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Get DiagramLink coordinates halfway in the link (Read 1794 times)

Bass YaBB Newbies Offline Posts: 31 Joined: Aug 27^th, 2010	Get DiagramLink coordinates halfway in the link Jun 15^th, 2011 at 10:05am	Print Post
	Hi, I would like to programmatically create a ControlNode halfway down a diagram link, but am not sure how to approach this. During diagram design, the user can drag and drop a ControlNode on a link, and this will split the link into two parts allowing the ControlNode to fit nicely in the middle. Now I want to the same thing pogrammatically, when the diagram is loaded and it is determined that a ControlNode exists for a particular link. The problem is that I want to create the ControlNode in the middle of the link. What would be a good way to get a PointF object based on the coordinates of the middle of the diagram link? The only alternative I see would be to save the coordinates with the ControlNode back to the database.. but I would like to avoid that if possible. Regards, Bas


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Stoyo God Member Offline MindFusion support Posts: 13230 Joined: Jul 20^th, 2005	Re: Get DiagramLink coordinates halfway in the lin Reply #1 - Jun 15^th, 2011 at 10:51am	Print Post
	Hi, Assuming a multi-segment Polyline or Cascading link, you can find the point at its exact middle using this method with 0.5 as argument: Code PointF PointAlongLength(DiagramLink link, float lengthFactor) { float lengthPos = lengthFactor * link.Length; float totalLength = 0; var segments = link.ControlPoints; for (int i = 0; i < segments.Count - 1; ++i) { PointF point1 = segments[i]; PointF point2 = segments[i + 1]; float segmentLength = Utilities.Distance(point1, point2); if (totalLength + segmentLength > lengthPos) { // the wanted point is in current segment float normalX = (point2.X - point1.X) / segmentLength; float normalY = (point2.Y - point1.Y) / segmentLength; float pointOffset = lengthPos - totalLength; return new PointF( point1.X + normalX * pointOffset, point1.Y + normalY * pointOffset); } totalLength += segmentLength; } return segments[0]; } If you need to find that for Bezier links, you will have to approximate them through straight-line segments. I hope that helps, Stoyan


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Bass YaBB Newbies Offline Posts: 31 Joined: Aug 27^th, 2010	Re: Get DiagramLink coordinates halfway in the lin Reply #2 - Jun 15^th, 2011 at 11:53am	Print Post
	Thanks for quick and working answer. A+ for support here. Regards, Bas


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