updated zenity frontend, added cli frontend

[lilass.git] / gui.py

diff --git a/gui.py b/gui.py
index 0f83c2396d28967d539af1d916493f3f9bf97014..d586442711a4a27cf45fb331b78cdeacf0a104a4 100644 (file)
--- a/gui.py
+++ b/gui.py
@@ -1,5 +1,5 @@
 # DSL - easy Display Setup for Laptops
 # 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
 #
 # 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


@@ -18,22 +18,121 @@
 # This file abstracts GUI stuff away, so that the actual dsl.py does not have to deal with it
 import sys
 
 # 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):
 
 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):
 
 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)
+    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
+
+from question_frontend import QuestionFrontend
+from screen import processOutputIt
+
+# 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(QuestionFrontend):
+    def error(self, message):
+        '''Displays a fatal error to the user'''
+        subprocess.check_call(["zenity", "--error", "--text="+message])
+    def userChoose (self, title, choices, returns, fallback):
+        assert len(choices) == len(returns)
+        args = ["zenity", "--list", "--text="+title, "--column="]+choices
+        switch = dict (list(zip (choices,returns)))
+        try:
+            for line in processOutputIt(*args):
+                return switch.get(line.strip(), fallback)
+        except Exception:
+            # on user cancel, the return code of zenity is nonzero
+            return fallback
+        # if the output was empty
+        return fallback
+    def isAvailable():
+        try:
+            processOutputIt("zenity", "--version")
+            return True
+        except FileNotFoundError:
+            return False
+        except PermissionError:
+            return False
+
+# CLI frontend
+class CLIFrontend(QuestionFrontend):
+    def error(self, message):
+        print(message, file=sys.stderr)
+
+    def userChoose (self, title, choices, returns, fallback):
+        while True:
+            # print question
+            print(title)
+            for i in range(len(choices)):
+                print("%d. %s"%(i,choices[i]))
+            print("Enter 'c' to cancel.")
+            # handle input
+            answer = input("> ")
+            if answer == "c":
+                return None
+            #else
+            try:
+                answerint = int(answer)
+                if answerint >= 0 and answerint < len(choices):
+                    return returns[answerint]
+            except ValueError:
+                pass
+            # if we are here something invalid was entered
+            print("INVALID ANSWER: '%s'" % answer)
+
+    @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
+            else:
+                raise Exception("Frontend %s not available" % name)
+        # frontend not found
+        raise Exception("Frontend %s not found" % 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")