properly open and close processes

[lilass.git] / gui.py

diff --git a/gui.py b/gui.py
index 83099e884b0bbd50cef5700fd26f6da5d4902f96..6dabe0f048df2f0e47bc8dfa363a785bcc3266f2 100644 (file)
--- a/gui.py
+++ b/gui.py
@@ -18,26 +18,53 @@
 # This file abstracts GUI stuff away, so that the actual dsl.py does not have to deal with it
 import sys
 
-qt_available = True
-try:
+'''
+This module implements two functions:
+
+def error(message):
+       This function displays the error message to the user in some appropriate fassion
+
+def setup(internalResolutions, externalResolutions):
+       Both arguments are lists of (width, height) tuples of resolutions. You can use dsl.res2user to obtain a user-readable representation of a resolution tuple.
+       The user should be asked about his display setup preferences.
+       The function returns None if the user cancelled, and an instance of dsl.ScreenSetup otherwise.
+'''
+
+# frontend detectors
+def qtAvailable():
+       try:
+               import PyQt4
+               return True
+       except ImportError:
+               return False
+
+def zenityAvailable():
+       try:
+               from dsl import processOutputIt
+               processOutputIt("zenity", "--version")
+               return True
+       except Exception:
+               return False
+
+# actual frontends
+if qtAvailable():
        from PyQt4 import QtGui
        from qt_dialogue import PositionSelection
        app = QtGui.QApplication(sys.argv)
-except Exception, e:
-       import subprocess
-       from zenity_dialogue import run as zenity_run
-       qt_available = False
-
-def error(message):
-       '''Displays a fatal error to the user'''
-       if qt_available:
+       
+       def error(message):
                QtGui.QMessageBox.critical(None, 'Fatal error', message)
-       else:
+       
+       def setup(internalResolutions, externalResolutions):
+               return PositionSelection(internalResolutions, externalResolutions).run()
+
+elif zenityAvailable():
+       import subprocess
+       from zenity_dialogue import run as setup # this provides the setup function
+       
+       def error(message):
+               '''Displays a fatal error to the user'''
                subprocess.check_call(["zenity", "--error", "--text="+message])
 
-def setup(internalResolutions, externalResolutions):
-       '''Returns a ScreenSetup instance, or None if the user canceled'''
-       if qt_available:
-               return PositionSelection(internalResolutions, externalResolutions).run()
-       else:
-               return zenity_run(internalResolutions, externalResolutions)
+else:
+       print >> sys.stderr, 'No GUI frontend available, please make sure PyQt4 or Zenity is installed'