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

   1 //------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation.FreeFormEditing
   6 {
   7     using System;
   8     using System.Globalization;
   9     using System.Windows;
  10     using System.Windows.Data;
  11     using System.Windows.Media;
  12     using System.Diagnostics.CodeAnalysis;
  13
  14     [SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses", Justification = "The class is used in xaml.")]
  15     class ConnectorLabelMarginConverter : IMultiValueConverter
  16     {
  17         const double EPS = 1e-6;
  18
  19         [SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", Justification = "The class is only used internally and not accessible externally.")]
  20         public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
  21         {
  22             Thickness margin = new Thickness(0);
  23             PointCollection connectorPoints = values[0] as PointCollection;
  24             // 8 and 4 is calcuated from the margin / padding settings related to the label in xaml
  25             double labelBorderWidth = (double)values[1] + 8;
  26             double labelBorderHeight = (double)values[2] + 4;
  27             if (connectorPoints != null)
  28             {
  29                 int longestSegmentIndex;
  30                 DesignerGeometryHelper.LongestSegmentLength(connectorPoints, out longestSegmentIndex);
  31                 if (longestSegmentIndex >= 0)
  32                 {
  33                     Point labelLocation = DesignerGeometryHelper.MidPointOfLineSegment(connectorPoints[longestSegmentIndex], connectorPoints[longestSegmentIndex + 1]);
  34                     labelLocation.X = (int)(labelLocation.X - labelBorderWidth / 2 + EPS);
  35                     labelLocation.Y = (int)(labelLocation.Y - labelBorderHeight / 2 + EPS);
  36                     margin.Top = labelLocation.Y;
  37                     margin.Left = labelLocation.X;
  38                 }
  39             }
  40             return margin;
  41         }
  42
  43         public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
  44         {
  45             throw FxTrace.Exception.AsError(new NotSupportedException());
  46         }
  47     }
  48 }