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
|
/* public domain, do as you wish
* http://www.tedunangst.com/flak/post/sct-set-color-temperature
*/
#include <X11/Xlib.h>
#include <X11/Xproto.h>
#include <X11/Xatom.h>
#include <X11/extensions/Xrandr.h>
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
/* cribbed from redshift, but truncated with 500K steps */
static const struct { float r; float g; float b; } whitepoints[] = {
{ 1.00000000, 0.18172716, 0.00000000, }, /* 1000K */
{ 1.00000000, 0.42322816, 0.00000000, },
{ 1.00000000, 0.54360078, 0.08679949, },
{ 1.00000000, 0.64373109, 0.28819679, },
{ 1.00000000, 0.71976951, 0.42860152, },
{ 1.00000000, 0.77987699, 0.54642268, },
{ 1.00000000, 0.82854786, 0.64816570, },
{ 1.00000000, 0.86860704, 0.73688797, },
{ 1.00000000, 0.90198230, 0.81465502, },
{ 1.00000000, 0.93853986, 0.88130458, },
{ 1.00000000, 0.97107439, 0.94305985, },
{ 1.00000000, 1.00000000, 1.00000000, }, /* 6500K */
{ 0.95160805, 0.96983355, 1.00000000, },
{ 0.91194747, 0.94470005, 1.00000000, },
{ 0.87906581, 0.92357340, 1.00000000, },
{ 0.85139976, 0.90559011, 1.00000000, },
{ 0.82782969, 0.89011714, 1.00000000, },
{ 0.80753191, 0.87667891, 1.00000000, },
{ 0.78988728, 0.86491137, 1.00000000, }, /* 10000K */
{ 0.77442176, 0.85453121, 1.00000000, },
};
void
usage()
{
printf("Usage: sct [temperature]\n"
"Temperatures must be in a range from 1000-10000\n"
"If no arguments are passed sct resets the display to the default temperature (6500K)\n"
"If -h is passed sct will display this usage information\n");
exit(0);
}
int
main(int argc, char **argv)
{
Display *dpy = XOpenDisplay(NULL);
int screen = DefaultScreen(dpy);
Window root = RootWindow(dpy, screen);
XRRScreenResources *res = XRRGetScreenResourcesCurrent(dpy, root);
int temp = 6500;
if (argc > 1) {
if (!strcmp(argv[1],"-h"))
usage();
temp = atoi(argv[1]);
if (temp < 1000 || temp > 10000)
usage();
}
temp -= 1000;
double ratio = temp % 500 / 500.0;
#define AVG(c) whitepoints[temp / 500].c * (1 - ratio) + whitepoints[temp / 500 + 1].c * ratio
double gammar = AVG(r);
double gammag = AVG(g);
double gammab = AVG(b);
for (int c = 0; c < res->ncrtc; c++) {
int crtcxid = res->crtcs[c];
int size = XRRGetCrtcGammaSize(dpy, crtcxid);
XRRCrtcGamma *crtc_gamma = XRRAllocGamma(size);
for (int i = 0; i < size; i++) {
double g = 65535.0 * i / size;
crtc_gamma->red[i] = g * gammar;
crtc_gamma->green[i] = g * gammag;
crtc_gamma->blue[i] = g * gammab;
}
XRRSetCrtcGamma(dpy, crtcxid, crtc_gamma);
XFree(crtc_gamma);
}
}
|