Userland: Add horizontal mouse scroll support

Meta/run.sh

@@ -214,6 +214,7 @@ if [ -z "$SERENITY_ETHERNET_DEVICE_TYPE" ]; then
   SERENITY_ETHERNET_DEVICE_TYPE="e1000"
 fi
 
+# add -machine vmport=off below to run the machine with ps/2 mouse
 if [ -z "$SERENITY_MACHINE" ]; then
     if [ "$SERENITY_ARCH" = "aarch64" ]; then
         SERENITY_MACHINE="-M raspi3b -serial stdio"

Userland/Applets/WorkspacePicker/DesktopStatusWindow.cpp

@@ -76,7 +76,7 @@ public:
 
         auto vcols = desktop.workspace_columns();
         auto vrows = desktop.workspace_rows();
-        auto direction = event.wheel_delta() < 0 ? 1 : -1;
+        auto direction = event.wheel_delta_y() < 0 ? 1 : -1;
 
         if (event.modifiers() & Mod_Shift)
             col = abs((int)col + direction) % vcols;

Userland/Applications/3DFileViewer/main.cpp

@@ -156,7 +156,7 @@ void GLContextWidget::mousemove_event(GUI::MouseEvent& event)
 
 void GLContextWidget::mousewheel_event(GUI::MouseEvent& event)
 {
-    if (event.wheel_delta() > 0)
+    if (event.wheel_delta_y() > 0)
         m_zoom /= 1.1f;
     else
         m_zoom *= 1.1f;

Userland/Applications/PDFViewer/PDFViewer.cpp

@@ -75,7 +75,7 @@ void PDFViewer::mousewheel_event(GUI::MouseEvent& event)
     if (!m_document)
         return;
 
-    bool scrolled_down = event.wheel_delta() > 0;
+    bool scrolled_down = event.wheel_delta_y() > 0;
 
     if (event.ctrl()) {
         if (scrolled_down) {

Userland/Applications/Piano/RollWidget.cpp

@@ -239,7 +239,12 @@ void RollWidget::mouseup_event([[maybe_unused]] GUI::MouseEvent& event)
 void RollWidget::mousewheel_event(GUI::MouseEvent& event)
 {
     if (event.modifiers() & KeyModifier::Mod_Shift) {
-        horizontal_scrollbar().increase_slider_by(event.wheel_delta() * horizontal_scroll_sensitivity);
+        horizontal_scrollbar().increase_slider_by(event.wheel_delta_y() * horizontal_scroll_sensitivity);
+        return;
+    }
+
+    if (event.wheel_delta_x() != 0) {
+        horizontal_scrollbar().increase_slider_by(event.wheel_delta_x() * horizontal_scroll_sensitivity);
         return;
     }
 
@@ -248,7 +253,7 @@ void RollWidget::mousewheel_event(GUI::MouseEvent& event)
         return;
     }
 
-    double multiplier = event.wheel_delta() >= 0 ? 0.5 : 2;
+    double multiplier = event.wheel_delta_y() >= 0 ? 0.5 : 2;
 
     if (m_zoom_level * multiplier > max_zoom)
         return;

Userland/Applications/PixelPaint/ImageEditor.cpp

@@ -257,7 +257,8 @@ GUI::MouseEvent ImageEditor::event_with_pan_and_scale_applied(GUI::MouseEvent co
         event.buttons(),
         event.button(),
         event.modifiers(),
-        event.wheel_delta()
+        event.wheel_delta_x(),
+        event.wheel_delta_y(),
     };
 }
 
@@ -271,7 +272,8 @@ GUI::MouseEvent ImageEditor::event_adjusted_for_layer(GUI::MouseEvent const& eve
         event.buttons(),
         event.button(),
         event.modifiers(),
-        event.wheel_delta()
+        event.wheel_delta_x(),
+        event.wheel_delta_y(),
     };
 }
 

Userland/Applications/SpaceAnalyzer/TreeMapWidget.cpp

@@ -316,8 +316,8 @@ void TreeMapWidget::doubleclick_event(GUI::MouseEvent& event)
 
 void TreeMapWidget::mousewheel_event(GUI::MouseEvent& event)
 {
-    int delta = event.wheel_delta();
+    int delta = event.wheel_delta_y();
-    // FIXME: The wheel_delta is premultiplied in the window server, we actually want a raw value here.
+    // FIXME: The wheel_delta_y is premultiplied in the window server, we actually want a raw value here.
     int step_size = GUI::WindowServerConnection::the().get_scroll_step_size();
     if (delta > 0) {
         size_t step_back = delta / step_size;

