matrix.c

#include <stdlib.h>
#include <curses.h>
#include <term.h>
#include <signal.h>
#include <unistd.h>

#define countof(x) (sizeof(x) / sizeof(*(x)))

const int min_length = 7;
const int max_length = 21;
const int min_spacing = 5;
const int max_spacing = 10;

const char symbols[] = "0123456789qwertyuiopasdfghjkl"
                       "zxcvbnm,.[]!@#$^&*()-=_+";

const int colors[] = {22, 28, 34, 40, 46, 82, 76, 64, 58};
const int dark_colors[] = {233, 234, 232, 235};

typedef struct {
    int length;
    int offset;
    bool shift;
} stripe_t;

volatile bool run = true;

void terminate(int sig)
{
    run = false;
}

int gen_char()
{
    return symbols[rand() % (sizeof(symbols) - 1)];
}

int main()
{
    signal(SIGINT, terminate);
    signal(SIGHUP, terminate);
    signal(SIGTERM, terminate);

    initscr();

    int width = getmaxx(stdscr);
    int count = width / 2 - 1;

    stripe_t stripes[count];

    for (int i = 0; i < count; i++) {
        stripes[i].length = rand() % (max_length - min_length) + min_length;
        stripes[i].offset = - (rand() % (max_spacing - min_spacing) + min_spacing);
        stripes[i].shift = false;
    }

    while (run) {
        for (int i = 0; i < count; i++) {
            int color;
            stripe_t *s = &stripes[i];

            if (s->shift)
                putchar(' ');

            if (++s->offset > 0) {
                color = colors[s->offset % countof(colors)];
            } else {
                color = dark_colors[s->offset % countof(dark_colors)];
            }

            tputs(tparm(tigetstr("setaf"), color), 1, putchar);
            putchar(gen_char());

            if (!s->shift)
                putchar(' ');

            if (s->offset > s->length) {
                s->length = rand() % (max_length - min_length) + min_length;
                s->offset = - (rand() % (max_spacing - min_spacing) + min_spacing);
                s->shift = !s->shift;
            }
        }

        tputs(tparm(tigetstr("sgr0")), 1, putchar);

        putchar('\r');
        putchar('\n');

        usleep(100000);
    }

    endwin();

    return EXIT_SUCCESS;
}