Matplotlib:如何指定X标签边框的宽度 [英] Matplotlib: how to specify width of x-label bounding box

问题描述

我正在尝试在 MatPlotLib 中创建一个堆叠条形图，顶部和底部有两个不同的 x 标签.上面的应该有一个与条本身宽度相同的边界框.

情节不太对

这是我创建标签的方式:

plt.tick_params(axis="both", left=False, bottom=False, labelleft=False)plt.xticks(ind，diagram.keys())ax.set_frame_on(False)对于标签，zip 中的 x([q[1] for q in diagram.values()], ind):ax.text(x, 1.05, '{:4.0%}'.format(label),ha ="center"，va ="center"，bbox = {"facecolor":蓝色"，"pad":3})

diagram 是一个类似于 {bottom-label: [[contents], top-label]}

的字典

所以我想我的问题归结为:如何操作文本对象的边界框?

非常感谢！

根据请求，一个可运行的示例:

 将matplotlib.pyplot导入为plt将numpy导入为npdef stacked_bar_chart(图表，标题="示例问题"，img_name="test_image"，宽度=0.7，集群=无，show_axes=True，show_legend=True，show_score=True):"""为等级构建一个或多个缩放的堆积条形图分布.将图像另存为png.:param show_score:分数是否应显示在最前面:param show_legend:是否应显示图例:param show_axes:问题名称是否应显示在底部:param clusters:要显示的簇的索引.:param width: 条的宽度作为可用空间的一部分:param title:图表标题:param img_name:输出路径:param diagram:字典:{x-label:[[等级分布]，分数]}:return: 没什么."""成绩= {"sehr 肠道": "#357100","gut": "#7fb96a","befriedigend": "#fdd902","ausreichend":#f18d04"，"mangelhaft":#e3540e"，ungenügend":#882d23"}#选择集群如果群集不是无:图= {i:集群中i的diagram [i]}#归一化分数分布=>投票总数= 1.0归一化 = []对于 diagram.values() 中的问题:s = sum(问题[0])normalized.append([x/s for x in question[0]])# 将字典值(分数分布)转置为列表列表转换 = 列表(地图(列表，zip(*标准化)))# 图表生成的输入值n = len(diagram)#列数ind = np.arange(n) # 条形中心的 x 值base = [0] * n#各个颜色集的下限条 = []无花果，ax = plt.subplots()#遍历成绩对于名称，zip 中的等级(grades.keys()，已转换):断言len(grade)== n，\在绘制成绩堆栈时出了问题" + img_namebar = plt.bar(ind,grade, width=width, color=grades[name], bottom=base)bar.append(bar)# 遍历条形对于 i, (rect, score) in enumerate(zip(bar,grade)):# 更新下一个柱节的下限基数[i] += 等级[i]# 带有百分比的标签#TODO文字颜色为白色ax.text(rect.get_x()+宽度/2，rect.get_height()/2 + rect.get_y()，"{0:.0f}％".format(分数* 100)，va="中心", ha="中心")#标签图plt.suptitle(标题)如果show_axes:plt.tick_params(axis ="both"，left = False，bottom = False，labelleft = False)plt.xticks(ind，diagram.keys())ax.set_frame_on(False)别的:plt.tick_params(axis ="both"，left = False，bottom = False，labelleft = False，labelbottom = False)plt.axis(关闭")# 在上面显示分数标签如果show_score:对于标签，zip 中的 x([q[1] for q in diagram.values()], ind):ax.text(x, 1.05, '{:4.0%}'.format(label),ha ="center"，va ="center"，bbox = {"facecolor":蓝色"，"pad":3})#创建图例如果show_legend:plt.图例(反转(条)，反转([*等级])，bbox_to_anchor=(1, 1), borderaxespad=0)# 保存存档plt.show()图 = {"q1":[[1、2、3、4、5、6]，0.6]，"q2":[[2，3，1，2，3，1]，0.4]}stacked_bar_chart(图表)

解决方案

有关为什么将文本框的宽度设置为定义的宽度很难的争论，请参阅

I'm trying to create a stacked bar chart in MatPlotLib with two distinct x-labels on top and bottom. The upper one is supposed to have a bounding box with the same width as the bars themselves.

Plot that's not quite right

This is how I create the labels:

plt.tick_params(axis="both", left=False, bottom=False, labelleft=False)
plt.xticks(ind, diagram.keys())
ax.set_frame_on(False)

for label, x in zip([q[1] for q in diagram.values()], ind):
    ax.text(
        x, 1.05, '{:4.0%}'.format(label), 
        ha="center", va="center", 
        bbox={"facecolor": "blue", "pad": 3}
    )

diagram is a dictionary like {bottom-label: [[contents], top-label]}

So I guess my question boils down to: How do I manipulate the bounding boxs of the text objects?