Userland/Demos/Mandelbrot/Mandelbrot.cpp

@@ -350,7 +350,7 @@ void Mandelbrot::mouseup_event(GUI::MouseEvent& event)
 
 void Mandelbrot::mousewheel_event(GUI::MouseEvent& event)
 {
-    zoom(event.wheel_delta() < 0 ? Zoom::In : Zoom::Out, event.position());
+    zoom(event.wheel_delta_y() < 0 ? Zoom::In : Zoom::Out, event.position());
 }
 
 void Mandelbrot::resize_event(GUI::ResizeEvent& event)

Userland/Demos/Mouse/main.cpp

@@ -138,7 +138,7 @@ public:
 
     void mousewheel_event(GUI::MouseEvent& event) override
     {
-        m_wheel_delta_acc = (m_wheel_delta_acc + event.wheel_delta() + 36) % 36;
+        m_wheel_delta_acc = (m_wheel_delta_acc + event.wheel_delta_y() + 36) % 36;
         m_show_scroll_wheel = true;
         update();
         if (!has_timer())

Userland/DevTools/Profiler/TimelineView.cpp

@@ -67,7 +67,7 @@ void TimelineView::mousewheel_event(GUI::MouseEvent& event)
 {
     if (event.modifiers() == Mod_Ctrl) {
         event.accept();
-        m_scale += event.wheel_delta();
+        m_scale += event.wheel_delta_y();
         m_scale = clamp(m_scale, 1.0f, 100.0f);
         for_each_child_of_type<TimelineTrack>([&](auto& track) {
             track.set_scale(m_scale);

Userland/Libraries/LibGUI/AbstractScrollableWidget.cpp

@@ -47,11 +47,26 @@ void AbstractScrollableWidget::handle_wheel_event(MouseEvent& event, Widget& eve
         event.ignore();
         return;
     }
-    // FIXME: The wheel delta multiplier should probably come from... somewhere?
+
+    int wheel_delta_x { 0 };
+    bool vertical_scroll_hijacked { false };
+
     if (event.shift() || &event_source == m_horizontal_scrollbar.ptr()) {
-        horizontal_scrollbar().increase_slider_by(event.wheel_delta() * 60);
+        wheel_delta_x = event.wheel_delta_y();
-    } else {
+        vertical_scroll_hijacked = true;
-        vertical_scrollbar().increase_slider_by(event.wheel_delta() * 20);
+    }
+
+    if (event.wheel_delta_x() != 0) {
+        wheel_delta_x = event.wheel_delta_x();
+    }
+
+    if (wheel_delta_x != 0) {
+        // FIXME: The wheel delta multiplier should probably come from... somewhere?
+        horizontal_scrollbar().increase_slider_by(wheel_delta_x * 60);
+    }
+
+    if (!vertical_scroll_hijacked && event.wheel_delta_y() != 0) {
+        vertical_scrollbar().increase_slider_by(event.wheel_delta_y() * 20);
     }
 }
 
@@ -283,5 +298,4 @@ Gfx::IntPoint AbstractScrollableWidget::to_widget_position(const Gfx::IntPoint&
     widget_position.translate_by(frame_thickness(), frame_thickness());
     return widget_position;
 }
-
 }

Userland/Libraries/LibGUI/AbstractZoomPanWidget.cpp

@@ -111,7 +111,7 @@ Gfx::FloatRect AbstractZoomPanWidget::content_to_frame_rect(Gfx::IntRect const&
 
 void AbstractZoomPanWidget::mousewheel_event(GUI::MouseEvent& event)
 {
-    float new_scale = scale() / AK::exp2(event.wheel_delta() / wheel_zoom_factor);
+    float new_scale = scale() / AK::exp2(event.wheel_delta_y() / wheel_zoom_factor);
     scale_centered(new_scale, event.position());
 }
 

