Oops, actually commit the source file

.hgignore

@@ -1,2 +1,3 @@
+syntax: glob
 find-cursor
 capture

find-cursor.c

@@ -0,0 +1,120 @@
+/*
+ * http://code.arp242.net/find-cursor
+ * Copyright © 2015 Martin Tournoij <martin@arp242.net>
+ * See below for full copyright
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <X11/Xlib.h>
+
+
+// Some variables you can play with :-)
+int size = 220;
+int step = 40;
+int speed = 400;
+int line_width = 2;
+char color_name[] = "black";
+
+
+int main(int argc, char* argv[]) {
+	// Setup display and such
+	char *display_name = getenv("DISPLAY");
+	if (!display_name) {
+		fprintf(stderr, "%s: cannot connect to X server '%s'\n", argv[0], display_name);
+		exit(1);
+	}
+
+	Display *display = XOpenDisplay(display_name);
+	int screen = DefaultScreen(display);
+
+	// Get the mouse cursor position
+	int win_x, win_y, root_x, root_y = 0;
+	unsigned int mask = 0;
+	Window child_win, root_win;
+	XQueryPointer(display, XRootWindow(display, screen),
+		&child_win, &root_win,
+		&root_x, &root_y, &win_x, &win_y, &mask);
+
+	// Create a window at the mouse position
+	XSetWindowAttributes window_attr;
+	window_attr.override_redirect = 1;
+	Window window = XCreateWindow(display, XRootWindow(display, screen),
+		root_x - size/2, root_y - size/2,   // x, y position
+		size, size,                         // width, height
+		0,                                  // border width
+		DefaultDepth(display, screen),      // depth
+		CopyFromParent,                     // class
+		DefaultVisual(display, screen),     // visual
+		CWOverrideRedirect,                 // valuemask
+		&window_attr                        // attributes
+	);
+	XMapWindow(display, window);
+
+	// Keep the window on top
+	XEvent e;
+	memset(&e, 0, sizeof(e));
+	e.xclient.type = ClientMessage;
+	e.xclient.message_type = XInternAtom(display, "_NET_WM_STATE", False);
+	e.xclient.display = display;
+	e.xclient.window = window;
+	e.xclient.format = 32;
+	e.xclient.data.l[0] = 1;
+	e.xclient.data.l[1] = XInternAtom(display, "_NET_WM_STATE_STAYS_ON_TOP", False);
+	XSendEvent(display, XRootWindow(display, screen), False, SubstructureRedirectMask, &e);
+
+	XRaiseWindow(display, window);
+	XFlush(display);
+
+	// Prepare to draw on this window
+	XGCValues values = { .graphics_exposures = False };
+	unsigned long valuemask = 0;
+	GC gc = XCreateGC(display, window, valuemask, &values);
+
+	Colormap colormap = DefaultColormap(display, screen);
+	XColor color;
+	XAllocNamedColor(display, colormap, color_name, &color, &color);
+	XSetForeground(display, gc, color.pixel);
+	XSetLineAttributes(display, gc, line_width, LineSolid, CapButt, JoinBevel);
+
+	// Draw the circles
+	for (int i=1; i<=size; i+=step) { 
+		XDrawArc(display, window, gc,
+			size/2 - i/2, size/2 - i/2,   // x, y position
+			i, i,                         // Size
+			0, 360 * 64);                 // Make it a full circle
+
+		XSync(display, False);
+		usleep(speed * 100);
+	}
+
+	XCloseDisplay(display);
+}
+
+
+/*
+ *  The MIT License (MIT)
+ * 
+ *  Copyright © 2015 Martin Tournoij
+ * 
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to
+ *  deal in the Software without restriction, including without limitation the
+ *  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ *  sell copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ * 
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ * 
+ *  The software is provided "as is", without warranty of any kind, express or
+ *  implied, including but not limited to the warranties of merchantability,
+ *  fitness for a particular purpose and noninfringement. In no event shall the
+ *  authors or copyright holders be liable for any claim, damages or other
+ *  liability, whether in an action of contract, tort or otherwise, arising
+ *  from, out of or in connection with the software or the use or other dealings
+ *  in the software.
+ */