mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/FreeFormEditing/AutoSplitHelper.cs

   1 //----------------------------------------------------------------
   2 // <copyright company="Microsoft Corporation">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //----------------------------------------------------------------
   6
   7 namespace System.Activities.Presentation.FreeFormEditing
   8 {
   9     using System.Collections.Generic;
  10     using System.Windows;
  11
  12     internal static class AutoSplitHelper
  13     {
  14         private const double ShapeMargin = 40;
  15
  16         public static void CalculateEntryExitEdges(Point mousePosition, Connector connector, out EdgeLocation entryEdge, out EdgeLocation exitEdge)
  17         {
  18             UIElement srcShape = FreeFormPanel.GetSourceConnectionPoint(connector).ParentDesigner;
  19             UIElement destShape = FreeFormPanel.GetDestinationConnectionPoint(connector).ParentDesigner;
  20             Point srcLocation = FreeFormPanel.GetLocation(srcShape);
  21             Point destLocation = FreeFormPanel.GetLocation(destShape);
  22             Size srcSize = FreeFormPanel.GetChildSize(srcShape);
  23             Size destSize = FreeFormPanel.GetChildSize(destShape);
  24
  25             Point srcCenter = new Point(srcLocation.X + (srcSize.Width / 2), srcLocation.Y + (srcSize.Height / 2));
  26             Point destCenter = new Point(destLocation.X + (destSize.Width / 2), destLocation.Y + (destSize.Height / 2));
  27
  28             entryEdge = CalculateEdgeLocation(mousePosition, srcCenter);
  29             exitEdge = CalculateEdgeLocation(mousePosition, destCenter);
  30
  31             if (exitEdge == entryEdge)
  32             {
  33                 switch (entryEdge)
  34                 {
  35                     case EdgeLocation.Top:
  36                         exitEdge = EdgeLocation.Bottom;
  37                         break;
  38
  39                     case EdgeLocation.Bottom:
  40                         exitEdge = EdgeLocation.Top;
  41                         break;
  42
  43                     case EdgeLocation.Left:
  44                         exitEdge = EdgeLocation.Right;
  45                         break;
  46
  47                     case EdgeLocation.Right:
  48                         exitEdge = EdgeLocation.Left;
  49                         break;
  50                 }
  51             }
  52         }
  53
  54         public static Point CalculateDropLocation(Point mousePosition, Point originalDropLocation, Connector connector, Size droppedSize, HashSet<Point> shapeLocations)
  55         {
  56             UIElement srcShape = FreeFormPanel.GetSourceConnectionPoint(connector).ParentDesigner;
  57             UIElement destShape = FreeFormPanel.GetDestinationConnectionPoint(connector).ParentDesigner;
  58             Point srcLocation = FreeFormPanel.GetLocation(srcShape);
  59             Point destLocation = FreeFormPanel.GetLocation(destShape);
  60             Size srcSize = FreeFormPanel.GetChildSize(srcShape);
  61             Size destSize = FreeFormPanel.GetChildSize(destShape);
  62
  63             return CalculateDropLocation(mousePosition, originalDropLocation, droppedSize, srcLocation, destLocation, srcSize, destSize, shapeLocations);
  64         }
  65
  66         internal static Point CalculateDropLocation(Point mousePosition, Point originalDropLocation, Size droppedSize, Point srcLocation, Point destLocation, Size srcSize, Size destSize, HashSet<Point> shapeLocations)
  67         {
  68             Point dropLocation = originalDropLocation;
  69
  70             double distToSrc = DesignerGeometryHelper.ManhattanDistanceBetweenPoints(mousePosition, new Point(srcLocation.X + (srcSize.Width / 2), srcLocation.Y + (srcSize.Height / 2)));
  71             double distToDest = DesignerGeometryHelper.ManhattanDistanceBetweenPoints(mousePosition, new Point(destLocation.X + (destSize.Width / 2), destLocation.Y + (destSize.Height / 2)));
  72
  73             AutoSplitAlignment srcAlignment = GetAlignment(mousePosition, srcLocation, srcSize);
  74             AutoSplitAlignment destAlignment = GetAlignment(mousePosition, destLocation, destSize);
  75
  76             if ((distToSrc <= distToDest || destAlignment == AutoSplitAlignment.None) && srcAlignment == AutoSplitAlignment.Vertical)
  77             {
  78                 dropLocation = CalculateDropLocationToAlignVertically(dropLocation, droppedSize, srcLocation, srcSize);
  79             }
