如何避免MatPlotLib 2.0.2版中的饼形图标签重叠? [英] How to avoid pie chart labels overlapping in MatPlotLib ver.2.0.2?

问题描述

关于饼图绘制中的标签重叠，存在很多问题.但是，除了将它们转换为图例之外，我找不到自动化的解决方案.因为我有很多值(大约60)，所以该解决方案对我不起作用，转换为图例会使情节看起来非常混乱和不清楚.所以我的问题是，如果我想在饼周围标记饼楔，是否有适用于MatPlotLib版本2.0.2的自动化解决方案，该解决方案可使标签具有良好的间距(无重叠)? 我发现的唯一解决方案是使用 annotation() 手动进行.请参见下面带有伪值的脚本.还可以用箭头将馅饼的楔形连接到相关标签吗?

There were a lot of questions posted regarding labels overlap for pie chart plotting. However, I couldn't find automated solution except for converting them to the legend. This solution doesn't work for me as I have a lot of values (around 60), and conversion to a legend will make the plot look very messy and unclear. So my question, if I want to label pie wedges around the pie, is the any automated solution for MatPlotLib version 2.0.2 that enables labels to have a good spacing (no overlapping) ? The only solution I found is to do it manually with annotation(). Please see below the script with dummy values. Also is it possible to connect the wedge of the pie to the related label with an arrow?

我使用Python 2.7和MatPlotLib 2.0.2

I use Python 2.7 and MatPlotLib 2.0.2

谢谢

示例1(重叠的标签)

示例2(手动更正)

import pylab 
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
l = ax.pie([1,0.2, 0.3,0.1,0.4,7,50,35,5,2],#[0, 0.1, 0, 0.1,0,0.1,0,0.1,0,0.1],
            #labels=("one","two","three made up sentences","four is also ther","five becomes a sentence","six it is","seven long", "eight long sent", "nine, as bla bel mo","ten is also short"),
            labels=("","","","","","six it is","seven long", "eight long sent", "nine, as bla bel mo","ten is also short"),
            colors=("b","g","r","y", "b","g","r","y","g","black"),
            startangle =20,
            radius=1,
            frame=True,   # Plot axes frame with the chart if true.
            labeldistance = 1.1 ) #returns a list of matplotlib.patches.Wedge objects

l2 = ax.pie([1,0.2, 0.3,0.1,0.4,7,50,35,5,2],#[0, 0.1, 0, 0.1,0,0.1,0,0.1,0,0.1],
            colors=("r","g","b","w", "g","b","y","r","w","black"),
            startangle =20,
            radius=1-0.7,
            frame=True)   # Plot axes frame with the chart if true.

coor = [t.get_position() for t in l[1]]

ax.axis('equal')
plt.annotate( 'one was very short now ext', xy= (coor[0][0], coor[0][1]) )      # https://kite.com/docs/python/matplotlib.pyplot.annotate
plt.annotate( 'two long sentense',          xy= (coor[1][0], coor[1][1]) ) 
plt.annotate('three things to say' ,        xy= (coor[2][0], coor[2][1]+0.02) ) 
plt.annotate( 'four main tasks to do',      xy= (coor[3][0], coor[3][1]+0.04) ) 
plt.annotate( 'five reasons to avoid',      xy= (coor[4][0], coor[4][1]+0.06 ))   

plt.savefig('test_draft.pdf')
plt.show()

推荐答案

您可以尝试旋转文本.下面为每个楔形确定一个角度，然后相应地旋转注释文本.需要一些额外的调整，具体取决于角度，以确定文本的对齐方式，并确保文本不会上下颠倒.您可能需要进一步优化.

You could experiment with rotating the text. The following determines an angle for each wedge and then rotates the annotation text accordingly. Some extra tweaks are needed depending on the angle to determine the text alignment and also to ensure the text does not appear upside down. You might need to further refine this.

import pylab 
import matplotlib.pyplot as plt
import math

fig, ax = plt.subplots()

labels= [
    "one",
    "two", 
    "three made up sentences", 
    "four is also there", 
    "five becomes a sentence",
    "six it is",
    "seven long", 
    "eight long sent", 
    "nine, as bla bel mo",
    "ten is also short"]

l = ax.pie([1,0.2, 0.3,0.1,0.4,7,50,35,5,2],
            labels=[''] * len(labels),
            colors=("b","g","r","y", "b","g","r","y","g","black"),
            startangle=20,
            radius=1,
            frame=True,   # Plot axes frame with the chart if true.
            labeldistance=1.1) #returns a list of matplotlib.patches.Wedge objects

l2 = ax.pie([1,0.2, 0.3,0.1,0.4,7,50,35,5,2],#[0, 0.1, 0, 0.1,0,0.1,0,0.1,0,0.1],
            colors=("r","g","b","w", "g","b","y","r","w","black"),
            startangle=20,
            radius=1-0.7,
            frame=True)   # Plot axes frame with the chart if true.

for label, t in zip(labels, l[1]):
    x, y = t.get_position()
    angle = int(math.degrees(math.atan2(y, x)))
    ha = "left"
    va = "bottom"

    if angle > 90:
        angle -= 180

    if angle < 0:
        va = "top"

    if -45 <= angle <= 0:
        ha = "right"
        va = "bottom"

    plt.annotate(label, xy=(x,y), rotation=angle, ha=ha, va=va, size=8)

ax.axis('equal')
plt.show() 

显示为:

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