openlp/openlp/core/display/screens.py

# -*- coding: utf-8 -*-
# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4

###############################################################################
# OpenLP - Open Source Lyrics Projection                                      #
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# Copyright (c) 2008-2017 OpenLP Developers                                   #
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# 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; version 2 of the License.                              #
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# 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.                                                               #
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# You should have received a copy of the GNU General Public License along     #
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"""
The :mod:`screen` module provides management functionality for a machines'
displays.
"""
import json
import logging

from PyQt5 import QtCore

from openlp.core.common.registry import Registry
from openlp.core.common.settings import Settings
from openlp.core.common.i18n import translate

log = logging.getLogger(__name__)


class Screen(object):
    """
    A Python representation of a screen
    """
    def __init__(self, number=None, geometry=None, is_primary=False, is_display=False):
        """
        Set up the screen object

        :param int number: The Qt number of this screen
        :param QRect geometry: The geometry of this screen as a QRect object
        :param bool is_primary: Whether or not this screen is the primary screen
        :param bool is_display: Whether or not this screen should be used to display lyrics
        """
        self.number = number
        self.geometry = geometry
        self.display_geometry = geometry
        self.is_primary = is_primary
        self.is_display = is_display

    def __str__(self):
        """
        Return a string for displaying this screen

        :return str: A nicely formatted string
        """
        name = '{screen} {number:d}'.format(screen=translate('OpenLP.ScreenList', 'Screen'), number=self.number + 1)
        if self.is_primary:
            name = '{name} ({primary})'.format(name=name, primary=translate('OpenLP.ScreenList', 'primary'))
        return name


class ScreenList(object):
    """
    Wrapper to handle the parameters of the display screen.

    To get access to the screen list call ``ScreenList()``.
    """
    log.info('Screen loaded')
    __instance__ = None

    def __new__(cls):
        """
        Re-implement __new__ to create a true singleton.
        """
        if not cls.__instance__:
            cls.__instance__ = object.__new__(cls)
        return cls.__instance__

    def __iter__(self):
        """
        Convert this object into an iterable, so that we can iterate over it instead of the inner list
        """
        for screen in self.screens:
            yield screen

    @classmethod
    def create(cls, desktop):
        """
        Initialise the screen list.

        :param desktop:  A QDesktopWidget object.
        """
        screen_list = cls()
        screen_list.desktop = desktop
        screen_list.screens = []
        screen_list.screen_count_changed()
        screen_list.load_screen_settings()
        screen_list.desktop.resized.connect(screen_list.on_screen_resolution_changed)
        screen_list.desktop.screenCountChanged.connect(screen_list.on_screen_count_changed)
        screen_list.desktop.primaryScreenChanged.connect(screen_list.on_primary_screen_changed)
        return screen_list

    def on_screen_resolution_changed(self, number):
        """
        Called when the resolution of a screen has changed.

        ``number``
            The number of the screen, which size has changed.
        """
        log.info('screen_resolution_changed {number:d}'.format(number=number))
        for screen in self.screens:
            if number == screen.number:
                screen.geometry = self.desktop.screenGeometry(number)
                screen.is_primary = self.desktop.primaryScreen() == number
                Registry().execute('config_screen_changed')
                break

    def on_screen_count_changed(self, changed_screen=None):
        """
        Called when a screen has been added or removed.

        ``changed_screen``
            The screen's number which has been (un)plugged.
        """
        # Do not log at start up.
        screen_count = self.desktop.screenCount()
        if changed_screen is not None:
            log.info('screen_count_changed {count:d}'.format(count=screen_count))
        # Remove unplugged screens.
        del self.screens[screen_count - 1:]
        # Add new screens.
        for number in range(self.desktop.screenCount()):
            if not self.has_screen(number):
                self.screens.append(Screen(number, self.desktop.getGeometry(number),
                                           self.desktop.primaryScreen() == number))
        # We do not want to send this message at start up.
        if changed_screen is not None:
            # Reload setting tabs to apply possible changes.
            Registry().execute('config_screen_changed')

    def on_primary_screen_changed(self):
        """
        The primary screen has changed, let's sort it out and then notify everyone
        """
        for screen in self.screens:
            screen.is_primary = self.desktop.primaryScreen() == screen.number
        Registry().execute('config_screen_changed')

    def get_display_screen_list(self):
        """
        Returns a list with the screens. This should only be used to display available screens to the user::

            ['Screen 1 (primary)', 'Screen 2']
        """
        screen_list = []
        for screen in self.screens:
            screen_name = '{name} {number:d}'.format(name=translate('OpenLP.ScreenList', 'Screen'),
                                                     number=screen.number + 1)
            if screen.is_primary:
                screen_name = '{name} ({primary})'.format(name=screen_name,
                                                          primary=translate('OpenLP.ScreenList', 'primary'))
            screen_list.append(screen_name)
        return screen_list

    def has_screen(self, number):
        """
        Confirms a screen is known.

        :param number: The screen number (int).
        """
        for screen in self.screens:
            if screen.number == number:
                return True
        return False

    def get_number_for_window(self, window):
        """
        Return the screen number that the centre of the passed window is in.

        :param window: A QWidget we are finding the location of.
        """
        for screen in self.screens:
            if screen.geometry == window.geometry() or screen.display_geometry == window.geometry():
                return screen
        return None

    def load_screen_settings(self):
        """
        Loads the screen size and the monitor number from the settings.
        """
        # Add the screen settings to the settings dict. This has to be done here due to cyclic dependency.
        # Do not do this anywhere else.
        screen_settings = {
            'core/monitors': '{}'
        }
        Settings.extend_default_settings(screen_settings)
        monitors = json.loads(Settings().value('core/monitors'))
        for screen in self.screens:
            monitor = monitors.get(screen.number)
            if monitor:
                screen.display_geometry = QtCore.QRect(monitor['x'], monitor['y'], monitor['width'], monitor['height'])
                screen.is_display = True