Userland/Libraries/LibGUI/ComboBox.cpp

@@ -36,7 +36,7 @@ private:
         if (!is_focused())
             set_focus(true);
         if (on_mousewheel)
-            on_mousewheel(event.wheel_delta());
+            on_mousewheel(event.wheel_delta_y());
     }
 
     virtual void keydown_event(KeyEvent& event) override

Userland/Libraries/LibGUI/Event.h

@@ -370,13 +370,14 @@ private:
 
 class MouseEvent final : public Event {
 public:
-    MouseEvent(Type type, const Gfx::IntPoint& position, unsigned buttons, MouseButton button, unsigned modifiers, int wheel_delta)
+    MouseEvent(Type type, const Gfx::IntPoint& position, unsigned buttons, MouseButton button, unsigned modifiers, int wheel_delta_x, int wheel_delta_y)
         : Event(type)
         , m_position(position)
         , m_buttons(buttons)
         , m_button(button)
         , m_modifiers(modifiers)
-        , m_wheel_delta(wheel_delta)
+        , m_wheel_delta_x(wheel_delta_x)
+        , m_wheel_delta_y(wheel_delta_y)
     {
     }
 
@@ -390,14 +391,16 @@ public:
     bool shift() const { return m_modifiers & Mod_Shift; }
     bool super() const { return m_modifiers & Mod_Super; }
     unsigned modifiers() const { return m_modifiers; }
-    int wheel_delta() const { return m_wheel_delta; }
+    int wheel_delta_x() const { return m_wheel_delta_x; }
+    int wheel_delta_y() const { return m_wheel_delta_y; }
 
 private:
     Gfx::IntPoint m_position;
     unsigned m_buttons { 0 };
     MouseButton m_button { MouseButton::None };
     unsigned m_modifiers { 0 };
-    int m_wheel_delta { 0 };
+    int m_wheel_delta_x { 0 };
+    int m_wheel_delta_y { 0 };
 };
 
 class DragEvent final : public Event {

Userland/Libraries/LibGUI/OpacitySlider.cpp

@@ -139,7 +139,7 @@ void OpacitySlider::mouseup_event(MouseEvent& event)
 
 void OpacitySlider::mousewheel_event(MouseEvent& event)
 {
-    decrease_slider_by(event.wheel_delta());
+    decrease_slider_by(event.wheel_delta_y());
 }
 
 }

Userland/Libraries/LibGUI/Scrollbar.cpp

@@ -299,7 +299,7 @@ void Scrollbar::mousewheel_event(MouseEvent& event)
 {
     if (!is_scrollable())
         return;
-    increase_slider_by_steps(event.wheel_delta());
+    increase_slider_by_steps(event.wheel_delta_y());
     Widget::mousewheel_event(event);
 }
 

Userland/Libraries/LibGUI/Slider.cpp

@@ -139,7 +139,7 @@ void Slider::mouseup_event(MouseEvent& event)
 void Slider::mousewheel_event(MouseEvent& event)
 {
     auto acceleration_modifier = step();
-    auto wheel_delta = event.wheel_delta();
+    auto wheel_delta = event.wheel_delta_y();
 
     if (event.modifiers() == KeyModifier::Mod_Ctrl)
         acceleration_modifier *= 6;

Userland/Libraries/LibGUI/SpinBox.cpp

@@ -87,7 +87,7 @@ void SpinBox::set_range(int min, int max, AllowCallback allow_callback)
 
 void SpinBox::mousewheel_event(MouseEvent& event)
 {
-    auto wheel_delta = event.wheel_delta() / abs(event.wheel_delta());
+    auto wheel_delta = event.wheel_delta_y() / abs(event.wheel_delta_y());
     if (event.modifiers() == KeyModifier::Mod_Ctrl)
         wheel_delta *= 6;
     set_value(m_value - wheel_delta);

Userland/Libraries/LibGUI/ValueSlider.cpp

@@ -162,7 +162,7 @@ void ValueSlider::leave_event(Core::Event&)
 
 void ValueSlider::mousewheel_event(MouseEvent& event)
 {
-    if (event.wheel_delta() < 0)
+    if (event.wheel_delta_y() < 0)
         increase_slider_by(1);
     else
         decrease_slider_by(1);

Userland/Libraries/LibGUI/Window.cpp

@@ -366,7 +366,7 @@ void Window::handle_mouse_event(MouseEvent& event)
     if (m_automatic_cursor_tracking_widget) {
         auto window_relative_rect = m_automatic_cursor_tracking_widget->window_relative_rect();
         Gfx::IntPoint local_point { event.x() - window_relative_rect.x(), event.y() - window_relative_rect.y() };
-        auto local_event = MouseEvent((Event::Type)event.type(), local_point, event.buttons(), event.button(), event.modifiers(), event.wheel_delta());
+        auto local_event = MouseEvent((Event::Type)event.type(), local_point, event.buttons(), event.button(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         m_automatic_cursor_tracking_widget->dispatch_event(local_event, this);
         if (event.buttons() == 0)
             m_automatic_cursor_tracking_widget = nullptr;
@@ -375,7 +375,7 @@ void Window::handle_mouse_event(MouseEvent& event)
     if (!m_main_widget)
         return;
     auto result = m_main_widget->hit_test(event.position());
-    auto local_event = MouseEvent((Event::Type)event.type(), result.local_position, event.buttons(), event.button(), event.modifiers(), event.wheel_delta());
+    auto local_event = MouseEvent((Event::Type)event.type(), result.local_position, event.buttons(), event.button(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
     VERIFY(result.widget);
     set_hovered_widget(result.widget);
     if (event.buttons() != 0 && !m_automatic_cursor_tracking_widget)

