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This example will show how to implement a custom object from a XAML template in LEADTOOLS Annotations. We will modify the appearance of the AnnNoteObject from a solid rectangle to a full XAML control.

1. Start with the project that you created in Working With Automated Annotations in WinRT.

2. Add a new class file (MyNoteObjectRenderer.cs) and add the following code:

   [C#]

   
                using System;
                using System.Collections.Generic;
                
                using Windows.Foundation;
                using Windows.UI;
                using Windows.UI.Xaml;
                using Windows.UI.Xaml.Media;
                using Windows.UI.Xaml.Shapes;
                using Windows.UI.Xaml.Controls;
                
                using Leadtools;
                using Leadtools.Annotations.Core;
                using Leadtools.Annotations.Rendering;
                
                namespace MyNamespace
                {
                   // Custom Note renderer
                   public class MyNoteObjectRenderer : AnnObjectRenderer
                   {
                      // The current object to render
                      private AnnNoteObject _annObject;
                      // Current object transform
                      private MatrixTransform _matrixTransform;
                      // Current mapper
                      private AnnContainerMapper _mapper;
                      // Current object bounds;
                      private LeadRectD _bounds;
                
                      // Override AnnObjectRenderer.VisualComponents, this gets called
                      // from Render to construct the object visuals
                      public override List<FrameworkElement> VisualComponents
                      {
                         get
                         {
                            // Get the rendering engine
                            AnnWinRTRenderingEngine engine = RenderingEngine as AnnWinRTRenderingEngine;
                
                            // Get the children canvas
                            Dictionary<AnnObject, AnnObjectVisual> childrenCanvas = engine.ChildrenCanvas;
                
                            // Get the visual object for this AnnObject
                            AnnObjectVisual annObjectVisual = childrenCanvas[_annObject];
                
                            FrameworkElement element;
                
                            // See if we are already added
                            if (!annObjectVisual.ContainsVisualComponents())
                            {
                               // No, add us, this is the XAML template
                               // This defines a Grid with three text blocks for the header/footer and content.
                               string xaml = "<Grid xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\" xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\"" +
                                  " Background=\"Red\" HorizontalAlignment=\"Stretch\" VerticalAlignment=\"Stretch\">" +
                                  "<Grid.RowDefinitions>" +
                                     "<RowDefinition Height=\"0.25*\"/>" +
                                     "<RowDefinition Height=\"*\"/>" +
                                     "<RowDefinition Height=\"0.25*\"/>" +
                                  "</Grid.RowDefinitions>" +
                                  "<Grid Grid.Row=\"0\" Background=\"Yellow\">" +
                                     "<TextBlock x:Name=\"Header\" Foreground=\"Black\" Text=\"Header\" TextAlignment=\"Center\" VerticalAlignment=\"Center\"/>" +
                                  "</Grid>" +
                                  "<TextBlock Grid.Row=\"1\" x:Name=\"Content\" Text=\"Content\" TextAlignment=\"Center\"/>" +
                                  "<Grid Grid.Row=\"2\" Background=\"Blue\">" +
                                     "<TextBlock x:Name=\"Footer\" Foreground=\"Yellow\" Text=\"Footer\" TextAlignment=\"Center\"  VerticalAlignment=\"Center\"/>" +
                                  "</Grid>" +
                               "</Grid>";
                
                               element = Windows.UI.Xaml.Markup.XamlReader.Load(xaml) as FrameworkElement;
                               annObjectVisual.VisualComponents.Add(element);
                            }
                
                            // Get the element
                            element = annObjectVisual.VisualComponents[0] as FrameworkElement;
                
                            // Set the text, find the Content element
                            TextBlock textBlock = element.FindName("Content") as TextBlock;
                            textBlock.Text = _annObject.Text;
                
                            // Set the size
                            element.Width = _bounds.Width;
                            element.Height = _bounds.Height;
                
                            // Set the location
                            if (!double.IsInfinity(_bounds.X) && !double.IsInfinity(_bounds.Y) &&
                               !double.IsNaN(_bounds.X) && !double.IsNaN(_bounds.Y))
                            {
                               Canvas.SetLeft(element, _bounds.X);
                               Canvas.SetTop(element, _bounds.Y);
                            }
                
                            // Set the transform
                            element.RenderTransform = _matrixTransform;
                
                            return annObjectVisual.VisualComponents;
                         }
                      }
                
                      public override void Render(AnnContainerMapper mapper, AnnObject annObject)
                      {
                         if (mapper == null) throw new ArgumentNullException("mapper");
                         if (annObject == null) throw new ArgumentNullException("annObject");
                
                         // Save the object and mapper
                         _annObject = annObject as AnnNoteObject;
                         _mapper = mapper;
                
                         if (_annObject.Bounds.Width == 0 && _annObject.Bounds.Height == 0)
                            return;
                
                         // Get the render points
                         LeadPointD[] renderPoints = GetRenderPoints(mapper, _annObject);
                
                         // Get the bounding rectangle in physical coordinates and save it
                         _bounds = mapper.RectFromContainerCoordinates(_annObject.Rect, _annObject.FixedStateOperations);
                
                         // Create the rotation transform
                
                         // Get the center point
                         LeadPointD center = LeadPointDHelper.Create(_bounds.X + _bounds.Width / 2, _bounds.Y + _bounds.Height / 2);
                
                         LeadMatrix objectRotation = LeadMatrix.Identity;
                         objectRotation.RotateAt(_annObject.Angle, center.X - _bounds.X, center.Y - _bounds.Y);
                
                         _matrixTransform = new MatrixTransform();
                         _matrixTransform.Matrix = new Matrix(objectRotation.M11, objectRotation.M12, objectRotation.M21, objectRotation.M22, objectRotation.OffsetX, objectRotation.OffsetY);
                
                         base.Render(mapper, annObject);
                
                         // Reset the parameters
                         _annObject = null;
                         _matrixTransform = null;
                         _mapper = null;
                         _bounds = LeadRectDHelper.Empty;
                      }
                   }
                }
                
   

3. Modify AutomationAttach method in MainPage as this:

   [C#]

   
                public void AutomationAttach(AnnContainer container)
                {
                   _container = container;
                   _engine = new AnnWinRTRenderingEngine(_container, _viewer);
               
                   // Replace the default note renderer with our own
                   IAnnObjectRenderer originalRenderer = renderingEngine.Renderers[AnnObject.NoteObjectId];
                   MyNoteObjectRenderer myNoteObjectRenderer = new MyNoteObjectRenderer();
                   myNoteObjectRenderer.LocationsThumbStyle = originalRenderer.LocationsThumbStyle;
                   myNoteObjectRenderer.RotateCenterThumbStyle = originalRenderer.RotateCenterThumbStyle;
                   myNoteObjectRenderer.RotateGripperThumbStyle = originalRenderer.RotateGripperThumbStyle;
                   _engine.Renderers[AnnObject.NoteObjectId] = myNoteObjectRenderer;
               
                   if (_engine != null)
                   {
                      _engine.Render(LeadRectDHelper.Create(0, 0, _viewer.Width, _viewer.Height), true);
                   }
                }
                
   

4. Build, and Run the program to test it.

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