#-------------- ------------------ ------------------- --------------------- ---
#Numpy and OpenCV to create a PowerPoint like animation of image.  This is an
#example of image appearing in either horizontal and vertical segments
#-------------- ------------------ ------------------- --------------------- ---
import numpy as np
import sys
import cv2

#-------------- ------------------ ------------------- --------------------- ---
def vidFromImgArray(imgArray, vidName, fps, 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 len(imgArray) <= 1:
		print("Number of frames <= 1, exiting! \n")
		sys.exit()
		
	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 imgAnimEntranceVertSegments(img, n):
	#Function to create vertical split entrance of image
	frames = []
	#Works for coloured images with Alpha channel and grayscale (BW) images
	im = cv2.imread(img)
	dw = im.shape[1] // n
	ht, wd, ch = im.shape
	frames.append(im)
	imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
	for j in range(1, dw, 1):
		imgMask = imgW
		for k in range(0, n, 1):
			imgMask[:, dw*k:j+dw*k, :] = 0
			imgMasked = cv2.bitwise_or(im, imgMask, mask=None)
			frames.append(imgMasked)
	
	#print("Number of frames in return array = ", len(frames))
	return frames

#-------------- ------------------ ------------------- --------------------- ---

def imgAnimEntranceHorizSegments(img, n):
	#Function to create vertical split entrance of image
	frames = []
	#Works for coloured images with Alpha channel and grayscale (BW) images
	im = cv2.imread(img)
	dh = im.shape[0] // n
	ht, wd, ch = im.shape
	frames.append(im)
	imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
	for j in range(1, dh, 1):
		imgMask = imgW
		for k in range(0, n, 1):
			imgMask[dh*k:j+dh*k, :, :] = 0
			imgMasked = cv2.bitwise_or(im, imgMask, mask=None)
			frames.append(imgMasked)
	
	#print("Number of frames in return array = ", len(frames))
	return frames
#-------------- ------------------ ------------------- --------------------- ---
	
imgFrames = imgAnimEntranceHorizSegments("0.jpg", 5)
vidFromImgArray(imgFrames, "BoxAnim.mp4", 500)