draw line in the middle of the web page with other controls

hi everyone
i have a web page and i want to draw lines in it. there are other controls that i create them dynamically in code here is the code i know for drawing lines but the problem is that in this code i cant specify the area for drawing line i can only  specify height and weight but not the top and left so it always start from the top 0 and left 0 point of page and it covers the other objects that i create in web page any solution will be great thanks in advance for your attention
Bitmap objBitmap; Graphics objGraphics; //only height and weight can be specified but i want to specify the top and left point in the case that i want it to be in the middle if the page with other controls above and below it objBitmap = new Bitmap(200, 200); objGraphics = Graphics.FromImage(objBitmap); objGraphics.Clear(Color.White); Pen penblackPen = new Pen(Color.Black, ...