We need to implement hand-writing pen on the diagram, just like InkCanvas from WPF. Any idea?

In the diagram.

Thanks, I'll try it

If the InkCanvas should be at the top, you will have to set its Is-HitTestVisible property to false to allow mouse input to get to the diagram. E.g. you could add an edit-ink toggle button to your UI that sets the InkCanvas.Is-HitTestVisible value to its negative.

It might be possible to draw polylines in the diagram if you create a custom DiagramLink or DiagramNode derived class and override its Start/Update/Complete-Create methods. If you derive from DiagramLink, you could add each additional point to the link's ControlPoints collection. If you derive from DiagramNode, you could collect the points in a List<Point> field and render them from the Draw override.

I hope that helps,
Stoyan

Thanks, your code works fine. But there is serious delay when I am drawing a long line. I fixed it with following code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Input;
using System.Windows.Ink;
using System.Windows.Input.StylusPlugIns;
using System.Windows.Media;

using MindFusion;
using MindFusion.Diagramming.Wpf;
using MindFusion.Diagramming.Wpf.Commands;
using MindFusion.Diagramming.Wpf.Layout;
using MindFusion.Layout;


namespace FCDemo
{
    class FreeLine : DiagramNode
    {
        private Stroke stroke;
        private StylusPointCollection points;
        public FreeLine( )
        {
            points = new StylusPointCollection( );
        }

        protected override void StartCreate( Point org )
        {
            base.StartCreate( org );
            var p = org - new Vector( Bounds.X , Bounds.Y );
            points.Add( new StylusPoint( p.X , p.Y ) );
            stroke = new Stroke( points );
        }

        protected override void UpdateCreate( System.Windows.Point current )
        {
            base.UpdateCreate( current );
            var p = current - new Vector( Bounds.X , Bounds.Y );
            stroke.StylusPoints.Add( new StylusPoint( p.X , p.Y ) );
        }

        protected override void CompleteCreate( Point end )
        {
            base.CompleteCreate( end );
            var p = end - new Vector( Bounds.X , Bounds.Y );
            stroke.StylusPoints.Add( new StylusPoint( p.X , p.Y ) );
        }

        public override void Draw( System.Windows.Media.DrawingContext graphics , MindFusion.Diagramming.Wpf.RenderOptions options )
        {
            if ( stroke!=null )
                stroke.Draw( graphics );
        }
    }
}
 

Now, there are two other problems:
1. I cann't draw the line from right to left and down to up.
2.how to update the bounds of the node?

Great!!!

But I cann't move the node after create it. The line didn't moved with the "Handle". Any problem in following code?

graphics.PushTransform( new TranslateTransform( -Bounds.X , -Bounds.Y ) );
		if ( stroke!=null )
		    stroke.Draw( graphics );
		graphics.Pop( );
 

Thanks for your help.

Hi,

I don't think the DynamicRenderer in your example does anything useful. It is returned as a first visual child of the custom panel, and then the Stroke objects are added directly to the panel too, becoming siblings of the DynamicRenderer rather than its children. The DynamicRenderer would matter if you add the strokes to its ContainerVisual instead to the panel:

protected override void OnMouseUp(MouseButtonEventArgs e)
{
    down = false;
    if (pen != null)
    {
        pen.Draw();
        //_col.Add(pen);
        (_col[0] as ContainerVisual).Children.Add(pen);
    }
} 

In either case, I can't see any difference in speed between the FreeLine rendering in my test app and the CustomPen from this sample project. Both just call Stroke.Draw(dc) anyway, so the problem shouldn't be related to rendering speed. Perhaps you should run a profiler to see what takes most time while drawing the lines. E.g. there might be delay if you handle some validation events, such as NodeCreating, and running longer operations in the handler methods.

I hope that helps,
Stoyan