How to convert existing woff / ttf / otf files to a font file supported by report lab?

Question

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Understanding The Problem

I've run into a problem. I have a need to convert an svg file with multiple custom fonts into a png. This is supported by svglib. I actually was able to convert one of the fonts into a proper format for svglib to properly transform an svg to a png with the font. The problem is, I don't necessarily know what fonts are going to be "good" fonts and what fonts are going to be "bad" fonts (otf fonts that load for some reason and otf fonts that don't load for some reason), so ideally, I'd have a function in Python 3.x.x to convert all fonts to the same workable format. According to this google group on the subject, its a complicated beast (as of 2013). However, I could load any font (ttf / otf / woff) into this site and use it to get python to pump out a png file, just by having the font in the same directory as the svg file with the same name as the font file as the font family, with the proper results, but I couldn't get the converted font using Python's fonttools to work with the below provided code:

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Code

from reportlab.graphics import renderPM
from svglib.svglib import svg2rlg
from fontTools import ttLib
from io import BytesIO
from PIL import Image

# Here I tried to take the font (which I had initially as a woff) and convert it to a ttf.
#woff2.decompress("./my_font.woff", "./my_font.ttf")

# Here I tried to take the original otf and convert it to a ttf
# font = ttLib.TTFont("my_font.otf")
# font.flavor = None 
# font.save("my_font.ttf")

buff = BytesIO()
drawing = svg2rlg("./test.svg")
renderPM.drawToFile(drawing, buff, fmt="PNG")
img = Image.open(buff)
# l, w = image.size
# img = img.resize()
new_buff = BytesIO()
img.save("new_test.png", dpi=(600, 600))

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Font For Minimal Reproduceable Example

I can upload a demo working font and the same font that is not working with the given format, but before I did that, I wanted to make sure that was part of the SO community guidelines to distribute potentially copyrighted (and other items of this nature with different licenses and EULAs) works - maybe a comment can confirm or deny this (I don't have the EULA, so I will probably find a link to a font that will be reproduceable). I think easiest is for me to find a link to a font online that I can reproduce the problem with, so I will get to looking and update the post with a link, but I mean... come on! I can't be the only person trying to solve this problem?!

Working font example

A non working font example - I could be wrong, but I think if you convert from a ttf to a woff back to a ttf using fonttools that you will be able to reproduce this issue. I'm still looking for an online example.

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Problem Statement

So to make sure the problem statement is well articulated, the goal is to: Take any otf / ttf / or woff (even for simplicity sake - just a woff) file and convert it to a ttf file via Python that is supported by reportlab (which would mean it would be supported by svglib).

Answer 1

As unfortunate as it is, I couldn't supply a font to help with the "minimal, reproducible example clause", because finding a font online to replicate this with is very challenging (maybe I wasn't searching in the right place). However, I could convert the font in fontforge and opted for that. I could use the scripting portion of fontforge to accomplish this, so I can use this to convert fonts in bulk, and despite being GPL, after reaching out to the community from fontforge, they said:

We do not consider fonts created with FontForge or scripts run in FontForge to be derivative works of FontForge, which is standard practice for content creation tools and script interpreters. The FontForge license thus has no implication upon the ownership of those fonts and scripts or the owner's right to use and to distribute them. FontForge depends heavily upon a number of GPL libraries at the moment, and that is unlikely to change.

So for my purposes, I am content with this solution.