fix(ui): match retail spell bar controls

Place favorite-bar arrows by their authored sides, import rollover and pressed media through the shared scrollbar, and preserve manual offsets across passive refreshes. Carry the mixed-parent DAT anchor chain to a fixed 18-cell favorite viewport so overflow controls and the Cast button remain inside the retail-sized combat frame.

Co-authored-by: Codex <codex@openai.com>

src/AcDream.App/UI/UiScrollbar.cs

@@ -21,6 +21,8 @@ namespace AcDream.App.UI;
 /// </remarks>
 public sealed class UiScrollbar : UiElement
 {
+    public override bool ReceivesHoverMouseMove => true;
+
     /// <summary>The scroll model this bar reflects + drives (shared with the transcript).</summary>
     public UiScrollable? Model { get; set; }
 
@@ -83,6 +85,14 @@ public sealed class UiScrollbar : UiElement
     /// <summary>Down-arrow button sprite id (0x06004C6C Normal state, element 0x10000072).</summary>
     public uint DownSprite { get; set; }
 
+    /// <summary>Rollover and pressed media for the start/decrement button.</summary>
+    public uint UpRolloverSprite { get; set; }
+    public uint UpPressedSprite { get; set; }
+
+    /// <summary>Rollover and pressed media for the end/increment button.</summary>
+    public uint DownRolloverSprite { get; set; }
+    public uint DownPressedSprite { get; set; }
+
     /// <summary>
     /// Authored extent of the decrement button along the scrollbar axis. Retail
     /// positions and subtracts the referenced button's real size; chat uses
@@ -108,6 +118,15 @@ public sealed class UiScrollbar : UiElement
     private bool _draggingThumb;
     private float _dragOffsetY;
     private float _dragOffsetX;
+    private EndButton _hoveredButton;
+    private EndButton _pressedButton;
+
+    private enum EndButton
+    {
+        None,
+        Decrement,
+        Increment,
+    }
 
     public UiScrollbar() { CapturesPointerDrag = true; }
 
@@ -201,8 +220,8 @@ public sealed class UiScrollbar : UiElement
         float incrementExtent = AxisExtent(IncrementButtonExtent, Height);
 
         // Decrement/up and increment/down use their authored button heights.
-        DrawSprite(ctx, resolve, UpSprite, 0f, 0f, Width, decrementExtent);
-        DrawSprite(ctx, resolve, DownSprite,
+        DrawSprite(ctx, resolve, ActiveStartSprite, 0f, 0f, Width, decrementExtent);
+        DrawSprite(ctx, resolve, ActiveEndSprite,
             0f, Height - incrementExtent, Width, incrementExtent);
 
         // Thumb — only when content overflows the view. Retail 3-slice: top cap +
@@ -235,8 +254,8 @@ public sealed class UiScrollbar : UiElement
         float decrementExtent = AxisExtent(DecrementButtonExtent, Width);
         float incrementExtent = AxisExtent(IncrementButtonExtent, Width);
         DrawTiled(ctx, resolve, TrackSprite, 0f, 0f, Width, Height);
-        DrawSprite(ctx, resolve, UpSprite, 0f, 0f, decrementExtent, Height);
-        DrawSprite(ctx, resolve, DownSprite,
+        DrawSprite(ctx, resolve, ActiveStartSprite, 0f, 0f, decrementExtent, Height);
+        DrawSprite(ctx, resolve, ActiveEndSprite,
             Width - incrementExtent, 0f, incrementExtent, Height);
         if (!model.HasOverflow) return;
 
@@ -322,9 +341,24 @@ public sealed class UiScrollbar : UiElement
         if (IsModelDisabled)
         {
             _draggingThumb = false;
+            _hoveredButton = EndButton.None;
+            _pressedButton = EndButton.None;
             return false;
         }
 
