rcparams - MNUtils

rcparams

Package-wide defaults, in one validated mapping.

Every knob that used to live in a module-level DEFAULT_* dict is a key in rcParams, the way matplotlib’s own rcParams works, and for the same reason: a default that is worth having is worth being able to change once at the top of a notebook instead of at every call site.

import mnutils

mnutils.rcParams["image.cmap"] = "viridis"          # for the whole session
with mnutils.rc_context({"grid.panel_height": "30rem"}):
    ...                                             # ...or just for a block
mnutils.rcdefaults()                                # back to the built-ins

Three rules make this safe to rely on:

Keys are validated on assignment. _VALIDATORS defines both the legal key set and what each key accepts, so a typo raises immediately (with a near-match suggestion) rather than being silently ignored until someone wonders why the colormap never changed.
Nothing reads a default at import time. Functions take None and resolve it in the body via resolve_rc, so assigning to rcParams after import mnutils actually takes effect. Binding a default in a signature (cmap=rcParams["image.cmap"]) freezes it at import and is the one mistake this module exists to prevent.
An explicit argument always wins. Precedence is argument > rc_context
rcParams > the built-in default in _DEFAULTS.

Attributes¶

Name	Description
`rcParams`	The live parameter mapping every MNUtils function reads its defaults from.
`rcParamsDefault`	The built-in defaults. Never mutated -- `rcdefaults` restores from here.
`rc_presets`

Classes¶

Name	Description
RcParams	A validated `str -> value` mapping of package defaults.

RcParams¶

rcparams.RcParams(mapping=None)

A validated str -> value mapping of package defaults.

Behaves like a dict, except that only keys in _VALIDATORS exist and every assignment goes through that key’s validator. Keys cannot be added or removed -- rcdefaults restores values, it never rebuilds the key set.

Methods¶

Name	Description
copy	A detached `RcParams` holding the same values.
group	The keys under `prefix`, with the prefix stripped.

copy¶

rcparams.RcParams.copy()

A detached RcParams holding the same values.

group¶

rcparams.RcParams.group(prefix)

The keys under prefix, with the prefix stripped.

rcParams.group("image.ax") gives {"xlabel": ..., "xticks": ...} -- the shape a matplotlib.axes.Axes.set call wants, which is why the axis defaults are stored as individual keys rather than as one opaque dict value.

Functions¶

Name	Description
rc_context	Temporarily override rcParams, restoring the previous values on exit.
rcdefaults	Restore every rcParam to its built-in default.
resolve_rc	Return `value`, or `rcParams[key]` when it is `None`.
validate_css_length	Accept `"30rem"`/`"400px"`/`"60vh"`, or a bare number read as rem.

rc_context¶

rcparams.rc_context(rc)

Temporarily override rcParams, restoring the previous values on exit.

Parameters¶

Name	Type	Description	Default
rc	dict	Overrides keyed by rcParam name, e.g. one of `rc_presets`. Names contain dots, so there is no keyword-argument form -- a mapping is the only way to spell them.	required

Returns¶

Name	Type	Description
	RcParams	The live mapping, bound by `as` inside the block, so it can be inspected or further modified there. (NumPy convention would call this a `Yields` section; quartodoc’s renderer raises on one, so it is spelled `Returns` here.)

Examples¶

>>> with rc_context({"image.cmap": "gray"}):
...     pass

rcdefaults¶

rcparams.rcdefaults()

Restore every rcParam to its built-in default.

resolve_rc¶

rcparams.resolve_rc(value, key)

Return value, or rcParams[key] when it is None.

The one-liner behind every param: T | None = None signature in the package. Resolving in the body rather than in the signature is what makes an assignment to rcParams after import take effect at all.

validate_css_length¶

rcparams.validate_css_length(value)

Accept "30rem"/"400px"/"60vh", or a bare number read as rem.

Public because call-site overrides (plotting.images.display_images’s panel_height) bypass rcParams and so bypass its validation, while ending up in the same style attribute.