Userland/Libraries/LibGUI/WindowServerConnection.cpp

@@ -228,38 +228,38 @@ static MouseButton to_mouse_button(u32 button)
     }
 }
 
-void WindowServerConnection::mouse_down(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta)
+void WindowServerConnection::mouse_down(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y)
 {
     if (auto* window = Window::from_window_id(window_id))
-        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseDown, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta));
+        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseDown, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta_x, wheel_delta_y));
 }
 
-void WindowServerConnection::mouse_up(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta)
+void WindowServerConnection::mouse_up(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y)
 {
     if (auto* window = Window::from_window_id(window_id))
-        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseUp, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta));
+        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseUp, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta_x, wheel_delta_y));
 }
 
-void WindowServerConnection::mouse_move(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta, bool is_drag, Vector<String> const& mime_types)
+void WindowServerConnection::mouse_move(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y, bool is_drag, Vector<String> const& mime_types)
 {
     if (auto* window = Window::from_window_id(window_id)) {
         if (is_drag)
             Core::EventLoop::current().post_event(*window, make<DragEvent>(Event::DragMove, mouse_position, mime_types));
         else
-            Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseMove, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta));
+            Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseMove, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta_x, wheel_delta_y));
     }
 }
 
-void WindowServerConnection::mouse_double_click(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta)
+void WindowServerConnection::mouse_double_click(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y)
 {
     if (auto* window = Window::from_window_id(window_id))
-        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseDoubleClick, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta));
+        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseDoubleClick, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta_x, wheel_delta_y));
 }
 
-void WindowServerConnection::mouse_wheel(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta)
+void WindowServerConnection::mouse_wheel(i32 window_id, Gfx::IntPoint const& mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y)
 {
     if (auto* window = Window::from_window_id(window_id))
-        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseWheel, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta));
+        Core::EventLoop::current().post_event(*window, make<MouseEvent>(Event::MouseWheel, mouse_position, buttons, to_mouse_button(button), modifiers, wheel_delta_x, wheel_delta_y));
 }
 
 void WindowServerConnection::menu_visibility_did_change(i32 menu_id, bool visible)

Userland/Libraries/LibGUI/WindowServerConnection.h

@@ -26,11 +26,11 @@ private:
 
     virtual void fast_greet(Vector<Gfx::IntRect> const&, u32, u32, u32, Core::AnonymousBuffer const&, String const&, String const&, i32) override;
     virtual void paint(i32, Gfx::IntSize const&, Vector<Gfx::IntRect> const&) override;
-    virtual void mouse_move(i32, Gfx::IntPoint const&, u32, u32, u32, i32, bool, Vector<String> const&) override;
+    virtual void mouse_move(i32, Gfx::IntPoint const&, u32, u32, u32, i32, i32, bool, Vector<String> const&) override;
-    virtual void mouse_down(i32, Gfx::IntPoint const&, u32, u32, u32, i32) override;
+    virtual void mouse_down(i32, Gfx::IntPoint const&, u32, u32, u32, i32, i32) override;
-    virtual void mouse_double_click(i32, Gfx::IntPoint const&, u32, u32, u32, i32) override;
+    virtual void mouse_double_click(i32, Gfx::IntPoint const&, u32, u32, u32, i32, i32) override;
-    virtual void mouse_up(i32, Gfx::IntPoint const&, u32, u32, u32, i32) override;
+    virtual void mouse_up(i32, Gfx::IntPoint const&, u32, u32, u32, i32, i32) override;
-    virtual void mouse_wheel(i32, Gfx::IntPoint const&, u32, u32, u32, i32) override;
+    virtual void mouse_wheel(i32, Gfx::IntPoint const&, u32, u32, u32, i32, i32) override;
     virtual void window_entered(i32) override;
     virtual void window_left(i32) override;
     virtual void key_down(i32, u32, u32, u32, u32) override;

