shows xmas tree animation on linux terminal

xmas-tree.c

/*
    Copyright (C) 2017 junhee lee
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <ctype.h>
#include <locale.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ioctl.h>

static struct winsize term;
static char** pane;

int term_init() {
    ioctl(1, TIOCGWINSZ, &term);
    printf("Termial window information\n");
    printf("==========================\n");
    printf("row: %d\n", term.ws_row);
    printf("col: %d\n", term.ws_col);
    printf("xpixel: %d\n", term.ws_xpixel);
    printf("ypixel: %d\n", term.ws_ypixel);

    if(term.ws_row < 30 || term.ws_col < 50) {
        puts("Your terminal is too narrow to render tree");
        return 1;
    }
    return 0;
}

void term_move(int row, int col) {
    printf("\x1B[%d;%dH", row, col);
}

void term_cursor_visibility(bool show) {
    if(show)
        printf("\x1B[?25h");
    else
        printf("\x1B[?25l");
    fflush(stdout);
}

void term_clear() {
    term_move(0, 0);
    for(int row = 0; row < term.ws_row; ++row)
        for(int col = 0; col < term.ws_col; ++col)
            putchar(' ');
    fflush(stdout);
    term_move(0, 0);
}

void term_reset(int signo) {
    term_cursor_visibility(true);
    exit(0);
}

char** pane_init() {
    char** frame = (char**)calloc(term.ws_row, sizeof(char*));
    for(int i = 0; i < term.ws_row; ++i) {
        frame[i] = (char*)calloc(term.ws_col, sizeof(char*));
    }
    return frame;
}

void pane_copy(char** lhs, char** rhs) {
    for(int row = 0; row < term.ws_row; ++row)
        for(int col = 0; col < term.ws_col; ++col)
            lhs[row][col] = rhs[row][col];
}

void pane_draw(char** pane) {
    for(int row = 0; row < term.ws_row; ++row) {
        // marquee
        if(row == 28) {
            char* line = pane[row];
            int line_size = 45;
            char last = pane[row][line_size - 1];
            memmove(line + 1, line, line_size - 1);
            line[0] = last;
        }

        // print pixel
        for(int col = 0; col < term.ws_col; ++col) {
            char c = pane[row][col];
            if(c == '*') {
                static int lastcolor = 0;
                printf("\x1B[%dm%c\x1B[0m", lastcolor + 30, c);
                lastcolor = (lastcolor + 1) % 10;
            } else if(c == '+') {
                printf("\x1B[%dm%c\x1B[0m", 32, c);
            } else {
                putchar(c);
            }
        }
    }
    fflush(stdout);
}

void pane_replace_char(char** pane, char old, char newer) {
    for(int row = 0; row < term.ws_row; ++row)
        for(int col = 0; col < term.ws_col; ++col)
            if(pane[row][col] == old)
                pane[row][col] = newer;
}

int main(int argc, char** argv) {
    setlocale(LC_NUMERIC, "");
    signal(SIGINT, term_reset);
    int error = term_init();
    if(error)
        return error;
    else
        term_cursor_visibility(false);
    term_clear();
    pane = pane_init();

    int r = 0;
    strcpy(pane[r++], "                      **                      \n");
    strcpy(pane[r++], "                     +  +                     \n");
    strcpy(pane[r++], "                  ++      ++                  \n");
    strcpy(pane[r++], "                ++          ++                \n");
    strcpy(pane[r++], "              ++          *+  ++              \n");
    strcpy(pane[r++], "            ++           +      ++            \n");
    strcpy(pane[r++], "          ++          *+          ++          \n");
    strcpy(pane[r++], "         +++++++    + *        +++++++        \n");
    strcpy(pane[r++], "             ++   + *    *     ++             \n");
    strcpy(pane[r++], "           ++   +           +    ++           \n");
    strcpy(pane[r++], "         ++               +        ++         \n");
    strcpy(pane[r++], "       ++               +            ++       \n");
    strcpy(pane[r++], "     ++           *   +            +   ++     \n");
    strcpy(pane[r++], "   ++            *  +            +       ++   \n");
    strcpy(pane[r++], "  +++++++         +            +     +++++++  \n");
    strcpy(pane[r++], "      ++   *    +          * +        ++      \n");
    strcpy(pane[r++], "    ++        +  *         +            ++    \n");
    strcpy(pane[r++], "  ++        +            +    *     +     ++  \n");
    strcpy(pane[r++], "++        +            +          +         ++\n");
    strcpy(pane[r++], "+++++++              +          +      +++++++\n");
    strcpy(pane[r++], "    ++        *    +          +         ++    \n");
    strcpy(pane[r++], "   ++            +      *   +         +  ++   \n");
    strcpy(pane[r++], "  ++     *     +          +   *     +     ++  \n");
    strcpy(pane[r++], " ++          +*         +         +        ++ \n");
    strcpy(pane[r++], "++         +       *  +         +           ++\n");
    strcpy(pane[r++], "++++++++++++++++++++++++++++++++++++++++++++++\n");
    strcpy(pane[r++], "                                              \n");
    strcpy(pane[r++], "2017.12.25 @makerj++++++++++++++++++++++++++++\n");
    strcpy(pane[r++], "         Merry Christmas for everyone !       \n");
    strcpy(pane[r++], "++++++++++++++++++++++++++++++++++++++++++++++\n");

    term_move(0, 0), pane_draw(pane);

    for(int i = 0; ; ++i) {
        term_move(0, 0), pane_draw(pane);
        usleep(100 * 1000);
    }

    return 0;
}