fix xdisplay bug for the case where DISPLAY is not set + xdisplay demo

Signed-off-by: Mattias Andrée <maandree@operamail.com>

2 files changed, 55 insertions, 8 deletions

diff --git a/examples/plugins/xdisplay b/examples/plugins/xdisplay
new file mode 100644
index 0000000..4c90d90
--- /dev/null
+++ b/examples/plugins/xdisplay
@@ -0,0 +1,38 @@
+# -*- python -*-
+
+# A xpybar configuration example testing the features of plugins.xdisplay
+
+import time
+import threading
+
+from plugins.xdisplay import XDisplay
+from plugins.clock import Clock
+
+
+OUTPUT, HEIGHT, YPOS, TOP = 0, 12, 24, True
+
+
+clock = Clock(sync_to = 30 * Clock.MINUTES)
+
+start_ = start
+def start():
+    start_()
+    async(lambda : clock.continuous_sync(lambda : bar.invalidate()))
+
+
+def redraw():
+    x = XDisplay()
+    
+    text = 'No DISPLAY environment variable set'
+    if x.connection is not None:
+        text = 'Connection: %s │ %s │ Display: %i │ %s'
+        text %= (x.connection,
+                 'Default host' if x.host is None else ('Host: %s' % x.host),
+                 x.display,
+                 'Default screen' if x.screen is None else ('Screen: %i' % x.screen))
+    
+    text += ' │ VT: %i' % x.vt
+    
+    bar.clear()
+    bar.draw_coloured_text(0, 10, 0, 2, text)
+
diff --git a/src/plugins/xdisplay.py b/src/plugins/xdisplay.py
index cba245a..907b6bf 100644
--- a/src/plugins/xdisplay.py
+++ b/src/plugins/xdisplay.py
@@ -26,13 +26,17 @@ from x import *
 
 class XDisplay:
     '''
-    Retrieve information about the used X display
+    Retrieve information about the used X display as specified by the DISPLAY environment variable
     
     @variable  connection:str?  The full X display information, `None` if X is not running
     @variable  host:str?        The host, often `None` one local conncetions and "localhost" on remote oonnection
-    @variable  display:int      The display number
-    @variable  screen:int?      The screen number, often `None`
+    @variable  display:int?     The display number
+    @variable  screen:int?      The screen number, often `None` (default screen)
     @varaible  vt:int           The VT the X display is allocated to
+    
+    host, dispay and screen is None if connectiopn is None, which means that you
+    have started xpybar's DISPLAY environment variable is not set, and that a display
+    was configured in the settings.
     '''
     
     
@@ -41,12 +45,17 @@ class XDisplay:
         Constructor
         '''
         self.connection = os.environ['DISPLAY'] if 'DISPLAY' in os.environ else None
-        self.host = self.connection.split(':')[0]
-        if self.host == '':
+        if self.connection is None:
             self.host = None
-        self.display, self.screen = (self.connection.split(':')[1] + '.').split('.')[:2]
-        self.display = int(self.display)
-        self.screen = None if self.screen == '' else int(self.screen)
+            self.display = None
+            self.screen = None
+        else:
+            self.host = self.connection.split(':')[0]
+            if self.host == '':
+                self.host = None
+            self.display, self.screen = (self.connection.split(':')[1] + '.').split('.')[:2]
+            self.display = int(self.display)
+            self.screen = None if self.screen == '' else int(self.screen)
         r = get_screen().root
         d = get_display()
         self.vt = r.get_full_property(d.get_atom('XFree86_VT'), Xlib.Xatom.INTEGER).value[0]