Userland/Libraries/LibVT/TerminalWidget.cpp

@@ -918,7 +918,7 @@ void TerminalWidget::mousewheel_event(GUI::MouseEvent& event)
     if (!is_scrollable())
         return;
     set_auto_scroll_direction(AutoScrollDirection::None);
-    m_scrollbar->increase_slider_by(event.wheel_delta() * scroll_length());
+    m_scrollbar->increase_slider_by(event.wheel_delta_y() * scroll_length());
     GUI::Frame::mousewheel_event(event);
 }
 

Userland/Libraries/LibWeb/InProcessWebView.cpp

@@ -237,7 +237,7 @@ void InProcessWebView::mouseup_event(GUI::MouseEvent& event)
 
 void InProcessWebView::mousewheel_event(GUI::MouseEvent& event)
 {
-    page().handle_mousewheel(to_content_position(event.position()), event.button(), event.modifiers(), event.wheel_delta());
+    page().handle_mousewheel(to_content_position(event.position()), event.button(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
     GUI::AbstractScrollableWidget::mousewheel_event(event);
 }
 

Userland/Libraries/LibWeb/Layout/BlockContainer.cpp

@@ -136,12 +136,12 @@ void BlockContainer::set_scroll_offset(const Gfx::FloatPoint& offset)
     set_needs_display();
 }
 
-bool BlockContainer::handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned int, unsigned int, int wheel_delta)
+bool BlockContainer::handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned int, unsigned int, int wheel_delta_x, int wheel_delta_y)
 {
     if (!is_scrollable())
         return false;
     auto new_offset = m_scroll_offset;
-    new_offset.translate_by(0, wheel_delta);
+    new_offset.translate_by(wheel_delta_x, wheel_delta_y);
     set_scroll_offset(new_offset);
 
     return true;

Userland/Libraries/LibWeb/Layout/BlockContainer.h

@@ -50,7 +50,7 @@ protected:
 private:
     virtual bool is_block_container() const final { return true; }
     virtual bool wants_mouse_events() const override { return false; }
-    virtual bool handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta) override;
+    virtual bool handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta_x, int wheel_delta_y) override;
 
     bool should_clip_overflow() const;
 

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -494,13 +494,13 @@ void Node::handle_mousemove(Badge<EventHandler>, const Gfx::IntPoint&, unsigned,
 {
 }
 
-bool Node::handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned, unsigned, int wheel_delta)
+bool Node::handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned, unsigned, int wheel_delta_x, int wheel_delta_y)
 {
     if (auto* containing_block = this->containing_block()) {
         if (!containing_block->is_scrollable())
             return false;
         auto new_offset = containing_block->scroll_offset();
-        new_offset.translate_by(0, wheel_delta);
+        new_offset.translate_by(wheel_delta_x, wheel_delta_y);
         containing_block->set_scroll_offset(new_offset);
         return true;
     }

Userland/Libraries/LibWeb/Layout/Node.h

@@ -89,7 +89,7 @@ public:
     virtual void handle_mousedown(Badge<EventHandler>, const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     virtual void handle_mouseup(Badge<EventHandler>, const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     virtual void handle_mousemove(Badge<EventHandler>, const Gfx::IntPoint&, unsigned buttons, unsigned modifiers);
-    virtual bool handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta);
+    virtual bool handle_mousewheel(Badge<EventHandler>, const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta_x, int wheel_delta_y);
 
     virtual void before_children_paint(PaintContext&, PaintPhase) {};
     virtual void paint(PaintContext&, PaintPhase) = 0;

Userland/Libraries/LibWeb/OutOfProcessWebView.cpp

@@ -183,7 +183,7 @@ void OutOfProcessWebView::mousemove_event(GUI::MouseEvent& event)
 
 void OutOfProcessWebView::mousewheel_event(GUI::MouseEvent& event)
 {
-    client().async_mouse_wheel(to_content_position(event.position()), event.button(), event.buttons(), event.modifiers(), event.wheel_delta());
+    client().async_mouse_wheel(to_content_position(event.position()), event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
 }
 
 void OutOfProcessWebView::theme_change_event(GUI::ThemeChangeEvent& event)

Userland/Libraries/LibWeb/Page/EventHandler.cpp

@@ -112,7 +112,7 @@ Layout::InitialContainingBlock* EventHandler::layout_root()
     return m_frame.active_document()->layout_node();
 }
 
