Source code for fluiddyn.output.colorchart

"""Helper to choose RGB sets of colors for figures
==================================================

Provides

.. autofunction:: make_colorchart

"""

from __future__ import division
from __future__ import print_function

# from builtins import str
from builtins import range
from colorsys import hsv_to_rgb

import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle

# import subprocess
# import os
# import shlex


[docs]def make_colorchart(nb_colors=4, darkest_gray=0.03, lightest_gray=0.85): """Produce a pdf with color charts. The color charts help choosing RGB sets of colors which are distinguishable both in black and white and in color. Notes ----- For many journals, it is very expensive to have figures with colors in the printed version. But nowadays, the printed version of a paper is not very important because most people get numerical papers on the web. So a good solution for many figures is to use colors that can be differentiated in black and white. This function produces pdf files with color charts helping researchers to choose colors adapted to this requirement. First author: Tobit CAUDWELL 2015 (tobit [AT] locta.fr). Parameters ---------- nb_colors : int nb of desired final colors. darkest_gray : float darkest gray level (between 0 and 1) lightest_gray : float lightest gray level (between 0 and 1) """ colors = [] nbHue = 30 # nb of hue values nbSV = 200 # nb of light/dark nuances # Creation of a table with colors sorted according to their hue for h in range(nbHue + 1): for sv in range(nbSV + 1): # variations along s RGBcolor = hsv_to_rgb(h / nbHue, sv / nbSV, 1) # multiply RGBcolor by 255 RGBcolor = tuple(i * 255 for i in RGBcolor) luminance = ( 0.2126 * RGBcolor[0] + 0.7152 * RGBcolor[1] + 0.0722 * RGBcolor[2] ) colors.append([h, RGBcolor, luminance]) # variations along v RGBcolor = hsv_to_rgb(h / nbHue, 1, sv / nbSV) # multiply RGBcolor by 255 RGBcolor = tuple(i * 255 for i in RGBcolor) luminance = ( 0.2126 * RGBcolor[0] + 0.7152 * RGBcolor[1] + 0.0722 * RGBcolor[2] ) colors.append([h, RGBcolor, luminance]) # round of luminance values lumRnd = 2.0 nbGray = int(round(256.0 / lumRnd)) # list of list where color are sorted color_table = [[0 for i in range(nbHue)] for j in range(nbGray)] for l in colors: h = l[0] luminance = l[2] # Position in color_table idx_lum = int(round(luminance / lumRnd)) - 1 # First dim = luminance, 2nd dim = HUE color_table[idx_lum][h - 1] = l darkest_gray = darkest_gray * 255 lightest_gray = lightest_gray * 255 gray_wanted = [ lightest_gray + i * (darkest_gray - lightest_gray) / (nb_colors - 1) for i in range(nb_colors) ] # equivalent to linspace # index of desired list in color_table idx = [int(round(x / lumRnd)) for x in gray_wanted] # Selection of final colors final_colors = [] for i in idx: colors = [x[1] for x in color_table[i]] final_colors.append(colors) # # create the text of the latex file # lines = [( # r"""\documentclass{standalone} # \usepackage{tikz,calc} # \begin{document} \small # \begin{tikzpicture}""")] # x = 0 # for line in reversed(final_colors): # y = 0 # for col in line: # coltxt = str([round(i/255, 2) for i in col]) # lines.append( # r'\definecolor{currentcolor}{rgb}{' + # coltxt[1:-1] + '}\n' # r'\node[fill=currentcolor, ' # 'minimum width=3cm, minimum height=1cm] at (' + # str(x) + "," + str(y) + r') {' + coltxt + '};') # y -= 1 # x += 3.5 # x = 0 # for g in reversed(gray_wanted): # coltxt = str([round(g/255, 2) for i in range(3)]) # lines.append( # r'\definecolor{currentcolor}{rgb}{' + # coltxt[1:-1] + '}\n' # r'\node[fill=currentcolor, minimum width=3cm, ' # 'minimum height=1cm] at (' + # str(x) + r',2) {' + coltxt + '};') # x += 3.5 # lines.append(r'\end{tikzpicture}' + '\n' + r'\end{document}') # # write the .tex file # file_name = "colorchart_using_" + str(nb_colors) + "_levels" # with open(file_name + ".tex", "w") as f: # f.write('\n'.join(lines)) # # PdfLaTeX compilation for PDF output # proc = subprocess.Popen(shlex.split('pdflatex ' + file_name + ".tex")) # proc.communicate() # # delete .tex .log and .aux # os.unlink(file_name + ".tex") # os.unlink(file_name + ".log") # os.unlink(file_name + ".aux") # print('Document ' + file_name + '.pdf written.') width = 10 height = 5 step_x = 1.2 * width step_y = 1.2 * height fig = plt.figure(figsize=(5, 9)) ax = fig.add_axes([0, 0, 1, 1]) for i0, line in enumerate(reversed(final_colors)): for i1, color in enumerate(line): x = 2 + i0 * step_x y = 2 + i1 * step_y color = [round(c / 255, 2) for c in color] ax.add_patch(Rectangle((x, y), width, height, color=color)) ax.text(x + 1, y + step_y / 4.0, str(color), fontsize=7) y += 1.5 * step_y for i0, g in enumerate(gray_wanted): color = [round(g / 255, 2)] * 3 x = 2 + i0 * step_x ax.add_patch(Rectangle((x, y), width, height, color=color)) ax.text(x + 1, y + step_y / 4.0, str(color), fontsize=7) ax.set_xlim([0, x + step_x]) ax.set_ylim([0, y + step_y]) ax.set_axis_off() return final_colors
if __name__ == "__main__": final_colors = make_colorchart( nb_colors=4, darkest_gray=0.5, lightest_gray=0.85 ) plt.show()