Created
August 17, 2021 09:46
-
-
Save SamWolski/6a53bf12a84cde17bc37b103ca095b30 to your computer and use it in GitHub Desktop.
Add custom metadata to matplotlib pdfs
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| """ | |
| Write metadata to pdf files with no warnings. | |
| Useful for provenance, and in this way we can suppress warnings for end users of a larger application | |
| """ | |
| from matplotlib.backends.backend_pdf import PdfPages | |
| import matplotlib.pyplot as plt | |
| import numpy as np | |
| import warnings | |
| ############################################################################## | |
| ## Generate some data that we want to plot | |
| x_data = np.linspace(0.0, 4.0, 101) | |
| y_data = np.sin(x_data) | |
| ############################################################################## | |
| ## Save with metadata in savefig call | |
| ## This generates warnings! But still works | |
| fig, axes = plt.subplots(1,1) | |
| axes.plot(x_data, y_data, marker='o', linestyle='', color='C0') | |
| fig.savefig("mpl_mdata_savefig.pdf", metadata={"Author": "Sam", "foo": "bar", "baz": "3"}) | |
| ############################################################################## | |
| ## Let's write a function that let's us do this without the warnings! | |
| def save_custom_pdf_metadata(fig_obj, target_path, metadata): | |
| ## Enter the context manager for the pdf object | |
| with PdfPages(target_path) as pdf_obj: | |
| ## Get metadata InfoDict object | |
| infodict = pdf_obj.infodict() | |
| ## Suppress warnings, but ONLY for the metadata addition step | |
| with warnings.catch_warnings(): | |
| ## Iterate over metadata elements and add them to infodict | |
| for key, value in metadata.items(): | |
| infodict[key] = value | |
| ## Save the current figure | |
| pdf_obj.savefig(fig_obj) | |
| ## Watch out for: | |
| ## - more possible kwargs in the call to savefig | |
| ## and/or | |
| ## - needs to be filtered by format at a higher level, as this only works for pdf! | |
| ## | |
| return fig_obj | |
| ## Now using the custom function | |
| fig, axes = plt.subplots(1,1) | |
| axes.plot(x_data, y_data, marker='o', linestyle='', color='C0') | |
| save_custom_pdf_metadata(fig, "mpl_mdata_suppressed.pdf", metadata={"Author": "Sam", "foo": "bar", "quux": "3"}) | |
| ## In a real application, the metadata will be generated automatically | |
| ## All the user needs to do is say "here's the fig object, save this (as a pdf)". |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment