python - 将两个图形添加到一个 pdf 文件中

Question

如何在一个 pdf 文件中添加两个图形(一个 条形图 和一个 表格)？我现在正在做的是:

from plotly import graph_objs as go
import numpy as np
import os
from IPython.display import Image

# Chart product views
fig = go.Figure(
    data = [go.Bar(
        x=[
            "01/09/2019 - 07/09/2019",
            "08/09/2019 - 14/09/2019", 
            "15/09/2019 - 21/09/2019",
            "22/09/2019 - 28/09/2019"
            ],
        y=[15, 25, 35, 32]
        ),
    ],
    layout=dict(
        yaxis=dict(
            title="Product views"
        ),
        autosize=False,
        width=1000,
        height=600,
    ),
)

# Table product views
fig2 = go.Figure(
    data=[
        go.Table(
            header=dict(values=["Period", "Views"]),
            cells=dict(values=[
                [
                    "01/09/2019 - 07/09/2019",
                    "08/09/2019 - 14/09/2019", 
                    "15/09/2019 - 21/09/2019",
                    "22/09/2019 - 28/09/2019"
                ],
                [15, 25, 35, 32]
            ])
        )
    ],
    layout=dict(
        autosize=False,
        width=800,
        height=300,
        title=dict(
            text="<b>Library Shelving</b> statistic"
        )
    )
)

if not os.path.exists("images"):
    os.mkdir("images")

fig.write_image("images/fig1.pdf")
fig2.write_image("images/fig2.pdf")

成功创建 2 个 pdf。有没有办法实现这一点？

Answer 1

我已经能够使用以下方法完成此任务:

• plotly.io.to_image() 将数字写入图像字节数据
• PIL.Image.open() 读取字节数据
• PIL.Image.convert() 将字节数据转换为RGB
• io.BytesIO()临时存储转换后的图像数据
• PIL.Image.save() 将第一张图像保存为 PDF 并将图形列表中的所有其他 PDF 附加到第一张图像

结果将是多页 PDF 图像。

您可能需要pip安装pillow

import plotly.io as pio
import io
from PIL import Image

figures = [fig1, fig2, fig3]
image_list = [pio.to_image(fig, format='png', width=1440, height=900, scale=1.5) for fig in figures]
for index, image in enumerate(image_list):
    with io.BytesIO() as tmp:
        tmp.write(image)  # write the image bytes to the io.BytesIO() temporary object
        image = Image.open(tmp).convert('RGB')  # convert and overwrite 'image' to prevent creating a new variable
        image_list[index] = image  # overwrite byte image data in list, replace with PIL converted image data

# pop first item from image_list, use that to access .save(). Then refer back to image_list to append the rest
image_list.pop(0).save(r'/Users/USERNAME/plotly_dash.pdf', 'PDF',
                       save_all=True, append_images=image_list, resolution=100.0)  # TODO improve resolution