Command Classes¶

Motivation

Encapsulate action users can perform when interacting with FreeCAD’s UI.

Command Classes are executed when users perform various actions in the workbench such as clicking a button in a toolbar or selecting an option in a menu.

OSE Workbench Command Classes are an opinionated extension to FreeCAD Command Classes with the following observed conventions:

Names sound like actions, typically begin with verbs, and always end with a “command” suffix
- For example, a command class to add a frame to the document might be named AddFrameCommand
- The command should be located in a module named after the command (e.g. add_frame_command.py)
Have a static NAME string constant
- Typically the same name as the command (e.g. 'AddFrameCommand')

Important

NAME must be unique for all commands within the scope of the workbench

Located and exposed by the command sub-package of the workbench package.

freecad/ose3dprinter/command
├── _add_frame/
│   ├── add_frame_command.py
│   └── __init__.py
└── __init__.py

Within _add_frame/__init__.py:

from .add_frame_command import AddFrameCommand

__all__ = ['AddFrameCommand']

Within freecad/ose3dprinter/command/__init__.py:

"""Commands users can perform in FreeCAD's GUI."""
from ._add_frame import AddFrameCommand

__all__ = ['AddFrameCommand',]

The following is a complete example taken from the ose-3d-printer-workbench:

import FreeCAD as App

from freecad.ose3dprinter.icon import get_icon_path
from freecad.ose3dprinter.part_feature import create_frame


class AddFrameCommand:
    """
    Command to add Frame object.
    """

    NAME = 'AddFrame'

    def Activated(self):
        document = App.ActiveDocument
        if not document:
            document = App.newDocument()
        create_frame(document, 'Frame')
        document.recompute()

    def IsActive(self):
        return True

    def GetResources(self):
        return {
            'Pixmap': get_icon_path('Frame.svg'),
            'MenuText': 'Add Frame',
            'ToolTip': 'Add Frame'
        }

For additional information, see Command on the FreeCAD Wiki.