FullscreenUI: Use system scroll rate and layout scale

Makes scrolling feel much more responsive, and doesn't vary
depending on the size of the window.

src/duckstation-qt/displaywidget.cpp

@@ -345,7 +345,11 @@ bool DisplayWidget::event(QEvent* event)
     case QEvent::Wheel:
     {
       const QWheelEvent* wheel_event = static_cast<QWheelEvent*>(event);
-      emit windowMouseWheelEvent(wheel_event->angleDelta());
+      const QPoint angle_delta = wheel_event->angleDelta();
+      const float dx = static_cast<float>(angle_delta.x()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep);
+      const float dy = (static_cast<float>(angle_delta.y()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep)) *
+                       static_cast<float>(QApplication::wheelScrollLines());
+      emit windowMouseWheelEvent(dx, dy);
       return true;
     }
 

src/duckstation-qt/displaywidget.h

@@ -44,7 +44,7 @@ Q_SIGNALS:
   void windowKeyEvent(int key_code, bool pressed);
   void windowTextEntered(const QString& text);
   void windowMouseButtonEvent(int button, bool pressed);
-  void windowMouseWheelEvent(const QPoint& angle_delta);
+  void windowMouseWheelEvent(float dx, float dy);
 
 protected:
   bool event(QEvent* event) override;

src/duckstation-qt/inputbindingdialog.cpp

@@ -97,7 +97,8 @@ bool InputBindingDialog::eventFilter(QObject* watched, QEvent* event)
   else if (event_type == QEvent::Wheel)
   {
     const QPoint delta_angle(static_cast<QWheelEvent*>(event)->angleDelta());
-    const float dx = std::clamp(static_cast<float>(delta_angle.x()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
+    const float dx = std::clamp(
+      static_cast<float>(delta_angle.x()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep), -1.0f, 1.0f);
     if (dx != 0.0f)
     {
       InputBindingKey key(InputManager::MakePointerAxisKey(0, InputPointerAxis::WheelX));
@@ -105,7 +106,8 @@ bool InputBindingDialog::eventFilter(QObject* watched, QEvent* event)
       m_new_bindings.push_back(key);
     }
 
-    const float dy = std::clamp(static_cast<float>(delta_angle.y()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
+    const float dy = std::clamp(
+      static_cast<float>(delta_angle.y()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep), -1.0f, 1.0f);
     if (dy != 0.0f)
     {
       InputBindingKey key(InputManager::MakePointerAxisKey(0, InputPointerAxis::WheelY));

src/duckstation-qt/inputbindingwidgets.cpp

@@ -124,7 +124,8 @@ bool InputBindingWidget::eventFilter(QObject* watched, QEvent* event)
   else if (event_type == QEvent::Wheel)
   {
     const QPoint delta_angle(static_cast<QWheelEvent*>(event)->angleDelta());
-    const float dx = std::clamp(static_cast<float>(delta_angle.x()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
+    const float dx = std::clamp(
+      static_cast<float>(delta_angle.x()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep), -1.0f, 1.0f);
     if (dx != 0.0f)
     {
       InputBindingKey key(InputManager::MakePointerAxisKey(0, InputPointerAxis::WheelX));
@@ -132,7 +133,8 @@ bool InputBindingWidget::eventFilter(QObject* watched, QEvent* event)
       m_new_bindings.push_back(key);
     }
 
-    const float dy = std::clamp(static_cast<float>(delta_angle.y()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
+    const float dy = std::clamp(
+      static_cast<float>(delta_angle.y()) / static_cast<float>(QWheelEvent::DefaultDeltasPerStep), -1.0f, 1.0f);
     if (dy != 0.0f)
     {
       InputBindingKey key(InputManager::MakePointerAxisKey(0, InputPointerAxis::WheelY));

src/duckstation-qt/qthost.cpp

@@ -903,15 +903,13 @@ void EmuThread::onDisplayWindowMouseButtonEvent(int button, bool pressed)
                              GenericInputBinding::Unknown);
 }
 
-void EmuThread::onDisplayWindowMouseWheelEvent(const QPoint& delta_angle)
+void EmuThread::onDisplayWindowMouseWheelEvent(float dx, float dy)
 {
   DebugAssert(isCurrentThread());
 
-  const float dx = std::clamp(static_cast<float>(delta_angle.x()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
   if (dx != 0.0f)
     InputManager::UpdatePointerRelativeDelta(0, InputPointerAxis::WheelX, dx);
 
-  const float dy = std::clamp(static_cast<float>(delta_angle.y()) / QtUtils::MOUSE_WHEEL_DELTA, -1.0f, 1.0f);
   if (dy != 0.0f)
     InputManager::UpdatePointerRelativeDelta(0, InputPointerAxis::WheelY, dy);
 }

src/duckstation-qt/qthost.h

@@ -223,7 +223,7 @@ public Q_SLOTS:
 private Q_SLOTS:
   void stopInThread();
   void onDisplayWindowMouseButtonEvent(int button, bool pressed);
-  void onDisplayWindowMouseWheelEvent(const QPoint& delta_angle);
+  void onDisplayWindowMouseWheelEvent(float dx, float dy);
   void onDisplayWindowResized(int width, int height, float scale);
   void onDisplayWindowKeyEvent(int key, bool pressed);
   void onDisplayWindowTextEntered(const QString& text);

src/duckstation-qt/qtutils.h

@@ -45,9 +45,6 @@ enum class EntryType : u8;
 
 namespace QtUtils {
 
-/// Wheel delta is 120 as in winapi.
-static constexpr float MOUSE_WHEEL_DELTA = 120.0f;
-
 /// Creates a horizontal line widget.
 QFrame* CreateHorizontalLine(QWidget* parent);
 

src/util/imgui_fullscreen.cpp

@@ -808,6 +808,7 @@ void ImGuiFullscreen::PushResetLayout()
   ImGui::PushStyleVar(ImGuiStyleVar_GrabMinSize, LayoutScale(10.0f));
   ImGui::PushStyleVar(ImGuiStyleVar_TabRounding, LayoutScale(4.0f));
   ImGui::PushStyleVar(ImGuiStyleVar_ScrollSmooth, UIStyle.SmoothScrolling ? SMOOTH_SCROLLING_SPEED : 1.0f);
+  ImGui::PushStyleVar(ImGuiStyleVar_ScrollStepSize, LayoutScale(LAYOUT_LARGE_FONT_SIZE, LAYOUT_MENU_BUTTON_HEIGHT));
   ImGui::PushStyleColor(ImGuiCol_Text, UIStyle.SecondaryTextColor);
   ImGui::PushStyleColor(ImGuiCol_TextDisabled, UIStyle.DisabledColor);
   ImGui::PushStyleColor(ImGuiCol_Button, UIStyle.SecondaryColor);
@@ -825,7 +826,7 @@ void ImGuiFullscreen::PushResetLayout()
 void ImGuiFullscreen::PopResetLayout()
 {
   ImGui::PopStyleColor(12);
-  ImGui::PopStyleVar(13);
+  ImGui::PopStyleVar(14);
 }
 
 void ImGuiFullscreen::QueueResetFocus(FocusResetType type)