app.py

import os
os.system("pip install gradio==2.9.4")
import gradio as gr
import numpy as np
import cv2 as cv
import sys
import math

"""
The following rotate function is only included for reference and is not called.
This shows how the recursion works, but does not provide any sort of interesting animation.
"""
def rotate(img, x, y, width):

    width = width // 2
        
    #divides the image into four region and slides them clockwise
    temp = np.copy(img[y:y + width, x:x + width])
    
    img[y:y + width, x:x + width] = img[y + width:y + 2 * width, x:x + width]
    img[y + width:y + 2 * width, x:x + width] = img[y + width:y + 2 * width, x + width:x + 2 * width]
    img[y + width:y + 2 * width, x + width:x + 2 * width] = img[y:y + width, x + width:x + 2 * width]
    img[y:y + width, x + width:x + 2 * width] = temp
    
    if width > 1:
        #recusively rotating the tiles
        rotate(img, x, y, width)
        rotate(img, x + width, y, width)
        rotate(img, x + width, y + width, width)
        rotate(img, x, y + width, width)

def rotate_with_steps(img, output, x, y, width, shift):
    
    temp = np.copy(img[y:y + width, x:x + width])
    
    output[y + width - shift:y + 2 * width - shift, x:x + width] = img[y + width:y + 2 * width, x:x + width]
    output[y + width:y + 2 * width, x + width - shift:x + 2 * width - shift] = img[y + width:y + 2 * width, x + width:x + 2 * width]
    output[y + shift:y + width + shift, x + width:x + 2 * width] = img[y:y + width, x + width:x + 2 * width]
    output[y:y + width, x + shift:x + width + shift] = temp

def is_power_of_two(n):
    return (n != 0) and (n & (n-1) == 0)



#read in the image
def run(image):
   image = cv.imread(image)
   
   #check if image is of the right size
   if not (is_power_of_two(image.shape[0]) and image.shape[0] == image.shape[1]):
       print("The image you have provided does not have dimensions N x N where N is a power of 2.")
       closest_valid_dimension = 2**round(math.log(min(image.shape[0], image.shape[1]), 2))
       #prompt user to either resize image to closest NxN where N is a power of 2
 
       image = cv.resize(image, (closest_valid_dimension, closest_valid_dimension))
   
   
   img_dim = image.shape[0]
   
   #make a video writer
   out_file_name = "out.mp4"
   out = cv.VideoWriter(out_file_name, cv.VideoWriter_fourcc('m','p','4','v'), 30, (img_dim, img_dim))
   
   #rotate the image 4 times
   for rotations in range(4):
   
       width = img_dim // 2
       number_of_frames = 2 * int(math.log2(img_dim))
   
       while width > 0:
           
           number_of_frames -= 2
           number_of_frames = max(1, number_of_frames)
   
           #create the sliding animation by gradually moving the tiles
           for i in range(0, number_of_frames):
           
               output_canvas = np.copy(image)
               shift = (width * (i + 1)) // number_of_frames
           
               for x in range(0, img_dim, 2 * width):
                   for y in range(0, img_dim, 2 * width):
                       rotate_with_steps(image, output_canvas, x, y, width, shift)
                       
      
               
               out.write(output_canvas)
           
           image = np.copy(output_canvas)
           width = width // 2
       
   out.release()
   return "out.mp4"
   
gr.Interface(run,gr.inputs.Image(type="filepath"),"playable_video").launch()