Thanks a lot!

As per request, a runnable example:

import matplotlib.pyplot as plt
import numpy as np


def stacked_bar_chart(
        diagram, title="example question", img_name="test_image", width=0.7, clusters=None, show_axes=True,
        show_legend=True, show_score=True):
    """
    Builds one or multiple scaled stacked bar charts for grade
    distributions. saves image as png.
    :param show_score: whether the score should be shown on top
    :param show_legend: whether the legend should be shown
    :param show_axes: whether question name should be shown on bottom
    :param clusters: indices of clusters to be displayed.
    :param width: the width of the bars as fraction of available space
    :param title: diagram title
    :param img_name: output path
    :param diagram: dictionary: {x-label: [[grade distribution], score]}
    :return: nothing.
    """

    grades = {
        "sehr gut":     "#357100",
        "gut":          "#7fb96a",
        "befriedigend": "#fdd902",
        "ausreichend":  "#f18d04",
        "mangelhaft":   "#e3540e",
        "ungenügend":   "#882d23"
    }

    # select clusters
    if clusters is not None:
        diagram = {i: diagram[i] for i in clusters}

    # normalize score distribution => sum of votes = 1.0
    normalized = []
    for question in diagram.values():
        s = sum(question[0])
        normalized.append([x / s for x in question[0]])

    # transpose dict values (score distributions) to list of lists
    transformed = list(map(list, zip(*normalized)))

    # input values for diagram generation
    n = len(diagram)  # number of columns
    ind = np.arange(n)  # x values for bar center
    base = [0] * n  # lower bounds for individual color set
    bars = []
    fig, ax = plt.subplots()

    # loop over grades
    for name, grade in zip(grades.keys(), transformed):
        assert len(grade) == n, \
            "something went wrong in plotting grade stack " + img_name
        bar = plt.bar(ind, grade, width=width, color=grades[name], bottom=base)
        bars.append(bar)

        # loop over bars
        for i, (rect, score) in enumerate(zip(bar, grade)):
            # update lower bound for next bar section
            base[i] += grade[i]
            # label with percentage
            # TODO text color white
            ax.text(
                rect.get_x() + width / 2, rect.get_height() / 2 + rect.get_y(), "{0:.0f}%".format(score * 100),
                va="center", ha="center")

    # label diagram

    plt.suptitle(title)
    if show_axes:
        plt.tick_params(axis="both", left=False, bottom=False, labelleft=False)
        plt.xticks(ind, diagram.keys())
        ax.set_frame_on(False)

    else:
        plt.tick_params(axis="both", left=False, bottom=False, labelleft=False, labelbottom=False)
        plt.axis("off")

    # show score label above
    if show_score:
        for label, x in zip([q[1] for q in diagram.values()], ind):
            ax.text(
                x, 1.05, '{:4.0%}'.format(label),
                ha="center", va="center",
                bbox={"facecolor": "blue", "pad": 3}
            )

    # create legend
    if show_legend:
        plt.legend(
            reversed(bars), reversed([*grades]),
            bbox_to_anchor=(1, 1), borderaxespad=0)

    # save file
    plt.show()


diagram = {
    "q1": [[1, 2, 3, 4, 5, 6], 0.6],
    "q2": [[2, 3, 1, 2, 3, 1], 0.4]
}
stacked_bar_chart(diagram)

解决方案

For arguments why setting the width of a text box to a defined width is hard see this question which is about setting the title text box width. In principle the answer over there could be used here as well - making this rather complicated.

A relatively easy solution would be to specify the x-position of the text in data coordinates and its y position in axes coordinates. This allows to create a rectangle as background for the text with the same coordinates such that it looks like a bounding box of the text.

import matplotlib.pyplot as plt
import numpy as np

ind = [1,2,4,5]
data = [4,5,6,4]
perc = np.array(data)/float(np.array(data).sum())
width=0.7 
pad = 3 # points


fig, ax = plt.subplots()
bar = ax.bar(ind, data, width=width)

fig.canvas.draw()
for label, x in zip(perc, ind):
    text = ax.text(
        x, 1.00, '{:4.0%}'.format(label),
        ha="center", va="center" , transform=ax.get_xaxis_transform(), zorder=4)
    bb= ax.get_window_extent()
    h = bb.height/fig.dpi
    height = ((text.get_size()+2*pad)/72.)/h
    rect = plt.Rectangle((x-width/2.,1.00-height/2.), width=width, height=height,
                         transform=ax.get_xaxis_transform(), zorder=3,
                         fill=True, facecolor="lightblue", clip_on=False)
    ax.add_patch(rect)


plt.show()

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