Add force desktop window type flag (#4)

* Add force desktop window type flag
This flag places xwinwrap behind desktop icons on ubuntu

* Update README.md

README.md

@@ -4,6 +4,8 @@ My fork of xwinwrap.
 Xwinwrap allows you to stick most of the apps to your desktop background.  
 My use case - can use gif as a background
 
+![demo gif](https://github.com/ujjwal96/xwinwrap/blob/demo/demo.gif)
+
 ### Installing
 
 ```
@@ -18,11 +20,12 @@ make clean
 ### Usage
 
 ```
-Usage: xwinwrap [-g {w}x{h}+{x}+{y}] [-ni] [-argb] [-fs] [-s] [-st] [-sp] [-a] [-b] [-nf] [-o OPACITY] [-sh SHAPE] [-ov]-- COMMAND ARG1...
+Usage: xwinwrap [-g {w}x{h}+{x}+{y}] [-ni] [-argb] [-fdt] [-fs] [-s] [-st] [-sp] [-a] [-d] [-b] [-nf] [-o OPACITY] [-sh SHAPE] [-ov]-- COMMAND ARG1...
 Options:
              -g      - Specify Geometry (w=width, h=height, x=x-coord, y=y-coord. ex: -g 640x480+100+100)
              -ni     - Ignore Input
              -argb   - RGB
+             -fdt    - force WID window a desktop type window
              -fs     - Full Screen
              -un     - Undecorated
              -s      - Sticky
@@ -34,6 +37,7 @@ Options:
              -o      - Opacity value between 0 to 1 (ex: -o 0.20)
              -sh     - Shape of window (choose between rectangle, circle or triangle. Default is rectangle)
              -ov     - Set override_redirect flag (For seamless desktop background integration in non-fullscreenmode)
+             -d      - Daemonize
              -debug  - Enable debug messages
 ```
 Example

xwinwrap.c

@@ -133,12 +133,13 @@ static void sigHandler (int sig)
 static void usage (void)
 {
     fprintf(stderr, "%s \n", NAME);
-    fprintf (stderr, "\nUsage: %s [-g {w}x{h}+{x}+{y}] [-ni] [-argb] [-fs] [-s] [-st] [-sp] [-a] "
+    fprintf (stderr, "\nUsage: %s [-g {w}x{h}+{x}+{y}] [-ni] [-argb] [-fdt] [-fs] [-s] [-st] [-sp] [-a] [-d] "
              "[-b] [-nf] [-o OPACITY] [-sh SHAPE] [-ov]-- COMMAND ARG1...\n", NAME);
     fprintf (stderr, "Options:\n \
             -g      - Specify Geometry (w=width, h=height, x=x-coord, y=y-coord. ex: -g 640x480+100+100)\n \
             -ni     - Ignore Input\n \
             -argb   - RGB\n \
+            -fdt    - force WID window a desktop type window\n \
             -fs     - Full Screen\n \
             -un     - Undecorated\n \
             -s      - Sticky\n \
@@ -150,6 +151,7 @@ static void usage (void)
             -o      - Opacity value between 0 to 1 (ex: -o 0.20)\n \
             -sh     - Shape of window (choose between rectangle, circle or triangle. Default is rectangle)\n \
             -ov     - Set override_redirect flag (For seamless desktop background integration in non-fullscreenmode)\n \
+            -d      - Daemonize\n \
             -debug  - Enable debug messages\n");
 }
 
@@ -274,6 +276,7 @@ int main(int argc, char **argv)
     bool have_argb_visual = false;
     bool noInput = false;
     bool argb = false;
+    bool set_desktop_type = false;
     bool fullscreen = false;
     bool noFocus = false;
     bool override = false;
@@ -283,6 +286,7 @@ int main(int argc, char **argv)
     bool above = false;
     bool skip_taskbar = false;
     bool skip_pager = false;
+    bool daemonize = false;
 
     win_shape   shape = SHAPE_RECT;
     Pixmap      mask;
@@ -307,6 +311,10 @@ int main(int argc, char **argv)
         {
             argb = true;
         }
+        else if (strcmp (argv[i], "-fdt") == 0)
+        {
+            set_desktop_type = true;
+        }
         else if (strcmp (argv[i], "-fs") == 0)
         {
             fullscreen = 1;
@@ -366,6 +374,10 @@ int main(int argc, char **argv)
         {
             debug = true;
         }
+        else if (strcmp (argv[i], "-d") == 0)
+        {
+            daemonize = true;
+        }
         else if (strcmp (argv[i], "--") == 0)
         {
             break;
@@ -377,6 +389,35 @@ int main(int argc, char **argv)
         }
     }
 
+    if (daemonize)
+    {
+        pid_t process_id = 0;
+        pid_t sid = 0;
+        process_id = fork();
+        if (process_id < 0)
+        {
+            fprintf(stderr, "fork failed!\n");
+            exit(1);
+        }
+
+        if (process_id > 0)
+        {
+            fprintf(stderr, "pid of child process %d \n", process_id);
+            exit(0);
+        }
+        umask(0);
+        sid = setsid();
+        if (sid < 0)
+        {
+            exit(1);
+        }
+
+        chdir("/");
+        close(STDIN_FILENO);
+        close(STDOUT_FILENO);
+        close(STDERR_FILENO);
+    }
+
     for (i = i + 1; i < argc; i++)
     {
         if (strcmp (argv[i], "WID") == 0)
@@ -491,7 +532,12 @@ int main(int argc, char **argv)
         xa = ATOM(_NET_WM_WINDOW_TYPE);
 
         Atom prop;
+        if (set_desktop_type)
+        {
+            prop = ATOM(_NET_WM_WINDOW_TYPE_DESKTOP);
+        } else {
             prop = ATOM(_NET_WM_WINDOW_TYPE_NORMAL);
+        }
 
         XChangeProperty(display, window.window, xa, XA_ATOM, 32,
                         PropModeReplace, (unsigned char *) &prop, 1);