Activities/Plot

Overview

Plot is an activity that plots mathematical functions.

Modifying Plot

For the ambitious, who don't mind programming:

Adding a function

1. Add to plotter/parse.py

Create an icon

Create an icon for the new function. As a convention, its name should be the same as the function name in all lowercase letters. There should be two files: one for the working copy, and an exported "Plain SVG" copy. There names should be <functionname>.svg for the plain svg and <functionname>-inkscape.svg for the working copy.

Create node class

Create a new file plotter/view/puzzletree/nodes/<functionname>.py.

In it place:

from .simplenode import SimpleNode
from gettext import gettext as _


class FunctionName(SimpleNode):
    """Node representing <some function>."""

    CLASS = "functionname"
    background = SimpleNode.loadbackground("functionname.svg")
    title = _("Function Name")
    description = _(u"Enter a description of the function here.")

    def __call__(self, x):
        """Calls the function... put a more descriptive comment here."""
        return functionname(x)


    def get_equation_string(self, variable):
        """Returns a string to use this function in the Python parser."""
        return "functionname(%s)" % variable

CLASS should be a unique identifier for the node class (the lowercase class name should work fine). This is used when saving to the journal to describe which nodes are used.

background should be loaded from the plain *.svg file created as an icon. Just give it the filename (not the full path).

title is shown above the description in the palette. It should reflect the common name for the function being added.

description is a longer description that gives more information about the function. Ideally, it should be understandable by those without advanced knowledge of Mathematics.

__call__ should return the value that the function would return for x. Additional modules may need to be imported in order to do this, depending on the function.

get_equation_string should return the string needed to apply the same function in the Python parse equation input. (NOTE: this may mean you'll need to add the function to the list of those available to the plotter.parse module.)

Add node appropriate category

Edit the file: plotter/view/puzzletree/nodes/__init__.py.

Add the node class you just created to the appropriate category (in this case: functions).

...

# functions
from .constant import Constant
from .identity import Identity
from .functionname import FunctionName

FUNCTIONS = [
    Constant,
    Identity,
    FunctionName
]

...

That's it! Your new function should now show up in the palette when you edit equations in the Plot activity.

Resources

• Activity download page
• Bug Tracker
• Source