Added option --format, which lets you change the output format. Useful to manually parse variables, and to avoid using eval.

README.md

 You can see my implementation of slop in a screenshooter here:
 https://gist.github.com/naelstrof/6530959
 
+For those of you who don't want eval to be an integral part of slop (Could be dangerous if I were evil!): You can change the output format and parse it manually like so:
+```bash
+#!/bin/bash
+slopoutput=$(slop -f "%x %y %w %h %g $i")
+X=$(echo $slopoutput | awk '{print $1}')
+Y=$(echo $slopoutput | awk '{print $2}')
+W=$(echo $slopoutput | awk '{print $3}')
+H=$(echo $slopoutput | awk '{print $4}')
+G=$(echo $slopoutput | awk '{print $5}')
+ID=$(echo $slopoutput | awk '{print $6}')
+maim -g $G -i $ID
+ffmpeg -f x11grab -s "$W"x"$H" -i :0.0+$X,$Y -f alsa -i pulse ~/myfile.webm
+```
+
 ## Lets see some action
 Ok. Here's a comparison between 'scrot -s's selection and slop's:
 ![scrotbad](http://farmpolice.com/content/images/2014-10-14-12:08:24.png)
 help
 ----
 ```text
-slop v3.1.5
+slop v3.1.7
 
-Copyright (C) 2014 Dalton Nell, Slop Contributors (https://github.com/naelstrof/slop/graphs/contributors)
+Copyright (C) 2014 Dalton Nell, Slop Contributors
+(https://github.com/naelstrof/slop/graphs/contributors)
 
 Usage: slop [options]
 
                                   highlights it. This is only useful when
                                   --color is set to a transparent color.
                                   (default=off)
+  -f, --format=STRING           Set the output format string. Format specifiers
+                                  are %x, %y, %w, %h, %i, %g, and %c.
+                                  (default=`X=%x\nY=%y\nW=%w\nH=%h\nG=%g\nID=%i\nCancel=%c\n')
 
 Examples
     $ # Gray, thick, transparent border for maximum visiblity.
 
     $ # Classic Windows XP selection.
     $ slop -l -c 0.3,0.4,0.6,0.4
+
+    $ # Change output format to use safer parsing
+    $ slopoutput=$(slop -f "%x %y %w %h")
+    $ X=$(echo $slopoutput | awk '{print $1}')
+    $ Y=$(echo $slopoutput | awk '{print $2}')
+    $ W=$(echo $slopoutput | awk '{print $3}')
+    $ H=$(echo $slopoutput | awk '{print $4}')
 ```

cmdline.c

   "      --min=INT                 Set the minimum output of width or height\n                                  values. This is useful to avoid outputting 0.\n                                  Setting min and max to the same value\n                                  disables drag selections.  (default=`0')",
   "      --max=INT                 Set the maximum output of width or height\n                                  values. Setting min and max to the same value\n                                  disables drag selections.  (default=`0')",
   "  -l, --highlight               Instead of outlining selections, slop\n                                  highlights it. This is only useful when\n                                  --color is set to a transparent color.\n                                  (default=off)",
-  "\nExamples\n    $ # Gray, thick, transparent border for maximum visiblity.\n    $ slop -b 20 -c 0.5,0.5,0.5,0.8\n\n    $ # Remove window decorations.\n    $ slop --nodecorations\n\n    $ # Disable window selections. Useful for selecting individual pixels.\n    $ slop -t 0\n\n    $ # Classic Windows XP selection.\n    $ slop -l -c 0.3,0.4,0.6,0.4\n",
+  "  -f, --format=STRING           Set the output format string. Format specifiers\n                                  are %x, %y, %w, %h, %i, %g, and %c.\n                                  (default=`X=%x\\nY=%y\\nW=%w\\nH=%h\\nG=%g\\nID=%i\\nCancel=%c\\n')",
+  "\nExamples\n    $ # Gray, thick, transparent border for maximum visiblity.\n    $ slop -b 20 -c 0.5,0.5,0.5,0.8\n\n    $ # Remove window decorations.\n    $ slop --nodecorations\n\n    $ # Disable window selections. Useful for selecting individual pixels.\n    $ slop -t 0\n\n    $ # Classic Windows XP selection.\n    $ slop -l -c 0.3,0.4,0.6,0.4\n\n    $ # Change output format to use safer parsing\n    $ slopoutput=$(slop -f \"%x %y %w %h\")\n    $ X=$(echo $slopoutput | awk '{print $1}')\n    $ Y=$(echo $slopoutput | awk '{print $2}')\n    $ W=$(echo $slopoutput | awk '{print $3}')\n    $ H=$(echo $slopoutput | awk '{print $4}')\n",
     0
 };
 
   args_info->min_given = 0 ;
   args_info->max_given = 0 ;
   args_info->highlight_given = 0 ;
+  args_info->format_given = 0 ;
 }
 
 static
   args_info->max_arg = 0;
   args_info->max_orig = NULL;
   args_info->highlight_flag = 0;
+  args_info->format_arg = gengetopt_strdup ("X=%x\nY=%y\nW=%w\nH=%h\nG=%g\nID=%i\nCancel=%c\n");
+  args_info->format_orig = NULL;
   