-bool EventHandler::handle_mousewheel(const Gfx::IntPoint& position, unsigned int buttons, unsigned int modifiers, int wheel_delta)
+bool EventHandler::handle_mousewheel(const Gfx::IntPoint& position, unsigned int buttons, unsigned int modifiers, int wheel_delta_x, int wheel_delta_y)
 {
     if (!layout_root())
         return false;
@@ -121,12 +121,12 @@ bool EventHandler::handle_mousewheel(const Gfx::IntPoint& position, unsigned int
 
     auto result = layout_root()->hit_test(position, Layout::HitTestType::Exact);
     if (result.layout_node) {
-        if (result.layout_node->handle_mousewheel({}, position, buttons, modifiers, wheel_delta))
+        if (result.layout_node->handle_mousewheel({}, position, buttons, modifiers, wheel_delta_x, wheel_delta_y))
             return true;
     }
 
     if (auto* page = m_frame.page()) {
-        page->client().page_did_request_scroll(0, wheel_delta * 20);
+        page->client().page_did_request_scroll(wheel_delta_x * 20, wheel_delta_y * 20);
         return true;
     }
 

Userland/Libraries/LibWeb/Page/EventHandler.h

@@ -25,7 +25,7 @@ public:
     bool handle_mouseup(const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     bool handle_mousedown(const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     bool handle_mousemove(const Gfx::IntPoint&, unsigned buttons, unsigned modifiers);
-    bool handle_mousewheel(const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta);
+    bool handle_mousewheel(const Gfx::IntPoint&, unsigned buttons, unsigned modifiers, int wheel_delta_x, int wheel_delta_y);
 
     bool handle_keydown(KeyCode, unsigned modifiers, u32 code_point);
     bool handle_keyup(KeyCode, unsigned modifiers, u32 code_point);

Userland/Libraries/LibWeb/Page/Page.cpp

@@ -61,9 +61,9 @@ CSS::PreferredColorScheme Page::preferred_color_scheme() const
     return m_client.preferred_color_scheme();
 }
 
-bool Page::handle_mousewheel(const Gfx::IntPoint& position, unsigned button, unsigned modifiers, int wheel_delta)
+bool Page::handle_mousewheel(const Gfx::IntPoint& position, unsigned button, unsigned modifiers, int wheel_delta_x, int wheel_delta_y)
 {
-    return top_level_browsing_context().event_handler().handle_mousewheel(position, button, modifiers, wheel_delta);
+    return top_level_browsing_context().event_handler().handle_mousewheel(position, button, modifiers, wheel_delta_x, wheel_delta_y);
 }
 
 bool Page::handle_mouseup(const Gfx::IntPoint& position, unsigned button, unsigned modifiers)

Userland/Libraries/LibWeb/Page/Page.h

@@ -50,7 +50,7 @@ public:
     bool handle_mouseup(const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     bool handle_mousedown(const Gfx::IntPoint&, unsigned button, unsigned modifiers);
     bool handle_mousemove(const Gfx::IntPoint&, unsigned buttons, unsigned modifiers);
-    bool handle_mousewheel(const Gfx::IntPoint&, unsigned button, unsigned modifiers, int wheel_delta);
+    bool handle_mousewheel(const Gfx::IntPoint&, unsigned button, unsigned modifiers, int wheel_delta_x, int wheel_delta_y);
 
     bool handle_keydown(KeyCode, unsigned modifiers, u32 code_point);
     bool handle_keyup(KeyCode, unsigned modifiers, u32 code_point);

Userland/Services/Taskbar/TaskbarWindow.cpp

@@ -211,7 +211,7 @@ void TaskbarWindow::event(Core::Event& event)
 
         if (adjusted_point != mouse_event.position()) {
             GUI::WindowServerConnection::the().async_set_global_cursor_position(position() + adjusted_point);
-            GUI::MouseEvent adjusted_event = { (GUI::Event::Type)mouse_event.type(), adjusted_point, mouse_event.buttons(), mouse_event.button(), mouse_event.modifiers(), mouse_event.wheel_delta() };
+            GUI::MouseEvent adjusted_event = { (GUI::Event::Type)mouse_event.type(), adjusted_point, mouse_event.buttons(), mouse_event.button(), mouse_event.modifiers(), mouse_event.wheel_delta_x(), mouse_event.wheel_delta_y() };
             Window::event(adjusted_event);
             return;
         }

