PySide6.QtCore.QFlag
====================

.. currentmodule:: PySide6.QtCore
.. py:decorator:: QFlag

    QFlag handles a variation of the Python Enum, the Flag class.

    Please do not confuse that with the Qt QFlags concept. Python does
    not use that concept, it has its own class hierarchy, instead.
    For more details, see the `Python enum documentation <https://docs.python.org/3/library/enum.html>`_.

    Example
    -------

    ::

        from enum import Flag, auto

        from PySide6.QtCore import QFlag, QObject

        class Demo(QObject):

            @QFlag
            class Color(Flag):
                RED = auto()
                BLUE = auto()
                GREEN = auto()
                WHITE = RED | BLUE | GREEN


    Details about Qt Flags:
    -----------------------

    There are some small differences between Qt flags and Python flags.
    In Qt, we have for instance these declarations:

    ::

        enum    QtGui::RenderHint { Antialiasing, TextAntialiasing, SmoothPixmapTransform,
                                    HighQualityAntialiasing, NonCosmeticDefaultPen }
        flags   QtGui::RenderHints

    The equivalent Python notation would look like this:

    ::

        @QFlag
        class RenderHints(enum.Flag)
            Antialiasing = auto()
            TextAntialiasing = auto()
            SmoothPixmapTransform = auto()
            HighQualityAntialiasing = auto()
            NonCosmeticDefaultPen = auto()


    As another example, the Qt::AlignmentFlag flag has 'AlignmentFlag' as the enum
    name, but 'Alignment' as the type name. Non flag enums have the same type and
    enum names.

    ::

        enum Qt::AlignmentFlag
        flags Qt::Alignment

    The Python way to specify this would be

    ::

        @QFlag
        class Alignment(enum.Flag):
            ...

    See :deco:`QEnum` for registering Python Enum derived classes.

    Meanwhile all enums and flags have been converted to Python Enums
    (default since ``PySide 6.4``), see the :ref:`NewEnumSystem` section.
