FREE HAND DRAWING

private void panel1_MouseUp(object sender, MouseEventArgs e)
{
a = 0;
}

private void panel1_MouseMove(object sender, MouseEventArgs e)
{
if (a == 1)
{
Graphics g = panel1.CreateGraphics();
Pen p = new Pen(c, 25);
cloc = e.Location;
g.DrawLine(p, ploc, cloc);
ploc = e.Location;
}
}

private void panel1_MouseDown(object sender, MouseEventArgs e)
{
a = 1;
ploc = e.Location;

Random rn = new Random();
c = Color.FromArgb(rn.Next(0, 255), rn.Next(0, 255), rn.Next(0, 255));

}