fdiff
is a Python command line comparison tool for differences in the OpenType table data between font files. The tool provides cross-platform support on macOS, Windows, and Linux systems with a Python v3.6+ interpreter.
- Takes two font file path arguments for comparison
- Dumps OpenType table data in the fontTools library TTX format (XML)
- Compares the OpenType table data across the two files using the unified diff format with 3 lines of surrounding context
- View colored diffs in the terminal with the
-c
or--color
flag - Filter OpenType tables with the
--include
or--exclude
options - Modify the number of context lines displayed in the diff with the
-l
or--lines
option - Display the first n lines of the diff output with the
--head
option - Display the last n lines of the diff output with the
--tail
option
Run fdiff --help
to view all available options.
fdiff
requires a Python 3.6+ interpreter.
Installation in a Python3 virtual environment is recommended.
Use any of the following installation approaches:
$ pip3 install fdiff
$ git clone https://github.com/source-foundry/fdiff.git
$ cd fdiff
$ pip3 install .
The following approach installs the project and associated optional developer dependencies so that source changes are available without the need for re-installation.
$ git clone https://github.com/source-foundry/fdiff.git
$ cd fdiff
$ pip3 install --ignore-installed -r requirements.txt -e ".[dev]"
$ fdiff [OPTIONS] [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
By default, an uncolored unified diff is performed on the two files defined with the local file paths in the above command.
To view a colored diff in your terminal, include either the -c
or --color
option in your command:
$ fdiff --color [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
To include only specified tables in your diff, use the --include
option with a comma separated list of table names:
$ fdiff --include head,post [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
To exclude specified tables in your diff, use the --exclude
option with a comma separated list of table names:
$ fdiff --exclude glyf,OS/2 [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
Do not include spaces between the comma separated table name values!
To change the number of lines of context above/below lines that have differences, use the -l
or --lines
option with an integer value for the desired number of lines. The following command reduces the contextual information to a single line above and below lines with differences:
$ fdiff -l 1 [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
Use the --head
option followed by an integer for the number of lines at the beginning of the output. For example, the following command displays the first 20 lines of the diff:
$ fdiff --head 20 [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
Use the --tail
option followed by an integer for the number of lines at the end of the output. For example, the following command displays the last 20 lines of the diff:
$ fdiff --tail 20 [PRE-FONT FILE PATH] [POST-FONT FILE PATH]
Use fdiff -h
to view all available options.
Please report issues on the project issue tracker.
Contributions are warmly welcomed. A development dependency environment can be installed in editable mode with the developer installation documentation above.
Please use the standard Github pull request approach to propose source changes.
Python source files are linted with flake8
. See the Makefile test-lint
target for details.
Static type checks are performed on Python source files with pytype
. See the Makefile test-type-check
target for details.
The project runs continuous integration testing on Travis CI and Appveyor CI with the pytest
and tox
testing toolchain. Test modules are located in the tests
directory of the repository.
Local testing by Python interpreter version can be performed with the following command executed from the root of the repository:
$ tox -e [PYTHON INTERPRETER VERSION]
Please see the tox
documentation for additional details.
Unit test coverage is executed with the coverage
tool. See the Makefile test-coverage
target for details.
fdiff
is built with the fantastic fontTools free software library and performs text diffs of binary font files using dumps of the TTX OpenType table data serialization format as defined in the fontTools library. The implementation of unified text file diffs is based on a (slightly) modified version of the Python difflib
standard library source. The modifications address diff performance issues with the lengthy text output from TTX dumps of font OpenType data.
Copyright 2019 Source Foundry Authors and Contributors
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
This project distributes a modified version of third party source code from the Python programming language standard library. The difflib.py
v3.7.4 module is Copyright © 2001-2019 Python Software Foundation; All Rights Reserved. This source is modified and distributed in this project under the PSF LICENSE AGREEMENT FOR PYTHON 3.7.4. The module is renamed to fdifflib.py
to distinguish it from the upstream source and modifications made here are documented in comments at the head of the module.