README.md

In this directory all the available patters will be stored.

Adding a new pattern

To add a new patter you will need to create a new class which inherits from Default.

The new class has to have:

• **kwargs as only argument (check out the other classes).
• call to super().__init__(**kwargs) as the first line of the init
• implementation of the fill method

Pixels attribute

The pixel status is store in the pixel dictionary. This dict has the following structure at initialization: pixels:Dict[Dict]. The first dictionary maps an index (the pixel position) to another dictionary containing its attributes, at initialization the only attribute is:

color:RGB.RGB

which is a RGB object. During the init or fill method you can add more attribute to each pixel as you see fit.

Fill method

To change the values of the pixel, the fill method has to be implemented. This method will be called once every loop iteration to change the attributes of the pixels which will be then written wih the set_pixels method.

Adding to init

To make the new pattern available to the database add it in the init file as the value of the Pattern dictionary.

Modifiers

Each pattern inherit a dictionary called modifiers which should be populated with instances from the Modifier class.

This class accepts two mandatory attributes and 3 (as for now) optional ones:

• name: str, the name which will be shown in the web/android app.
• value: the initial value.
• min/max: by default, if the value is an int/float, it will be scaled at setting time to be in range [min,max].
• choices: for multi-choice options, provide a list of allowed values.

It is fundamental that the key in the modifiers dict and the instance name are the same for the app to correctly identify them. For example the pattern Fire shows:

class Fire(Default):
    """
    Fire pattern
    """

    def __init__(self, **kwargs):

        super().__init__(**kwargs)

        self.cooling = Modifier('cooling', 10, minimum=1, maximum=self.strip_length)
        self.sparking = Modifier('sparking', 40, minimum=1, maximum=255)
        self.cooldown_list = [0 for _ in range(self.strip_length)]
        self.pattern_name = "Fire"
        self.mid = self.strip_length // 2

        self.modifiers = dict(
            cooling=self.cooling,
            sparking=self.sparking
        )

Notice how the modifiers names "self.cooling" and "self.sparking" are the same as they appear in the dictionary keys.

Since Modifier is a custom class you need to access it's value with a call function, e.g. self.cooling() and set it with: self.cooling.value=1

Properties

Some time you want to have some rule to set an attribute before actually setting it. In this case you would normally use a @proprety and wrap it with your custom function.

To allow the same thing with the modifiers dictionary take a look at the following simplified example of the Equation Pattern:

class Equation(Default):
    """
    Use user-defined function for the rgb values. The function may depend on :
        - the pixel position in the led strip 'idx'
        - the current timestep 't' which cycles in a predefined allowed range.
        - both
        - none
    """

    def __init__(self, **kwargs):

        super().__init__(**kwargs)

        self.pattern_name = "Equation"

        self.fns = {}

        # r,g,b functions in string format
        self.red_equation = Modifier('red equation', "cos(t)", on_change=self.on_change_red)

       
        self.modifiers = dict(
            red_equation=self.red_equation,
        )

    def on_change_red(self, value):
        assert isinstance(value, str), pattern_logger.warning("The equation value is not a string")
        self.fns['r_fn'] = Expression(value, ["t", "idx"])

As you can see from the init function, the modifier instance uses an additional parameter on_change which takes a function as input. The function will be then called whenever there is a change in the modifier value.

In this case we are checking that the value to change is a string and then setting the red function key of the self.fns dictionary to the Expression.