As the OP states, there are two parts (and probably also a third part):

1. Use PIL to generate images from fonts.

2. Use an image analysis toolkit, like OpenCV (which has Python bindings) to compare different shapes. There are a variety of standard techniques to compare different objects to see whether they're similar. For example, scale invariant moments work fairly well and are part of the OpenCv toolkit.

3. Most of the standard tools in #2 are designed to look for similar but not necessarily identical shapes, but for font comparison this might not be what you want, since the differences between fonts can be based on very fine details. For fine-detail analysis, try comparing the x and y profiles of a perimeter path around the each letter, appropriately normalized, of course. (This, or a more mathematically complicated variant of it, has been used with good success in font analysis.)

At the moment the Amazon Textract does not support font recognition. These two projects might help you:

1. DeepFont: Identify Your Font from An Image

• Paper: https://arxiv.org/pdf/1507.03196v1.pdf
• GitHub: https://github.com/robinreni96/Font_Recognition-DeepFont

2. Typefont: The first open-source library that detects the font of a text in a image.(It's read only now.)

• GitHub: https://github.com/Vasile-Peste/Typefont

This seems like a valid answer to your question:

from PIL import ImageFont, ImageDraw, Image

def find_font_size(text, font, image, target_width_ratio):
    tested_font_size = 100
    tested_font = ImageFont.truetype(font, tested_font_size)
    observed_width, observed_height = get_text_size(text, image, tested_font)
    estimated_font_size = tested_font_size / (observed_width / image.width) * target_width_ratio
    return round(estimated_font_size)

def get_text_size(text, image, font):
    im = Image.new('RGB', (image.width, image.height))
    return draw.textsize(text, font)

width_ratio = 0.5
font_family = "arial.ttf"
text = "Hello World"

image = Image.open('pp.png')
editable_image = ImageDraw.Draw(image)
font_size = find_font_size(text, font_family, image, width_ratio)
font = ImageFont.truetype(font_family, font_size)
print(f"Font size found = {font_size} - Target ratio = {width_ratio} - Measured ratio = {get_text_size(text, image, font)[0] / image.width}")

editable_image.text((10, 10), text, font=font)
image.save('output.png')

You do have to install the PIL package tho, comment here if you need help doing that.

You will also have to download this: https://github.com/JotJunior/PHP-Boleto-ZF2/blob/master/public/assets/fonts/arial.ttf?raw=true