Remove FlyoutPlacementMode and improve PlacementMode instead

src/Avalonia.Controls/Flyouts/FlyoutBase.cs

@@ -29,8 +29,8 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Defines the <see cref="Placement"/> property
         /// </summary>
-        public static readonly StyledProperty<FlyoutPlacementMode> PlacementProperty =
-            AvaloniaProperty.Register<FlyoutBase, FlyoutPlacementMode>(nameof(Placement));
+        public static readonly StyledProperty<PlacementMode> PlacementProperty =
+            AvaloniaProperty.Register<FlyoutBase, PlacementMode>(nameof(Placement));
 
         /// <summary>
         /// Defines the <see cref="ShowMode"/> property
@@ -87,7 +87,7 @@ namespace Avalonia.Controls.Primitives
         /// <summary>
         /// Gets or sets the desired placement
         /// </summary>
-        public FlyoutPlacementMode Placement
+        public PlacementMode Placement
         {
             get => GetValue(PlacementProperty);
             set => SetValue(PlacementProperty, value);
@@ -452,93 +452,11 @@ namespace Avalonia.Controls.Primitives
             }
             else
             {
-                Popup.PlacementMode = PlacementMode.AnchorAndGravity;
+                Popup.PlacementMode = Placement;
                 Popup.PlacementConstraintAdjustment =
                     PopupPositioning.PopupPositionerConstraintAdjustment.SlideX |
                     PopupPositioning.PopupPositionerConstraintAdjustment.SlideY;
             }
-
-            var trgtBnds = Target?.Bounds ?? default;
-
-            switch (Placement)
-            {
-                case FlyoutPlacementMode.Top: //Above & centered
-                    Popup.PlacementRect = new Rect(0, 0, trgtBnds.Width - 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.Top;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Top;
-                    break;
-
-                case FlyoutPlacementMode.TopEdgeAlignedLeft:
-                    Popup.PlacementRect = new Rect(0, 0, 0, 0);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.TopRight;
-                    break;
-
-                case FlyoutPlacementMode.TopEdgeAlignedRight:
-                    Popup.PlacementRect = new Rect(trgtBnds.Width - 1, 0, 10, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.TopLeft;
-                    break;
-
-                case FlyoutPlacementMode.RightEdgeAlignedTop:
-                    Popup.PlacementRect = new Rect(trgtBnds.Width - 1, 0, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.BottomRight;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Right;
-                    break;
-
-                case FlyoutPlacementMode.Right: //Right & centered
-                    Popup.PlacementRect = new Rect(trgtBnds.Width - 1, 0, 1, trgtBnds.Height);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.Right;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Right;
-                    break;
-
-                case FlyoutPlacementMode.RightEdgeAlignedBottom:
-                    Popup.PlacementRect = new Rect(trgtBnds.Width - 1, trgtBnds.Height - 1, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.TopRight;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Right;
-                    break;
-
-                case FlyoutPlacementMode.Bottom: //Below & centered
-                    Popup.PlacementRect = new Rect(0, trgtBnds.Height - 1, trgtBnds.Width, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.Bottom;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Bottom;
-                    break;
-
-                case FlyoutPlacementMode.BottomEdgeAlignedLeft:
-                    Popup.PlacementRect = new Rect(0, trgtBnds.Height - 1, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.BottomRight;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Bottom;
-                    break;
-
-                case FlyoutPlacementMode.BottomEdgeAlignedRight:
-                    Popup.PlacementRect = new Rect(trgtBnds.Width - 1, trgtBnds.Height - 1, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.BottomLeft;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Bottom;
-                    break;
-
-                case FlyoutPlacementMode.LeftEdgeAlignedTop:
-                    Popup.PlacementRect = new Rect(0, 0, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.BottomLeft;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Left;
-                    break;
-
-                case FlyoutPlacementMode.Left: //Left & centered
-                    Popup.PlacementRect = new Rect(0, 0, 1, trgtBnds.Height);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.Left;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.Left;
-                    break;
-
-                case FlyoutPlacementMode.LeftEdgeAlignedBottom:
-                    Popup.PlacementRect = new Rect(0, trgtBnds.Height - 1, 1, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.TopLeft;
-                    Popup.PlacementAnchor = PopupPositioning.PopupAnchor.BottomLeft;
-                    break;
-
-                //includes Auto (not sure what determines that)...
-                default:
-                    //This is just FlyoutPlacementMode.Top behavior (above & centered)
-                    Popup.PlacementRect = new Rect(-sz.Width / 2, 0, sz.Width, 1);
-                    Popup.PlacementGravity = PopupPositioning.PopupGravity.Top;
-                    break;
-            }
         }
 
