#-------------- ------------------ ------------------- --------------------- ---
#Numpy and OpenCV to create a PowerPoint like animation of image.  This is an
#example of appearance of an image in small rectangular boxes.  
#-------------- ------------------ ------------------- --------------------- ---
import numpy as np
import sys
import cv2

#-------------- ------------------ ------------------- --------------------- ---
def vidFromImgArray(imgArray, vidName, fps=50, vidW=0, vidH = 0):
	#Function to create an MP4 file from array of images
	#Image or video width should be even number else they would be truncated 
	#to the nearest lower even numbers
	if vidW == 0 or vidH == 0:
		ht, wd, ch = imgArray[0].shape
		size = (wd, ht)
	else:
		size = (vidW, vidH)
		
	codec = cv2.VideoWriter_fourcc(*'mp4v')
	video = cv2.VideoWriter(vidName, codec, fps, size)
	
	for img in imgArray:
		if vidW > 0 and vidH > 0:
			img=cv2.resize(img, size, interpolation=cv2.INTER_LINEAR)
		video.write(img)
	video.release()
#-------------- ------------------ ------------------- ------------------------

def imgWipeDiagonalBox(img, wBox):
	#Function to create box-shaped entrance of image from centre to edges
	frames = []
	#Works for coloured images with Alpha channel and grayscale (BW) images
	img = cv2.imread(img)
	ht, wd, ch = img.shape
	
	#Number of segments in the width direction
	nw = wd // wBox   
	#Dimension of each box in the height direction
	nh = ht // wBox     

	for k in range(1, wBox, 1):
		imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
		
		for i in range(0, nw, 1):
			w1 = i * wBox + k
			w2 = (i+1) * wBox
			
			for j in range(0, nh, 1):
				h1 = j * wBox + k
				h2 = (j+1) * wBox
				imgW[h1:h2, w1:w2, :] = 0
	
		cropImg = cv2.bitwise_or(img, imgW, mask=None)
		frames.append(cropImg)
		
	return frames
#-------------- ------------------ ------------------- ------------------------

def imgWipeUniformBox(img, wBox):
	#Function to create box-shaped entrance of image from centre to edges
	frames = []
	#Works for coloured images with Alpha channel and grayscale (BW) images
	img = cv2.imread(img)
	ht, wd, ch = img.shape
	
	#Number of segments in the width direction
	nw = wd // wBox   
	#Dimension of each box in the height direction
	nh = ht // wBox     

	for k in range(1, wBox, 1):
		imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
		
		for i in range(0, nw, 1):
			w1 = i * wBox + k
			w2 = (i+1) * wBox - k - 1
			
			for j in range(0, nh, 1):
				h1 = j * wBox + k
				h2 = (j+1) * wBox - k - 1
				imgW[h1:h2, w1:w2, :] = 0
	
		cropImg = cv2.bitwise_or(img, imgW, mask=None)
		frames.append(cropImg)
		
	return frames
#-------------- ------------------ ------------------- ------------------------

def imgAppearUniformBox(img, wBox):
	#Function to create box-shaped entrance of image from centre to edges
	frames = []
	#Works for coloured images with Alpha channel and grayscale (BW) images
	img = cv2.imread(img)
	ht, wd, ch = img.shape
	
	#Number of segments in the width direction
	nw = wd // wBox   
	#Dimension of each box in the height direction
	nh = ht // wBox     

	for k in range(1, wBox, 1):
		imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
		
		for i in range(0, nw, 1):
			w1 = i * wBox
			w2 = w1 + k
			w4 = (i+1) * wBox
			w3 = w4 - k 
			
			for j in range(0, nh, 1):
				h1 = j * wBox
				h2 = h1 + k
				h4 = (j+1) * wBox
				h3 = h4 - k
				imgW[h1:h2, w1:w2, :] = 0
				imgW[h3:h4, w1:w2, :] = 0
				imgW[h1:h2, w3:w4, :] = 0
				imgW[h3:h4, w3:w4, :] = 0
				
		cropImg = cv2.bitwise_or(img, imgW, mask=None)
		frames.append(cropImg)
		
	return frames
#-------------- ------------------ ------------------- ------------------------

img = "Lena-with-Roses.jpg"
imgArray1 = imgWipeDiagonalBox(img, 50)
imgArray2 = imgWipeUniformBox(img, 50)
imgArray3 = imgAppearUniformBox(img, 50)

imgFrames = np.concatenate([imgArray1, imgArray2, imgArray3])
vidFromImgArray(imgFrames, "imgBoxSegments.mp4", 20)