Python中的 Matplotlib.colors.to_rgb()

Matplotlib是Python中用于数组二维图的惊人可视化库。 Matplotlib 是一个基于 NumPy 数组构建的多平台数据可视化库，旨在与更广泛的 SciPy 堆栈配合使用。

matplotlib.colors.to_rgb()

matplotlib.colors.to_rgb()函数用于将 c（即颜色）转换为 RGB 颜色。它将颜色名称转换为 RGB 编码颜色数组。它返回从 0-1 的三个浮点数的 RGB 元组。

Syntax: matplotlib.colors.to_rgb(c)
Parameters: 
 

• c: This accepts a string that represents the name of the color. It can be an RGB or RGBA sequence or a string in any of several forms: 
  1. a hex color string, like ‘#000FFF’ 
      
  2. a standard name, like ‘green’ 
      
  3. a letter from the set ‘rgbcmykw’ 
      
  4. a string representation of a float, like ‘0.4’, indicating gray on a 0-1 scale 
      

 

示例 1：

Python3

import matplotlib.pyplot as plt
import matplotlib.colors as mcolors
 
 
# helper function to plot a color table
def colortable(colors, title, colors_sort = True, emptycols = 0):
  
    # cell dimensions
    width = 212
    height = 22
    swatch_width = 48
    margin = 12
    topmargin = 40
  
    # Sorting colors based on hue, saturation,
    # value and name.
    if colors_sort is True:
        to_hsv = sorted((tuple(mcolors.rgb_to_hsv(mcolors.to_rgb(color))),
                         name)
                        for name, color in colors.items())
         
        names = [name for hsv, name in to_hsv]
         
    else:
        names = list(colors)
  
    length_of_names = len(names)
    length_cols = 4 - emptycols
    length_rows = length_of_names // length_cols + int(length_of_names % length_cols > 0)
  
    width2 = width * 4 + 2 * margin
    height2 = height * length_rows + margin + topmargin
    dpi = 72
  
    figure, axes = plt.subplots(figsize =(width2 / dpi, height2 / dpi), dpi = dpi)
    figure.subplots_adjust(margin / width2, margin / height2,
                        (width2-margin)/width2, (height2-topmargin)/height2)
     
    axes.set_xlim(0, width * 4)
    axes.set_ylim(height * (length_rows-0.5), -height / 2.)
    axes.yaxis.set_visible(False)
    axes.xaxis.set_visible(False)
    axes.set_axis_off()
    axes.set_title(title, fontsize = 24, loc ="left", pad = 10)
  
    for i, name in enumerate(names):
         
        rows = i % length_rows
        cols = i // length_rows
        y = rows * height
  
        swatch_start_x = width * cols
        swatch_end_x = width * cols + swatch_width
        text_pos_x = width * cols + swatch_width + 7
  
        axes.text(text_pos_x, y, name, fontsize = 14,
                horizontalalignment ='left',
                verticalalignment ='center')
  
        axes.hlines(y, swatch_start_x, swatch_end_x,
                  color = colors[name], linewidth = 18)
  
    return figure
  
colortable(mcolors.BASE_COLORS, "Base Colors",
                colors_sort = False, emptycols = 1)
colortable(mcolors.TABLEAU_COLORS, "Tableau Palette",
                colors_sort = False, emptycols = 2)
colortable(mcolors.CSS4_COLORS, "CSS Colors")
  
plt.show()

输出：

示例 2：

Python3

from matplotlib import colors
import matplotlib.pyplot as plt
 
 
alpha = 0.5
 
kwargs = dict(edgecolors ='none', s = 3900, marker ='s')
 
for i, color in enumerate(['pink', 'brown', 'green']):
 
    rgb = colors.to_rgb(color)
    plt.scatter([i], [0], color = color, **kwargs)
    plt.scatter([i], [1], color = color,
                alpha = alpha, **kwargs)
    plt.scatter([i], [2], color = rgb, **kwargs)

输出：