Support color inner rectangle of RectangleAdorner (helix-toolkit#2085)

Source/HelixToolkit.Wpf.Shared/Adorners/RectangleAdorner.cs

@@ -29,6 +29,11 @@ public class RectangleAdorner : Adorner
  /// </summary>
  private readonly Pen pen;
 
+ /// <summary>
+ /// The brush to color the inner rectangle
+ /// </summary>
+ private Brush fillBrush;
+
  /// <summary>
  /// The pen 2.
  /// </summary>
@@ -58,6 +63,8 @@ public class RectangleAdorner : Adorner
  /// <param name="crossHairSize">
  /// Size of the cross hair.
  /// </param>
+ ///<exception cref="ArgumentNullException">
+ ///</exception>
  public RectangleAdorner(
  UIElement adornedElement,
  Rect rectangle,
@@ -66,7 +73,7 @@ public class RectangleAdorner : Adorner
  double thickness1 = 1.0,
  double thickness2 = 1.0,
  double crossHairSize = 10)
- : this(adornedElement, rectangle, color1, color2, thickness1, thickness2, crossHairSize, DashStyles.Dash)
+ : this(adornedElement, rectangle, color1, color2, thickness1, thickness2, crossHairSize, DashStyles.Dash, null)
  {
  }
 
@@ -97,6 +104,11 @@ public class RectangleAdorner : Adorner
  /// <param name="dashStyle2">
  /// The dash style2.
  /// </param>
+ /// <param name="fillBrush">
+ /// The brush to color the inner rectangle
+ /// </param>
+ /// <exception cref="ArgumentNullException">
+ /// </exception>
  public RectangleAdorner(
  UIElement adornedElement,
  Rect rectangle,
@@ -105,7 +117,8 @@ public class RectangleAdorner : Adorner
  double thickness1,
  double thickness2,
  double crossHairSize,
- DashStyle dashStyle2)
+ DashStyle dashStyle2,
+ Brush fillBrush = null)
  : base(adornedElement)
  {
  if (adornedElement == null)
@@ -135,6 +148,7 @@ public class RectangleAdorner : Adorner
  this.pen2 = new Pen(new SolidColorBrush(color2), thickness2 * dpiFactor);
  this.pen2.DashStyle = dashStyle2;
  this.crossHairSize = crossHairSize;
+ this.fillBrush = fillBrush;
  }
 
  /// <summary>
@@ -173,7 +187,7 @@ protected override void OnRender(DrawingContext dc)
  guidelines.GuidelinesY.Add(my + halfPenWidth);
 
  dc.PushGuidelineSet(guidelines);*/
- dc.DrawRectangle(null, this.pen, rect);
+ dc.DrawRectangle(fillBrush, this.pen, rect);
  dc.DrawRectangle(null, this.pen2, rect);
 
  if (this.crossHairSize > 0)