X-Git-Url: https://git.ralfj.de/lilass.git/blobdiff_plain/27f354daddc74c3859fdaee2bfab43f3282522b8..a2545a3dcb3a2ff732b2427d4da5e08d7605455a:/gui.py

diff --git a/gui.py b/gui.py
index 0f83c23..c069761 100644
--- a/gui.py
+++ b/gui.py
@@ -18,22 +18,92 @@
 # 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:
-	from PyQt4 import QtGui
-	from qt_dialogue import PositionSelection
-	app = QtGui.QApplication(sys.argv)
-except Exception, e:
-	from zenity_dialogue import run as zenity_run
-	qt_available = False
+'''
+This module implements two functions:
 
 def error(message):
-	'''Displays a fatal error to the user'''
-	QtGui.QMessageBox.critical(None, 'Fatal error', message)
+	This function displays the error message to the user in some appropriate fassion
 
 def setup(internalResolutions, externalResolutions):
-	'''Returns a ScreenSetup instance, or None if the user canceled'''
-	if qt_available:
+	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.
+'''
+import subprocess, collections
+
+# Qt frontend
+class QtFrontend:
+	def __init__(self):
+		from PyQt4 import QtGui
+		self.app = QtGui.QApplication(sys.argv)
+		print("Qt loaded")
+	
+	def error(self, message):
+		from PyQt4 import QtGui
+		QtGui.QMessageBox.critical(None, 'Fatal error', message)
+	
+	def setup(self, internalResolutions, externalResolutions):
+		from qt_dialogue import PositionSelection
 		return PositionSelection(internalResolutions, externalResolutions).run()
-	else:
-		return zenity_run(internalResolutions, externalResolutions)
+	
+	@staticmethod
+	def isAvailable():
+		try:
+			import PyQt4
+			return True
+		except ImportError:
+			return False
+
+
+# Zenity frontend
+class ZenityFrontend:
+	def error(message):
+		'''Displays a fatal error to the user'''
+		subprocess.check_call(["zenity", "--error", "--text="+message])
+	
+	def setup(self, internalResolutions, externalResolutions):
+		from zenity_dialogue import run
+		run(internalResolutions, externalResolutions)
+	
+	@staticmethod
+	def isAvailable():
+		try:
+			from dsl import processOutputIt
+			processOutputIt("zenity", "--version")
+			return True
+		except Exception:
+			return False
+
+
+# CLI frontend
+class CLIFrontend:
+	def error(self, message):
+		print(message, file=sys.stderr)
+	
+	def setup(self, internalResolutions, externalResolutions):
+		raise Exception("Choosing the setup interactively is not supported with the CLI frontend")
+	
+	@staticmethod
+	def isAvailable():
+		return True
+
+# list of available frontends
+frontends = collections.OrderedDict()
+frontends["qt"] = QtFrontend
+frontends["zenity"] = ZenityFrontend
+frontends["cli"] = CLIFrontend
+
+# get a frontend
+def getFrontend(name = None):
+	# by name
+	if name is not None:
+		if name in frontends:
+			if frontends[name].isAvailable():
+				return frontends[name]() # call constructor
+		# frontend not found or not available
+		raise Exception("Frontend %s not found or not available" % name)
+	# auto-detect
+	for frontend in frontends.values():
+		if frontend.isAvailable():
+			return frontend() # call constructor
+	raise Exception("No frontend is available - this should not happen")