matplotlib/matplotlib · error · ValueError

RGBA values should be within 0-1 range

Error message

RGBA values should be within 0-1 range

What it means

Error "RGBA values should be within 0-1 range" thrown in matplotlib/matplotlib.

Source

Thrown at lib/matplotlib/colors.py:442

        if c.ndim == 2 and c.shape[0] == 1:
            c = c.reshape(-1)
    # tuple color.
    if not np.iterable(c):
        raise ValueError(f"Invalid RGBA argument: {orig_c!r}")
    if len(c) not in [3, 4]:
        raise ValueError("RGBA sequence should have length 3 or 4")
    if not all(isinstance(x, Real) for x in c):
        # Checks that don't work: `map(float, ...)`, `np.array(..., float)` and
        # `np.array(...).astype(float)` would all convert "0.5" to 0.5.
        raise ValueError(f"Invalid RGBA argument: {orig_c!r}")
    # Return a tuple to prevent the cached value from being modified.
    c = tuple(map(float, c))
    if len(c) == 3 and alpha is None:
        alpha = 1
    if alpha is not None:
        c = c[:3] + (alpha,)
    if any(elem < 0 or elem > 1 for elem in c):
        raise ValueError("RGBA values should be within 0-1 range")
    return c


def to_rgba_array(c, alpha=None):
    """
    Convert *c* to a (n, 4) array of RGBA colors.

    Parameters
    ----------
    c : :mpltype:`color` or list of :mpltype:`color` or RGB(A) array
        If *c* is a masked array, an `~numpy.ndarray` is returned with a
        (0, 0, 0, 0) row for each masked value or row in *c*.

    alpha : float or sequence of floats, optional
        If *alpha* is given, force the alpha value of the returned RGBA tuple
        to *alpha*.

        If None, the alpha value from *c* is used. If *c* does not have an

View on GitHub (pinned to b379c1b69e)

When it happens

Trigger: Thrown at lib/matplotlib/colors.py:442 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of matplotlib/matplotlib@b379c1b69e (2026-08-21). Data as JSON: /api/errors/492fd14ad1537692. Report an issue: GitHub.