Fixed bug where slop would ignore the environment variable DISPLAY.

CMakeLists.txt

 project( "slop" )
 set( slop_VERSION_MAJOR 3 )
 set( slop_VERSION_MINOR 1 )
-set( slop_VERSION_PATCH 10 )
+set( slop_VERSION_PATCH 11 )
 
 set( BIN_TARGET     "${PROJECT_NAME}" )
 set( CMAKE_INSTALL_PREFIX "/usr/bin" )

README.md

 help
 ----
 ```text
-slop v3.1.10
+slop v3.1.11
 
 Copyright (C) 2014 Dalton Nell, Slop Contributors
 (https://github.com/naelstrof/slop/graphs/contributors)
   -V, --version                 Print version and exit
 Options
       --xdisplay=hostname:number.screen_number
-                                Sets the x display.  (default=`:0')
+                                Sets the x display.
       --nokeyboard              Disables the ability to cancel selections with
                                   the keyboard.  (default=off)
   -b, --bordersize=INT          Set the selection rectangle's thickness. Does

src/cmdline.c

   "  -h, --help                    Print help and exit",
   "  -V, --version                 Print version and exit",
   "Options",
-  "      --xdisplay=hostname:number.screen_number\n                                Sets the x display.  (default=`:0')",
+  "      --xdisplay=hostname:number.screen_number\n                                Sets the x display.",
   "      --nokeyboard              Disables the ability to cancel selections with\n                                  the keyboard.  (default=off)",
   "  -b, --bordersize=INT          Set the selection rectangle's thickness. Does\n                                  nothing when --highlight is enabled.\n                                  (default=`5')",
   "  -p, --padding=INT             Set the padding size of the selection. Can be\n                                  negative.  (default=`0')",
 void clear_args (struct gengetopt_args_info *args_info)
 {
   FIX_UNUSED (args_info);
-  args_info->xdisplay_arg = gengetopt_strdup (":0");
+  args_info->xdisplay_arg = NULL;
   args_info->xdisplay_orig = NULL;
   args_info->nokeyboard_flag = 0;
   args_info->bordersize_arg = 5;
           
             if (update_arg( (void *)&(args_info->xdisplay_arg), 
                  &(args_info->xdisplay_orig), &(args_info->xdisplay_given),
-                &(local_args_info.xdisplay_given), optarg, 0, ":0", ARG_STRING,
+                &(local_args_info.xdisplay_given), optarg, 0, 0, ARG_STRING,
                 check_ambiguity, override, 0, 0,
                 "xdisplay", '-',
                 additional_error))

src/cmdline.in

 {
   const char *help_help; /**< @brief Print help and exit help description.  */
   const char *version_help; /**< @brief Print version and exit help description.  */
-  char * xdisplay_arg;	/**< @brief Sets the x display. (default=':0').  */
+  char * xdisplay_arg;	/**< @brief Sets the x display..  */
   char * xdisplay_orig;	/**< @brief Sets the x display. original value given at command line.  */
   const char *xdisplay_help; /**< @brief Sets the x display. help description.  */
   int nokeyboard_flag;	/**< @brief Disables the ability to cancel selections with the keyboard. (default=off).  */

src/main.cpp

     slop::Rectangle* selection = NULL;
     Window window = None;
     Window windowmemory = None;
-    std::string xdisplay = options.xdisplay_arg;
+    std::string xdisplay;
+    if ( options.xdisplay_given ) {
+        xdisplay = options.xdisplay_arg;
+    } else {
+        // If we weren't specifically given a xdisplay, we try
+        // to parse it from environment variables
+        char* display = getenv( "DISPLAY" );
+        if ( display ) {
+            xdisplay = display;
+        } else {
+            fprintf( stderr, "Warning: Failed to parse environment variable: DISPLAY. Using \":0\" instead.\n" );
+            xdisplay = ":0";
+        }
+    }
     int padding = options.padding_arg;
     int borderSize = options.bordersize_arg;
     int tolerance = options.tolerance_arg;

src/options.ggo

 option "xdisplay" - "Sets the x display."
     string
     typestr="hostname:number.screen_number"
-    default=":0"
     optional
 
 option "nokeyboard" - "Disables the ability to cancel selections with the keyboard."