import colorsys from itertools import cycle import numpy as np import matplotlib as mpl from .external import husl from .utils import desaturate, get_color_cycle from .colors import xkcd_rgb, crayons from ._compat import get_colormap __all__ = ["color_palette", "hls_palette", "husl_palette", "mpl_palette", "dark_palette", "light_palette", "diverging_palette", "blend_palette", "xkcd_palette", "crayon_palette", "cubehelix_palette", "set_color_codes"] SEABORN_PALETTES = dict( deep=["#4C72B0", "#DD8452", "#55A868", "#C44E52", "#8172B3", "#937860", "#DA8BC3", "#8C8C8C", "#CCB974", "#64B5CD"], deep6=["#4C72B0", "#55A868", "#C44E52", "#8172B3", "#CCB974", "#64B5CD"], muted=["#4878D0", "#EE854A", "#6ACC64", "#D65F5F", "#956CB4", "#8C613C", "#DC7EC0", "#797979", "#D5BB67", "#82C6E2"], muted6=["#4878D0", "#6ACC64", "#D65F5F", "#956CB4", "#D5BB67", "#82C6E2"], pastel=["#A1C9F4", "#FFB482", "#8DE5A1", "#FF9F9B", "#D0BBFF", "#DEBB9B", "#FAB0E4", "#CFCFCF", "#FFFEA3", "#B9F2F0"], pastel6=["#A1C9F4", "#8DE5A1", "#FF9F9B", "#D0BBFF", "#FFFEA3", "#B9F2F0"], bright=["#023EFF", "#FF7C00", "#1AC938", "#E8000B", "#8B2BE2", "#9F4800", "#F14CC1", "#A3A3A3", "#FFC400", "#00D7FF"], bright6=["#023EFF", "#1AC938", "#E8000B", "#8B2BE2", "#FFC400", "#00D7FF"], dark=["#001C7F", "#B1400D", "#12711C", "#8C0800", "#591E71", "#592F0D", "#A23582", "#3C3C3C", "#B8850A", "#006374"], dark6=["#001C7F", "#12711C", "#8C0800", "#591E71", "#B8850A", "#006374"], colorblind=["#0173B2", "#DE8F05", "#029E73", "#D55E00", "#CC78BC", "#CA9161", "#FBAFE4", "#949494", "#ECE133", "#56B4E9"], colorblind6=["#0173B2", "#029E73", "#D55E00", "#CC78BC", "#ECE133", "#56B4E9"] ) MPL_QUAL_PALS = { "tab10": 10, "tab20": 20, "tab20b": 20, "tab20c": 20, "Set1": 9, "Set2": 8, "Set3": 12, "Accent": 8, "Paired": 12, "Pastel1": 9, "Pastel2": 8, "Dark2": 8, } QUAL_PALETTE_SIZES = MPL_QUAL_PALS.copy() QUAL_PALETTE_SIZES.update({k: len(v) for k, v in SEABORN_PALETTES.items()}) QUAL_PALETTES = list(QUAL_PALETTE_SIZES.keys()) class _ColorPalette(list): """Set the color palette in a with statement, otherwise be a list.""" def __enter__(self): """Open the context.""" from .rcmod import set_palette self._orig_palette = color_palette() set_palette(self) return self def __exit__(self, *args): """Close the context.""" from .rcmod import set_palette set_palette(self._orig_palette) def as_hex(self): """Return a color palette with hex codes instead of RGB values.""" hex = [mpl.colors.rgb2hex(rgb) for rgb in self] return _ColorPalette(hex) def _repr_html_(self): """Rich display of the color palette in an HTML frontend.""" s = 55 n = len(self) html = f'' for i, c in enumerate(self.as_hex()): html += ( f'' ) html += '' return html def _patch_colormap_display(): """Simplify the rich display of matplotlib color maps in a notebook.""" def _repr_png_(self): """Generate a PNG representation of the Colormap.""" import io from PIL import Image import numpy as np IMAGE_SIZE = (400, 50) X = np.tile(np.linspace(0, 1, IMAGE_SIZE[0]), (IMAGE_SIZE[1], 1)) pixels = self(X, bytes=True) png_bytes = io.BytesIO() Image.fromarray(pixels).save(png_bytes, format='png') return png_bytes.getvalue() def _repr_html_(self): """Generate an HTML representation of the Colormap.""" import base64 png_bytes = self._repr_png_() png_base64 = base64.b64encode(png_bytes).decode('ascii') return ('') mpl.colors.Colormap._repr_png_ = _repr_png_ mpl.colors.Colormap._repr_html_ = _repr_html_ def color_palette(palette=None, n_colors=None, desat=None, as_cmap=False): """Return a list of colors or continuous colormap defining a palette. Possible ``palette`` values include: - Name of a seaborn palette (deep, muted, bright, pastel, dark, colorblind) - Name of matplotlib colormap - 'husl' or 'hls' - 'ch:' - 'light:', 'dark:', 'blend:,', - A sequence of colors in any format matplotlib