(#346) Try to fix getting the wrong descendant bounds of an item...

(#346) Try to fix getting the wrong descendant bounds of an item (TreeViewItem) with our own GetVisibleDescendantBounds version

Credits and idea goes to @Metritutus

src/GongSolutions.WPF.DragDrop/DragDrop.cs

@@ -57,7 +57,7 @@ private static DragDropPreview GetDragDropPreview(DropInfo dropInfo, UIElement t
 
                         if (useVisualSourceItemSizeForDragAdorner)
                         {
-                            var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
+                            var bounds = VisualTreeExtensions.GetVisibleDescendantBounds(dragInfo.VisualSourceItem);
                             itemsControl.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
                         }
 
@@ -78,7 +78,7 @@ private static DragDropPreview GetDragDropPreview(DropInfo dropInfo, UIElement t
 
                     if (useVisualSourceItemSizeForDragAdorner)
                     {
-                        var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
+                        var bounds = VisualTreeExtensions.GetVisibleDescendantBounds(dragInfo.VisualSourceItem);
                         contentPresenter.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
                         contentPresenter.SetValue(FrameworkElement.MinHeightProperty, bounds.Height);
                     }

src/GongSolutions.WPF.DragDrop/DropTargetHighlightAdorner.cs

@@ -4,6 +4,8 @@
 
 namespace GongSolutions.Wpf.DragDrop
 {
+    using GongSolutions.Wpf.DragDrop.Utilities;
+
     public class DropTargetHighlightAdorner : DropTargetAdorner
     {
         public DropTargetHighlightAdorner(UIElement adornedElement, DropInfo dropInfo)
@@ -28,17 +30,19 @@ protected override void OnRender(DrawingContext drawingContext)
                 var tvItem = visualTargetItem as TreeViewItem;
                 if (tvItem != null && VisualTreeHelper.GetChildrenCount(tvItem) > 0)
                 {
-                    var descendant = VisualTreeHelper.GetDescendantBounds(tvItem);
+                    var descendant = VisualTreeExtensions.GetVisibleDescendantBounds(tvItem);
                     var translatePoint = tvItem.TranslatePoint(new Point(), this.AdornedElement);
                     var itemRect = new Rect(translatePoint, tvItem.RenderSize);
                     descendant.Union(itemRect);
                     translatePoint.Offset(1, 0);
                     rect = new Rect(translatePoint, new Size(descendant.Width - translatePoint.X - 1, tvItem.ActualHeight));
                 }
+
                 if (rect.IsEmpty)
                 {
-                    rect = new Rect(visualTargetItem.TranslatePoint(new Point(), this.AdornedElement), VisualTreeHelper.GetDescendantBounds(visualTargetItem).Size);
+                    rect = new Rect(visualTargetItem.TranslatePoint(new Point(), this.AdornedElement), VisualTreeExtensions.GetVisibleDescendantBounds(visualTargetItem).Size);
                 }
+
                 drawingContext.DrawRoundedRectangle(null, this.Pen, rect, 2, 2);
             }
         }

src/GongSolutions.WPF.DragDrop/Utilities/DragDropExtensions.cs

@@ -52,7 +52,7 @@ public static bool DirectlyOverElement(this Point dropPosition, UIElement elemen
 
             var relativeItemPosition = element.TranslatePoint(new Point(0, 0), relativeToElement);
             var relativeDropPosition = new Point(dropPosition.X - relativeItemPosition.X, dropPosition.Y - relativeItemPosition.Y);
-            return VisualTreeHelper.GetDescendantBounds(element).Contains(relativeDropPosition);
+            return VisualTreeExtensions.GetVisibleDescendantBounds(element).Contains(relativeDropPosition);
         }
 
         /// <summary>
@@ -91,18 +91,19 @@ private static BitmapSource CaptureScreen(Visual target, FlowDirection flowDirec
             }
 
             var bounds = VisualTreeHelper.GetDescendantBounds(target);
+            var cropBounds = VisualTreeExtensions.GetVisibleDescendantBounds(target);
 