 }
 
   args_info->min_help = gengetopt_args_info_help[11] ;
   args_info->max_help = gengetopt_args_info_help[12] ;
   args_info->highlight_help = gengetopt_args_info_help[13] ;
+  args_info->format_help = gengetopt_args_info_help[14] ;
   
 }
 
   free_string_field (&(args_info->color_orig));
   free_string_field (&(args_info->min_orig));
   free_string_field (&(args_info->max_orig));
+  free_string_field (&(args_info->format_arg));
+  free_string_field (&(args_info->format_orig));
   
   
 
     write_into_file(outfile, "max", args_info->max_orig, 0);
   if (args_info->highlight_given)
     write_into_file(outfile, "highlight", 0, 0 );
+  if (args_info->format_given)
+    write_into_file(outfile, "format", args_info->format_orig, 0);
   
 
   i = EXIT_SUCCESS;
         { "min",	1, NULL, 0 },
         { "max",	1, NULL, 0 },
         { "highlight",	0, NULL, 'l' },
+        { "format",	1, NULL, 'f' },
         { 0,  0, 0, 0 }
       };
 
-      c = getopt_long (argc, argv, "hVb:p:t:g:c:nl", long_options, &option_index);
+      c = getopt_long (argc, argv, "hVb:p:t:g:c:nlf:", long_options, &option_index);
 
       if (c == -1) break;	/* Exit from `while (1)' loop.  */
 
             goto failure;
         
           break;
+        case 'f':	/* Set the output format string. Format specifiers are %x, %y, %w, %h, %i, %g, and %c..  */
+        
+        
+          if (update_arg( (void *)&(args_info->format_arg), 
+               &(args_info->format_orig), &(args_info->format_given),
+              &(local_args_info.format_given), optarg, 0, "X=%x\nY=%y\nW=%w\nH=%h\nG=%g\nID=%i\nCancel=%c\n", ARG_STRING,
+              check_ambiguity, override, 0, 0,
+              "format", 'f',
+              additional_error))
+            goto failure;
+        
+          break;
 
         case 0:	/* Long option with no short option */
           /* Sets the x display..  */

cmdline.h

 
 #ifndef CMDLINE_PARSER_VERSION
 /** @brief the program version */
-#define CMDLINE_PARSER_VERSION "v3.1.5"
+#define CMDLINE_PARSER_VERSION "v3.1.7"
 #endif
 
 /** @brief Where the command line options are stored */
   const char *max_help; /**< @brief Set the maximum output of width or height values. Setting min and max to the same value disables drag selections. help description.  */
   int highlight_flag;	/**< @brief Instead of outlining selections, slop highlights it. This is only useful when --color is set to a transparent color. (default=off).  */
   const char *highlight_help; /**< @brief Instead of outlining selections, slop highlights it. This is only useful when --color is set to a transparent color. help description.  */
+  char * format_arg;	/**< @brief Set the output format string. Format specifiers are %x, %y, %w, %h, %i, %g, and %c. (default='REPLACEME').  */
+  char * format_orig;	/**< @brief Set the output format string. Format specifiers are %x, %y, %w, %h, %i, %g, and %c. original value given at command line.  */
+  const char *format_help; /**< @brief Set the output format string. Format specifiers are %x, %y, %w, %h, %i, %g, and %c. help description.  */
   
   unsigned int help_given ;	/**< @brief Whether help was given.  */
   unsigned int version_given ;	/**< @brief Whether version was given.  */
   unsigned int min_given ;	/**< @brief Whether min was given.  */
   unsigned int max_given ;	/**< @brief Whether max was given.  */
   unsigned int highlight_given ;	/**< @brief Whether highlight was given.  */
+  unsigned int format_given ;	/**< @brief Whether format was given.  */
 
 } ;
 

gengetopt.sh

+#!/bin/bash
+# This is used because a bug in gengetopt keeps you from putting \n in default string options. All it does is replace REPLACEME with the correct code to make the application work properly.
+gengetopt < options.ggo
+sed -i '0,/REPLACEME/{s/REPLACEME/X=%x\\\\nY=%y\\\\nW=%w\\\\nH=%h\\\\nG=%g\\\\nID=%i\\\\nCancel=%c\\\\n/}' cmdline.c
+sed -i 's/REPLACEME/X=%x\\nY=%y\\nW=%w\\nH=%h\\nG=%g\\nID=%i\\nCancel=%c\\n/' cmdline.c

main.cpp

  */
 #include <unistd.h>
 #include <cstdio>
+#include <sstream>
 #include "x.hpp"
 #include "rectangle.hpp"
 #include "cmdline.h"
 
