animationDecorator.py

from math import sqrt

class AnimationFrame(object):

    def __init__(self, index, factor):
        self._index = index
        self._factor = factor
    
    def index(self):
        return self._index
        
    def factor(self):
        return self._factor
        
    def linearFactor(self, b=0, c=1, d=1):
        t = self._factor
        return c * t / d + b

    def easeInQuadFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d
        return c * t * t + b

    def easeOutQuadFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d
        return -c * t * (t - 2) + b

    def easeInOutQuadFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d / 2
        if t < 1:
            return c / 2 * t * t + b
        t -= 1
        return -c / 2 * (t * (t - 2) - 1) + b

    def easeInCubicFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d
        return c * t * t * t + b

    def easeOutCubicFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d
        t -= 1
        return c * (t * t * t + 1) + b

    def easeInOutCubicFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d / 2
        if t < 1:
            return c / 2 * t * t * t + b
        t -= 2
        return c / 2 * (t * t * t + 2) + b

    def easeInOutCircFactor(self, b=0, c=1, d=1):
        t = self._factor
        t /= d / 2
        if t < 1:
            return -c / 2 * (sqrt(1 - t * t) - 1) + b
        t -= 2
        return c / 2 * (sqrt(1 - t * t) + 1) + b


    
def animation(frames=10, size=(100, 100), backgroundColor=(1, 1, 1), loop=True):
    framesIndexes = range(frames)
    if loop:
        framesIndexes = list(framesIndexes) + list(reversed(framesIndexes[1:-1]))

    def wrapper(func):        
        width, height = size
        for frameIndex in framesIndexes:
            newPage(width, height)
            with savedState():
                fill(*backgroundColor)
                rect(0, 0, width, height)
            factor = frameIndex / (frames - 1)
            func(AnimationFrame(frameIndex, factor))        
    return wrapper




##############

@animation(frames=10, size=(50, 50), backgroundColor=(1, 0, 1))
def render(frame):
    fill(1, 0, 0)
    rect(0, 0, width() * frame.easeInOutCircFactor(), height())
    fontSize(50)
    fill(frame.easeInQuadFactor(), 1, 0)
    text(str(frame.index()), (10, 10))


saveImage("test.gif")