install.py 文件源码

def _set_matplotlib_default_backend():
    """
    matplotlib will try to print to a display if it is available, but don't want
    to run it in interactive mode. we tried setting the backend to 'Agg'' before
    importing, but it was still resulting in issues. we replace the existing
    backend with 'agg' in the default matplotlibrc. This is a hack until we can
    find a better solution
    """
    if _matplotlib_installed():
        import matplotlib
        matplotlib.use('Agg', force=True)
        config = matplotlib.matplotlib_fname()
        with file_transaction(config) as tx_out_file:
            with open(config) as in_file, open(tx_out_file, "w") as out_file:
                for line in in_file:
                    if line.split(":")[0].strip() == "backend":
                        out_file.write("backend: agg\n")
                    else:
                        out_file.write(line)