+        if (e.Type == UiEventType.HoverEnter)
+        {
+            _hoveredButton = ButtonAt(e.Data1, e.Data2);
+            return true;
+        }
+        if (e.Type == UiEventType.HoverLeave)
+        {
+            _hoveredButton = EndButton.None;
+            return true;
+        }
+        if (e.Type == UiEventType.MouseMove)
+            _hoveredButton = ButtonAt(e.Data1, e.Data2);
+
         if (Horizontal && ScalarChanged is not null)
             return OnScalarEvent(e);
 
@@ -339,6 +373,7 @@ public sealed class UiScrollbar : UiElement
             {
                 // e.Data1 = local X, e.Data2 = local Y (int pixel coords, see UiRoot hit dispatch).
                 float ly = e.Data2;
+                _pressedButton = ButtonAt(e.Data1, e.Data2);
                 float decrementExtent = AxisExtent(DecrementButtonExtent, Height);
                 float incrementExtent = AxisExtent(IncrementButtonExtent, Height);
 
@@ -386,6 +421,7 @@ public sealed class UiScrollbar : UiElement
 
             case UiEventType.MouseUp:
                 _draggingThumb = false;
+                _pressedButton = EndButton.None;
                 return true;
         }
 
@@ -400,6 +436,7 @@ public sealed class UiScrollbar : UiElement
             case UiEventType.MouseDown:
             {
                 float x = e.Data1;
+                _pressedButton = ButtonAt(e.Data1, e.Data2);
                 float decrementExtent = AxisExtent(DecrementButtonExtent, Width);
                 float incrementExtent = AxisExtent(IncrementButtonExtent, Width);
                 if (x < decrementExtent) { m.ScrollByLines(-1); return true; }
@@ -437,6 +474,7 @@ public sealed class UiScrollbar : UiElement
 
             case UiEventType.MouseUp:
                 _draggingThumb = false;
+                _pressedButton = EndButton.None;
                 return true;
         }
         return false;
@@ -475,6 +513,7 @@ public sealed class UiScrollbar : UiElement
 
             case UiEventType.MouseUp:
                 _draggingThumb = false;
+                _pressedButton = EndButton.None;
                 return true;
         }
 
@@ -497,6 +536,48 @@ public sealed class UiScrollbar : UiElement
         ScalarChanged?.Invoke(ScalarPosition);
     }
 
+    private EndButton ButtonAt(float x, float y)
+    {
+        if (x < 0f || x >= Width || y < 0f || y >= Height)
+            return EndButton.None;
+
+        if (Horizontal)
+        {
+            if (x < AxisExtent(DecrementButtonExtent, Width))
+                return EndButton.Decrement;
+            if (x >= Width - AxisExtent(IncrementButtonExtent, Width))
+                return EndButton.Increment;
+            return EndButton.None;
+        }
+
+        if (y < AxisExtent(DecrementButtonExtent, Height))
+            return EndButton.Decrement;
+        if (y >= Height - AxisExtent(IncrementButtonExtent, Height))
+            return EndButton.Increment;
+        return EndButton.None;
+    }
+
+    private uint ActiveStartSprite
+        => _pressedButton == EndButton.Decrement
+            && _hoveredButton == EndButton.Decrement
+            && UpPressedSprite != 0u
+            ? UpPressedSprite
+            : _hoveredButton == EndButton.Decrement && UpRolloverSprite != 0u
+                ? UpRolloverSprite
+                : UpSprite;
+
+    private uint ActiveEndSprite
+        => _pressedButton == EndButton.Increment
+            && _hoveredButton == EndButton.Increment
+            && DownPressedSprite != 0u
+            ? DownPressedSprite
+            : _hoveredButton == EndButton.Increment && DownRolloverSprite != 0u
+                ? DownRolloverSprite
+                : DownSprite;
+
+    internal uint ActiveStartSpriteForTest => ActiveStartSprite;
+    internal uint ActiveEndSpriteForTest => ActiveEndSprite;
+
     private static float AxisExtent(float authoredExtent, float axisLength)
         => Math.Clamp(authoredExtent, 0f, MathF.Max(0f, axisLength));
 }