Simple "hours remaining" countdown clock for Pebble. Counts down until the deadline for my Masters project!

iib_countdown.c

#include "pebble_os.h"
#include "pebble_app.h"
#include "pebble_fonts.h"


#define MY_UUID { 0x8B, 0xA6, 0x5F, 0x1D, 0xB1, 0x08, 0x44, 0xAA, 0xA8, 0x17, 0x17, 0xFE, 0xCD, 0x3A, 0x89, 0xDA }
PBL_APP_INFO(MY_UUID,
             "IIB Countdown", "Adam Greig",
             1, 0, /* App version */
             DEFAULT_MENU_ICON,
             APP_INFO_WATCH_FACE);

Window window;
TextLayer hours_text;
TextLayer static_text;
char buf[4];
int last = 0;

void fill_buf(int number, char* buf) {
    char hundreds = number / 100 + '0';
    char tens = number % 100 / 10 + '0';
    char ones = number % 10 + '0';
    if(hundreds != '0') {
        buf[0] = hundreds; buf[1] = tens; buf[2] = ones; buf[3] = 0;
    } else if(tens != '0') {
        buf[0] = tens; buf[1] = ones; buf[2] = 0;
    } else {
        buf[0] = ones; buf[1] = 0;
    }
}

void update_time(PblTm* t) {
    int hours = (148 - t->tm_yday)*24 + (15 - t->tm_hour);
    if(hours != last) {
        if(hours > 0) {
            fill_buf(hours, buf);
            text_layer_set_text(&hours_text, buf);
            if(hours == 1) {
                text_layer_set_text(&static_text, "HOUR\nREMAINS");
            }
            last = hours;
        } else if(hours == 0) {
            int mins = 60 - t->tm_min;
            fill_buf(mins, buf);
            text_layer_set_text(&hours_text, buf);
            if(mins > 1) {
                text_layer_set_text(&static_text, "MINUTES\nREMAIN");
            } else {
                text_layer_set_text(&static_text, "MINUTE\nREMAINS");
            }
            last = mins;
        } else {
            text_layer_set_text(&hours_text, "DONE");
            text_layer_set_text(&static_text, "IT'S ALL\nOVER!");
            last = hours;
        }
    }
}

void handle_init(AppContextRef ctx) {
    (void)ctx;

    window_init(&window, "IIB Countdown");
    window_set_background_color(&window, GColorBlack);

    GFont hours_font = fonts_get_system_font(FONT_KEY_GOTHAM_42_BOLD);
    text_layer_init(&hours_text, GRect(0, 10, window.layer.frame.size.w, 50));
    text_layer_set_background_color(&hours_text, GColorBlack);
    text_layer_set_text_color(&hours_text, GColorWhite);
    text_layer_set_text_alignment(&hours_text, GTextAlignmentCenter);
    text_layer_set_font(&hours_text, hours_font);
    layer_add_child(&window.layer, &hours_text.layer);

    GFont static_font = fonts_get_system_font(FONT_KEY_GOTHIC_28);
    text_layer_init(&static_text, GRect(0, 60, window.layer.frame.size.w,
                                        window.layer.frame.size.h - 60));
    text_layer_set_background_color(&static_text, GColorBlack);
    text_layer_set_text_color(&static_text, GColorWhite);
    text_layer_set_font(&static_text, static_font);
    text_layer_set_text_alignment(&static_text, GTextAlignmentCenter);
    text_layer_set_text(&static_text, "HOURS\nREMAIN");
    layer_add_child(&window.layer, &static_text.layer);

    PblTm t;
    get_time(&t);
    update_time(&t);

    window_stack_push(&window, true);
}


static void handle_minute_tick(AppContextRef app_ctx, PebbleTickEvent* e) {
    update_time(e->tick_time);
}

void pbl_main(void *params) {
    PebbleAppHandlers handlers = {
        .init_handler = &handle_init,
        .tick_info = {
            .tick_handler = &handle_minute_tick,
            .tick_units = MINUTE_UNIT
        }
    };
    app_event_loop(params, &handlers);
}