void PointGraphPaint(object sender, PaintEventArgs e)
{
CreateCoordinate obj = new CreateCoordinate();
obj.DrawXY(cloudgraph);
OriginPoint = obj.Origin;
orginpoint.Text = "(" + OriginPoint.X.ToString() + "," + OriginPoint.Y.ToString() + ")";
}
void 重绘坐标系ToolStripMenuItemClick(object sender, EventArgs e)
{
CreateCoordinate obj = new CreateCoordinate();
obj.DrawXY(cloudgraph);
}