The grid has always been drawn slowly with a small grid size, we haven't changed anything related to the grid in version 4. If you have recently moved to .NET 2, probably the SetPixel method is slower in the .NET 2 Graphics class? Or have you changed the size of the flowchart, if it is now larger - there could be much more calls to SetPixel to make ?

Yes, with the new dll's it seem to be faster.

But there's another speed problem. FlowChart.Net is generally slower since version 4.01.
As an example I tested the command "CreateControlHost". In version 4.00 it lasts about 170 ms to create 10 ControlHost, every controlhost is create in about 15 ms.
In 4.01, 4.02 (and the yesterday's dlls) 10 controlhosts are created in about 800 ms.
When I have 50 ControlHosts on a Flowchart, this is a significant difference.

Or have you started using .NET 2 / VS2005 with version 4.0.1 of the control? The time needed to create .NET controls (hosted in the ControlHosts) might have increased in .NET 2.

I have checked the SourceSafe history for the Flowchart.net project, the only recent change related to ControlHost nodes is that now shadows are painted for them. I don't think that would slow down ControlHost creation that much.

We will run some tests with both versions and I will let you know if we find what the problem might be.

We've run this test with the 4.0.0 version, it took 4326 milliseconds to complete:

private void button1_Click(object sender, EventArgs e)
{
  fc.ValidityChecks = false;
  fc.DefaultControlType = typeof(Button);
  fc.SuspendLayout();

  DateTime start = DateTime.Now;
  for (int i = 0; i < 500; ++i)
  {
    fc.CreateControlHost((i % 10) * 40, (i / 10) * 40, 30, 30);
  }
  DateTime end = DateTime.Now;

  TimeSpan ellapsed = end - start;
  MessageBox.Show(ellapsed.TotalMilliseconds.ToString());
 
  fc.ResumeLayout();
  fc.FitDocToObjects(0);

}

Now we'll test that with the 4.0.2 version.

A new feature in the 4.0.1 version - "Now the scrollbars are hidden if they are not needed" - actually overrides the Control.OnLayout method to compare the visible area with the document size. That should not add that much overhead; still you can prevent the calculations being done after each control is added by using the SuspendLayout/ResumeLayout methods. OnLayout is called after a child control is added to another control, so that could slow a bit the CreateControlHost method.

That's great 8) Ok, we have probably found a good tip here, I will pass it to Iva so she documents it in next version's help file.