Aspose.Font FOSS
Python
Troubleshooting Aspose.Font FOSS for Python

Troubleshooting Aspose.Font FOSS for Python

Import Errors

ModuleNotFoundError: No module named 'aspose_font'

The package is not installed in the active Python environment. Install it:

pip install "aspose-font>=1.0.0"

Ensure you are installing into the correct virtual environment if you use one.

ImportError: cannot import name 'FontType' from 'aspose_font'

FontType is exported from the top-level aspose_font package. Use:

from aspose_font import FontType  # correct

If you see this error, confirm you have aspose-font>=1.0.0 installed in your active environment.

Font Loading Errors

FontLoadException when calling FontLoader.open()

Possible causes:

  • The file path is incorrect or the file does not exist
  • The file is corrupted or has a non-standard header
  • You passed a bytes object that is not a valid font

Check the file exists before loading:

import os
from aspose_font.loader import FontLoader

path = "MyFont.ttf"
if not os.path.exists(path):
    raise FileNotFoundError(path)
font = FontLoader.open(path)

Windows path backslash issues

Use raw strings or forward slashes on Windows:

font = FontLoader.open(r"C:\Fonts\MyFont.ttf")
# or
font = FontLoader.open("C:/Fonts/MyFont.ttf")

API Errors

AttributeError: 'Font' object has no attribute 'ttf_tables'

ttf_tables is a property on TtfFont, not the base Font class. Use a type annotation:

from aspose_font.ttf.font import TtfFont
ttf_font: TtfFont = FontLoader.open("MyFont.ttf")
tables = ttf_font.ttf_tables

NotImplementedError from Font.to_bytes()

Font.to_bytes() raises NotImplementedError only when called on the abstract base class. All concrete font classes (TtfFont, CffFont, WoffFont, Woff2Font, etc.) implement to_bytes() and return the font bytes. If you call FontLoader.open() you get a concrete instance — call to_bytes() directly, or use FontConverter.convert() to change format first:

from aspose_font.converter import FontConverter
from aspose_font import FontType

woff2 = FontConverter.convert(font, FontType.WOFF2)

See Also