Create a Custom Annotation with the Document Viewer - WinForms C#

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Caching; 
using Leadtools.Annotations.WinForms; 
using Leadtools.Annotations.Automation; 
using Leadtools.Annotations.Designers; 
using Leadtools.Document; 
using Leadtools.Document.Viewer; 

using System;  
using Leadtools;  
using Leadtools.Annotations.Engine;  
using Leadtools.Annotations.Designers;  
  
namespace Create_a_Custom_Annotation  
{  
    class AnnCircleDrawDesigner : AnnRectangleDrawDesigner  
    {  
        //We need 2 points, a beginning and an ending point  
        private LeadPointD begin = LeadPointD.Empty;  
        private LeadPointD end = LeadPointD.Empty;  
  
        /// <summary>  
        /// Constructor for the AnnCircleDrawDesigner  
        /// </summary>  
        public AnnCircleDrawDesigner(IAnnAutomationControl automationControl, AnnContainer container, AnnCircleObject annObject)  
           : base(automationControl, container, annObject) { }  
  
        /// <summary>  
        /// override the pointer down event  
        /// set the beginning and ending points to the location of the first click  
        /// </summary>  
        public override bool OnPointerDown(AnnContainer sender, AnnPointerEventArgs e)  
        {  
            begin = e.Location;  
            end = begin;  
  
            return base.OnPointerDown(sender, e);  
        }  
  
        /// <summary>  
        /// override the pointer move event  
        /// set the new mouse point to the end variable  
        /// do some math to create a circle object (width/height stay equal)  
        /// </summary>  
        public override bool OnPointerMove(AnnContainer sender, AnnPointerEventArgs e)  
        {  
            end = e.Location;  
            AnnCircleObject circle = (AnnCircleObject)TargetObject;  
            double x = (end.X - begin.X);  
            double y = Math.Abs(end.Y - begin.Y);  
            double scaleX = 1;  
            double scaleY = 1;  
  
            if (x < y)  
                scaleX = y / x;  
            else  
                scaleY = x / y;  
  
            circle.Rect = LeadRectD.Create(begin.X, begin.Y, Math.Abs(end.X - begin.X) * Math.Abs(scaleX), Math.Abs(end.Y - begin.Y) * Math.Abs(scaleY));  
  
            Invalidate(LeadRectD.Empty);  
            return true;  
        }  
    }  
}  

using Leadtools.Annotations.Engine;  
  
namespace Create_a_Custom_Annotation  
{  
    class AnnCircleObject : AnnEllipseObject  
    {  
        //set the id to the UserObjectID  
        public const int CircleObjectId = UserObjectId;  
  
        /// <summary>  
        /// Constructor for the object  
        /// set the id of the object to the circle object ID  
        /// </summary>  
        public AnnCircleObject()  
           : base()  
        {  
            SetId(CircleObjectId);  
            Tag = null;  
        }  
  
        protected override AnnObject Create()  
        {  
            return new AnnCircleObject();  
        }  
    }  
}  

using System.Collections.Generic;  
using Leadtools.Annotations.Rendering;  
using Leadtools.Annotations.Automation;  
using Leadtools.Annotations.Engine;  
using Leadtools;  
  
namespace Create_a_Custom_Annotation  
{  
    class AnnCircleObjectRenderer : AnnEllipseObjectRenderer  
    {  
        /// <summary>  
        /// Constructor for the renderer  
        /// get the ellipse object renderer and use the same styles for the circle  
        /// </summary>  
        public AnnCircleObjectRenderer(AnnAutomationManager manager)  
           : base()  
        {  
            IAnnObjectRenderer annEllipseObjRenderer = manager.RenderingEngine.Renderers[AnnObject.EllipseObjectId];  
            LabelRenderer = annEllipseObjRenderer.LabelRenderer;  
            LocationsThumbStyle = annEllipseObjRenderer.LocationsThumbStyle;  
            RotateCenterThumbStyle = annEllipseObjRenderer.RotateCenterThumbStyle;  
            RotateGripperThumbStyle = annEllipseObjRenderer.RotateGripperThumbStyle;  
            // The below snippet changes the annotation's thumbnail size  
            //LeadSizeD newThumbSize = LeadSizeD.Create(300, 300); // New size of the thumbnails, change as necessary  
            //LocationsThumbStyle.Size = newThumbSize;  
            //RotateCenterThumbStyle.Size = newThumbSize;  
            //RotateGripperThumbStyle.Size = newThumbSize;  
        }  
  
        /// <summary>  
        /// override the RenderThumbs method  
        /// go through the thumbs and remove the top bottom left and right thumbs so it cannot be changed from a circle  
        /// </summary>  
        public override void RenderThumbs(AnnContainerMapper mapper, LeadPointD[] thumbLocations, AnnFixedStateOperations operations)  
        {  
            List<LeadPointD> newThumbs = new List<LeadPointD>();  
            for (int i = 0; i < thumbLocations.Length; i += 2)  
                newThumbs.Add(thumbLocations[i]);  
  
            base.RenderThumbs(mapper, newThumbs.ToArray(), operations);  
        }  
    }  
}  

var automationManagerHelper = new AutomationManagerHelper(automationManager); 
 
CreateCustomObject(automationManager); 

private void CreateCustomObject(AnnAutomationManager annManager)  
{  
    // Create the circle object, assign the designers, set the toolbar image, and then add it to the manager and rendering engine  
    AnnAutomationObject circleAutomationObject = new AnnAutomationObject();  
    circleAutomationObject.Id = AnnCircleObject.CircleObjectId;  
    circleAutomationObject.Name = "Circle";  
    circleAutomationObject.ToolBarToolTipText = circleAutomationObject.Name;  
    circleAutomationObject.DrawDesignerType = typeof(AnnCircleDrawDesigner);  
    circleAutomationObject.EditDesignerType = typeof(AnnRectangleEditDesigner);  
    circleAutomationObject.RunDesignerType = typeof(AnnRunDesigner);  
    circleAutomationObject.ObjectTemplate = new AnnCircleObject();  
    circleAutomationObject.ToolBarImage = new Bitmap(typeof(Form1), "Resources.Create-a-Custom-Annotation-Circle-Icon.png");  
    circleAutomationObject.ContextMenu = new ObjectContextMenu();  
    annManager.Objects.Add(circleAutomationObject);  
    annManager.RenderingEngine.Renderers.Add(AnnCircleObject.CircleObjectId, new AnnCircleObjectRenderer(annManager));  
}