Writing Orange Add-ons

We officially supported add-ons in Orange 2.6. You should start by checking the list of available add-ons. We pull those automatically from the PyPi, which is our preferred distribution channel. Try to install an add-on by either:

  • writing “pip install <add-on name>” in the terminal or
  • from the Orange Canvas GUI. Select “Options / Add-ons…” in the menu.

Everything should just work. Writing add-ons is as easy as writing your own Orange Widgets or Orange Scripts. Just follow this tutorial and you will have your brand-new Orange add-on on PyPi in no time (an hour at most).

Orange Add Ons

Orange 2.6

A new version of Orange, 2.6, has been uploaded to Python Package Index. Since the version on the Orange website is always up to date (we post daily builds), this may not affect you. Nevertheless, let us explain what we were working on for the last year.

The most important improvement to Orange is an implementation of add-on framework that is much more “standard pythonic”. As a consequence, the add-on installation procedure has been simplified for both individual users and system administrators. For developers, the new framework eases the development and distribution of add-ons. This enabled us to make first steps towards the goal of removing the rarely used parts of Orange from the core distribution, which will ultimately result in less external dependencies and less warnings on module import. Orange 2.6 lacks the modules for network analysis (Orange.network) and prediction reliability assesment (Orange.reliability), but fear not: you can get them back by installing the Orange-Network and Orange-Reliability add-ons.

Apart from that, we have been mostly squashing bugs. A fun spare time activity – you can join us anytime by cloning our repository and sending us a pull request. 🙂

If our version numbering system confuses you, let us try to explain. For the last (couple of) year(s), our version numbers have been a mess. Orange2.5a4 was uploaded to pypi almost a year ago, and was followed by a 2.6a2 release that was never available outisde our repository/daily builds. From this day forth, our versioning system should be as follows.

  • If you install orange from pypi, the version (Orange.version.full_version) will be something like 2.6 or 2.6.1.
  • If you use our daily builds or build orange yourself from the source available in our repository, your version will be 2.6.1.dev-8804fbc. (minor will be larger by one and .dev- suffix will show the source control revision that was used for the build)

The easy way to install add-ons

The possibility of extending functionality of Orange through add-ons has been present for a long time. In fact, we never provided the toolbox for crunching bioinformatical data as an integral part of Orange; it has always been an add-on. The exact mechanism of distribution of add-ons has changed significantly in the last year to simplify the process for add-on authors and to make it more standards-compliant. Among other things, this enables system administrators to install add-ons system-wide directly from PyPi using easy_install or pip. Unfortunately there were also negative side effects of this process, notably the temporary breakage of the add-on management dialog within the Orange Canvas.

We are happy to report that this is now being taken care of and you are encouraged to test the functionality.

Screenshot of the Add-on Management Dialog

Select “Add-ons…” in the Options menu. A dialog will open that will list and describe existing add-ons. You can see the same list on the appropriate part of Orange website, but there is more. In the dialog, you can simply pick the add-ons you wish to use, confirm the selection and you should be good to go: widgets that come with the selected add-ons will become available immediately.

In case you change your mind, on some systems you can also uninstall add-ons by removing the check marks in front of them. This only works if you have pip installed, which is uncommon on Windows systems.

This might be a good time to warn you that the described functionality is new and not thoroughly tested on all the platforms on which Orange runs. If you stumble upon any strange or unwanted behavior, please let us now on the Orange forum, preferrably in the Bugs section.

Note that the Orange-Text add-on requires a compiler and appropriate libraries on your computer, and it as of now still refuses to be installed using the dialog. This is a known bug.