1# ------------------------------------------------------------------------------
2# Copyright (c) 2011, Enthought, Inc.
3# All rights reserved.
4#
5# This software is provided without warranty under the terms of the BSD
6# license included in LICENSE.txt and may be redistributed only
7# under the conditions described in the aforementioned license.  The license
8# is also available online at http://www.enthought.com/licenses/BSD.txt
9# Thanks for using Enthought open source!
10#
11# Author: Evan Patterson
12# ------------------------------------------------------------------------------
13
14""" Defines a Traits UI View that allows for the customization of Qt-specific
15    widget properties.
16"""
17
18# Standard library imports.
19import logging
20
21# System library imports.
22from pyface.qt import QtGui
23
24# Enthought library imports.
25from traits.api import File, List, Str
26from traitsui.view import View
27from io import open
28
29# Logger.
30logger = logging.getLogger(__name__)
31
32
33class QtView(View):
34    """ A View that allows the specification of Qt style sheets.
35    """
36
37    #: An optional string containing a Qt style sheet.
38    style_sheet = Str()
39
40    #: An optional file path for a Qt style sheet.
41    style_sheet_path = File()
42
43    #: A list of trait names that defines the order for focus switching via
44    #: Tab/Shift+Tab. If the view contains multiple items for a specified trait
45    # name, the order is undefined.
46    tab_order = List(Str)
47
48    # -------------------------------------------------------------------------
49    #  Creates a UI user interface object:
50    # -------------------------------------------------------------------------
51
52    def ui(
53        self,
54        context,
55        parent=None,
56        kind=None,
57        view_elements=None,
58        handler=None,
59        id="",
60        scrollable=None,
61        args=None,
62    ):
63        ui = super(QtView, self).ui(
64            context, parent, kind, view_elements, handler, id, scrollable, args
65        )
66
67        if self.style_sheet:
68            ui.control.setStyleSheet(self.style_sheet)
69
70        if self.style_sheet_path:
71            try:
72                with open(self.style_sheet_path, "r", encoding="utf8") as f:
73                    ui.control.setStyleSheet(f.read())
74            except IOError:
75                logger.exception("Error loading Qt style sheet")
76
77        if len(self.tab_order) >= 2:
78            previous = self._get_editor_control(ui, self.tab_order[0])
79            for i in range(1, len(self.tab_order)):
80                current = self._get_editor_control(ui, self.tab_order[i])
81                QtGui.QWidget.setTabOrder(previous, current)
82                previous = current
83
84        return ui
85
86    # -------------------------------------------------------------------------
87    #  Private interface:
88    # -------------------------------------------------------------------------
89
90    def _get_editor_control(self, ui, name):
91        control = None
92        editors = ui.get_editors(name)
93        if editors:
94            control = editors[0].control
95        else:
96            logger.warning("No item for '%s' trait" % name)
97        return control
98