X-Git-Url: https://git.ralfj.de/lilass.git/blobdiff_plain/f9da06538394990906d6148d7cbc2dad7a7967c7..a9394222c323143c0fea03848a3f1daf79017a00:/gui.py

diff --git a/gui.py b/gui.py
index 83099e8..6dabe0f 100644
--- 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'