Next, we are going to start drawing to the screen; this is where things get interesting.
The following program demonstrates how to draw a line on the screen. You can then use this as a base to further explore creating new shapes if you wish.
Let's start by creating a new file to store this program in:
vim sixth_c_prog.c
The following code demonstrates how to turn the screen black and draw a line on it. With these two concepts you should be able to go on to create more complex graphics drawing programs. The line forms the basis of any shape, such as a triangle or square.
Add the following code to the file you created:
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
char *device_map = 0;
struct fb_fix_screeninfo fixed_info;
struct fb_var_screeninfo var_info;
void pixel_plotter(int x, int y, int c)
{
unsigned int pix_offset = x + y * fixed_info.line_length;...