Implementing XAML based AnnObjectRenderer in WinRT (Windows Store)

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.