accepts Calling this function with ``palette=None`` will return the current matplotlib color cycle. This function can also be used in a ``with`` statement to temporarily set the color cycle for a plot or set of plots. See the :ref:`tutorial ` for more information. Parameters ---------- palette : None, string, or sequence, optional Name of palette or None to return current palette. If a sequence, input colors are used but possibly cycled and desaturated. n_colors : int, optional Number of colors in the palette. If ``None``, the default will depend on how ``palette`` is specified. Named palettes default to 6 colors, but grabbing the current palette or passing in a list of colors will not change the number of colors unless this is specified. Asking for more colors than exist in the palette will cause it to cycle. Ignored when ``as_cmap`` is True. desat : float, optional Proportion to desaturate each color by. as_cmap : bool If True, return a :class:`matplotlib.colors.ListedColormap`. Returns ------- list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- set_palette : Set the default color cycle for all plots. set_color_codes : Reassign color codes like ``"b"``, ``"g"``, etc. to colors from one of the seaborn palettes. Examples -------- .. include:: ../docstrings/color_palette.rst """ if palette is None: palette = get_color_cycle() if n_colors is None: n_colors = len(palette) elif not isinstance(palette, str): palette = palette if n_colors is None: n_colors = len(palette) else: if n_colors is None: # Use all colors in a qualitative palette or 6 of another kind n_colors = QUAL_PALETTE_SIZES.get(palette, 6) if palette in SEABORN_PALETTES: # Named "seaborn variant" of matplotlib default color cycle palette = SEABORN_PALETTES[palette] elif palette == "hls": # Evenly spaced colors in cylindrical RGB space palette = hls_palette(n_colors, as_cmap=as_cmap) elif palette == "husl": # Evenly spaced colors in cylindrical Lab space palette = husl_palette(n_colors, as_cmap=as_cmap) elif palette.lower() == "jet": # Paternalism raise ValueError("No.") elif palette.startswith("ch:"): # Cubehelix palette with params specified in string args, kwargs = _parse_cubehelix_args(palette) palette = cubehelix_palette(n_colors, *args, **kwargs, as_cmap=as_cmap) elif palette.startswith("light:"): # light palette to color specified in string _, color = palette.split(":") reverse = color.endswith("_r") if reverse: color = color[:-2] palette = light_palette(color, n_colors, reverse=reverse, as_cmap=as_cmap) elif palette.startswith("dark:"): # light palette to color specified in string _, color = palette.split(":") reverse = color.endswith("_r") if reverse: color = color[:-2] palette = dark_palette(color, n_colors, reverse=reverse, as_cmap=as_cmap) elif palette.startswith("blend:"): # blend palette between colors specified in string _, colors = palette.split(":") colors = colors.split(",") palette = blend_palette(colors, n_colors, as_cmap=as_cmap) else: try: # Perhaps a named matplotlib colormap? palette = mpl_palette(palette, n_colors, as_cmap=as_cmap) except (ValueError, KeyError): # Error class changed in mpl36 raise ValueError(f"{palette!r} is not a valid palette name") if desat is not None: palette = [desaturate(c, desat) for c in palette] if not as_cmap: # Always return as many colors as we asked for pal_cycle = cycle(palette) palette = [next(pal_cycle) for _ in range(n_colors)] # Always return in r, g, b tuple format try: palette = map(mpl.colors.colorConverter.to_rgb, palette) palette = _ColorPalette(palette) except ValueError: raise ValueError(f"Could not generate a palette for {palette}") return palette def hls_palette(n_colors=6, h=.01, l=.6, s=.65, as_cmap=False): # noqa """ Return hues with constant lightness and saturation in the HLS system. The hues are evenly sampled