  80             else if ((distToSrc <= distToDest || destAlignment == AutoSplitAlignment.None) && srcAlignment == AutoSplitAlignment.Horizontal)
  81             {
  82                 dropLocation = CalculateDropLocationToAlignHorizontally(dropLocation, droppedSize, srcLocation, srcSize);
  83             }
  84             else if ((distToSrc >= distToDest || srcAlignment == AutoSplitAlignment.None) && destAlignment == AutoSplitAlignment.Vertical)
  85             {
  86                 dropLocation = CalculateDropLocationToAlignVertically(dropLocation, droppedSize, destLocation, destSize);
  87             }
  88             else if ((distToSrc >= distToDest || srcAlignment == AutoSplitAlignment.None) && destAlignment == AutoSplitAlignment.Horizontal)
  89             {
  90                 dropLocation = CalculateDropLocationToAlignHorizontally(dropLocation, droppedSize, destLocation, destSize);
  91             }
  92
  93             dropLocation.X = dropLocation.X < 0 ? 0 : dropLocation.X;
  94             dropLocation.Y = dropLocation.Y < 0 ? 0 : dropLocation.Y;
  95
  96             // To avoid overlaps with existing shapes
  97             if (shapeLocations != null)
  98             {
  99                 while (shapeLocations.Contains(dropLocation))
 100                 {
 101                     dropLocation.Offset(FreeFormPanel.GridSize, FreeFormPanel.GridSize);
 102                 }
 103             }
 104
 105             return dropLocation;
 106         }
 107
 108         internal static AutoSplitAlignment GetAlignment(Point mousePosition, Point targetLocation, Size targetSize)
 109         {
 110             AutoSplitAlignment alignment = AutoSplitAlignment.None;
 111             if (mousePosition.X >= targetLocation.X && mousePosition.X <= targetLocation.X + targetSize.Width)
 112             {
 113                 alignment = AutoSplitAlignment.Vertical;
 114             }
 115             else if (mousePosition.Y >= targetLocation.Y && mousePosition.Y <= targetLocation.Y + targetSize.Height)
 116             {
 117                 alignment = AutoSplitAlignment.Horizontal;
 118             }
 119
 120             return alignment;
 121         }
 122
 123         internal static Point CalculateDropLocationToAlignVertically(Point originalDropLocation, Size droppedSize, Point targetLocation, Size targetSize)
 124         {
 125             Point dropLocation = originalDropLocation;
 126             dropLocation.X = targetLocation.X + ((targetSize.Width - droppedSize.Width) / 2);
 127             if (dropLocation.Y >= targetLocation.Y && dropLocation.Y <= targetLocation.Y + targetSize.Height + ShapeMargin)
 128             {
 129                 dropLocation.Y = targetLocation.Y + targetSize.Height + ShapeMargin;
 130             }
 131             else if (dropLocation.Y + droppedSize.Height + ShapeMargin >= targetLocation.Y && dropLocation.Y <= targetLocation.Y)
 132             {
 133                 dropLocation.Y = targetLocation.Y - droppedSize.Height - ShapeMargin;
 134             }
 135
 136             return dropLocation;
 137         }
 138
 139         internal static Point CalculateDropLocationToAlignHorizontally(Point originalDropLocation, Size droppedSize, Point targetLocation, Size targetSize)
 140         {
 141             Point dropLocation = originalDropLocation;
 142             dropLocation.Y = targetLocation.Y + ((targetSize.Height - droppedSize.Height) / 2);
 143             if (dropLocation.X >= targetLocation.X && dropLocation.X <= targetLocation.X + targetSize.Width + ShapeMargin)
 144             {
 145                 dropLocation.X = targetLocation.X + targetSize.Width + ShapeMargin;
 146             }
 147             else if (dropLocation.X + droppedSize.Width + ShapeMargin >= targetLocation.X && dropLocation.X <= targetLocation.X)
 148             {
 149                 dropLocation.X = targetLocation.X - droppedSize.Width - ShapeMargin;
 150             }
 151
 152             return dropLocation;
 153         }
 154
 155         internal static EdgeLocation CalculateEdgeLocation(Point mousePosition, Point shapeCenter)
 156         {
 157             double distX = Math.Abs(shapeCenter.X - mousePosition.X);
 158             double distY = Math.Abs(shapeCenter.Y - mousePosition.Y);
 159             if (distX > distY)
 160             {
 161                 return shapeCenter.X < mousePosition.X ? EdgeLocation.Left : EdgeLocation.Right;
 162             }
 163             else
 164             {
 165                 return shapeCenter.Y < mousePosition.Y ? EdgeLocation.Top : EdgeLocation.Bottom;
 166             }
 167         }
 168     }
 169 }