Python rcsetup.validate_backend方法代码示例

# 需要导入模块: from matplotlib import rcsetup [as 别名]
# 或者: from matplotlib.rcsetup import validate_backend [as 别名]
def use(arg, warn=True, force=False):
    """
    Set the matplotlib backend to one of the known backends.

    To find out which backend is currently set, see
    :func:`matplotlib.get_backend`.


    Parameters
    ----------
    arg : str
        The backend to switch to.  This can either be one of the
        'standard' backend names or a string of the form
        ``module://my.module.name``.  This value is case-insensitive.

    warn : bool, optional
        If True, warn if this is called after pyplot has been imported
        and a backend is set up.

        defaults to True

    force : bool, optional
        If True, attempt to switch the backend.  This defaults to
        False.


    """
    name = validate_backend(arg)

    # if setting back to the same thing, do nothing
    if (dict.__getitem__(rcParams, 'backend') == name):
        pass

    # Check if we have already imported pyplot and triggered
    # backend selection, do a bit more work
    elif 'matplotlib.pyplot' in sys.modules:
        # If we are here then the requested is different than the current.
        # If we are going to force the switch, never warn, else, if warn
        # is True, then direct users to `plt.switch_backend`
        if (not force) and warn:
            warnings.warn(
                ("matplotlib.pyplot as already been imported, "
                 "this call will have no effect."),
                stacklevel=2)

        # if we are going to force switching the backend, pull in
        # `switch_backend` from pyplot.  This will only happen if
        # pyplot is already imported.
        if force:
            from matplotlib.pyplot import switch_backend
            switch_backend(name)
    # Finally if pyplot is not imported update both rcParams and
    # rcDefaults so restoring the defaults later with rcdefaults
    # won't change the backend.  This is a bit of overkill as 'backend'
    # is already in style.core.STYLE_BLACKLIST, but better to be safe.
    else:
        rcParams['backend'] = rcParamsDefault['backend'] = name 

# 需要导入模块: from matplotlib import rcsetup [as 别名]
# 或者: from matplotlib.rcsetup import validate_backend [as 别名]
def use(arg, warn=True, force=False):
    """
    Set the matplotlib backend to one of the known backends.

    The argument is case-insensitive. *warn* specifies whether a
    warning should be issued if a backend has already been set up.
    *force* is an **experimental** flag that tells matplotlib to
    attempt to initialize a new backend by reloading the backend
    module.

    .. note::

        This function must be called *before* importing pyplot for
        the first time; or, if you are not using pyplot, it must be called
        before importing matplotlib.backends.  If warn is True, a warning
        is issued if you try and call this after pylab or pyplot have been
        loaded.  In certain black magic use cases, e.g.
        :func:`pyplot.switch_backend`, we are doing the reloading necessary to
        make the backend switch work (in some cases, e.g., pure image
        backends) so one can set warn=False to suppress the warnings.

    To find out which backend is currently set, see
    :func:`matplotlib.get_backend`.

    """
    # Lets determine the proper backend name first
    if arg.startswith('module://'):
        name = arg
    else:
        # Lowercase only non-module backend names (modules are case-sensitive)
        arg = arg.lower()
        name = validate_backend(arg)

    # Check if we've already set up a backend
    if 'matplotlib.backends' in sys.modules:
        # Warn only if called with a different name
        if (rcParams['backend'] != name) and warn:
            import matplotlib.backends
            warnings.warn(
                _use_error_msg.format(
                    backend=rcParams['backend'],
                    tb=matplotlib.backends._backend_loading_tb),
                stacklevel=2)

        # Unless we've been told to force it, just return
        if not force:
            return
        need_reload = True
    else:
        need_reload = False

    # Store the backend name
    rcParams['backend'] = name

    # If needed we reload here because a lot of setup code is triggered on
    # module import. See backends/__init__.py for more detail.
    if need_reload:
        reload(sys.modules['matplotlib.backends'])