wpftoolkit/ExtendedWPFToolkitSolution/Src/WPFToolkit.Extended/Core/Primitives/ShapeBase.cs

/************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   This program can be provided to you by Xceed Software Inc. under a
   proprietary commercial license agreement for use in non-Open Source
   projects. The commercial version of Extended WPF Toolkit also includes
   priority technical support, commercial updates, and many additional 
   useful WPF controls if you license Xceed Business Suite for WPF.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System;
using System.Diagnostics;
using System.Windows;
using System.Windows.Media;
using System.Windows.Shapes;
using Xceed.Wpf.Toolkit.Core.Utilities;

namespace Xceed.Wpf.Toolkit.Primitives
{
  public abstract class ShapeBase : Shape
  {
    #region Constructors

    static ShapeBase()
    {
      ShapeBase.StrokeDashArrayProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeDashCapProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeDashOffsetProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeEndLineCapProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeLineJoinProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeMiterLimitProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeStartLineCapProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
      ShapeBase.StrokeThicknessProperty.OverrideMetadata( typeof( ShapeBase ), new FrameworkPropertyMetadata( new PropertyChangedCallback( ShapeBase.OnStrokeChanged ) ) );
    }

    #endregion

    #region IsPenEmptyOrUndefined Internal Property

    internal bool IsPenEmptyOrUndefined
    {
      get
      {
        double strokeThickness = this.StrokeThickness;
        return ( this.Stroke == null ) || DoubleHelper.IsNaN( strokeThickness ) || DoubleHelper.AreVirtuallyEqual( 0, strokeThickness );
      }
    }

    #endregion

    #region DefiningGeometry Protected Property

    protected abstract override Geometry DefiningGeometry
    {
      get;
    }

    #endregion

    internal virtual Rect GetDefiningGeometryBounds()
    {
      Geometry geometry = this.DefiningGeometry;

      Debug.Assert( geometry != null );

      return geometry.Bounds;
    }

    internal virtual Size GetNaturalSize()
    {
      Geometry geometry = this.DefiningGeometry;

      Debug.Assert( geometry != null );

      Rect bounds = geometry.GetRenderBounds( GetPen() );

      return new Size( Math.Max( bounds.Right, 0 ), Math.Max( bounds.Bottom, 0 ) );
    }

    internal Pen GetPen()
    {
      if( this.IsPenEmptyOrUndefined )
        return null;

      if( _pen == null )
      {
        _pen = this.MakePen();
      }

      return _pen;
    }

    internal double GetStrokeThickness()
    {
      if( this.IsPenEmptyOrUndefined )
        return 0d;

      return Math.Abs( this.StrokeThickness );
    }

    internal bool IsSizeEmptyOrUndefined( Size size )
    {
      return ( DoubleHelper.IsNaN( size.Width ) || DoubleHelper.IsNaN( size.Height ) || size.IsEmpty );
    }

    private static void OnStrokeChanged( DependencyObject d, DependencyPropertyChangedEventArgs e )
    {
      ( ( ShapeBase )d )._pen = null;
    }

    private Pen MakePen()
    {
      Pen pen = new Pen();
      pen.Brush = this.Stroke;
      pen.DashCap = this.StrokeDashCap;
      if( this.StrokeDashArray != null || this.StrokeDashOffset != 0.0 )
      {
        pen.DashStyle = new DashStyle( this.StrokeDashArray, this.StrokeDashOffset );
      }
      pen.EndLineCap = this.StrokeEndLineCap;
      pen.LineJoin = this.StrokeLineJoin;
      pen.MiterLimit = this.StrokeMiterLimit;
      pen.StartLineCap = this.StrokeStartLineCap;
      pen.Thickness = Math.Abs( this.StrokeThickness );

      return pen;
    }

    #region Private Fields

    private Pen _pen = null;

    #endregion
  }
}