Commit: 2513bfa7e36e0fc2dcb4988b330d10d69fe168dc
Author: Fabian Foerg
Date: Fri, 20 Nov 2015 19:32:42 -0500
Initial commit
Diffstat:
A | README.md | | | 33 | +++++++++++++++++++++++++++++++++ |
A | sct.c | | | 111 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
2 files changed, 144 insertions(+), 0 deletions(-)
diff --git a/README.md b/README.md
@@ -0,0 +1,33 @@
+# About
+
+Sct (set color temperature) is a UNIX tool which allows you to set the color
+temperature of your screen. It is simpler than Redshift and f.lux.
+
+Original code was published by Ted Unangst:
+http://www.tedunangst.com/flak/post/sct-set-color-temperature
+
+Minor modifications were made in order to get sct to:
+- compile on Ubuntu 14.04
+- iterate over all screens of the default display and change the color
+ temperature
+- free the Display structure
+- return 0
+
+# Installation
+
+Compile the code using the following command:
+
+~~~
+cc -std=c99 -O2 -I /usr/X11R6/include -o sct sct.c -L /usr/X11R6/lib -lm -lX11 -lXrandr
+~~~
+
+Execute sct using the following command:
+
+~~~
+./sct 3700
+~~~
+
+The first parameter (`3700` above) denotes the color temperature and can be
+between `1000` and `10000`.
+If `sct` is called without parameters, sct sets the color temperature to `6500`.
+
diff --git a/sct.c b/sct.c
@@ -0,0 +1,111 @@
+/*
+ * sct - set color temperature
+ *
+ * Compile the code using the following command:
+ * cc -std=c99 -O2 -I /usr/X11R6/include -o sct sct.c -L /usr/X11R6/lib -lm -lX11 -lXrandr
+ *
+ * Original code published by Ted Unangst:
+ * http://www.tedunangst.com/flak/post/sct-set-color-temperature
+ *
+ * Modified by Fabian Foerg in order to:
+ * - compile on Ubuntu 14.04
+ * - iterate over all screens of the default display and change the color
+ * temperature
+ * - free the Display structure
+ * - return 0
+ */
+
+#include <inttypes.h>
+#include <math.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#include <X11/Xlibint.h>
+#include <X11/Xproto.h>
+#include <X11/extensions/Xrandr.h>
+#include <X11/extensions/Xrender.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, },
+};
+
+static void
+sct_for_screen(Display *dpy, int screen, int temp)
+{
+ Window root = RootWindow(dpy, screen);
+ XRRScreenResources *res = XRRGetScreenResourcesCurrent(dpy, root);
+
+ 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);
+
+ int num_crtcs = res->ncrtc;
+ for (int c = 0; c < res->ncrtc; c++) {
+ int crtcxid = res->crtcs[c];
+ XRRCrtcInfo *crtc_info = XRRGetCrtcInfo(dpy, res, crtcxid);
+
+ 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);
+ }
+}
+
+int
+main(int argc, char **argv)
+{
+ Display *dpy = XOpenDisplay(NULL);
+ int screens = XScreenCount(dpy);
+
+ int temp = 6500;
+ if (argc > 1)
+ temp = atoi(argv[1]);
+ if (temp < 1000 || temp > 10000)
+ temp = 6500;
+
+ for (int screen = 0; screen < screens; screen++)
+ sct_for_screen(dpy, screen, temp);
+
+ XCloseDisplay(dpy);
+
+ return 0;
+}
+