#----------------------IMAGE to VIDEO by ROTATION and PADDING-------------------
#This Python and OpenCV code contains function to rotate an image, pad rotated
#image to resize it to width and height of the desired video. The colour of un
#defined region in rotation and padding can be defined separately. There is a
#check if the diagonal length of input image exceeed the height or width of the
#video size and images are not rotated or padded- hence no video is created.
#
import numpy as np
import cv2
import math, os, sys
#
# -------------------------User Input Starts------------------------------------
imgName = 'Sample.jpg'
vidName = 'imgRot.mp4'
vidH = 450
vidW = 800
nfs = 11
#Color for image rotation (warpAffine) and padding (copyMakeBorder)
clrRot = (255, 255, 255)
clrPad = (255, 255, 255)
#Rotation angle increment and total rotation angle (starts with q = 0)
delta_q = 2
total_q = 180
# ------------------------User Input Ends---------------------------------------

def rotateImage(img, angleInDeg, vid_w, vid_h, clr):
	h = img.shape[0]
	w = img.shape[1]
	#This is a basic check assuming rotation angle > 45 degrees
	diagLen = int(math.sqrt(h*h + w*w))
	if (int(diagLen) > vid_w or int(diagLen) > vid_h):
		print("Size of rotated image shall exceed height or width of Video")
		print( "No image rotation performed. \n")
		sys.exit()
	img_c = (w/2, h/2)
	rot_mtx = cv2.getRotationMatrix2D(img_c, angleInDeg, 1)
	rad = math.radians(angleInDeg)
	sin = math.sin(rad)
	cos = math.cos(rad)
	b_w = int((h * abs(sin)) + (w * abs(cos)))
	b_h = int((h * abs(cos)) + (w * abs(sin)))
	rs = (b_w, b_h)
	rot_mtx [0, 2] = rot_mtx [0, 2] + ((b_w/2) - img_c[0])
	rot_mtx [1, 2] = rot_mtx [1, 2] + ((b_h/2) - img_c[1])
	bm = cv2.BORDER_CONSTANT
	fg = cv2.INTER_LINEAR
	rImg=cv2.warpAffine(img,rot_mtx,rs, borderMode=bm,borderValue=clr,flags=fg)
	return rImg
#-------------------------------------------------------------------------------
def paddedImage(img, vid_w, vid_h, clr):
	delta_w = vid_w - img.shape[1]
	delta_h = vid_h - img.shape[0]
	if delta_w < 0 or delta_h < 0:
		print("Specified video size< input image, no video created. \n")
		sys.exit()
	pad_w = delta_w // 2
	pad_h = delta_h // 2
	top, bot  = pad_h, delta_h - pad_h
	lft, rgt  = pad_w, delta_w - pad_w
	
	#Copy img image into center of result image
	brdr   = cv2.BORDER_CONSTANT
	padimg = cv2.copyMakeBorder(img, top,bot, lft,rgt, brdr, value=clr)
	return padimg
#-------------------------------------------------------------------------------
def rotPadImg2Vid(imgName, del_q,q_tot, vidName,fps, vid_w,vid_h, c_rot,c_pad):
	if not os.path.exists(imgName):
		print("Specified Image File does not Exist. \n")
		sys.exit()
	img   = cv2.imread(imgName)
	codec = cv2.VideoWriter_fourcc(*'mp4v')
	vid   = cv2.VideoWriter(vidName, codec, nfs, (vid_w, vid_h))
	n     = int(q_tot / del_q + 1)
	for i in range(0, n):
		angle  = i * delta_q
		rotImg = rotateImage(img, angle, vid_w, vid_h, c_rot)
		padImg = paddedImage(rotImg, vid_w, vid_h, c_pad)
		vid.write(padImg)
	vid.release()
#-------------------------------------------------------------------------------
#Create video using Function
rotPadImg2Vid(imgName, delta_q,total_q, vidName,nfs, vidW,vidH, clrRot,clrPad)
#
'''
#Create video using inline command
codec= cv2.VideoWriter_fourcc(*'mp4v')
img = cv2.imread(imgName)
vid = cv2.VideoWriter(vidName, codec, nfs, (vidW, vidH))
n = int(total_q / delta_q + 1)
for i in range(0, n):
	angle= i * delta_q
	rotImg = rotateImage(img, angle, clrRot, vidW, vidH)
	padImg = paddedImage(rotImg, vidW, vidH, clrPad)
	vid.write(padImg)
vid.release()
cv2.destroyA11Windows()
'''