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 Leadtools.Annotations.Core.AnnNoteObject from a solid rectangle to a full XAML control.

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

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;
                   }
                }
             }

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);
                }
             }

Build, and Run the program to test it.