SpinAnimation

main.py

"""
Author: DZ Chan 
Date:   2017-09-24 
Description: This is a animation generator
"""

from PIL import Image, ImageDraw
import sys, math

'''
according to the definition in WIKI:
https://zh.wikipedia.org/wiki/%E6%9E%81%E5%9D%90%E6%A0%87%E7%B3%BB
'''
def clearPixels(img, theta1, theta2):
    SIZE = img.size
    CENTER_POINT = (SIZE[0]/2, SIZE[1]/2)

    for x in range(SIZE[0]):
        for y in range(SIZE[1]):
            relative_point = (x - CENTER_POINT[0], y - CENTER_POINT[1])
            theta = math.atan2(relative_point[1], relative_point[0])
            theta = theta * 180 / math.pi + 180

            if theta2 > 360:
                if theta >= theta1 or theta < theta2 - 360:
                    draw = ImageDraw.Draw(img, 'RGBA')
                    draw.point([x, y], (0, 0, 0, 0))    # write null pixel
                continue

            if theta >= theta1 and theta < theta2:
                draw = ImageDraw.Draw(img, 'RGBA')
                draw.point([x, y], (0, 0, 0, 0))    # write null pixel

if __name__ == '__main__':
    img = Image.open(sys.argv[1]).convert('RGBA')

    MAX_NUM = int(sys.argv[2])
    for i in range(MAX_NUM):
        copy = img.copy()
        angles = int((i / MAX_NUM) * 360)
        print('generating angle:' + str(angles))
        clearPixels(copy, 90, angles+90)
        copy.save('red-animations/red_ani_' + str(i) + '.png', 'PNG')