-void printSelection( bool cancelled, int x, int y, int w, int h, int window ) {
-    printf( "X=%i\n", x );
-    printf( "Y=%i\n", y );
-    printf( "W=%i\n", w );
-    printf( "H=%i\n", h );
-    printf( "G=%ix%i", w, h );
-    if ( x >= 0 ) {
-        printf( "+%i", x );
-    } else {
-        // Negative is already included
-        printf( "%i", x );
-    }
-    if ( y >= 0 ) {
-        printf( "+%i", y );
-    } else {
-        // Negative is already included
-        printf( "%i", y );
+int printSelection( std::string format, bool cancelled, int x, int y, int w, int h, int window ) {
+    size_t pos = 0;
+    while ( ( pos = format.find( "%", pos ) ) != std::string::npos ) {
+        if ( pos + 1 > format.size() ) {
+            fprintf( stderr, "Format error: %% found at the end of format string.\n", format[ pos + 1 ] );
+            return 1;
+        }
+        std::stringstream foo;
+        switch( format[ pos + 1 ] ) {
+            case '%':
+                format.replace( pos, 2, "%" );
+                pos += 1;
+                break;
+            case 'x':
+            case 'X':
+                foo << x;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'y':
+            case 'Y':
+                foo << y;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'w':
+            case 'W':
+                foo << w;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'h':
+            case 'H':
+                foo << h;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'g':
+            case 'G':
+                foo << w << 'x' << h << '+' << x << '+' << y;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'i':
+            case 'I':
+                foo << window;
+                format.replace( pos, 2, foo.str() );
+                break;
+            case 'c':
+            case 'C':
+                format.replace( pos, 2, cancelled ? "true" : "false" );
+                break;
+            default:
+                fprintf( stderr, "Format error: %%%c is an unknown replacement identifier.\n", format[ pos + 1 ] );
+                fprintf( stderr, "Valid replacements: %%x, %%y, %%w, %%h, %%i, %%c, %%.\n" );
+                return 1;
+                break;
+        }
     }
-    printf( "\n" );
-    printf( "ID=%i\n", window );
-    if ( cancelled ) {
-        printf( "Cancel=true\n" );
-    } else {
-        printf( "Cancel=false\n" );
+    pos = 0;
+    while ( ( pos = format.find( "\\", pos ) ) != std::string::npos ) {
+        if ( pos + 1 > format.size() ) {
+            break;
+        }
+        if ( format[ pos + 1 ] == 'n' ) {
+            format.replace( pos, 2, "\n" );
+        }
+        pos = pos + 1;
     }
+    printf( "%s", format.c_str() );
+    return 0;
 }
 
 int parseColor( std::string arg, float* r, float* g, float* b, float* a ) {
     int hmem = 0;
     int minimumsize = options.min_arg;
     int maximumsize = options.max_arg;
+    std::string format = options.format_arg;
     cmdline_parser_free( &options );
 
     // First we set up the x interface and grab the mouse,
     // if we fail for either we exit immediately.
     err = xengine->init( xdisplay.c_str() );
     if ( err ) {
-        printSelection( true, 0, 0, 0, 0, None );
+        printSelection( format, true, 0, 0, 0, 0, None );
         return err;
     }
     err = xengine->grabCursor( slop::Cross );
     if ( err ) {
-        printSelection( true, 0, 0, 0, 0, None );
+        printSelection( format, true, 0, 0, 0, 0, None );
         return err;
     }
     if ( keyboard ) {
         double starti = double( start.tv_sec*1000000000L + start.tv_nsec )/1000000000.f;
         if ( timei - starti > gracetime ) {
             if ( ( xengine->anyKeyPressed() && keyboard ) || xengine->mouseDown( 3 ) ) {
-                printSelection( true, 0, 0, 0, 0, None );
+                printSelection( format, true, 0, 0, 0, 0, None );
                 fprintf( stderr, "User pressed key. Canceled selection.\n" );
                 state = -1;
                 running = false;
                 // Delete the rectangle, which will remove it from the screen.
                 delete selection;
                 // Print the selection :)
-                printSelection( false, x, y, w, h, window );
+                printSelection( format, false, x, y, w, h, window );
                 break;
             }
         }

options.ggo

 package "slop"
-version "v3.1.5"
+version "v3.1.7"
 usage "slop [options]"
 description "slop (Select Operation) is an application that queries for a selection from the user and prints the region to stdout."
 versiontext "Copyright (C) 2014 Dalton Nell, Slop Contributors (https://github.com/naelstrof/slop/graphs/contributors)"
     flag
     off
 
+option "format" f "Set the output format string. Format specifiers are %x, %y, %w, %h, %i, %g, and %c."
+    string
+    default="REPLACEME"
+    optional
+
 text "\nExamples\n"
 text "    $ # Gray, thick, transparent border for maximum visiblity.\n"
 text "    $ slop -b 20 -c 0.5,0.5,0.5,0.8\n"
 text "\n"
 text "    $ # Classic Windows XP selection.\n"
 text "    $ slop -l -c 0.3,0.4,0.6,0.4\n"
+text "\n"
+text "    $ # Change output format to use safer parsing\n"
+text "    $ slopoutput=$(slop -f \"%x %y %w %h\")\n"
+text "    $ X=$(echo $slopoutput | awk '{print $1}')\n"
+text "    $ Y=$(echo $slopoutput | awk '{print $2}')\n"
+text "    $ W=$(echo $slopoutput | awk '{print $3}')\n"
+text "    $ H=$(echo $slopoutput | awk '{print $4}')\n"