         private static void OnContextFlyoutPropertyChanged(AvaloniaPropertyChangedEventArgs args)

src/Avalonia.Controls/Flyouts/FlyoutPlacementMode.cs

@@ -1,77 +0,0 @@
-namespace Avalonia.Controls
-{
-    public enum FlyoutPlacementMode
-    {
-        /// <summary>
-        /// Preferred location is above the target element
-        /// </summary>
-        Top = 0,
-
-        /// <summary>
-        /// Preferred location is below the target element
-        /// </summary>
-        Bottom = 1,
-
-        /// <summary>
-        /// Preferred location is to the left of the target element
-        /// </summary>
-        Left = 2,
-
-        /// <summary>
-        /// Preferred location is to the right of the target element
-        /// </summary>
-        Right = 3,
-
-        //TODO
-        // <summary>
-        // Preferred location is centered on the screen
-        // </summary>
-        //Full = 4,
-
-        /// <summary>
-        /// Preferred location is above the target element, with the left edge of the flyout
-        /// aligned with the left edge of the target element
-        /// </summary>
-        TopEdgeAlignedLeft = 5,
-
-        /// <summary>
-        /// Preferred location is above the target element, with the right edge of flyout aligned with right edge of the target element.
-        /// </summary>
-        TopEdgeAlignedRight = 6,
-
-        /// <summary>
-        /// Preferred location is below the target element, with the left edge of flyout aligned with left edge of the target element.
-        /// </summary>
-        BottomEdgeAlignedLeft = 7,
-
-        /// <summary>
-        /// Preferred location is below the target element, with the right edge of flyout aligned with right edge of the target element.
-        /// </summary>
-        BottomEdgeAlignedRight = 8,
-
-        /// <summary>
-        /// Preferred location is to the left of the target element, with the top edge of flyout aligned with top edge of the target element.
-        /// </summary>
-        LeftEdgeAlignedTop = 9,
-
-        /// <summary>
-        /// Preferred location is to the left of the target element, with the bottom edge of flyout aligned with bottom edge of the target element.
-        /// </summary>
-        LeftEdgeAlignedBottom = 10,
-
-        /// <summary>
-        /// Preferred location is to the right of the target element, with the top edge of flyout aligned with top edge of the target element.
-        /// </summary>
-        RightEdgeAlignedTop = 11,
-
-        /// <summary>
-        /// Preferred location is to the right of the target element, with the bottom edge of flyout aligned with bottom edge of the target element.
-        /// </summary>
-        RightEdgeAlignedBottom = 12,
-
-        /// <summary>
-        /// Preferred location is determined automatically.
-        /// </summary>
-        Auto = 13
-    }
-}

src/Avalonia.Controls/PlacementMode.cs

@@ -13,28 +13,69 @@ namespace Avalonia.Controls
         Pointer,
 
         /// <summary>
-        /// The popup is placed at the bottom left of its target.
+        /// Preferred location is below the target element.
         /// </summary>
         Bottom,
 
         /// <summary>
-        /// The popup is placed at the top right of its target.
+        /// Preferred location is to the right of the target element.
         /// </summary>
         Right,
         
         /// <summary>
-        /// The popup is placed at the top left of its target.
+        /// Preferred location is to the left of the target element.
         /// </summary>
         Left,
         
         /// <summary>
-        /// The popup is placed at the top left of its target.
+        /// Preferred location is above the target element.
         /// </summary>
         Top,
+
+        /// <summary>
+        /// The popup is placed according to <see cref="Popup.PlacementAnchor"/> and <see cref="Popup.PlacementGravity"/> rules.
+        /// </summary>
+        AnchorAndGravity,
         
