void SetLabelsSize()
{
string str = " ";
foreach (AxisLabel aL in labelsCollection)
{
if (aL.Text[0].Length > str.Length)
{
str = aL.Text[0];
}
}
SizeF sf = ParentControl.CreateGraphics().MeasureString(str, Font);
labelSize = new Size((int)sf.Width, (int)sf.Height);
}