Adafruit_CircuitPython_LED_Animation/adafruit_led_animation/animation/comet.py

# SPDX-FileCopyrightText: 2020 Kattni Rembor for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
`adafruit_led_animation.animation.comet`
================================================================================

Comet animation for CircuitPython helper library for LED animations.

* Author(s): Kattni Rembor

Implementation Notes
--------------------

**Hardware:**

* `Adafruit NeoPixels <https://www.adafruit.com/category/168>`_
* `Adafruit DotStars <https://www.adafruit.com/category/885>`_

**Software and Dependencies:**

* Adafruit CircuitPython firmware for the supported boards:
  https://circuitpython.org/downloads


"""

from adafruit_led_animation.animation import Animation
from adafruit_led_animation.color import BLACK, calculate_intensity


class Comet(Animation):
    """
    A comet animation.

    :param pixel_object: The initialised LED object.
    :param float speed: Animation speed in seconds, e.g. ``0.1``.
    :param color: Animation color in ``(r, g, b)`` tuple, or ``0x000000`` hex format.
    :param background_color: Background color in ``(r, g, b)`` tuple, or ``0x000000`` hex format.
                             Defaults to BLACK.
    :param int tail_length: The length of the comet. Defaults to 25% of the length of the
                            ``pixel_object``. Automatically compensates for a minimum of 2 and a
                            maximum of the length of the ``pixel_object``.
    :param bool reverse: Animates the comet in the reverse order. Defaults to ``False``.
    :param bool bounce: Comet will bounce back and forth. Defaults to ``False``.
    :param Optional[string] name: A human-readable name for the Animation.
                                  Used by the to string function.
    :param bool ring: Ring mode.  Defaults to ``False``.
    """

    # pylint: disable=too-many-arguments,too-many-instance-attributes
    def __init__(
        self,
        pixel_object,
        speed,
        color,
        background_color=BLACK,
        tail_length=0,
        reverse=False,
        bounce=False,
        name=None,
        ring=False,
    ):
        if tail_length == 0:
            tail_length = len(pixel_object) // 4
        if bounce and ring:
            raise ValueError("Cannot combine bounce and ring mode")
        self.bounce = bounce
        self._reverse = reverse
        self._initial_reverse = reverse
        self._tail_length = tail_length
        self._color_step = 0.95 / tail_length
        self._comet_colors = None
        self._computed_color = color
        self._background_color = background_color
        self._num_pixels = len(pixel_object)
        self._direction = -1 if reverse else 1
        self._left_side = -self._tail_length
        self._right_side = self._num_pixels
        self._tail_start = 0
        self._ring = ring
        if ring:
            self._left_side = 0
        self.reset()
        super().__init__(pixel_object, speed, color, name=name)

    on_cycle_complete_supported = True

    def _set_color(self, color):
        self._comet_colors = [self._background_color]
        for n in range(self._tail_length):
            self._comet_colors.append(
                calculate_intensity(color, n * self._color_step + 0.05)
            )
        self._computed_color = color

    @property
    def reverse(self):
        """
        Whether the animation is reversed
        """
        return self._reverse

    @reverse.setter
    def reverse(self, value):
        self._reverse = value
        self._direction = -1 if self._reverse else 1

    @property
    def ring(self):
        """
        Ring mode.
        """
        return self._ring

    @ring.setter
    def ring(self, value):
        if self.bounce and value:
            raise ValueError("Cannot combine bounce and ring mode")
        self._ring = value
        self._left_side = 0 if value else -self._tail_length
        self.reset()

    def draw(self):
        colors = self._comet_colors
        if self.reverse:
            colors = reversed(colors)

        pixels = self.pixel_object
        start = self._tail_start
        npixels = len(pixels)
        if self._ring:
            start %= npixels
            for color in colors:
                pixels[start] = color
                start += 1
                if start == npixels:
                    start = 0
        else:
            for color in colors:
                if start >= npixels:
                    break
                if start >= 0:
                    pixels[start] = color
                start += 1

        self._tail_start += self._direction

        if self._tail_start < self._left_side or (
            self._tail_start >= self._right_side and not self._reverse
        ):
            if self.bounce:
                self.reverse = not self.reverse
            elif self._ring:
                self._tail_start = self._tail_start % self._num_pixels
            else:
                self.reset()

            self.cycle_complete = True

    def reset(self):
        """
        Resets to the first state.
        """
        if self.reverse:
            self._tail_start = self._num_pixels + self._tail_length + 1
        else:
            self._tail_start = -self._tail_length - 1

        if self._ring:
            self._tail_start = self._tail_start % self._num_pixels