evennia/docs/sphinx/source/wiki/RemovingColour.rst

Tutorial: Removing colour from your game
========================================

This is a small tutorial for customizing your character objects, using
the example of letting users turn on and off ansii colour parsing.

In the Building guide's `Colours <Colours.html>`_ page you can learn how
to add Colour to your game by using special markup. Colours enhance the
gaming experience, but not all users want colour. Examples would be
users working from clients that don't support colour, or people with
various seeing disabilities that rely on screen readers to play your
game.

So here's how to allow those users to remove colour. It basically means
you implementing a simple configuration system for your characters. This
is the basic sequence:

#. Define your own default character typeclass, inheriting from
   Evennia's default.
#. Set an attribute on the character to control markup on/off.
#. Set your custom character class to be the default for new players.
#. Overload the ``msg()`` method on the typeclass and change how it uses
   markup.
#. Create a custom command to allow users to change their setting.

Setting up a custom Typeclass
-----------------------------

Create a new module in ``game/gamesrc/objects`` named, for example,
``mycharacter.py``.

In your new module, create a new `typeclass <Typeclasses.html>`_
inheriting from ``game.gamesrc.objects.baseobjecs.Character``.

::

    from game.gamesrc.objects.baseobjects import Characterclass ColourableCharacter(Character):
        at_object_creation(self):              
            # set a colour config value
            self.db.config_colour = True

Above we set a simple config value as an `attribute <Attributes.html>`_.

Let's make sure that new characters are created of this type. Edit your
``game/settings.py`` file and change ``BASE_CHARACTER_TYPECLASS`` to
point to your new character class. Observe that this will only affect
*new* characters, not those already created. You have to convert already
created characters to the new typeclass by using the ``@typeclass``
command (try on a secondary character first though, to test that
everything works - you don't want to render your root user unusable!).

::

    @typeclass/reset/force mycharacter.ColourableCharacter

The ``/reset`` switch clears all attributes and properties back to the
default for the new typeclass and forces the object to re-run all its
creation hooks (important in this case). ``/force`` might be needed if
you edit the typeclass and want to update the object despite the actual
typeclass name not having changed.

Overload the ``msg()`` method
-----------------------------

Next we need to overload the ``msg()`` method. What we want is to check
the configuration value before calling the main function. The original
``msg`` method is found on ``src.objects.models.ObjectDB`` and is called
like this:

::

    msg(message, from_obj=None, data=None)

As long as we define a method on our custom object with the same name
and keep the same number of arguments/keywords we will overload the
original. Here's how it could look:

::

    from src.utils import ansimsg(self, message, from_obj=None, data=None):
        "our custom msg()"
        if not self.db.config_colour:
            message = ansi.parse_ansi(message, strip_ansi=True)
        self.dbobj.msg(message, from_obj, data)

Above we create a custom version of the ``msg()`` method that cleans all
ansi characters if the config value is not set to True. Once that's
done, we pass it all on to the normal ``msg()`` on the database object
(``ObjectDB``) to do its thing.

Since we put this custom ``msg()`` in our typeclass
``ColourableCharacter``, it will be searched for and called rather than
the default method on ``ObjectDB`` (which we now instead call manually).

There we go! Just flip the attribute ``config_colour`` to False and your
users will not see any colour.

Custom colour config command
----------------------------

For completeness, let's add a custom command so users can turn off their
colour display themselves if they want.

In game/gamesrc/commands, create a new file, call it for example
``configcmds.py`` (it's likely that you'll want to add other commands
for configuration down the line).

::

    from game.gamesrc.commands.basecommand import MuxCommandclass ConfigColourCmd(MuxCommand):
        """
        Configures your colour    Usage:
          @setcolour on|off    This turns ansii-colours on/off. 
        Default is on. 
        """    key = "@setcolour"
        aliases = ["@setcolor"]    def func(self):
            "Implements the command" 
            if not self.args or not self.args in ("on", "off"):
                self.caller.msg("Usage: @setcolour on|off") 
                return
            if self.args == "on":
                self.caller.db.config_colour = True
            else:
                self.caller.db.config_colour = False  
            self.caller.msg("Colour was turned %s." % self.args)

Lastly, we make this command available to the user by adding it to the
default command set. Easiest is to add it to the end of
``DefaultCmdSet`` class in gamesrc/commands/basecmdset.py:

::

    from game.gamesrc.commands import configcmds
    class DefaultCmdSet(cmdset_default.DefaultCmdSet):
       
        key = "DefaultMUX"
        
        def at_cmdset_creation(self):       
            super(DefaultCmdSet, self).at_cmdset_creation()        
            self.add(configcmds.ConfigColourCmd())

When adding a new command to a cmdset like this you need to run the
``@reload`` command (or reboot the server). From here on out, your users
should be able to turn on or off their colour as they please.