Win32: Use listview's builtin "scroll into view" implementation.

The default implementation doesn't work well in details view
because we scroll by items and it expects pixels. List view,
where we scroll by columns, is likely similar.

xalia/Interop/Win32.cs

@@ -1271,6 +1271,7 @@ public struct COMBOBOXINFO
         public const int LVM_FIRST = 0x1000;
         public const int LVM_GETITEMCOUNT = LVM_FIRST + 4;
         public const int LVM_GETITEMRECT = LVM_FIRST + 14;
+        public const int LVM_ENSUREVISIBLE = LVM_FIRST + 19;
         public const int LVM_SCROLL = LVM_FIRST + 20;
         public const int LVM_GETCOLUMNWIDTH = LVM_FIRST + 29;
         public const int LVM_GETHEADER = LVM_FIRST + 31;

xalia/Ui/UiMain.cs

@@ -953,7 +953,7 @@ internal void TargetMove(Direction direction)
 
             TargetedElement = best_element;
 
-            ScrollIntoView(TargetedElement);
+            Utils.RunTask(ScrollIntoView(TargetedElement));
         }
 
         private bool AdjustValue(UiDomElement targetedElement, Direction direction)
@@ -1051,8 +1051,18 @@ internal void TargetMoveRoutineStopped()
                 target_box.Hide();
         }
 
-        private void ScrollIntoView(UiDomElement targetedElement)
+        private async Task ScrollIntoView(UiDomElement targetedElement)
         {
+            var scroll_to = targetedElement.ProviderByType<IUiDomScrollToProvider>();
+
+            if (!(scroll_to is null))
+            {
+                if (await scroll_to.ScrollToAsync())
+                {
+                    return;
+                }
+            }
+
             if (!TryGetElementTargetBounds(targetedElement, out var bounds))
                 return;
 
@@ -1105,7 +1115,7 @@ private void ScrollIntoView(UiDomElement targetedElement)
                         queue.Enqueue(st);
                         queue.Enqueue(new InputState(InputStateKind.Disconnected));
 
-                        Utils.RunTask(routine.ProcessInputQueue(queue));
+                        await routine.ProcessInputQueue(queue);
                     }
 
                     break;

xalia/UiDom/IUiDomScrollToProvider.cs

@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace Xalia.UiDom
+{
+    internal interface IUiDomScrollToProvider : IUiDomProvider
+    {
+        Task<bool> ScrollToAsync();
+    }
+}

xalia/Win32/HwndListViewItemProvider.cs

@@ -8,7 +8,7 @@
 
 namespace Xalia.Win32
 {
-    internal class HwndListViewItemProvider : UiDomProviderBase, IWin32LocationChange
+    internal class HwndListViewItemProvider : UiDomProviderBase, IWin32LocationChange, IUiDomScrollToProvider
     {
         public HwndListViewItemProvider(HwndListViewProvider parent, UiDomElement element)
         {
@@ -388,5 +388,11 @@ await SendMessageAsync(Parent.Hwnd, LVM_SETITEMSTATE,
                     (IntPtr)(ChildId - 1), (IntPtr)(long)memory.Address);
             }
         }
+
+        public async Task<bool> ScrollToAsync()
+        {
+            await SendMessageAsync(Parent.Hwnd, LVM_ENSUREVISIBLE, (IntPtr)(ChildId - 1), (IntPtr)(1));
+            return true;
+        }
     }
 }

xalia/xalia.csproj

@@ -108,6 +108,7 @@
     <Compile Include="Sdl\SplitOverlayBox.cs" />
     <Compile Include="Sdl\Win32LayeredBox.cs" />
     <Compile Include="UiDom\IUiDomProvider.cs" />
+    <Compile Include="UiDom\IUiDomScrollToProvider.cs" />
     <Compile Include="UiDom\IUiDomValueProvider.cs" />
     <Compile Include="UiDom\UiDomAdjustScrollbars.cs" />
     <Compile Include="Gudl\ApplyExpression.cs" />