problem with background

I’d like to know if it’s possible to draw displays in background(for me the background is displays of control screen) and just move a pointer(on that displays)but when I call glutPostRedisplay it’s redrawn me the pointer but also all the background(so it’s slowier).Is it possible to have something which fixes the background and something which allows me to animate the pointer(without redrawing the background or without erasing the background)
i know i am not very clear,but I need your help,thank you

What is your background? An image or a rendered scene? But any how I think the basic answer to your question is you have to draw both, but there are probably many ways to speed this up

My background is displays that I have drawn with glBegin(GL_POLYGON)…,it’s not an image.I’d like to know if I consider one pixel which has a first color(the background color) and after has an second color(pointer’s color) on the same pixel, then I want to put off this second color to have back the first color(which is the background’s color)
Thank you for your answer.