ENH: tablewise Styler.background_gradient #15204 (#21259) · pandas-dev/pandas@bdb6168 (original) (raw)
`@@ -913,21 +913,22 @@ def background_gradient(self, cmap='PuBu', low=0, high=0, axis=0,
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`def _background_gradient(s, cmap='PuBu', low=0, high=0,
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`text_color_threshold=0.408):
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`"""Color background in a range according to the data."""
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if (not isinstance(text_color_threshold, (float, int)) or
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not 0 <= text_color_threshold <= 1):
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msg = "text_color_threshold must be a value from 0 to 1."
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raise ValueError(msg)
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`with _mpl(Styler.background_gradient) as (plt, colors):
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rng = s.max() - s.min()
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smin = s.values.min()
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smax = s.values.max()
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rng = smax - smin
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`# extend lower / upper bounds, compresses color range
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norm = colors.Normalize(s.min() - (rng * low),
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s.max() + (rng * high))
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matplotlib modifies inplace?
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norm = colors.Normalize(smin - (rng * low), smax + (rng * high))
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matplotlib colors.Normalize modifies inplace?
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`# https://github.com/matplotlib/matplotlib/issues/5427
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normed = norm(s.values)
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``
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c = [colors.rgb2hex(x) for x in plt.cm.get_cmap(cmap)(normed)]
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``
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if (not isinstance(text_color_threshold, (float, int)) or
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not 0 <= text_color_threshold <= 1):
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msg = "text_color_threshold must be a value from 0 to 1."
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raise ValueError(msg)
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rgbas = plt.cm.get_cmap(cmap)(norm(s.values))
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`-
def relative_luminance(color):
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def relative_luminance(rgba):
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`"""
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` Calculate relative luminance of a color.
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`@@ -936,25 +937,33 @@ def relative_luminance(color):
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` Parameters
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` ----------
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color : matplotlib color
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Hex code, rgb-tuple, or HTML color name.
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color : rgb or rgba tuple
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` Returns
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` -------
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` float
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` The relative luminance as a value from 0 to 1
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` """
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rgb = colors.colorConverter.to_rgba_array(color)[:, :3]
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rgb = np.where(rgb <= .03928, rgb / 12.92,
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((rgb + .055) / 1.055) ** 2.4)
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lum = rgb.dot([.2126, .7152, .0722])
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return lum.item()
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text_colors = ['#f1f1f1' if relative_luminance(x) <
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text_color_threshold else '#000000' for x in c]
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return ['background-color: {color};color: {tc}'.format(
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color=color, tc=tc) for color, tc in zip(c, text_colors)]
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r, g, b = (
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x / 12.92 if x <= 0.03928 else ((x + 0.055) / 1.055 ** 2.4)
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for x in rgba[:3]
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)
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return 0.2126 * r + 0.7152 * g + 0.0722 * b
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def css(rgba):
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dark = relative_luminance(rgba) < text_color_threshold
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text_color = '#f1f1f1' if dark else '#000000'
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return 'background-color: {b};color: {c};'.format(
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b=colors.rgb2hex(rgba), c=text_color
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)
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if s.ndim == 1:
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return [css(rgba) for rgba in rgbas]
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else:
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return pd.DataFrame(
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[[css(rgba) for rgba in row] for row in rgbas],
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index=s.index, columns=s.columns
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)
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`def set_properties(self, subset=None, **kwargs):
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`"""
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