along a circular path. The resulting palette will be appropriate for categorical or cyclical data. The `h`, `l`, and `s` values should be between 0 and 1. .. note:: While the separation of the resulting colors will be mathematically constant, the HLS system does not construct a perceptually-uniform space, so their apparent intensity will vary. Parameters ---------- n_colors : int Number of colors in the palette. h : float The value of the first hue. l : float The lightness value. s : float The saturation intensity. as_cmap : bool If True, return a matplotlib colormap object. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- husl_palette : Make a palette using evenly spaced hues in the HUSL system. Examples -------- .. include:: ../docstrings/hls_palette.rst """ if as_cmap: n_colors = 256 hues = np.linspace(0, 1, int(n_colors) + 1)[:-1] hues += h hues %= 1 hues -= hues.astype(int) palette = [colorsys.hls_to_rgb(h_i, l, s) for h_i in hues] if as_cmap: return mpl.colors.ListedColormap(palette, "hls") else: return _ColorPalette(palette) def husl_palette(n_colors=6, h=.01, s=.9, l=.65, as_cmap=False): # noqa """ Return hues with constant lightness and saturation in the HUSL system. The hues are evenly sampled along a circular path. The resulting palette will be appropriate for categorical or cyclical data. The `h`, `l`, and `s` values should be between 0 and 1. This function is similar to :func:`hls_palette`, but it uses a nonlinear color space that is more perceptually uniform. Parameters ---------- n_colors : int Number of colors in the palette. h : float The value of the first hue. l : float The lightness value. s : float The saturation intensity. as_cmap : bool If True, return a matplotlib colormap object. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- hls_palette : Make a palette using evenly spaced hues in the HSL system. Examples -------- .. include:: ../docstrings/husl_palette.rst """ if as_cmap: n_colors = 256 hues = np.linspace(0, 1, int(n_colors) + 1)[:-1] hues += h hues %= 1 hues *= 359 s *= 99 l *= 99 # noqa palette = [_color_to_rgb((h_i, s, l), input="husl") for h_i in hues] if as_cmap: return mpl.colors.ListedColormap(palette, "hsl") else: return _ColorPalette(palette) def mpl_palette(name, n_colors=6, as_cmap=False): """ Return a palette or colormap from the matplotlib registry. For continuous palettes, evenly-spaced discrete samples are chosen while excluding the minimum and maximum value in the colormap to provide better contrast at the extremes. For qualitative palettes (e.g. those from colorbrewer), exact values are indexed (rather than interpolated), but fewer than `n_colors` can be returned if the palette does not define that many. Parameters ---------- name : string Name of the palette. This should be a named matplotlib colormap. n_colors : int Number of discrete colors in the palette. Returns ------- list of RGB tuples or :class:`matplotlib.colors.ListedColormap` Examples -------- .. include:: ../docstrings/mpl_palette.rst """ if name.endswith("_d"): sub_name = name[:-2] if sub_name.endswith("_r"): reverse = True sub_name = sub_name[:-2] else: reverse = False pal = color_palette(sub_name, 2) + ["#333333"] if reverse: pal = pal[::-1] cmap = blend_palette(pal, n_colors, as_cmap=True) else: cmap = get_colormap(name) if name in MPL_QUAL_PALS: bins = np.linspace(0, 1, MPL_QUAL_PALS[name])[:n_colors] else: bins = np.linspace(0, 1, int(n_colors) + 2)[1:-1] palette = list(map(tuple, cmap(bins)[:, :3])) if as_cmap: return cmap else: return _ColorPalette(palette) def _color_to_rgb(color, input): """Add some more flexibility to color choices.""" if input == "hls": color = colorsys.hls_to_rgb(*color) elif input == "husl": color = husl.husl_to_rgb(*color) color = tuple(np.clip(color, 0, 1)) elif input == "xkcd": color = xkcd_rgb[color] return mpl.colors.to_rgb(color) def dark_palette(color, n_colors=6, reverse=False, as_cmap=False, input="rgb"): """Make a sequential palette that blends from dark to ``color``. This kind of palette is good for data that range between relatively uninteresting low values and interesting high values. The ``color`` parameter can be specified in a number of ways, including all options for defining a color in matplotlib and several additional color spaces that are handled by seaborn. You can also use the database of named colors from the XKCD color survey. If you are using the IPython notebook, you can also choose this palette interactively with the :func:`choose_dark_palette` function. Parameters ---------- color : base color for high values hex, rgb-tuple, or html color name n_colors : int, optional number of colors in the palette reverse : bool, optional if True, reverse the direction of the blend as_cmap : bool, optional If True, return a :class:`matplotlib.colors.ListedColormap`. input : {'rgb', 'hls', 'husl', xkcd'} Color space to interpret the input color. The first three options apply to tuple inputs and the latter applies to string inputs. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- light_palette : Create a sequential palette with bright low values. diverging_palette : Create a diverging palette with two colors. Examples -------- .. include:: ../docstrings/dark_palette.rst """ rgb = _color_to_rgb(color, input) hue, sat, _ = husl.rgb_to_husl(*rgb) gray_s, gray_l = .15 * sat, 15 gray = _color_to_rgb((hue, gray_s, gray_l), input="husl") colors = [rgb, gray] if reverse else [gray, rgb] return blend_palette(colors, n_colors, as_cmap) def light_palette(color, n_colors=6, reverse=False, as_cmap=False, input="rgb"): """Make a sequential palette that blends from light to ``color``. The ``color`` parameter can be specified in a number of ways, including all options for defining a color in matplotlib and several additional color spaces that are handled by seaborn. You can also use the database of named colors from the XKCD color survey. If you are using a Jupyter notebook, you can also choose this palette interactively with the :func:`choose_light_palette` function. Parameters ---------- color : base color for high values hex code, html color name, or tuple in `input` space. n_colors : int, optional number of colors in the palette reverse : bool, optional if True, reverse the direction of the blend as_cmap : bool, optional If True, return a :class:`matplotlib.colors.ListedColormap`. input : {'rgb', 'hls', 'husl', xkcd'} Color space to interpret the input color. The first three options apply to tuple inputs and the latter applies to string inputs. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- dark_palette : Create a sequential palette with dark low values. diverging_palette : Create a diverging palette with two colors. Examples -------- .. include:: ../docstrings/light_palette.rst """ rgb = _color_to_rgb(color, input) hue, sat, _ = husl.rgb_to_husl(*rgb) gray_s, gray_l = .15 * sat, 95 gray = _color_to_rgb((hue, gray_s, gray_l), input="husl") colors = [rgb, gray] if reverse else [gray, rgb] return blend_palette(colors, n_colors, as_cmap) def diverging_palette(h_neg, h_pos, s=75, l=50, sep=1, n=6, # noqa center="light", as_cmap=False): """Make a diverging palette between two HUSL colors. If you are using the IPython notebook, you can also choose this palette interactively with the :func:`choose_diverging_palette` function. Parameters ---------- h_neg, h_pos : float in [0, 359] Anchor hues for negative and positive extents of the map. s : float in [0, 100], optional Anchor saturation for both extents of the map. l : float in [0, 100], optional Anchor lightness for both extents of the map. sep : int, optional Size of the intermediate region. n : int, optional Number of colors in the palette (if not returning a cmap) center : {"light", "dark"}, optional Whether the center of the palette is light or dark as_cmap : bool, optional If True, return a :class:`matplotlib.colors.ListedColormap`. