_maximum_frames_per_second(m_client_state.page_index, m_maximum_frames_per_second);
     client().async_set_system_visibility_state(m_client_state.page_index, m_system_visibility_state);
     client().async_set_document_cookie_version_buffer(m_client_state.page_index, m_document_cookie_version_buffer);

Libraries/LibWebView/ViewImplementation.h

@@ -30,6 +30,7 @@
 #include <LibWeb/HTML/SelectItem.h>
 #include <LibWeb/Page/EventResult.h>
 #include <LibWeb/Page/InputEvent.h>
+#include <LibWeb/Page/ViewportIsFullscreen.h>
 #include <LibWebView/DOMNodeProperties.h>
 #include <LibWebView/Forward.h>
 #include <LibWebView/PageInfo.h>
@@ -135,6 +136,8 @@ public:
     void js_console_input(String const&);
     void exit_fullscreen();
 
+    void set_is_fullscreen(Web::ViewportIsFullscreen is_fullscreen);
+
     void alert_closed();
     void confirm_closed(bool accepted);
     void prompt_closed(Optional<String> const& response);
@@ -381,6 +384,8 @@ protected:
 
     Web::HTML::MuteState m_mute_state { Web::HTML::MuteState::Unmuted };
 
+    Web::ViewportIsFullscreen m_is_fullscreen { Web::ViewportIsFullscreen::No };
+
     Core::AnonymousBuffer m_document_cookie_version_buffer;
     HashMap<String, Core::SharedVersionIndex> m_document_cookie_version_indices;
 

Services/WebContent/ConnectionFromClient.cpp

@@ -196,7 +196,7 @@ void ConnectionFromClient::traverse_the_history_by_delta(u64 page_id, i32 delta)
         page->page().traverse_the_history_by_delta(delta);
 }
 
-void ConnectionFromClient::set_viewport(u64 page_id, Web::DevicePixelSize size, double device_pixel_ratio)
+void ConnectionFromClient::set_viewport(u64 page_id, Web::DevicePixelSize size, double device_pixel_ratio, Web::ViewportIsFullscreen)
 {
     if (auto page = this->page(page_id); page.has_value())
         page->set_viewport(size, device_pixel_ratio);

Services/WebContent/ConnectionFromClient.h

@@ -21,6 +21,7 @@
 #include <LibWeb/Loader/FileRequest.h>
 #include <LibWeb/Page/EventResult.h>
 #include <LibWeb/Page/InputEvent.h>
+#include <LibWeb/Page/ViewportIsFullscreen.h>
 #include <LibWeb/Platform/Timer.h>
 #include <LibWebView/DOMNodeProperties.h>
 #include <LibWebView/Forward.h>
@@ -71,7 +72,7 @@ private:
     virtual void load_html(u64 page_id, ByteString) override;
     virtual void reload(u64 page_id) override;
     virtual void traverse_the_history_by_delta(u64 page_id, i32 delta) override;
-    virtual void set_viewport(u64 page_id, Web::DevicePixelSize, double device_pixel_ratio) override;
+    virtual void set_viewport(u64 page_id, Web::DevicePixelSize, double device_pixel_ratio, Web::ViewportIsFullscreen is_fullscreen) override;
     virtual void key_event(u64 page_id, Web::KeyEvent) override;
     virtual void mouse_event(u64 page_id, Web::MouseEvent) override;
     virtual void drag_event(u64 page_id, Web::DragEvent) override;

Services/WebContent/WebContentServer.ipc

@@ -14,6 +14,7 @@
 #include <LibWeb/HTML/SelectedFile.h>
 #include <LibWeb/HTML/VisibilityState.h>
 #include <LibWeb/Page/InputEvent.h>
+#include <LibWeb/Page/ViewportIsFullscreen.h>
 #include <LibWeb/WebDriver/ExecuteScript.h>
 #include <LibWebView/Attribute.h>
 #include <LibWebView/DOMNodeProperties.h>
@@ -42,7 +43,7 @@ endpoint WebContentServer
 
     ready_to_paint(u64 page_id) =|
 
-    set_viewport(u64 page_id, Web::DevicePixelSize size, double device_pixel_ratio) =|
+    set_viewport(u64 page_id, Web::DevicePixelSize size, double device_pixel_ratio, Web::ViewportIsFullscreen is_fullscreen) =|
 
     key_event(u64 page_id, Web::KeyEvent event) =|
     mouse_event(u64 page_id, Web::MouseEvent event) =|

Tests/LibWeb/test-web/TestWebView.cpp

@@ -60,7 +60,8 @@ void TestWebView::on_test_complete(TestCompletion completion)
     m_pending_screenshot.clear();
     m_pending_dialog = Web::Page::PendingDialog::None;
     m_pending_prompt_text.clear();
-    client().async_set_viewport(m_client_state.page_index, viewport_size(), 1.0);
+    m_is_fullscreen = Web::ViewportIsFullscreen::No;
+    client().async_set_viewport(m_client_state.page_index, viewport_size(), 1.0, Web::ViewportIsFullscreen::No);
 
     m_test_promise->resolve(move(completion));
 }

UI/Android/src/main/cpp/WebViewImplementationNative.cpp

@@ -61,7 +61,7 @@ void WebViewImplementationNative::initialize_client(WebView::ViewImplementation:
     m_client_state.client_handle = MUST(Web::Crypto::generate_random_uuid());
     client().async_set_window_handle(0, m_client_state.client_handle);
 
