The other mode that the UltraChart supports is:

annotation.Location.Type = LocationType.Percentage;

You can try setting the location of the annotation as a percentage of the chart.

This did not work for me. Probably I was not clear enough on my requirement.

1. There is a tool which let a user pick any location on the polar chart window - not necessarily within chart-bounds.

2. When the user release the mouse button, a forms comes up and he enter the annotation text.

3. When the form is saved/oked, the annotation is placed at the location where he clicked.

4. Now, the question was, how to make this annotation stick to its selected location when the chart window is re-sized.

Please check for my current solution posted on this page.

Here is the solution I am using today

//1. Event to track window-size changes ..

this.DipAzimuthPolarChart.SizeChanged += new System.EventHandler(this.checkAnnotations);

//2. Set a flag when this event happen.

private void checkAnnotations(object sender, EventArgs args)

{

this.updateAnnotation = true;

}

// 3. In FillSceneGraph event handler, update annotations if required.

if (this.updateAnnotation)

{

              this.updateAnnotations();

}

// 4. And in updateAnnotations, update points with reference to the center of the circle.

private void updateAnnotations()

{

int newRadius = polarlayer.RadiusResolved;

System.Drawing.Point newCenter = this.polarlayer.CenterResolved;

for (int k = 0; k < this.DipAzimuthPolarChart.Annotations.Annotations.Count; k++)

{

Annotation ca = this.DipAzimuthPolarChart.Annotations.Annotations[k] as Annotation;

double newlocX = ca.Location.LocationX ;

double newlocY = ca.Location.LocationY ;

if (newRadius != this.currentRadius)

{

newlocX = newCenter.X + (newlocX - this.currentCenter.X) * (newRadius / currentRadius);

newlocY = newCenter.Y + (newlocY - this.currentCenter.Y) * (newRadius / currentRadius);

}

else if (this.currentCenter.X != newCenter.X)

{

newlocX = newlocX + (newCenter.X - this.currentCenter.X);

}

else if (this.currentCenter.Y != newCenter.Y)

{

newlocY = newlocY + (newCenter.Y - this.currentCenter.Y);

}

this.DipAzimuthPolarChart.Annotations.Annotations[k].Location.LocationX = newlocX;

this.DipAzimuthPolarChart.Annotations.Annotations[k].Location.LocationY = newlocY;

}

this.currentRadius = newRadius;

this.currentCenter = newCenter;

this.updateAnnotation = false;

}