I am working on a project that involves generating captcha images using Python’s Pillow (PIL) library. I want to add a feature where each individual letter in the captcha string is rotated on the image to make it a more difficult captcha.

import random
from PIL import Image, ImageDraw, ImageFont

def generate_random_string(length):
    random_string = ""
    for i in range(length):
        random_string += random.choice('1234567890ABCDEFGHIJKLMNOPQRSTUVQXYZ')
    return random_string

def generate_captcha():
    fonts = ["Aaargh.ttf", "SerpentineBoldItalic.ttf", "FUTURAM.ttf"]
    randomFont = random.choice(fonts)
    character_count = random.randrange(6, 10)
    captcha_string = generate_random_string(character_count)
    
    captcha_image = Image.new("RGBA", (400, 200), (default_color_red, default_color_green, default_color_blue))
    draw = ImageDraw.Draw(captcha_image, "RGBA")
    
    for i in range(1, 20):
        draw_random_ellipse(draw)
    
    # Arbitrary starting co-ordinates for the text we will write
    x = 10 + random.randrange(0, 100, 1)
    y = 79 + random.randrange(-10, 10, 1)
    
    for letter in captcha_string:
        selected_font = random.choice(fonts)
        font_style = ImageFont.truetype(selected_font, 50)
        
        draw.text((x, y), letter, (0, 0, 0), font=font_style)
       
        x = x + 35
        y = y + random.randrange(-10, 10, 1)
    
    return (captcha_image, captcha_string)

I attempted to find a solution to this problem on my own but couldn’t locate a clear answer. I would greatly appreciate any assistance on how to achieve the goal of rotating each individual letter within a PIL image. Thank you in advance for any help!

>Solution :

Here’s how you can modify your generate_captcha() function to rotate each letter: create a separate image for each letter, draw the letter on this separate image, rotate the image, paste the rotated image onto the main captcha image.

def generate_captcha():
    fonts = ["Aaargh.ttf", "SerpentineBoldItalic.ttf", "FUTURAM.ttf"]
    character_count = random.randrange(6, 10)
    captcha_string = generate_random_string(character_count)
    
    captcha_image = Image.new("RGBA", (400, 200), (default_color_red, default_color_green, default_color_blue))
    draw = ImageDraw.Draw(captcha_image, "RGBA")
    
    for i in range(1, 20):
        draw_random_ellipse(draw)

    x = 10 + random.randrange(0, 100, 1)
    y = 79 + random.randrange(-10, 10, 1)
    
    for letter in captcha_string:
        selected_font = random.choice(fonts)
        font_style = ImageFont.truetype(selected_font, 50)
        letter_image = Image.new("RGBA", (55, 55), (0, 0, 0, 0)) # Using transparency for empty space
        letter_draw = ImageDraw.Draw(letter_image)
        letter_draw.text((0, 0), letter, (0, 0, 0), font=font_style)
        angle = random.randint(-30, 30)
        rotated_letter = letter_image.rotate(angle, resample=Image.BICUBIC, expand=True)
        paste_pos = (x - rotated_letter.width // 2 + 25, y - rotated_letter.height // 2 + 25)
        captcha_image.paste(rotated_letter, paste_pos, rotated_letter)
        
        x = x + 35
        y = y + random.randrange(-10, 10, 1)
    
    return (captcha_image, captcha_string)