@

feat(D.2b): chat polish — typing fix, opacity, scrollbar 3-slice, retail channel menu

Visual-iteration batch (decomp-grounded), each fix verified against the retail screenshots:
- typing: UiElement.HitTest aborted on ClickThrough BEFORE walking children, so the
  ClickThrough UiDatElement panels blocked hit-testing to the input/transcript inside
  them. Check ClickThrough AFTER the child walk (it only gates whether THIS element
  claims the hit). Restores input focus + typing.
- opacity: UiElement.Opacity + a UiRenderContext alpha stack applied to sprite/rect
  draws (text bypasses it, stays sharp); chat frame Opacity=0.75 → translucent chat.
- brown sliver: grow the transcript panel up 9px to cover the dropped resize-bar strip.
- scrollbar: real 3-slice thumb (caps 0x06004C60/66 + tiled mid) + tiled track.
- max/min: shifted one button-width left of the scrollbar (dat right-anchors collide).
- system text now green (retail ChatMessageType 5; was yellow).
- word-wrap: transcript lines wrap to the panel width (greedy, ports GlyphList::Recalculate).
- channel menu reworked to retail gmMainChatUI::InitTalkFocusMenu: "Chat" button + a
  TWO-COLUMN popup of the 14 talk-focus items (Squelch, Tell to Selected, Chat to All,
  Tell to Fellows, ...) on a tan panel; channel items set the active outbound channel.

Build + 392 App tests green. Visual confirmation in progress.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
@

src/AcDream.App/UI/UiChatScrollbar.cs

@@ -33,10 +33,15 @@ public sealed class UiChatScrollbar : UiElement
     /// <summary>Track background sprite id (0x06004C5F from layout 0x2100003E element 0x10000455).</summary>
     public uint TrackSprite { get; set; }
 
-    /// <summary>Thumb sprite id (3-slice middle tile: 0x06004C63; the widget draws
-    /// a single stretched sprite for simplicity — Task H can upgrade to 3-slice).</summary>
+    /// <summary>Thumb 3-slice MIDDLE tile sprite id (0x06004C63), tiled between the caps.</summary>
     public uint ThumbSprite { get; set; }
 
+    /// <summary>Thumb 3-slice TOP cap sprite id (0x06004C60, 3px tall).</summary>
+    public uint ThumbTopSprite { get; set; }
+
+    /// <summary>Thumb 3-slice BOTTOM cap sprite id (0x06004C66, 3px tall).</summary>
+    public uint ThumbBotSprite { get; set; }
+
     /// <summary>Up-arrow button sprite id (0x06004C69 Normal state, element 0x10000071).</summary>
     public uint UpSprite { get; set; }
 
@@ -46,6 +51,9 @@ public sealed class UiChatScrollbar : UiElement
     /// <summary>Retail attribute 0x89 floor: minimum thumb height in pixels.</summary>
     private const float MinThumb = 8f;
 
+    /// <summary>Thumb cap height (native sprite height from base layout 0x2100003E).</summary>
+    private const float CapH = 3f;
+
     /// <summary>Up/down button height in pixels. Matches element height 16px from
     /// the up/down button children in base layout 0x2100003E.</summary>
     private const float ButtonH = 16f;
@@ -77,34 +85,59 @@ public sealed class UiChatScrollbar : UiElement
     {
         if (Model is not { } m || SpriteResolve is not { } resolve) return;
 
-        // Track background, full element bounds.
-        DrawSprite(ctx, resolve, TrackSprite, 0f, 0f, Width, Height);
+        // Track background — TILED vertically (retail DrawMode=Normal). The native track
+        // sprite (~16×32) repeats to fill the element height instead of stretch-distorting.
+        DrawTiled(ctx, resolve, TrackSprite, 0f, 0f, Width, Height);
 
-        // Up button — top ButtonH rows.
+        // Up button — top ButtonH rows (directional arrow art, drawn 1:1).
         DrawSprite(ctx, resolve, UpSprite, 0f, 0f, Width, ButtonH);
 
         // Down button — bottom ButtonH rows.
         DrawSprite(ctx, resolve, DownSprite, 0f, Height - ButtonH, Width, ButtonH);
 
-        // Thumb — only when content overflows the view.
+        // Thumb — only when content overflows the view. Retail 3-slice: top cap +
+        // tiled middle + bottom cap (base layout 0x2100003E thumb sub-elements
+        // 0x10000364/65/66). Falls back to a single tiled middle if the caps are unset
+        // or the thumb is too short to hold both caps.
         if (m.HasOverflow)
         {
             float trackTop = ButtonH;
             float trackLen = Height - 2f * ButtonH;
             var (ty, th) = ThumbRect(m, trackTop, trackLen);
-            DrawSprite(ctx, resolve, ThumbSprite, 0f, ty, Width, th);
+            if (ThumbTopSprite != 0 && ThumbBotSprite != 0 && th >= 2f * CapH)
+            {
+                DrawSprite(ctx, resolve, ThumbTopSprite, 0f, ty, Width, CapH);
+                DrawTiled(ctx, resolve, ThumbSprite, 0f, ty + CapH, Width, th - 2f * CapH);
+                DrawSprite(ctx, resolve, ThumbBotSprite, 0f, ty + th - CapH, Width, CapH);
+            }
+            else
+            {
+                DrawTiled(ctx, resolve, ThumbSprite, 0f, ty, Width, th);
+            }
         }
     }
 
+    /// <summary>Draw a sprite stretched 1:1 to the dest rect.</summary>
     private void DrawSprite(UiRenderContext ctx, Func<uint, (uint tex, int w, int h)> resolve,
         uint id, float x, float y, float w, float h)
     {
-        if (id == 0) return;
+        if (id == 0 || w <= 0f || h <= 0f) return;
         var (tex, _, _) = resolve(id);
         if (tex == 0) return;
         ctx.DrawSprite(tex, x, y, w, h, 0f, 0f, 1f, 1f, Vector4.One);
     }
 
+    /// <summary>Draw a sprite TILED to fill the dest rect (UV-repeat at native size on
+    /// both axes — the UI texture is GL_REPEAT-wrapped). A native-width axis gives 1:1.</summary>
+    private void DrawTiled(UiRenderContext ctx, Func<uint, (uint tex, int w, int h)> resolve,
+        uint id, float x, float y, float w, float h)
+    {
+        if (id == 0 || w <= 0f || h <= 0f) return;
+        var (tex, tw, th) = resolve(id);
+        if (tex == 0 || tw == 0 || th == 0) return;
+        ctx.DrawSprite(tex, x, y, w, h, 0f, 0f, w / tw, h / th, Vector4.One);
+    }
+
     public override bool OnEvent(in UiEvent e)
     {
         if (Model is not { } m) return false;