Hi,
I have been googling all day looking for APIs exposed by the linux kernel for graphics n i haven found any information anywhere. please help me out u guys.

Thanks in advance.

That's because, pretty much, there AREN'T any.

The idea is "separation of concerns".

The "kernel" handles low-level things (like managing processes, and coordinating device I/O). It's up to higher-level programs and libraries to handle higher-level things (like drawing "lines", "arcs", "polygons" or still higher-level things like "windows" and "scrollbars").

This is a Good Thing.

Soooooooooooo -

Are you interested in the mechanics of driving a "graphics device"? In that case, you might be interested in things like:

1) framebuffer code (in the Linux kernel)
2) video drivers (in the X windows code)

Otherwise, if you're interested in actually "doing graphics", I'd encourage you to look at one of these API's (just a few examples among many):

1) SDL

2) OpenGL

3) GTK+/Cairo

4) Etc. etc [substitute your favorite API for your favorite language/application here ]

but, pardon my inquisitiveness,...am I correct if I say that Opengl for instance uses frame buffer apis to draw its points n lines.......?

No, the OpenGL API would delegate to the video driver.

thank u so much.....

Just to add, there once *used* to be a project, written about in a Dr. Dobbs magazine, about kernel-ly graphics type thingies, which, AFAIR, was called KGI.
Oh, and does anyone remember SVGALib?

I remember playing DOOM on my old 486, in terminal mode, and when I pressed alt-f2 to go to another terminal, and then came back to the original one, the machine would crash.