don't hard-code the path to the python interpreter

[lilass.git] / gui.py

diff --git a/gui.py b/gui.py
index 0ae8958061e78536a02bd43c8532802108ce2a61..998783f65c68f4c7372af00771768607f035bdb3 100644 (file)
--- a/gui.py
+++ b/gui.py
@@ -1,5 +1,5 @@
 # DSL - easy Display Setup for Laptops
-# Copyright (C) 2012 Ralf Jung <post@ralfj.de>
+# Copyright (C) 2012-2015 Ralf Jung <post@ralfj.de>
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -12,19 +12,98 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program (gpl.txt); if not, write to the Free Software
+# along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 
 # This file abstracts GUI stuff away, so that the actual dsl.py does not have to deal with it
 import sys
-from PyQt4 import QtGui
-from qt_dialogue import PositionSelection
-app = QtGui.QApplication(sys.argv)
+
+'''
+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'''
-       return PositionSelection(internalResolutions, externalResolutions).run()
+    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, situation):
+        from qt_dialogue import PositionSelection
+        return PositionSelection(situation).run()
+    
+    @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, situation):
+        from zenity_dialogue import run
+        return run(situation.internalResolutions(), situation.externalResolutions())
+    
+    @staticmethod
+    def isAvailable():
+        try:
+            from screen 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, commonRes):
+        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")