Johtull's Binary Clock Source

#include <pebble.h>
//custom font: http://pastebin.com/agK5KeDn
static Window *s_main_window;
static TextLayer *s_time_hours;
static TextLayer *s_time_minutes;
static GFont s_time_font;

static char *tochar(int i, char *p) {
    if (i / 10 == 0) {
        *p++ = i + '0';
        *p = '\0';
        return p;
    }
    p = tochar(i / 10, p);
    *p++ = i % 10 + '0';
    *p = '\0';
    return p;
}

static void decimal_binary(char* result) {
  int n = atoi(result);
  int rem, i=1, binary=0;
  while (n!=0) {
      rem=n%2;
      n/=2;
      binary+=rem*i;
      i*=10;
  }
  tochar(binary, result);
}

static void update_time() {
  time_t temp = time(NULL);
  struct tm *tick_time = localtime(&temp);

  static char hours[] = "000000";
  static char minutes[] = "000000";

  strftime(hours, sizeof("00"), "%H", tick_time);
  strftime(minutes, sizeof("00"), "%M", tick_time);

  decimal_binary(hours);
  decimal_binary(minutes);

  text_layer_set_text(s_time_hours, hours);
  text_layer_set_text(s_time_minutes, minutes);
}



//144×168
static void main_window_load(Window *window) {
  s_time_hours = text_layer_create(GRect(0, 46, 144, 40));
  text_layer_set_background_color(s_time_hours, GColorClear);
  text_layer_set_text_color(s_time_hours, GColorBlack);
  text_layer_set_text(s_time_hours, "0");
  s_time_minutes = text_layer_create(GRect(0, 86, 144, 40));
  text_layer_set_background_color(s_time_minutes, GColorClear);
  text_layer_set_text_color(s_time_minutes, GColorBlack);
  text_layer_set_text(s_time_minutes, "1");


  s_time_font = fonts_load_custom_font(resource_get_handle(RESOURCE_ID_FONT_BINARY_BLOCKS_25));

  text_layer_set_font(s_time_hours, s_time_font);
  text_layer_set_text_alignment(s_time_hours, GTextAlignmentCenter);
  text_layer_set_font(s_time_minutes, s_time_font);
  text_layer_set_text_alignment(s_time_minutes, GTextAlignmentCenter);

  layer_add_child(window_get_root_layer(window), text_layer_get_layer(s_time_hours));
  layer_add_child(window_get_root_layer(window), text_layer_get_layer(s_time_minutes));

  update_time();
}

static void main_window_unload(Window *window) {
  text_layer_destroy(s_time_hours);
  text_layer_destroy(s_time_minutes);
  fonts_unload_custom_font(s_time_font);
}

static void tick_handler(struct tm *tick_time, TimeUnits units_changed) {
  update_time();
}

static void init() {
  s_main_window = window_create();

  window_set_window_handlers(s_main_window, (WindowHandlers) {
    .load = main_window_load,
    .unload = main_window_unload
  });

  window_stack_push(s_main_window, true);

  tick_timer_service_subscribe(MINUTE_UNIT, tick_handler);
}

static void deinit() {
  window_destroy(s_main_window);
}

int main(void) {
  init();
  app_event_loop();
  deinit();
}