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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/**
* crt-calibrator – Calibration utility for CRT monitors
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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 "framebuffer.h"
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <stropts.h>
#include <linux/fb.h>
#include <errno.h>
/**
* The psuedodevice pathname pattern used to access a framebuffer
*/
#ifndef FB_DEVICE_PATTERN
# define FB_DEVICE_PATTERN "/dev/fb%lu"
#endif
/**
* The number of elements to allocates to a buffer for a framebuffer device pathname
*/
#define FB_DEVICE_MAX_LEN (sizeof(FB_DEVICE_PATTERN) / sizeof(char) + 3 * sizeof(size_t))
/**
* Figure out how many framebuffers there are on the system
*
* @return The number of framebuffers on the system
*/
size_t fb_count(void)
{
char buf[FB_DEVICE_MAX_LEN];
size_t count = 0;
for (;; count++)
{
sprintf(buf, FB_DEVICE_PATTERN, count);
if (access(buf, F_OK) < 0)
return count;
}
}
/**
* Open a framebuffer
*
* @param index The index of the framebuffer to open
* @param fb Framebuffer information to fill in
* @return Zero on success, -1 on error
*/
int fb_open(size_t index, framebuffer_t* restrict fb)
{
char buf[FB_DEVICE_MAX_LEN];
struct fb_fix_screeninfo fix_info;
struct fb_var_screeninfo var_info;
int old_errno;
fb->fd = 0;
fb->mem = MAP_FAILED;
sprintf(buf, FB_DEVICE_PATTERN, index);
fb->fd = open(buf, O_RDWR);
if (fb->fd == 0)
goto fail;
if (ioctl(fb->fd, FBIOGET_FSCREENINFO, &fix_info) ||
ioctl(fb->fd, FBIOGET_VSCREENINFO, &var_info))
goto fail;
fb->mem = mmap(NULL, fix_info.smem_len, PROT_WRITE, MAP_SHARED, fb->fd, 0);
if (fb->mem == MAP_FAILED)
goto fail;
fb->mem += var_info.xoffset * (var_info.bits_per_pixel / 8);
fb->mem += var_info.yoffset * fix_info.line_length;
fb->width = var_info.xres;
fb->height = var_info.yres;
fb->bytes_per_pixel = var_info.bits_per_pixel / 8;
fb->line_length = fix_info.line_length;
return 0;
fail:
old_errno = errno;
fb_close(fb);
errno = old_errno;
return -1;
}
/**
* Close a framebuffer
*
* @param fb The framebuffer information
*/
void fb_close(framebuffer_t* restrict fb)
{
if (fb->fd)
close(fb->fd);
}
uint32_t fb_colour(int red, int green, int blue)
{
uint32_t rc = 0;
rc |= red, rc <<= 8;
rc |= green, rc <<= 8;
rc |= blue;
return rc;
}
void fb_fill_rectangle(framebuffer_t* restrict fb, uint32_t colour,
uint32_t x, uint32_t y, uint32_t width, uint32_t height)
{
int8_t* mem = fb->mem + y * fb->line_length;
size_t x1 = x * fb->bytes_per_pixel;
size_t x2 = (x + width) * fb->bytes_per_pixel;
size_t y2 = y + height;
size_t x_, y_;
for (y_ = y; y_ != y2; y_++, mem += fb->line_length)
for (x_ = x1; x_ != x2; x_ += fb->bytes_per_pixel)
{
int8_t* pixel = mem + x_;
*(uint32_t*)pixel = colour;
}
}
int main()
{
framebuffer_t fb;
fb_open(0, &fb);
fb_fill_rectangle(&fb, fb_colour(36, 149, 190), 20, 20, fb.width - 40, fb.height - 40);
fb_close(&fb);
return 0;
}
|
