gistfile1.c

/*
 * Build with 'gcc miku.c -o miku -lncurses -std=c99'
 */
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <termcap.h>
#include <unistd.h>

void clear_screen()
{
    char buf[1024];
    char *str;
    tgetent(buf, getenv("TERM"));
    str = tgetstr("cl", NULL);
    fputs(str, stdout);
}

bool is_in_love(int x, int y, int heart_size)
{
    const float HEART_COEFFICIENT = 0.7f;
    const float width = 2.2f;
    const float height = 3.0f;

    float check_x = (((float)x / (float)(heart_size)) - 0.5f) * width;
    float check_y = (((float)(heart_size - y) / (float)heart_size) - 0.4f) * height;

    float top_y = 0.0f;
    float bottom_y = 0.0f;

    if (check_x >= 0) {
        top_y = sqrt(1 - (check_x * check_x)) + (HEART_COEFFICIENT * sqrt(check_x));
        bottom_y = -sqrt(1 - (check_x * check_x)) + (HEART_COEFFICIENT * sqrt(check_x));
    } else {
        top_y = sqrt(1 - (check_x * check_x)) + (HEART_COEFFICIENT * sqrt(-check_x));
        bottom_y = -sqrt(1 - (check_x * check_x)) + (HEART_COEFFICIENT * sqrt(-check_x));
    }

    return (bottom_y <= check_y) && (check_y <= top_y);
}

void draw_heart(int heart_size)
{
    const char message[] = " SYSTEMATIC LOVE ";
    int message_indent = ((heart_size / 2) - (sizeof(message) / 4)) - 1;

    for (int y = 0; y < heart_size; ++y) {
        for (int x = 0; x < heart_size; ++x) {
            fputs((is_in_love(x, y, heart_size)) ? "vv" : "  ", stdout);

            if (y == (heart_size / 2) - 1) {
                if (x == message_indent) {
                    fputs(message, stdout);
                    x += (sizeof(message) / 2);
                }
            }
        }
        fputs("\n", stdout);
    }
}

int main(void)
{
    const int delay = (1000000 / 30);

    while (true) {
        for (int heart_size = 30; heart_size <= 39; ++heart_size) {
            clear_screen();
            draw_heart(heart_size);
            usleep(delay);
        }
        for (int heart_size = 39; heart_size > 30; --heart_size) {
            clear_screen();
            draw_heart(heart_size);
            usleep(delay);
        }
    }
    return 0;
}