Matplotlib Barh 过渡平滑

Question

总的来说，当涉及到 Matplotlib 和可视化时，我是个菜鸟。 我一直在关注本教程： https : //thecleverprogrammer.com/2020/06/23/bar-chart-race-tutorial-in-python-with-matplotlib/

这为解决我的问题提供了一个很好的基础，我唯一的问题是过渡非常突然- 我将如何添加这样的平滑过渡 - 这是过渡看起来如何不介意实际数据的示例：

据我所知 - 动画功能为每个间隔生成一个帧 - 我怎样才能获得条形相互动画的帧？

编辑：

这是我正在查看的代码

import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
import matplotlib.animation as animation
from matplotlib.offsetbox import OffsetImage, AnnotationBbox
from moviepy.editor import VideoClip
from moviepy.video.io.bindings import mplfig_to_npimage

url = 'https://gist.githubusercontent.com/johnburnmurdoch/4199dbe55095c3e13de8d5b2e5e5307a/raw/fa018b25c24b7b5f47fd0568937ff6c04e384786/city_populations'

df = pd.read_csv(url, usecols=['name', 'group', 'year', 'value'])
df.head(3)

colors = dict(zip(
    ["India", "Europe", "Asia", "Latin America", "Middle East", "North America", "Africa"],
    ["#adb0ff", "#ffb3ff", "#90d595", "#e48381", "#aafbff", "#f7bb5f", "#eafb50"]
))
group_lk = df.set_index('name')['group'].to_dict()

fig, ax = plt.subplots(figsize=(15, 8))


def draw_barchart(current_year):
    dff = df[df['year'].eq(current_year)].sort_values(by='value', ascending=True).tail(10)
    ax.clear()
    ax.barh(dff['name'], dff['value'], color=[colors[group_lk[x]] for x in dff['name']])
    dx = dff['value'].max() / 200
    for i, (value, name) in enumerate(zip(dff['value'], dff['name'])):
        ax.text(value-dx, i,     "   {} ({})".format(name,round(value, 2)),           size=12, color='#777777' ,weight=600, ha='left', va='center')

    ax.text(1, 0.4, current_year, transform=ax.transAxes, color='#777777', size=46, ha='right', weight=800)
    #ax.text(0, 1.06, 'Population (thousands)', transform=ax.transAxes, size=12, color='#777777')
    ax.xaxis.set_major_formatter(ticker.StrMethodFormatter('{x:,.0f}'))
    ax.xaxis.set_ticks_position('bottom')
    ax.tick_params(axis='x', colors='#777777', labelsize=12)
    ax.set_yticks([])
    ax.margins(0, 0.01)
    ax.grid(which='major', axis='x', linestyle='-')
    ax.set_axisbelow(True)
    ax.text(0, 1.15, 'This is a title',
            transform=ax.transAxes, size=24, weight=600, ha='left', va='top', color="#777")
    ax.text(1, 0, "My description here", transform=ax.transAxes, color='#777777', ha='right',
            bbox=dict(facecolor='white', alpha=0.8, edgecolor='white'))
    plt.box(False)
    plt.subplots_adjust(left=0.15, right=0.80, bottom=0.20, top=0.86)
    


fig, ax = plt.subplots(figsize=(15, 8))
plt.show()
animator = animation.FuncAnimation(fig, draw_barchart, frames=range(1900, 2019))
animator.save('linex.gif', dpi=180, writer='imagemagick')

Answer 1

正如评论中提到的，matplotlib 动画不允许平滑过渡。 这是因为图形是逐帧创建和播放的。 它不会创建一个图表来在帧之间进行补充。 如果您想使用 python 进行条形图跟踪，python 中有一些很好的专用库。 它的名字是bar_char_race 。 您还可以调整细节。 根据文件格式，您可能需要预先安装 ffmpeg 或其他软件。

import pandas as pd
import bar_chart_race as bcr

url = 'https://gist.githubusercontent.com/johnburnmurdoch/4199dbe55095c3e13de8d5b2e5e5307a/raw/fa018b25c24b7b5f47fd0568937ff6c04e384786/city_populations'

df = pd.read_csv(url, usecols=['name', 'group', 'year', 'value'])

df.value = df.value.astype(int)
# top 10 city
dfs = df.groupby(['group','name'],as_index=False)['value'].max().sort_values(by='value', ascending=False).head(10)
top10 = dfs.name[:10].values

dff = df.query('year >= 1900 and name in @top10')
dff = dff.pivot_table(index='year',columns='name', values='value')
dff.fillna(0, axis=1, inplace=True)
dff.index = pd.to_datetime(dff.index, format='%Y')

bcr.bar_chart_race(df=dff, n_bars=10, filename='poptop10.mp4', period_fmt='%Y')