colorcycletemplate.py

import apa102
import time

class ColorCycleTemplate:
    """
    This class is the basis of all color cycles, such as rainbow or 
    theater chase.
    A specific color cycle must subclass this template, and implement 
    at least the 'update' method.
    """
    def __init__(self, numLEDs=144, pauseValue = 0, numStepsPerCycle = 100, numCycles = -1, globalBrightness = 4, order = 'rgb'): # Init method
        self.numLEDs = numLEDs # The number of LEDs in the strip
        self.pauseValue = pauseValue # How long to pause between two runs
        self.numStepsPerCycle = numStepsPerCycle # The number of steps in one cycle.
        self.numCycles = numCycles # How many times will the program run
        self.globalBrightness = globalBrightness # Brightness of the strip
        self.order = order # Strip colour ordering

    def init(self, strip, numLEDs):
        """
        void init()
        This method is called to initialize a color program.
        """
        # The default does nothing. A particular subclass could setup variables, or
        # even light the strip in an initial color.
        pass

    def shutdown(self, strip, numLEDs):
        """
        void shutdown()
        This method is called at the end, when the light program 
        should terminate
        """
        # The default does nothing
        pass

    def update(self, strip, numLEDs, numStepsPerCycle, currentStep, currentCycle):
        """
        void update()
        This method paints one subcycle. It must be implemented.
        currentStep: This goes from zero to numStepsPerCycle-1, and then 
            back to zero. It is up to the subclass to define what is done in 
            one cycle. One cycle could be one pass through the rainbow. 
            Or it could be one pixel wandering through the entire strip 
            (so for this case, the numStepsPerCycle should be equal to numLEDs).
        currentCycle: Starts with zero, and goes up by one whenever a 
            full cycle has completed.
        """
        raise NotImplementedError("Please implement the update() method")

    def cleanup(self, strip):
        self.shutdown(strip, self.numLEDs)
        strip.clearStrip()
        strip.cleanup()

    def start(self):
        """
        Start the actual work
        """
        try:
            strip = apa102.APA102(
                numLEDs=self.numLEDs, 
                globalBrightness=self.globalBrightness, 
                order=self.order) # Initialize the strip
            strip.clearStrip()
            self.init(strip, self.numLEDs) # Call the subclasses init method
            strip.show()
            currentCycle = 0
            while True:  # Loop forever 
                for currentStep in range (self.numStepsPerCycle):
                    needRepaint = self.update(
                        strip, 
                        self.numLEDs, 
                        self.numStepsPerCycle, 
                        currentStep, 
                        currentCycle) # Call the subclasses update method
                    if (needRepaint): strip.show() # Display, only if required
                    time.sleep(self.pauseValue) # Pause until the next step
                currentCycle += 1
                if (self.numCycles != -1):
                    if (currentCycle >= self.numCycles): break
            # Finished, cleanup everything
            self.cleanup(strip)

        except KeyboardInterrupt:  # Ctrl-C can halt the light program
            print('Interrupted...')
            self.cleanup(strip)