How to join png into one file or one pdf and how to join more pdf files

I had the will to join more images taken from a Powerpoint file in just one vertical image file. Searching on Stack overflow I found something and I modified so that it works with any file in the directory where you have the png files (instead of 3 of a given name).

import numpy as np
from PIL import Image
import glob

list_im = glob.glob("*.png")
imgs    = [ Image.open(i) for i in list_im ]
# pick the image which is the smallest, and resize the others to match it (can be arbitrary image shape here)
min_shape = sorted( [(np.sum(i.size), i.size ) for i in imgs])[0][1]
imgs_comb = np.hstack( (np.asarray( i.resize(min_shape) ) for i in imgs ) )

# save that beautiful picture
imgs_comb = Image.fromarray( imgs_comb)
imgs_comb.save( 'Trifecta.png' )    

# for a vertical stacking it is simple: use vstack
imgs_comb = np.vstack( (np.asarray( i.resize(min_shape) ) for i in imgs ) )
imgs_comb = Image.fromarray( imgs_comb)
imgs_comb.save( 'Trifecta_vertical.png' )

Utilities

How to join more png in one pdf file

If you want instead join more png into one pdf, use this script.

from PIL import Image
from glob import glob
import os

iml = []


files = glob("*.png")
# rgb.save(PDF_FILE, 'PDF', resoultion=100.0)
for f in files:
    print(f)
    print(f[:-4])
    newname = f[:-4] + ".png"
    print(newname)
    os.rename(f, newname)
files = glob("*.png")
print(files)
# rgba = Image.open(PNG_FILE)
# To avoid ValueError: cannot save mode RGBA 
rgba = Image.open(glob("*.png")[0])
rgb = Image.new('RGB', rgba.size, (255, 255, 255))  # white background
rgb.paste(rgba, mask=rgba.split()[3])               # paste using alpha channel as mask
for img in files:
    rgba2 = Image.open(img)
    rgb2 = Image.new('RGB', rgba2.size, (255, 255, 255))  # white background
    rgb2.paste(rgba2, mask=rgba2.split()[3])               # paste using alpha channel as mask
    iml.append(rgb2)
pdf = "ALL.pdf"

rgb.save(pdf, "PDF" ,resolution=100.0, save_all=True, append_images=iml)

How to make one pdf from more pdf

You need the PyPDF2 module

import os
from PyPDF2 import PdfFileMerger

x = sorted([a for a in os.listdir() if a.endswith(".pdf")])
print(x)
merger = PdfFileMerger()

for pdf in x:
    merger.append(open(pdf, 'rb'))

with open("result.pdf", "wb") as fout:
    merger.write(fout)
os.startfile("result.PDF")

Find the code here

https://github.com/formazione/pypdf