##############################################################
#Set your paths here

#path to provided foreground images
fg_path = "fg"
#path to provided alpha mattes
a_path = "alpha"
#Path to background images
bg_path = "bg"
#Path to folder where you want the composited images to go
out_path = "composited_images"

fg_files = [line.rstrip('\n') for line in open('./transparent-460-test-fg-names.txt')]
bg_files = [line.rstrip('\n') for line in open('./transparent-460-test-bg-names.txt')]
##############################################################

from PIL import Image
import os 
import math
import time

def composite4(fg, bg, a, w, h):
    
    bbox = fg.getbbox()
    bg = bg.crop((0,0,w,h))
    
    fg_list = fg.load()
    bg_list = bg.load()
    a_list = a.load()
    
    for y in range(h):
        for x in range (w):
            alpha = a_list[x,y][0] / 255
            t = fg_list[x,y][0]
            t2 = bg_list[x,y][0]
            if alpha >= 1:
                r = int(fg_list[x,y][0])
                g = int(fg_list[x,y][1])
                b = int(fg_list[x,y][2])
                bg_list[x,y] = (r, g, b, 255)
            elif alpha > 0:
                r = int(alpha * fg_list[x,y][0] + (1-alpha) * bg_list[x,y][0])
                g = int(alpha * fg_list[x,y][1] + (1-alpha) * bg_list[x,y][1])
                b = int(alpha * fg_list[x,y][2] + (1-alpha) * bg_list[x,y][2])
                bg_list[x,y] = (r, g, b, 255)

    return bg

num_bgs = 20

bg_iter = iter(bg_files)
num = 0
for im_name in fg_files:

    im = Image.open(os.path.join(fg_path, im_name))
    a = Image.open(os.path.join(a_path, im_name.split(".")[0]+".png"))
    bbox = im.size
    w = bbox[0]
    h = bbox[1]
    
    if im.mode != 'RGB' and im.mode != 'RGBA':
        im = im.convert('RGB')
    
    bcount = 0 
    for i in range(num_bgs):

        bg_name = next(bg_iter)
        bg = Image.open(os.path.join(bg_path, bg_name))
        if bg.mode != 'RGB':
            bg = bg.convert('RGB')

        bg_bbox = bg.size
        bw = bg_bbox[0]
        bh = bg_bbox[1]
        wratio = w / bw
        hratio = h / bh
        ratio = wratio if wratio > hratio else hratio     
        if ratio > 1:        
            bg = bg.resize((math.ceil(bw*ratio),math.ceil(bh*ratio)), Image.BICUBIC)
                     
        out = composite4(im, bg, a, w, h)   

        out.save(out_path + im_name[:len(im_name)-4] + '_' + str(bcount) + '.png', "PNG")        
        print(out_path + im_name[:len(im_name)-4] + '_' + str(bcount) + '.png') 
        bcount += 1


print("Finished")