create/src/Mod/Draft/draftobjects/base.py

# ***************************************************************************
# *   Copyright (c) 2009, 2010 Yorik van Havre <yorik@uncreated.net>        *
# *   Copyright (c) 2009, 2010 Ken Cline <cline@frii.com>                   *
# *   Copyright (c) 2019 Eliud Cabrera Castillo <e.cabrera-castillo@tum.de> *
# *                                                                         *
# *   This program is free software; you can redistribute it and/or modify  *
# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
# *   as published by the Free Software Foundation; either version 2 of     *
# *   the License, or (at your option) any later version.                   *
# *   for detail see the LICENCE text file.                                 *
# *                                                                         *
# *   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 Library General Public License for more details.                  *
# *                                                                         *
# *   You should have received a copy of the GNU Library General Public     *
# *   License along with this program; if not, write to the Free Software   *
# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
# *   USA                                                                   *
# *                                                                         *
# ***************************************************************************
"""This module provides the object code for the basic Draft object.
"""
## @package base
# \ingroup DRAFT
# \brief This module provides the object code for the basic Draft object.

class DraftObject(object):
    """The base class for Draft objects.

    Parameters
    ----------
    obj : a base C++ object
        The base object instantiated during creation,
        which commonly may be of types `Part::Part2DObjectPython`,
        `Part::FeaturePython`, or `App::FeaturePython`.

            >>> obj = App.ActiveDocument.addObject('Part::Part2DObjectPython')
            >>> DraftObject(obj)

        This class instance is stored in the `Proxy` attribute
        of the base object.
        ::
            obj.Proxy = self

    tp : str, optional
        It defaults to `'Unknown'`.
        It indicates the type of this scripted object,
        which will be assigned to the Proxy's `Type` attribute.

        This is useful to distinguish different types of scripted objects
        that may be derived from the same C++ class.

    Attributes
    ----------
    Type : str
        It indicates the type of scripted object.
        Normally `Type = tp`.

        All objects have a `TypeId` attribute, but this attribute
        refers to the C++ class only. Using the `Type` attribute
        allows distinguishing among various types of objects
        derived from the same C++ class.

            >>> print(A.TypeId, "->", A.Proxy.Type)
            Part::Part2DObjectPython -> Wire
            >>> print(B.TypeId, "->", B.Proxy.Type)
            Part::Part2DObjectPython -> Circle

    This class attribute is accessible through the `Proxy` object:
    `obj.Proxy.Type`.
    """
    def __init__(self, obj, tp="Unknown"):
        # This class is assigned to the Proxy attribute
        if obj:
            obj.Proxy = self
        self.Type = tp

    def __getstate__(self):
        """Return a tuple of all serializable objects or None.

        When saving the document this object gets stored
        using Python's `json` module.

        Override this method to define the serializable objects to return.

        By default it returns the `Type` attribute.

        Returns
        -------
        str
            Returns the value of `Type`
        """
        return self.Type

    def __setstate__(self, state):
        """Set some internal properties for all restored objects.

        When a document is restored this method is used to set some properties
        for the objects stored with `json`.

        Override this method to define the properties to change for the
        restored serialized objects.

        By default the `Type` was serialized, so `state` holds this value,
        which is re-assigned to the `Type` attribute.
        ::
            self.Type = state

        Parameters
        ---------
        state : state
            A serialized object.
        """
        if state:
            self.Type = state

    def execute(self, obj):
        """This method is run when the object is created or recomputed.

        Override this method to produce effects when the object
        is newly created, and whenever the document is recomputed.

        By default it does nothing.

        Parameters
        ----------
        obj : the scripted object.
            This commonly may be of types `Part::Part2DObjectPython`,
            `Part::FeaturePython`, or `App::FeaturePython`.
        """
        pass

    def onChanged(self, obj, prop):
        """This method is run when a property is changed.

        Override this method to handle the behavior
        of the object depending on changes that occur to its properties.

        By default it does nothing.

        Parameters
        ----------
        obj : the scripted object.
            This commonly may be of types `Part::Part2DObjectPython`,
            `Part::FeaturePython`, or `App::FeaturePython`.

        prop : str
            Name of the property that was modified.
        """
        pass


_DraftObject = DraftObject