summary refs log tree commit diff
path: root/bin/fbclock.c
blob: ddc32db632754566f9e235145fd2a4b98e6a87ac (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/* Copyright (C) 2018  C. McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <assert.h>
#include <err.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>
#include <zlib.h>

#include "scheme.h"

static const uint32_t PSF2Magic = 0x864AB572;
struct PSF2Header {
	uint32_t magic;
	uint32_t version;
	uint32_t headerSize;
	uint32_t flags;
	uint32_t glyphCount;
	uint32_t glyphSize;
	uint32_t glyphHeight;
	uint32_t glyphWidth;
};

int main() {
	size_t len;

	const char *fontPath = getenv("FONT");
	if (!fontPath) {
		fontPath = "/usr/share/kbd/consolefonts/Lat2-Terminus16.psfu.gz";
	}

	gzFile font = gzopen(fontPath, "r");
	if (!font) err(EX_NOINPUT, "%s", fontPath);

	struct PSF2Header header;
	len = gzfread(&header, sizeof(header), 1, font);
	if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing header", fontPath);
	if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));

	if (header.magic != PSF2Magic) {
		errx(
			EX_DATAERR, "%s: invalid header magic %08X",
			fontPath, header.magic
		);
	}
	if (header.headerSize != sizeof(struct PSF2Header)) {
		errx(
			EX_DATAERR, "%s: weird header size %d",
			fontPath, header.headerSize
		);
	}

	uint8_t glyphs[128][header.glyphSize];
	len = gzfread(glyphs, header.glyphSize, 128, font);
	if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing glyphs", fontPath);
	if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));

	gzclose(font);

	const char *fbPath = getenv("FRAMEBUFFER");
	if (!fbPath) fbPath = "/dev/fb0";

	int fb = open(fbPath, O_RDWR);
	if (fb < 0) err(EX_OSFILE, "%s", fbPath);

	struct fb_var_screeninfo info;
	int error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
	if (error) err(EX_IOERR, "%s", fbPath);

	size_t size = 4 * info.xres * info.yres;
	uint32_t *buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
	if (buf == MAP_FAILED) err(EX_IOERR, "%s", fbPath);

	for (;;) {
		time_t t = time(NULL);
		if (t < 0) err(EX_OSERR, "time");
		const struct tm *local = localtime(&t);
		if (!local) err(EX_OSERR, "localtime");

		char str[64];
		len = strftime(str, sizeof(str), "%H:%M", local);
		assert(len);

		for (int i = 0; i < (60 - local->tm_sec); ++i, sleep(1)) {
			uint32_t left = info.xres - header.glyphWidth * len;
			uint32_t bottom = header.glyphHeight;

			for (uint32_t y = 0; y < bottom; ++y) {
				buf[y * info.xres + left - 1] = DarkWhite;
			}
			for (uint32_t x = left - 1; x < info.xres; ++x) {
				buf[bottom * info.xres + x] = DarkWhite;
			}

			for (const char *s = str; *s; ++s) {
				const uint8_t *glyph = glyphs[(unsigned)*s];
				uint32_t stride = header.glyphSize / header.glyphHeight;
				for (uint32_t y = 0; y < header.glyphHeight; ++y) {
					for (uint32_t x = 0; x < header.glyphWidth; ++x) {
						uint8_t bits = glyph[y * stride + x / 8];
						uint8_t bit = bits >> (7 - x % 8) & 1;
						buf[y * info.xres + left + x] = bit
							? DarkWhite
							: DarkBlack;
					}
				}
				left += header.glyphWidth;
			}
		}
	}
}