settings.py

   1 ##
   2 ## This file is part of the sigrok-meter project.
   3 ##
   4 ## Copyright (C) 2015 Jens Steinhauser <jens.steinhauser@gmail.com>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, write to the Free Software
  18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19 ##
  20
  21 import qtcompat
  22
  23 QtCore = qtcompat.QtCore
  24 QtGui = qtcompat.QtGui
  25
  26 class Setting(QtCore.QObject):
  27     '''Wrapper class around the raw 'QSettings' class that emits signals
  28     when the value of the setting changes.'''
  29
  30     '''Signal emitted when the setting has changed.'''
  31     changed = QtCore.Signal(object)
  32
  33     def __init__(self, key, default=None, conv=None):
  34         '''Initializes the Settings object.
  35
  36         :param key: The key of the used 'QSettings' object.
  37         :param default: Value returned if the setting doesn't already exist.
  38         :param conv: Function used to convert the setting to the correct type.
  39         '''
  40
  41         super(self.__class__, self).__init__()
  42
  43         self._key = key
  44         self._default = default
  45         self._conv = conv
  46         self._value = None
  47
  48     def value(self):
  49         s = QtCore.QSettings()
  50         v = s.value(self._key, self._default)
  51         self._value = self._conv(v) if self._conv else v
  52         return self._value
  53
  54     @QtCore.Slot(object)
  55     def setValue(self, value):
  56         if value != self._value:
  57             s = QtCore.QSettings()
  58             s.setValue(self._key, value)
  59             s.sync()
  60             self._value = value
  61             self.changed.emit(self._value)
  62
  63 class _SettingsGroup(object):
  64     '''Dummy class to group multiple 'Setting' objects together.'''
  65     pass
  66
  67 def init():
  68     '''Creates the 'Settings' objects for all known settings and places them
  69     into the module's namespace.
  70
  71     A QApplication must have been created before this function can be called.
  72     '''
  73
  74     app = QtGui.QApplication.instance()
  75     app.setApplicationName('sigrok-meter')
  76     app.setOrganizationName('sigrok')
  77     app.setOrganizationDomain('sigrok.org')
  78
  79     mainwindow = _SettingsGroup()
  80     mainwindow.size = Setting('mainwindow/size', QtCore.QSize(900, 550))
  81     mainwindow.pos  = Setting('mainwindow/pos')
  82     globals()['mainwindow'] = mainwindow
  83
  84     graph = _SettingsGroup()
  85     graph.backlog = Setting('graph/backlog', 30, conv=int)
  86     globals()['graph'] = graph