#-------------- ------------------ ------------------- --------------------- ---
#Numpy and OpenCV to create a PowerPoint like animation of an image. This is an
#example of BOX-appearance starting from centre of the image.  There are also 
#example of wiping an image from centre to the edges and from Top-Left corner to
#the Bottom-Right corner. This code is a good demonstration of slicing of arrays
#in NumPy along with use of numpy.insert and numpy.append operations. Creation
#of sub-matrix and cropping of an image while maitaining size same as input
#image can also be achieved with this piece of code.
#-------------- ------------------ ------------------- --------------------- ---
import numpy as np
import sys
import cv2

def imgAnimBoxEntrance(img, fps):
	#Works for coloured images with Alpha channel and grayscale (BW) images
	img = cv2.imread(img)
	h_half = img.shape[0]//2
	w_half = img.shape[1]//2
	even = img.shape[0] % 2
	arat = img.shape[1]/img.shape[0]
	
	#Check if image is colored with or without alpha layer
	if len(img.shape) > 2:
		ht, wd, ch = img.shape
		imgW = np.ones([ht, wd, ch], dtype=np.uint8) * 255
		
		for i in range(1, h_half, 1):
			j = int (i * arat)
			imgW[h_half-i:h_half+i, w_half-j:w_half+j, :] = 0
			cv2.imshow("Masked", cv2.bitwise_or(img, imgW, mask=None))
			t = int(1000/fps)
			cv2.waitKey(t)

	#Process image as Black-and-White pixels
	else:
		ht, wd = img. shape
		imgW = np.ones([ht, wd], dtype=np.uint8) * 255
		for i in range(1, h_half, 1):
			j = int(i * arat)
			imgW[h_half-i:h_half+i, w_half-j:w_half+j] = 0 
			cv2.imshow("Masked", cv2.bitwise_or(img, imgW, mask = None))
			t = int(1000/fps)
			cv2.waitKey(t)
	cv2.destroyAllWindows()
#-------------- ------------------ ------------------- --------------------- ---
def imgPptAnimWipeTL2BR(img, fps):
	#This function works only for coloured images with no Alpha channel
	img = cv2.imread(img)
	if len(img.shape) < 3 or len(img.shape) > 3:
		print("Image is either grayscale or coloured with Alpha channel")
		print("Image not process, exited normally!")
		sys.exit()
		
	h_half = img.shape[0]//2
	w_half = img.shape[1]//2
	even = img.shape[0] % 2
	arat = img.shape[1]/img.shape[0]
	for i in range(1, h_half, 1):
		j = int(i * arat)

		#Box Wipe - TL Corner towards BR corner
		img[0:i*2+2, 0:j*2+2, :] = 255
	
		cv2.imshow("Image", img)
		t = int(1000/fps)
		cv2.waitKey(t)
	cv2.destroyAllWindows()
#-------------- ------------------ ------------------- --------------------- ---
def imgPptAnimWipeCen2Edge(img, fps):
	#This function works only for coloured images with no Alpha channel
	img = cv2.imread(img)
	if len(img.shape) < 3 or len(img.shape) > 3:
		print("Image is either grayscale or coloured with Alpha channel")
		print("Image not process, exited normally!")
		sys.exit()
	h_half = img.shape[0]//2
	w_half = img.shape[1]//2
	even = img.shape[0] % 2
	arat = img.shape[1]/img.shape[0]
	for i in range(1, h_half, 1):
		j = int(i * arat)
	
		#Box Wipe - Centre towards outwards
		img[h_half-i:h_half+i, w_half-j:w_half+j, :] = 255
	
		cv2.imshow("Image", img)
		t = int(1000/fps)
		cv2.waitKey(t)
	cv2.destroyAllWindows()
#-------------- ------------------ ------------------- --------------------- ---	

imgPptAnimWipeTL2BR("3.jpg", 20)
imgPptAnimWipeCen2Edge("3.jpg", 20)
imgAnimBoxEntrance("3.jpg", 20)