Userland/Services/WebContent/ClientConnection.cpp

@@ -154,9 +154,9 @@ void ClientConnection::mouse_up(const Gfx::IntPoint& position, unsigned int butt
     page().handle_mouseup(position, button, modifiers);
 }
 
-void ClientConnection::mouse_wheel(const Gfx::IntPoint& position, unsigned int button, [[maybe_unused]] unsigned int buttons, unsigned int modifiers, i32 wheel_delta)
+void ClientConnection::mouse_wheel(const Gfx::IntPoint& position, unsigned int button, [[maybe_unused]] unsigned int buttons, unsigned int modifiers, i32 wheel_delta_x, i32 wheel_delta_y)
 {
-    page().handle_mousewheel(position, button, modifiers, wheel_delta);
+    page().handle_mousewheel(position, button, modifiers, wheel_delta_x, wheel_delta_y);
 }
 
 void ClientConnection::key_down(i32 key, unsigned int modifiers, u32 code_point)

Userland/Services/WebContent/ClientConnection.h

@@ -47,7 +47,7 @@ private:
     virtual void mouse_down(Gfx::IntPoint const&, unsigned, unsigned, unsigned) override;
     virtual void mouse_move(Gfx::IntPoint const&, unsigned, unsigned, unsigned) override;
     virtual void mouse_up(Gfx::IntPoint const&, unsigned, unsigned, unsigned) override;
-    virtual void mouse_wheel(Gfx::IntPoint const&, unsigned, unsigned, unsigned, i32) override;
+    virtual void mouse_wheel(Gfx::IntPoint const&, unsigned, unsigned, unsigned, i32, i32) override;
     virtual void key_down(i32, unsigned, u32) override;
     virtual void key_up(i32, unsigned, u32) override;
     virtual void add_backing_store(i32, Gfx::ShareableBitmap const&) override;

Userland/Services/WebContent/WebContentServer.ipc

@@ -21,7 +21,7 @@ endpoint WebContentServer
     mouse_down(Gfx::IntPoint position, unsigned button, unsigned buttons, unsigned modifiers) =|
     mouse_move(Gfx::IntPoint position, unsigned button, unsigned buttons, unsigned modifiers) =|
     mouse_up(Gfx::IntPoint position, unsigned button, unsigned buttons, unsigned modifiers) =|
-    mouse_wheel(Gfx::IntPoint position, unsigned button, unsigned buttons, unsigned modifiers, i32 wheel_delta) =|
+    mouse_wheel(Gfx::IntPoint position, unsigned button, unsigned buttons, unsigned modifiers, i32 wheel_delta_x, i32 wheel_delta_y) =|
 
     key_down(i32 key, unsigned modifiers, u32 code_point) =|
     key_up(i32 key, unsigned modifiers, u32 code_point) =|

Userland/Services/WindowServer/Event.h

@@ -88,13 +88,14 @@ private:
 
 class MouseEvent final : public Event {
 public:
-    MouseEvent(Type type, const Gfx::IntPoint& position, unsigned buttons, MouseButton button, unsigned modifiers, int wheel_delta = 0)
+    MouseEvent(Type type, const Gfx::IntPoint& position, unsigned buttons, MouseButton button, unsigned modifiers, int wheel_delta_x = 0, int wheel_delta_y = 0)
         : Event(type)
         , m_position(position)
         , m_buttons(buttons)
         , m_button(button)
         , m_modifiers(modifiers)
-        , m_wheel_delta(wheel_delta)
+        , m_wheel_delta_x(wheel_delta_x)
+        , m_wheel_delta_y(wheel_delta_y)
     {
     }
 
@@ -104,7 +105,8 @@ public:
     MouseButton button() const { return m_button; }
     unsigned buttons() const { return m_buttons; }
     unsigned modifiers() const { return m_modifiers; }
-    int wheel_delta() const { return m_wheel_delta; }
+    int wheel_delta_x() const { return m_wheel_delta_x; }
+    int wheel_delta_y() const { return m_wheel_delta_y; }
     bool is_drag() const { return m_drag; }
 
     Vector<String> mime_types() const
@@ -129,7 +131,8 @@ private:
     unsigned m_buttons { 0 };
     MouseButton m_button { MouseButton::None };
     unsigned m_modifiers { 0 };
-    int m_wheel_delta { 0 };
+    int m_wheel_delta_x { 0 };
+    int m_wheel_delta_y { 0 };
     bool m_drag { false };
     RefPtr<const Core::MimeData> m_mime_data;
 };