         /// <summary>
-        /// The popup is placed according to anchor and gravity rules
+        /// Preferred location is above the target element, with the left edge of the popup
+        /// aligned with the left edge of the target element.
+        /// </summary>
+        TopEdgeAlignedLeft,
+
+        /// <summary>
+        /// Preferred location is above the target element, with the right edge of popup aligned with right edge of the target element.
+        /// </summary>
+        TopEdgeAlignedRight,
+
+        /// <summary>
+        /// Preferred location is below the target element, with the left edge of popup aligned with left edge of the target element.
+        /// </summary>
+        BottomEdgeAlignedLeft,
+
+        /// <summary>
+        /// Preferred location is below the target element, with the right edge of popup aligned with right edge of the target element.
+        /// </summary>
+        BottomEdgeAlignedRight,
+
+        /// <summary>
+        /// Preferred location is to the left of the target element, with the top edge of popup aligned with top edge of the target element.
+        /// </summary>
+        LeftEdgeAlignedTop,
+
+        /// <summary>
+        /// Preferred location is to the left of the target element, with the bottom edge of popup aligned with bottom edge of the target element.
+        /// </summary>
+        LeftEdgeAlignedBottom,
+
+        /// <summary>
+        /// Preferred location is to the right of the target element, with the top edge of popup aligned with top edge of the target element.
+        /// </summary>
+        RightEdgeAlignedTop,
+
+        /// <summary>
+        /// Preferred location is to the right of the target element, with the bottom edge of popup aligned with bottom edge of the target element.
         /// </summary>
-        AnchorAndGravity
+        RightEdgeAlignedBottom
     }
 }

src/Avalonia.Controls/Primitives/PopupPositioning/IPopupPositioner.cs

@@ -480,33 +480,26 @@ namespace Avalonia.Controls.Primitives.PopupPositioning
                 var anchorRect = rect ?? bounds;
                 positionerParameters.AnchorRectangle = anchorRect.Intersect(bounds).TransformToAABB(matrix.Value);
 
-                if (placement == PlacementMode.Right)
+                var parameters = placement switch
                 {
-                    positionerParameters.Anchor = PopupAnchor.TopRight;
-                    positionerParameters.Gravity = PopupGravity.BottomRight;
-                }
-                else if (placement == PlacementMode.Bottom)
-                {
-                    positionerParameters.Anchor = PopupAnchor.BottomLeft;
-                    positionerParameters.Gravity = PopupGravity.BottomRight;
-                }
-                else if (placement == PlacementMode.Left)
-                {
-                    positionerParameters.Anchor = PopupAnchor.TopLeft;
-                    positionerParameters.Gravity = PopupGravity.BottomLeft;
-                }
-                else if (placement == PlacementMode.Top)
-                {
-                    positionerParameters.Anchor = PopupAnchor.TopLeft;
-                    positionerParameters.Gravity = PopupGravity.TopRight;
-                }
-                else if (placement == PlacementMode.AnchorAndGravity)
-                {
-                    positionerParameters.Anchor = anchor;
-                    positionerParameters.Gravity = gravity;
-                }
-                else
-                    throw new InvalidOperationException("Invalid value for Popup.PlacementMode");
+                    PlacementMode.Bottom => (PopupAnchor.Bottom, PopupGravity.Bottom),
+                    PlacementMode.Right => (PopupAnchor.Right, PopupGravity.Right),
+                    PlacementMode.Left => (PopupAnchor.Left, PopupGravity.Left),
+                    PlacementMode.Top => (PopupAnchor.Top, PopupGravity.Top),
+                    PlacementMode.AnchorAndGravity => (anchor, gravity),
+                    PlacementMode.TopEdgeAlignedRight => (PopupAnchor.TopRight, PopupGravity.TopLeft),
+                    PlacementMode.TopEdgeAlignedLeft => (PopupAnchor.TopLeft, PopupGravity.TopRight),
+                    PlacementMode.BottomEdgeAlignedLeft => (PopupAnchor.BottomLeft, PopupGravity.BottomRight),
+                    PlacementMode.BottomEdgeAlignedRight => (PopupAnchor.BottomRight, PopupGravity.BottomLeft),
+                    PlacementMode.LeftEdgeAlignedTop => (PopupAnchor.TopLeft, PopupGravity.BottomLeft),
+                    PlacementMode.LeftEdgeAlignedBottom => (PopupAnchor.BottomLeft, PopupGravity.TopLeft),
+                    PlacementMode.RightEdgeAlignedTop => (PopupAnchor.TopRight, PopupGravity.BottomRight),
+                    PlacementMode.RightEdgeAlignedBottom => (PopupAnchor.BottomRight, PopupGravity.TopRight),
+                    _ => throw new ArgumentOutOfRangeException(nameof(placement), placement,
+                        "Invalid value for Popup.PlacementMode")
+                };
+                positionerParameters.Anchor = parameters.Item1;
+                positionerParameters.Gravity = parameters.Item2;
             }
 
             // Invert coordinate system if FlowDirection is RTL