Add the source code

dirot.c

@@ -0,0 +1,45 @@
+#include <X11/Xlib.h>
+#include <X11/extensions/Xrandr.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <err.h>
+
+void test_and_fail(void *ptr, char *msg) {
+	if (ptr == NULL) {
+		fprintf(stderr, "Fatal error: %s\n", msg);
+		exit(2);
+	}
+}
+
+int ror4 (int x) {
+	// Just rotate right by 1 bit
+	int num = x & 0xf;
+	int lowbit = x & 0x1;
+	return (num >> 1) | (lowbit << 3);
+}
+
+int main (void) {
+	Display *dpy = XOpenDisplay(NULL);
+	test_and_fail(dpy, "Could not open display");
+
+	int screen_number = XDefaultScreen(dpy);
+	Screen *screen = XDefaultScreenOfDisplay(dpy);
+	Window root = XRootWindow(dpy, screen_number);
+
+	// TODO: Early check that RandR is supported by dpy
+
+	Rotation current;
+	Rotation all;
+	all = XRRRotations(dpy, screen_number, &current);
+
+	Rotation new = ror4(current);
+
+	Time cfg_ts;
+	Rotation cfg_rot;
+	XRRScreenConfiguration *cfg = XRRGetScreenInfo(dpy, root);
+	XRRSetScreenConfig(dpy, cfg, root, XRRConfigCurrentConfiguration(cfg, &cfg_rot), new, XRRConfigTimes(cfg, &cfg_ts));
+	
+	XRRFreeScreenConfigInfo(cfg);
+	return 0;
+}