Drawing help

Hey all,



How can i draw something on a form with a background on it, but still i can see the background?


I mean, imagine i have some black lines on a white surface. I want to paint boxes on it, but still see the black lines.


Thanks :)

Like this...

My background is several balck lines (a box) on a white surface. I made it in paint, its a bmp picture.

When i draw with the methods shown in the drawing chapter of your book, they cover my back lines.

If i draw a red circle i don't see the black lines under it. How can i make the things i draw (circles and rectangles) transparent ?



I do somthing like this:



Code:


private Bitmap Sup = new Bitmap (mybmppath);

this.BackgroundImage = Sup;


Graphics g = Graphics.FromImage(Sup);
Rectangle rect = new Rectangle(X , Y, 10, 10);

//X and Y are user given coordinates

g.FillEllipse(Brushes.Green, rect);


private void Map_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
this.BackgroundImage = Sup;
}






Problem is that the circle coveres the black lines in the bmp. How can i overcome that?


BIIIIGGGGGGGGGGGG THANKS!!