digitclk.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
#include <ncurses.h>

#define DIGIT_SIZE_X 5
#define DIGIT_SIZE_Y 7
#define SPACE_SIZE 2
#define COLON_SIZE 1

#define CLOCK_SIZE_X (6*DIGIT_SIZE_X + 2*COLON_SIZE + 7*SPACE_SIZE)
#define CLOCK_SIZE_Y DIGIT_SIZE_Y

#define COLON "  o o  "
#define SEG_H 		" --- "
#define SEG_H_EMPTY "     "
#define SEG_V		 " || "
#define SEG_V_EMPTY "     "

#define H_SEG_DISTANCE 3
#define V_SEG_DISTANCE 4

// digits defined as segments: [digit][segment]; 1 = full; / 0 = empty
static _Bool digits[10][7] ={
{1,1,1,0,1,1,1},/*  segment numbers */
{0,0,1,0,0,1,0},
{1,0,1,1,1,0,1},//         000   
{1,0,1,1,0,1,1},//        1   2  
{0,1,1,1,0,1,0},//        1   2  
{1,1,0,1,0,1,1},//         333   
{1,1,0,1,1,1,1},//        4   5  
{1,0,1,0,0,1,0},//        4   5  
{1,1,1,1,1,1,1},//         666   
{1,1,1,1,0,1,1}};

void updateTime(struct tm** timeInfo) {
	time_t rawTime;
	time(&rawTime);
	*timeInfo = localtime(&rawTime);
}

void ncInit() {
	initscr(); // initialize the curses library
	cbreak(); // take input chars one at a time, no wait for \n
	noecho();
	nl(); // tell curses to do NL->CR/NL on output
	keypad(stdscr,1);
	curs_set(0); // hide cursor	
	halfdelay(10); // wait 1 s for getch()
	refresh();
	clear();
}

void ncEnd() {
	endwin();
}

void mvaddstrV(int y, int x, const char* s) {
	/* mvaddstr vertical */
	char tmp[] = {0,0};
	for (unsigned int i = 0; i < strlen(s); i++) {
		*tmp = s[i];
		mvaddstr(y+i, x, tmp);
	}
}

void printColon(int *y, int *x) {
	mvaddstrV(*y, *x, COLON);
	*x += COLON_SIZE + SPACE_SIZE;
}

void printSegH(int y, int x, _Bool space) {
	mvaddstr(y, x, space ? SEG_H_EMPTY : SEG_H);
}

void printSegV(int y, int x, _Bool space) {
	mvaddstrV(y, x, space ? SEG_V_EMPTY : SEG_V);
}

void printSeg(int y, int x, int segment, _Bool space) {
	switch(segment) {
		// horizontal
		case 0: printSegH(y,x,space); break;
		case 3: printSegH(y+H_SEG_DISTANCE,x,space); break;
		case 6: printSegH(y+2*H_SEG_DISTANCE,x,space); break;
		
		// vertical left
		case 1: printSegV(y,x,space); break;
		case 2: printSegV(y,x+V_SEG_DISTANCE,space); break;
		
		// vertical right
		case 4: printSegV(y+H_SEG_DISTANCE,x,space); break;
		case 5: printSegV(y+H_SEG_DISTANCE,x+V_SEG_DISTANCE,space); break;
	}
}

void printDigit(int *y, int *x, int digit) {
	// print spaces or segments
	for (int i = 0; i < 7; i++) printSeg(*y, *x, i, !digits[digit][i]);
	*x += DIGIT_SIZE_X + SPACE_SIZE;
}

void printTime(struct tm* t) {
	// set position to center the clock
	int posY = (getmaxy(stdscr) - CLOCK_SIZE_Y)/2;
	int posX = (getmaxx(stdscr) - CLOCK_SIZE_X)/2;
	
	printDigit(&posY, &posX, t->tm_hour/10);
	printDigit(&posY, &posX, t->tm_hour%10);
	printColon(&posY, &posX); 
	printDigit(&posY, &posX, t->tm_min/10);
	printDigit(&posY, &posX, t->tm_min%10);
	printColon(&posY, &posX);
	printDigit(&posY, &posX, t->tm_sec/10);
	printDigit(&posY, &posX, t->tm_sec%10);
	refresh();
}

int main() {
	ncInit();
	
	struct tm* timeInfo;
	while (getch() == ERR) {
		updateTime(&timeInfo);
		printTime(timeInfo);
	}
	
	ncEnd();
	return 0;
}