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- dark_palette : Create a sequential palette with dark values. light_palette : Create a sequential palette with light values. Examples -------- .. include: ../docstrings/diverging_palette.rst """ palfunc = dict(dark=dark_palette, light=light_palette)[center] n_half = int(128 - (sep // 2)) neg = palfunc((h_neg, s, l), n_half, reverse=True, input="husl") pos = palfunc((h_pos, s, l), n_half, input="husl") midpoint = dict(light=[(.95, .95, .95)], dark=[(.133, .133, .133)])[center] mid = midpoint * sep pal = blend_palette(np.concatenate([neg, mid, pos]), n, as_cmap=as_cmap) return pal def blend_palette(colors, n_colors=6, as_cmap=False, input="rgb"): """Make a palette that blends between a list of colors. Parameters ---------- colors : sequence of colors in various formats interpreted by `input` hex code, html color name, or tuple in `input` space. n_colors : int, optional Number of colors in the palette. as_cmap : bool, optional If True, return a :class:`matplotlib.colors.ListedColormap`. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` Examples -------- .. include: ../docstrings/blend_palette.rst """ colors = [_color_to_rgb(color, input) for color in colors] name = "blend" pal = mpl.colors.LinearSegmentedColormap.from_list(name, colors) if not as_cmap: rgb_array = pal(np.linspace(0, 1, int(n_colors)))[:, :3] # no alpha pal = _ColorPalette(map(tuple, rgb_array)) return pal def xkcd_palette(colors): """Make a palette with color names from the xkcd color survey. See xkcd for the full list of colors: https://xkcd.com/color/rgb/ This is just a simple wrapper around the `seaborn.xkcd_rgb` dictionary. Parameters ---------- colors : list of strings List of keys in the `seaborn.xkcd_rgb` dictionary. Returns ------- palette A list of colors as RGB tuples. See Also -------- crayon_palette : Make a palette with Crayola crayon colors. """ palette = [xkcd_rgb[name] for name in colors] return color_palette(palette, len(palette)) def crayon_palette(colors): """Make a palette with color names from Crayola crayons. Colors are taken from here: https://en.wikipedia.org/wiki/List_of_Crayola_crayon_colors This is just a simple wrapper around the `seaborn.crayons` dictionary. Parameters ---------- colors : list of strings List of keys in the `seaborn.crayons` dictionary. Returns ------- palette A list of colors as RGB tuples. See Also -------- xkcd_palette : Make a palette with named colors from the XKCD color survey. """ palette = [crayons[name] for name in colors] return color_palette(palette, len(palette)) def cubehelix_palette(n_colors=6, start=0, rot=.4, gamma=1.0, hue=0.8, light=.85, dark=.15, reverse=False, as_cmap=False): """Make a sequential palette from the cubehelix system. This produces a colormap with linearly-decreasing (or increasing) brightness. That means that information will be preserved if printed to black and white or viewed by someone who is colorblind. "cubehelix" is also available as a matplotlib-based palette, but this function gives the user more control over the look of the palette and has a different set of defaults. In addition to using this function, it is also possible to generate a cubehelix palette generally in seaborn using a string starting with `ch:` and containing other parameters (e.g. `"ch:s=.25,r=-.5"`). Parameters ---------- n_colors : int Number of colors in the palette. start : float, 0 <= start <= 3 The hue value at the start of the helix. rot : float Rotations around the hue wheel over the range of the palette. gamma : float 0 <= gamma Nonlinearity to emphasize dark (gamma < 1) or light (gamma > 1) colors. hue : float, 0 <= hue <= 1 Saturation of the colors. dark : float 0 <= dark <= 1 Intensity of the darkest color in the palette. light : float 0 <= light <= 1 Intensity of the lightest color in the palette. reverse : bool If True, the palette will go from dark to light. as_cmap : bool If True, return a :class:`matplotlib.colors.ListedColormap`. Returns ------- palette list of RGB tuples or :class:`matplotlib.colors.ListedColormap` See Also -------- choose_cubehelix_palette : Launch an interactive widget to select cubehelix palette parameters. dark_palette : Create a sequential palette with dark low values. light_palette : Create a sequential palette with bright low values. References ---------- Green, D. A. (2011). "A colour scheme for the display of astronomical intensity images". Bulletin of the Astromical Society of India, Vol. 39, p. 289-295. Examples -------- .. include:: ../docstrings/cubehelix_palette.rst """ def get_color_function(p0, p1): # Copied from matplotlib because it lives in private module def color(x): # Apply gamma factor to emphasise low or high intensity values xg = x ** gamma # Calculate amplitude and angle of deviation from the black # to white diagonal in the plane of constant # perceived intensity. a = hue * xg * (1 - xg) / 2 phi = 2 * np.pi * (start / 3 + rot * x) return xg + a * (p0 * np.cos(phi) + p1 * np.sin(phi)) return color cdict = { "red": get_color_function(-0.14861, 1.78277), "green": get_color_function(-0.29227, -0.90649), "blue": get_color_function(1.97294, 0.0), } cmap = mpl.colors.LinearSegmentedColormap("cubehelix", cdict) x = np.linspace(light, dark, int(n_colors)) pal = cmap(x)[:, :3].tolist() if reverse: pal = pal[::-1] if as_cmap: x_256 = np.linspace(light, dark, 256) if reverse: x_256 = x_256[::-1] pal_256 = cmap(x_256) cmap = mpl.colors.ListedColormap(pal_256, "seaborn_cubehelix") return cmap else: return _ColorPalette(pal) def _parse_cubehelix_args(argstr): """Turn stringified cubehelix params into args/kwargs.""" if argstr.startswith("ch:"): argstr = argstr[3:] if argstr.endswith("_r"): reverse = True argstr = argstr[:-2] else: reverse = False if not argstr: return [], {"reverse": reverse} all_args = argstr.split(",") args = [float(a.strip(" ")) for a in all_args if "=" not in a] kwargs = [a.split("=") for a in all_args if "=" in a] kwargs = {k.strip(" "): float(v.strip(" ")) for k, v in kwargs} kwarg_map = dict( s="start", r="rot", g="gamma", h="hue", l="light", d="dark", # noqa: E741 ) kwargs = {kwarg_map.get(k, k): v for k, v in kwargs.items()} if reverse: kwargs["reverse"] = True return args, kwargs def set_color_codes(palette="deep"): """Change how matplotlib color shorthands are interpreted. Calling this will change how shorthand codes like "b" or "g" are interpreted by matplotlib in subsequent plots. Parameters ---------- palette : {deep, muted, pastel, dark, bright, colorblind} Named seaborn palette to use as the source of colors. See Also -------- set : Color codes can be set through the high-level seaborn style manager. set_palette : Color codes can also be set through the function that sets the matplotlib color cycle. """ if palette == "reset": colors = [ (0., 0., 1.), (0., .5, 0.), (1., 0., 0.), (.75, 0., .75), (.75, .75, 0.), (0., .75, .75), (0., 0., 0.) ] elif not isinstance(palette, str): err = "set_color_codes requires a named seaborn palette" raise TypeError(err) elif palette in SEABORN_PALETTES: if not palette.endswith("6"): palette = palette + "6" colors = SEABORN_PALETTES[palette] + [(.1, .1, .1)] else: err = f"Cannot set colors with palette '{palette}'" raise ValueError(err) for code, color in zip("bgrmyck", colors): rgb = mpl.colors.colorConverter.to_rgb(color) mpl.colors.colorConverter.colors[code] = rgb