 #if NET461 || NET46 || NET452 || NET451 || NET45
             var dpiX = DpiHelper.DpiX;
             var dpiY = DpiHelper.DpiY;
 
-            var dpiBounds = DpiHelper.LogicalRectToDevice(bounds);
+            var dpiBounds = DpiHelper.LogicalRectToDevice(cropBounds);
 #else
             var dpiScale = VisualTreeHelper.GetDpi(target);
             var dpiX = dpiScale.PixelsPerInchX;
             var dpiY = dpiScale.PixelsPerInchY;
 
-            var dpiBounds = DpiHelper.LogicalRectToDevice(bounds, dpiScale.DpiScaleX, dpiScale.DpiScaleY);
+            var dpiBounds = DpiHelper.LogicalRectToDevice(cropBounds, dpiScale.DpiScaleX, dpiScale.DpiScaleY);
 #endif
 
             var pixelWidth = (int)Math.Ceiling(dpiBounds.Width);
@@ -118,6 +119,10 @@ private static BitmapSource CaptureScreen(Visual target, FlowDirection flowDirec
             using (var ctx = dv.RenderOpen())
             {
                 var vb = new VisualBrush(target);
+
+                vb.ViewportUnits = BrushMappingMode.Absolute;
+                vb.Viewport = bounds;
+
                 if (flowDirection == FlowDirection.RightToLeft)
                 {
                     var transformGroup = new TransformGroup();

src/GongSolutions.WPF.DragDrop/Utilities/VisualTreeExtensions.cs

@@ -22,6 +22,7 @@ public static UIElement TryGetNextAncestorDropTargetElement(this UIElement eleme
             {
                 return null;
             }
+
             var ancestor = element.GetVisualAncestor<UIElement>();
             while (ancestor != null)
             {
@@ -29,8 +30,10 @@ public static UIElement TryGetNextAncestorDropTargetElement(this UIElement eleme
                 {
                     return ancestor;
                 }
+
                 ancestor = ancestor.GetVisualAncestor<UIElement>();
             }
+
             return null;
         }
 
@@ -70,6 +73,7 @@ public static T GetVisualAncestor<T>(this DependencyObject d)
                 {
                     return itemAsT;
                 }
+
                 item = VisualTreeHelper.GetParent(item);
             }
 
@@ -97,11 +101,13 @@ public static DependencyObject GetVisualAncestor(this DependencyObject d, Type i
                         return currentVisual;
                     }
                 }
+
                 if (itemContainerSearchType.IsAssignableFrom(currentVisualType))
                 {
                     // ok, we found an ItemsControl (maybe an empty)
                     return null;
                 }
+
                 currentVisual = VisualTreeHelper.GetParent(currentVisual);
             }
 
@@ -125,12 +131,14 @@ public static DependencyObject GetVisualAncestor(this DependencyObject d, Type i
                 {
                     return lastFoundItemByType;
                 }
+
                 var currentVisualType = currentVisual.GetType();
                 if ((currentVisualType == itemSearchType || currentVisualType.IsSubclassOf(itemSearchType))
                     && (itemsControl.ItemContainerGenerator.IndexFromContainer(currentVisual) != -1))
                 {
                     lastFoundItemByType = currentVisual;
                 }
+
                 currentVisual = VisualTreeHelper.GetParent(currentVisual);
             }
 
@@ -165,5 +173,19 @@ public static IEnumerable<T> GetVisualDescendents<T>(this DependencyObject d)
 
             yield break;
         }
+
+        public static Rect GetVisibleDescendantBounds(Visual visual)
+        {
+            var bounds = VisualTreeHelper.GetDescendantBounds(visual);
+
+            if (visual is UIElement uiElement)
+            {
+                var cropBounds = new Rect(bounds.Location, new Size(bounds.Width, uiElement.DesiredSize.Height));
+
+                return cropBounds;
+            }
+
+            return bounds;
+        }
     }
 }
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