I found some example codes, but I don't know the meaning of 1.0f in this code. Anyone know the meaning pls advise.
e.Graphics.PageUnit=GraphicsUnit.Inch
Dim dpix As Single = e.Graphics.DpiX
Dim dpiy As Single = e.Graphics.DpiY
Dim p As new Pen(Color.Black,3)
Dim mx As new Matrix(1f/dpix,0,0,1f/dpiy,0,0)
p.Transform=mx
e.Graphics.DrawRectangle(p,0.5f,0.5f,1,1)