Add custom captions, like subtitles, to images easily

caption.py

# -*- coding: utf-8 -*-

# usage: caption.py image.jpg "The text"
# you can use a | to force a newline

# settings
strokew = 4 # outline width
stroke_color = "#101010" # outline color

font_color = "#f0f0f0" # ebeb0b=yellow, f0f0f0=white
font_name = "arial.ttf"
font_div = 14 # image height / this = font size

chars_per_line = 42 # according to Netflix: https://partnerhelp.netflixstudios.com/hc/en-us/articles/215274938-What-is-the-maximum-number-of-characters-per-line-allowed-in-Timed-Text-assets-

### end of settings

import re, sys, io, time, textwrap, os, datetime
from PIL import Image, ImageDraw, ImageFont

safe_chars = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789." # safe chars to use in filename

if len(sys.argv) < 3:
	print("usage:\n\tcaption.py image.jpg \"The text\"")
	print()
	sys.exit(1)

def safe_filename(text):
	string = []
	for c in text:
		if c in safe_chars:
			string.append(c)
	return "".join(string)

def make_frame_captioned(in_img, text, out):
	# generate subtitle frame
	image = Image.open(in_img)
	im_w,im_h = image.size[0], image.size[1]
	draw = ImageDraw.Draw(image)
	fo = ImageFont.truetype(font_name, int(im_h/font_div))
	w,h = draw.textsize(text, font=fo)
	draw.text( ( ((im_w-w)/2), ((im_h-h)/1.15) ), text, fill=font_color, font=fo, stroke_width=strokew, stroke_fill=stroke_color)
	image.save(out)

picture = sys.argv[1]

if not os.path.isfile(picture):
	print("error: image not found:", picture)
	sys.exit(1)

caption = " ".join(sys.argv[2:])
output = safe_filename(datetime.datetime.now().strftime("%Y%m%d%H%M%S") + "_" + caption[0:50] + ".jpg")

caption = textwrap.fill(caption,chars_per_line)
caption = caption.replace("|","\n") # use a | to force newline

print(picture, "-->")
print(caption)
print("-->", output)

make_frame_captioned(picture,caption,output)