Hi,
I have sent you a sample application. i am facing following problem:
1. I want that when i start application my Diagram should cover entire client area

2.scrollbar position should be at center of the diagram so that zoom in/out can be done from the center.

Thanks
Ayush Neema

Hi Stoyo,
thanks for quick replay. but  i want that when i start application my Diagram should cover entire client area.
Right now when i start the application diagram apppear as a strip on the center of the client and rest of the area of client remain blank.

Hi Stoyan,

We have tried this as well. Now it is covering entire client area but in a special case behavior is still not good.

If there are large no of nodes in a line (Horizontal or Vertical) then on zooming all nodes is moving to left (In case of vertical line)

How we can get zooming from center in this case. I am sending a sample image at your support id for that vertical alignment. Please have a look at it and suggest what we could do to get the desired result?

Regards,
Anshul

Thanks stoyan for the suggestion.

We are getting nodes in the middle but the problem is that if in this arrangement we do zoom-in/zoom-out all nodes moves to left side. We want same arrangement in zoom-in/zoom-out as well.

Regards,
Anshul

Rect newBounds = diagram.ClientToDoc(
	new Rect(0, 0, scrollViewer.ActualWidth, scrollViewer.ActualHeight)); 

This code in your SetZoom method grows the diagram to the right while keeping it centered, so the nodes seem to move to the left. You could get just the size from this rect, find its difference from the current diagram.Bounds.Size, and use the Rect.Inflate method to add the difference to all sides of diagram.Bounds, instead of the Union method you are using now.

There are a couple of things wrong now in SetZoom. First the Rect constructor throws an exception when the width or height arguments are negative, which happens when you calculate the difference, and you just catch and ignore the exception. Another problem is that Rect is a value type, and diagram.Bounds returns a value in the local execution stack rather than a reference to the actual Bounds rectangle, so diagram.Bounds.Inflate() grows the stack value but does not change  diagram.Bounds. Assuming you need Bounds only to grow, you could do that like this:

double sizeDX = newBounds.Size.Width - currentDiagramSize.Width;
if (sizeDX < 0)
	sizeDX = 0;

double sizeDY = newBounds.Size.Height - currentDiagramSize.Height;
if (sizeDY < 0)
	sizeDY = 0;

Rect diagBounds = diagram.Bounds;
diagBounds.Inflate(sizeDX, sizeDY);
diagram.Bounds = diagBounds;
 

Are you trying to preserve the diagram point that was at the center of the diagram visible area, so it remains there after zooming in/out? And at the same time, grow diagram.Bounds, so it fills the entire scroll viewer? The code below implements that.

public void SetZoom(double percentage)
{
	Point oldCenter = scrollViewer.TransformToDescendant(diagram.DocumentPlane).Transform(
		new Point(scrollViewer.ActualWidth / 2, scrollViewer.ActualHeight / 2));

	percentage = Math.Max(10, Math.Min(200, percentage));
	diagram.ZoomFactor = percentage;

	Rect newBounds = diagram.ClientToDoc(
		new Rect(0, 0, scrollViewer.ActualWidth, scrollViewer.ActualHeight));
	Size currentDiagramSize = diagram.Bounds.Size;

	double sizeDX = newBounds.Size.Width - currentDiagramSize.Width;
	if (sizeDX < 0)
		sizeDX = 0;

	double sizeDY = newBounds.Size.Height - currentDiagramSize.Height;
	if (sizeDY < 0)
		sizeDY = 0;

	Rect diagBounds = diagram.Bounds;
	diagBounds.Inflate(sizeDX, sizeDY);
	diagram.Bounds = diagBounds;

	double newScrollX = oldCenter.X - newBounds.Width / 2;
	double newScrollY = oldCenter.Y - newBounds.Height / 2;

	diagram.ScrollTo(new Point(newScrollX, newScrollY));
}
 

If in the Loaded handler you initialize the column of nodes to be at the center of the viewer, the nodes should stay in the center of the scroll viewer when you call SetZoom from the MouseWheel handler.