Paint Pixels to Screen via Linux FrameBuffer

Question

I was recently struck by a curious idea to take input from /dev/urandom, convert relevant characters to random integers, and use those integers as the rgb/x-y values for pix

Answer 1

When I used this program to write full screen it had crashed that is due screen size calculation is wrong.

// Figure out the size of the screen in bytes     
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

This supposed to be:

/* Calculate the size of the screen in bytes */   
screensize = vinfo.xres_virtual * vinfo.yres_virtual * (vinfo.bits_per_pixel / 8);