Userland/Services/WindowServer/Menu.cpp

@@ -393,7 +393,7 @@ void Menu::event(Core::Event& event)
         VERIFY(menu_window());
         auto& mouse_event = static_cast<const MouseEvent&>(event);
         auto previous_scroll_offset = m_scroll_offset;
-        m_scroll_offset += mouse_event.wheel_delta();
+        m_scroll_offset += mouse_event.wheel_delta_y();
         m_scroll_offset = clamp(m_scroll_offset, 0, m_max_scroll_offset);
         if (m_scroll_offset != previous_scroll_offset)
             redraw();

Userland/Services/WindowServer/Screen.cpp

@@ -461,8 +461,8 @@ void ScreenInput::on_receive_mouse_data(const MousePacket& packet)
         Core::EventLoop::current().post_event(WindowManager::the(), move(message));
     }
 
-    if (packet.z) {
+    if (packet.z || packet.w) {
-        auto message = make<MouseEvent>(Event::MouseWheel, m_cursor_location, buttons, MouseButton::None, m_modifiers, packet.z * m_scroll_step_size);
+        auto message = make<MouseEvent>(Event::MouseWheel, m_cursor_location, buttons, MouseButton::None, m_modifiers, packet.w * m_scroll_step_size, packet.z * m_scroll_step_size);
         Core::EventLoop::current().post_event(WindowManager::the(), move(message));
     }
 

Userland/Services/WindowServer/Window.cpp

@@ -264,19 +264,19 @@ void Window::handle_mouse_event(const MouseEvent& event)
 
     switch (event.type()) {
     case Event::MouseMove:
-        m_client->async_mouse_move(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta(), event.is_drag(), event.mime_types());
+        m_client->async_mouse_move(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y(), event.is_drag(), event.mime_types());
         break;
     case Event::MouseDown:
-        m_client->async_mouse_down(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta());
+        m_client->async_mouse_down(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         break;
     case Event::MouseDoubleClick:
-        m_client->async_mouse_double_click(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta());
+        m_client->async_mouse_double_click(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         break;
     case Event::MouseUp:
-        m_client->async_mouse_up(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta());
+        m_client->async_mouse_up(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         break;
     case Event::MouseWheel:
-        m_client->async_mouse_wheel(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta());
+        m_client->async_mouse_wheel(m_window_id, event.position(), (u32)event.button(), event.buttons(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         break;
     default:
         VERIFY_NOT_REACHED();

Userland/Services/WindowServer/WindowClient.ipc

@@ -6,11 +6,11 @@ endpoint WindowClient
     fast_greet(Vector<Gfx::IntRect> screen_rects, u32 main_screen_index, u32 workspace_rows, u32 workspace_columns, Core::AnonymousBuffer theme_buffer, String default_font_query, String fixed_width_font_query, i32 client_id) =|
 
     paint(i32 window_id, Gfx::IntSize window_size, Vector<Gfx::IntRect> rects) =|
-    mouse_move(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta, bool is_drag, Vector<String> mime_types) =|
+    mouse_move(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y, bool is_drag, Vector<String> mime_types) =|
-    mouse_down(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta) =|
+    mouse_down(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y) =|
-    mouse_double_click(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta) =|
+    mouse_double_click(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y) =|
-    mouse_up(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta) =|
+    mouse_up(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y) =|
-    mouse_wheel(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta) =|
+    mouse_wheel(i32 window_id, Gfx::IntPoint mouse_position, u32 button, u32 buttons, u32 modifiers, i32 wheel_delta_x, i32 wheel_delta_y) =|
     window_entered(i32 window_id) =|
     window_left(i32 window_id) =|
     window_input_entered(i32 window_id) =|

Userland/Services/WindowServer/WindowManager.cpp

@@ -1099,7 +1099,7 @@ void WindowManager::process_event_for_doubleclick(Window& window, MouseEvent& ev
     } else {
         dbgln_if(DOUBLECLICK_DEBUG, "Transforming MouseUp to MouseDoubleClick ({} < {})!", metadata.clock.elapsed(), m_double_click_speed);
 
-        event = MouseEvent(Event::MouseDoubleClick, event.position(), event.buttons(), event.button(), event.modifiers(), event.wheel_delta());
+        event = MouseEvent(Event::MouseDoubleClick, event.position(), event.buttons(), event.button(), event.modifiers(), event.wheel_delta_x(), event.wheel_delta_y());
         // invalidate this now we've delivered a doubleclick, otherwise
         // tripleclick will deliver two doubleclick events (incorrectly).
         metadata.clock = {};