-    client().async_set_viewport(0, viewport_size(), m_device_pixel_ratio);
+    client().async_set_viewport(0, viewport_size(), m_device_pixel_ratio, Web::ViewportIsFullscreen::No);
     client().async_set_zoom_level(0, m_zoom_level);
 
     set_system_visibility_state(Web::HTML::VisibilityState::Visible);

UI/AppKit/Interface/LadybirdWebView.h

@@ -59,6 +59,8 @@
 - (void)handleResize;
 - (void)handleDevicePixelRatioChange;
 - (void)handleDisplayRefreshRateChange;
+- (void)handleEnteredFullScreen;
+- (void)handleExitedFullScreen;
 - (void)handleExitFullScreen;
 - (void)handleVisibility:(BOOL)is_visible;
 

UI/AppKit/Interface/LadybirdWebView.mm

@@ -205,6 +205,16 @@ struct HideCursor {
     m_web_view_bridge->set_maximum_frames_per_second([[[self window] screen] maximumFramesPerSecond]);
 }
 
+- (void)handleEnteredFullScreen
+{
+    m_web_view_bridge->set_is_fullscreen(Web::ViewportIsFullscreen::Yes);
+}
+
+- (void)handleExitedFullScreen
+{
+    m_web_view_bridge->set_is_fullscreen(Web::ViewportIsFullscreen::No);
+}
+
 - (void)handleExitFullScreen
 {
     m_web_view_bridge->exit_fullscreen();
@@ -854,7 +864,6 @@ struct HideCursor {
         }
 
         [self.observer onEnterFullscreenWindow];
-        m_web_view_bridge->did_update_window_rect();
     };
 
     m_web_view_bridge->on_exit_fullscreen_window = [weak_self]() {
@@ -864,7 +873,6 @@ struct HideCursor {
         }
 
         [self.observer onExitFullscreenWindow];
-        m_web_view_bridge->did_update_window_rect();
     };
 
     m_web_view_bridge->on_theme_color_change = [weak_self](auto color) {

UI/AppKit/Interface/TabController.mm

@@ -493,6 +493,18 @@ static NSString* const TOOLBAR_TAB_OVERVIEW_IDENTIFIER = @"ToolbarTabOverviewIde
     }
 }
 
+- (void)windowDidEnterFullScreen:(NSNotification*)notification
+{
+    if (m_fullscreen_requested_for_web_content)
+        [[[self tab] web_view] handleEnteredFullScreen];
+}
+
+- (void)windowWillExitFullScreen:(NSNotification*)notification
+{
+    if (exchange(m_fullscreen_exit_was_ui_initiated, true))
+        [[[self tab] web_view] handleExitFullScreen];
+}
+
 - (void)windowDidExitFullScreen:(NSNotification*)notification
 {
     if (exchange(m_fullscreen_requested_for_web_content, false)) {
@@ -503,8 +515,7 @@ static NSString* const TOOLBAR_TAB_OVERVIEW_IDENTIFIER = @"ToolbarTabOverviewIde
         }
     }
 
-    if (exchange(m_fullscreen_exit_was_ui_initiated, true))
-        [[[self tab] web_view] handleExitFullScreen];
+    [[[self tab] web_view] handleExitedFullScreen];
 }
 
 - (NSApplicationPresentationOptions)window:(NSWindow*)window

UI/Qt/BrowserWindow.cpp

@@ -728,8 +728,15 @@ void BrowserWindow::changeEvent(QEvent* event)
 {
     if (event->type() == QEvent::WindowStateChange) {
         QWindowStateChangeEvent* stateChangeEvent = static_cast<QWindowStateChangeEvent*>(event);
-        if (windowState() & Qt::WindowFullScreen && !(stateChangeEvent->oldState() & Qt::WindowFullScreen)) {
+        bool was_fullscreen = stateChangeEvent->oldState() & Qt::WindowFullScreen;
+        bool is_fullscreen = windowState() & Qt::WindowFullScreen;
+
+        if (is_fullscreen && !was_fullscreen) {
             m_fullscreen_mode->entered_fullscreen();
+            if (m_fullscreen_mode->is_api_fullscreen())
+                view().set_is_fullscreen(Web::ViewportIsFullscreen::Yes);
+        } else if (!is_fullscreen && was_fullscreen) {
+            view().set_is_fullscreen(Web::ViewportIsFullscreen::No);
         }
     }
     QWidget::changeEvent(event);

UI/Qt/Tab.cpp

@@ -392,13 +392,11 @@ Tab::Tab(BrowserWindow* window, RefPtr<WebView::WebContentClient> parent_client,
     view().on_fullscreen_window = [this]() {
         m_toolbar->hide();
         m_window->fullscreen_mode().enter(this);
-        view().did_update_window_rect();
     };
 
     view().on_exit_fullscreen_window = [this]() {
         m_window->fullscreen_mode().exit(FullscreenMode::ExitInitiatedBy::WebContent);
         m_toolbar->show();
-        view().did_update_window_rect();
     };
 
     view().on_audio_play_state_changed = [this](auto play_state) {