keyboard_bright.c

/**
 * keyboard_bright
 * Copyright (C) 2010 Kenny Parnell <k.parnell@gmail.com>
 * 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 <http://www.gnu.org/licenses/
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef EXISTS_XOSD
#include <xosd.h>
#endif
#define CTL_FILE "/sys/devices/platform/applesmc.768/leds/smc::kbd_backlight/brightness"
#define MAX 255
#define MIN 0
#define STEP 17

int usage(char *argv[]) {
    printf("usage: %s up|down|max|min\n\n", argv[0]);
    return EXIT_FAILURE;
}

int get_current() {
    int val;
    FILE *ctl_file;

    ctl_file = fopen(CTL_FILE, "r");
    fscanf(ctl_file, "%i", &val);
    fclose(ctl_file);

    return val;
}

void set_current(int val) {
    if (val > MAX) val = MAX;
    if (val < MIN) val = MIN;

    printf("Value: %i", val);
    FILE *ctl_file;

    ctl_file = fopen(CTL_FILE, "w");
    fprintf(ctl_file, "%i", val);
    fclose(ctl_file);

    // Display OSD
#ifdef XOSD_H
    xosd *osd;

    osd = xosd_create(3);

    if (osd == NULL) return;

    int percentage = (int)(100.0 * val / MAX);

    xosd_set_pos(osd, XOSD_bottom);
    xosd_set_align(osd, XOSD_center);
    xosd_set_timeout(osd, 1);
    xosd_set_shadow_offset(osd, 1);

    xosd_display(osd, 0, XOSD_string, "Brightness");
    xosd_display(osd, 2, XOSD_percentage, percentage);

    xosd_wait_until_no_display(osd);

    xosd_destroy(osd);
#endif
}

int main(int argc, char *argv[]) {
    // Make sure we have required arg
    if (argc != 2) return usage(argv);

    // fetch the current value
    int val = get_current();

    // Increment/Decrement the current value
    if (strcmp(argv[1], "up") == 0) {
        val += STEP;
    } else if (strcmp(argv[1], "down") == 0) {
        val -= STEP;
    } else if (strcmp(argv[1], "min") == 0) {
        val = MIN;
    } else if (strcmp(argv[1], "max") == 0) {
        val = MAX;
    } else {
        return usage(argv);
    }

    // write the new value
    set_current(val);

    return EXIT_SUCCESS;
}