Initial commit: Futonizer MKV track stripper

Services/SmoothScrollHelper.cs

@@ -0,0 +1,44 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+
+namespace Futonizer.Services;
+
+/// <summary>
+/// Scrolls a list/grid by an amount proportional to the mouse wheel delta
+/// instead of relying on WPF's default per-event line scrolling. Mouse
+/// "smooth scroll" utilities send many finer-grained wheel events per
+/// physical notch to animate motion; WPF's default handling treats each
+/// event as a full notch regardless of its magnitude, which multiplies the
+/// effective scroll speed far beyond what the user intended.
+/// </summary>
+public static class SmoothScrollHelper
+{
+    private const double PixelsPerStandardNotch = 48.0;
+
+    public static void HandlePreviewMouseWheel(object sender, MouseWheelEventArgs e)
+    {
+        if (sender is not DependencyObject start) return;
+        var scrollViewer = FindVisualChild<ScrollViewer>(start);
+        if (scrollViewer == null) return;
+
+        double offsetDelta = -(e.Delta / 120.0) * PixelsPerStandardNotch;
+        scrollViewer.ScrollToVerticalOffset(scrollViewer.VerticalOffset + offsetDelta);
+        e.Handled = true;
+    }
+
+    private static T? FindVisualChild<T>(DependencyObject parent) where T : DependencyObject
+    {
+        int count = VisualTreeHelper.GetChildrenCount(parent);
+        for (int i = 0; i < count; i++)
+        {
+            var child = VisualTreeHelper.GetChild(parent, i);
+            if (child is T typed) return typed;
+
+            var descendant = FindVisualChild<T>(child);
+            if (descendant != null) return descendant;
+        }
+        return null;
+    }
+}