Number of Lines that can be drawn with DrawLines Method - vb.net

Question

I am drawing a series of lines on a PrintPreviewControl using the DrawLines method. Here is my code where I take x and y values and convert them into coordinates inside a page rectangle, adding them to a list. I then call DrawLines with a pen and the list converted to an array. I have found that DrawLines will only draw 8125 lines using 8126 point pairs. I receive no exception when DrawLines fails. Any way to increase the number of point pairs that DrawLines will use? Alternatively, I could draw each line individually, or I could parse the points array into 8000 point blocks.
Private Sub DrawGammaLog(ByVal gr As Graphics)
Try
'draw log in chart area
If Points.Count <> 0I Then
gr.SetClip(LogRect)
Dim LPoints As New List(Of PointF)
For Each pt In Points
Dim PointY As Single = LogRect.Top + ((pt.Depth - VScaleMinValue) * VScale)
Dim PointX As Single = LogRect.Left + (pt.Count * HScale)
If PointY >= LogRect.Top AndAlso PointY <= LogRect.Bottom Then
LPoints.Add(New PointF(PointX, PointY))
End If
Next
Debug.Print("{0}", LPoints.Count)
If LPoints.Count >= 2I Then gr.DrawLines(gpp.LogPen, LPoints.ToArray)
End If
'draw box around chart area
gr.DrawRectangle(gpp.LogPen, Rectangle.Round(LogRect))
Catch ex As Exception
MessageBox.Show(ex.Message.ToString & ", " & ex.Source.ToString, Me.Text & " DrawGammaLog")
Finally
gr.ResetClip()
End Try
End Sub

Answer 1

Same issue here using c# in Visual Studio 2010. 8125 seems to be the limit, even if there are no references to this problem online...
I have splitted my array into 8000 PointF[] array blocks as a work-around.
int counter = 0;
int block_size = Math.Min(data.Length, 8000);
PointF[] data_subset;
while (counter != data.Length)
{
data_subset = new PointF[block_size];
Array.Copy(data, counter, data_subset, 0, data_subset.Length);
g.DrawLines(p, data_subset);
counter += block_size;
block_size = Math.Min(data.Length - counter, 8000);
}