Add caption to image

captions.py

"""Add a text label to an image

Uses Pillow, install with `pip install pillow`
"""
from os.path import expanduser, join, basename
from glob import glob
from PIL import Image, ImageDraw, ImageFont

## full path to your image directory, ~ = your home directory
img_dir = expanduser('~/stimuli/nsd/special100')

## find the paths to each .png file in the directory
img_paths = glob(join(img_dir, '*.png'))[:5]

## define how tall the new area for the label will be
EXTRA_HEIGHT_PIXELS = 50

## Current size of images
WIDTH, HEIGHT = 425, 425

## space between edge and text
MARGIN = 10

## the text to add
LABEL = 'My text label'

## define the font to use
font = ImageFont.truetype('Times New Roman.ttf', 20)

## process each image
for img_fpath in img_paths:

    img = Image.open(img_fpath)

    ## We "crop" with a larger size than the current one to expand the image
    ## (the numbers are the x and y coordinates of the top-left and bottom-right corners)
    img = img.crop((0, 0, WIDTH, HEIGHT+EXTRA_HEIGHT_PIXELS))

    ## create a "draw" object to add elements 
    draw = ImageDraw.Draw(img)

    ## draw a white background for the label
    ## (the numbers are the x and y coordinates of the top-left and bottom-right corners)
    draw.rectangle((0, HEIGHT, WIDTH, HEIGHT+EXTRA_HEIGHT_PIXELS), fill='white')

    ## Add Text to an image
    draw.text((MARGIN, HEIGHT+MARGIN), LABEL, fill='black', font=font)

    ## Save the edited image
    img.save('labeled_'+basename(img_fpath))