Save and restore settings.

[sigrok-meter.git] / settings.py

diff --git a/settings.py b/settings.py
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+##
+## This file is part of the sigrok-meter project.
+##
+## Copyright (C) 2015 Jens Steinhauser <jens.steinhauser@gmail.com>
+##
+## 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
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+##
+
+import qtcompat
+
+QtCore = qtcompat.QtCore
+QtGui = qtcompat.QtGui
+
+class Setting(QtCore.QObject):
+    '''Wrapper class around the raw 'QSettings' class that emits signals
+    when the value of the setting changes.'''
+
+    '''Signal emitted when the setting has changed.'''
+    changed = QtCore.Signal(object)
+
+    def __init__(self, key, default=None):
+        super(self.__class__, self).__init__()
+
+        self._key = key
+        self._default = default
+        self._value = None
+
+    def value(self):
+        s = QtCore.QSettings()
+        self._value = s.value(self._key, self._default)
+        return self._value
+
+    @QtCore.Slot(object)
+    def setValue(self, value):
+        if value != self._value:
+            s = QtCore.QSettings()
+            s.setValue(self._key, value)
+            s.sync()
+            self._value = value
+            self.changed.emit(self._value)
+
+class _SettingsGroup(object):
+    '''Dummy class to group multiple 'Setting' objects together.'''
+    pass
+
+def init():
+    '''Creates the 'Settings' objects for all known settings and places them
+    into the module's namespace.
+
+    A QApplication must have been created before this function can be called.
+    '''
+
+    app = QtGui.QApplication.instance()
+    app.setApplicationName('sigrok-meter')
+    app.setOrganizationName('sigrok')
+    app.setOrganizationDomain('sigrok.org')
+
+    mainwindow = _SettingsGroup()
+    mainwindow.size = Setting('mainwindow/size', QtCore.QSize(900, 550))
+    mainwindow.pos  = Setting('mainwindow/pos')
+    globals()['mainwindow'] = mainwindow