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from __future__ import annotations
import itertools
from typing import (
TYPE_CHECKING,
Collection,
Iterator,
cast,
)
import warnings
import matplotlib as mpl
import matplotlib.colors
import numpy as np
from pandas._typing import MatplotlibColor as Color
from pandas.util._exceptions import find_stack_level
from pandas.core.dtypes.common import is_list_like
import pandas.core.common as com
if TYPE_CHECKING:
from matplotlib.colors import Colormap
def get_standard_colors(
num_colors: int,
colormap: Colormap | None = None,
color_type: str = "default",
color: dict[str, Color] | Color | Collection[Color] | None = None,
):
"""
Get standard colors based on `colormap`, `color_type` or `color` inputs.
Parameters
----------
num_colors : int
Minimum number of colors to be returned.
Ignored if `color` is a dictionary.
colormap : :py:class:`matplotlib.colors.Colormap`, optional
Matplotlib colormap.
When provided, the resulting colors will be derived from the colormap.
color_type : {"default", "random"}, optional
Type of colors to derive. Used if provided `color` and `colormap` are None.
Ignored if either `color` or `colormap` are not None.
color : dict or str or sequence, optional
Color(s) to be used for deriving sequence of colors.
Can be either be a dictionary, or a single color (single color string,
or sequence of floats representing a single color),
or a sequence of colors.
Returns
-------
dict or list
Standard colors. Can either be a mapping if `color` was a dictionary,
or a list of colors with a length of `num_colors` or more.
Warns
-----
UserWarning
If both `colormap` and `color` are provided.
Parameter `color` will override.
"""
if isinstance(color, dict):
return color
colors = _derive_colors(
color=color,
colormap=colormap,
color_type=color_type,
num_colors=num_colors,
)
return list(_cycle_colors(colors, num_colors=num_colors))
def _derive_colors(
*,
color: Color | Collection[Color] | None,
colormap: str | Colormap | None,
color_type: str,
num_colors: int,
) -> list[Color]:
"""
Derive colors from either `colormap`, `color_type` or `color` inputs.
Get a list of colors either from `colormap`, or from `color`,
or from `color_type` (if both `colormap` and `color` are None).
Parameters
----------
color : str or sequence, optional
Color(s) to be used for deriving sequence of colors.
Can be either be a single color (single color string, or sequence of floats
representing a single color), or a sequence of colors.
colormap : :py:class:`matplotlib.colors.Colormap`, optional
Matplotlib colormap.
When provided, the resulting colors will be derived from the colormap.
color_type : {"default", "random"}, optional
Type of colors to derive. Used if provided `color` and `colormap` are None.
Ignored if either `color` or `colormap`` are not None.
num_colors : int
Number of colors to be extracted.
Returns
-------
list
List of colors extracted.
Warns
-----
UserWarning
If both `colormap` and `color` are provided.
Parameter `color` will override.
"""
if color is None and colormap is not None:
return _get_colors_from_colormap(colormap, num_colors=num_colors)
elif color is not None:
if colormap is not None:
warnings.warn(
"'color' and 'colormap' cannot be used simultaneously. Using 'color'",
stacklevel=find_stack_level(),
)
return _get_colors_from_color(color)
else:
return _get_colors_from_color_type(color_type, num_colors=num_colors)
def _cycle_colors(colors: list[Color], num_colors: int) -> Iterator[Color]:
"""Cycle colors until achieving max of `num_colors` or length of `colors`.
Extra colors will be ignored by matplotlib if there are more colors
than needed and nothing needs to be done here.
"""
max_colors = max(num_colors, len(colors))
yield from itertools.islice(itertools.cycle(colors), max_colors)
def _get_colors_from_colormap(
colormap: str | Colormap,
num_colors: int,
) -> list[Color]:
"""Get colors from colormap."""
cmap = _get_cmap_instance(colormap)
return [cmap(num) for num in np.linspace(0, 1, num=num_colors)]
def _get_cmap_instance(colormap: str | Colormap) -> Colormap:
"""Get instance of matplotlib colormap."""
if isinstance(colormap, str):
cmap = colormap
colormap = mpl.colormaps[colormap]
if colormap is None:
raise ValueError(f"Colormap {cmap} is not recognized")
return colormap
def _get_colors_from_color(
color: Color | Collection[Color],
) -> list[Color]:
"""Get colors from user input color."""
if len(color) == 0:
raise ValueError(f"Invalid color argument: {color}")
if _is_single_color(color):
color = cast(Color, color)
return [color]
color = cast(Collection[Color], color)
return list(_gen_list_of_colors_from_iterable(color))
def _is_single_color(color: Color | Collection[Color]) -> bool:
"""Check if `color` is a single color, not a sequence of colors.
Single color is of these kinds:
- Named color "red", "C0", "firebrick"
- Alias "g"
- Sequence of floats, such as (0.1, 0.2, 0.3) or (0.1, 0.2, 0.3, 0.4).
See Also
--------
_is_single_string_color
"""
if isinstance(color, str) and _is_single_string_color(color):
# GH #36972
return True
if _is_floats_color(color):
return True
return False
def _gen_list_of_colors_from_iterable(color: Collection[Color]) -> Iterator[Color]:
"""
Yield colors from string of several letters or from collection of colors.
"""
for x in color:
if _is_single_color(x):
yield x
else:
raise ValueError(f"Invalid color {x}")
def _is_floats_color(color: Color | Collection[Color]) -> bool:
"""Check if color comprises a sequence of floats representing color."""
return bool(
is_list_like(color)
and (len(color) == 3 or len(color) == 4)
and all(isinstance(x, (int, float)) for x in color)
)
def _get_colors_from_color_type(color_type: str, num_colors: int) -> list[Color]:
"""Get colors from user input color type."""
if color_type == "default":
return _get_default_colors(num_colors)
elif color_type == "random":
return _get_random_colors(num_colors)
else:
raise ValueError("color_type must be either 'default' or 'random'")
def _get_default_colors(num_colors: int) -> list[Color]:
"""Get `num_colors` of default colors from matplotlib rc params."""
import matplotlib.pyplot as plt
colors = [c["color"] for c in plt.rcParams["axes.prop_cycle"]]
return colors[0:num_colors]
def _get_random_colors(num_colors: int) -> list[Color]:
"""Get `num_colors` of random colors."""
return [_random_color(num) for num in range(num_colors)]
def _random_color(column: int) -> list[float]:
"""Get a random color represented as a list of length 3"""
# GH17525 use common._random_state to avoid resetting the seed
rs = com.random_state(column)
return rs.rand(3).tolist()
def _is_single_string_color(color: Color) -> bool:
"""Check if `color` is a single string color.
Examples of single string colors:
- 'r'
- 'g'
- 'red'
- 'green'
- 'C3'
- 'firebrick'
Parameters
----------
color : Color
Color string or sequence of floats.
Returns
-------
bool
True if `color` looks like a valid color.
False otherwise.
"""
conv = matplotlib.colors.ColorConverter()
try:
conv.to_rgba(color)
except ValueError:
return False
else:
return True
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