Matplotlib figure to PDF without saving

问题

I have to create a group of matplotlib figures, which I would like to directly present in a PDF report without saving them as a file.

The data for my plots is stored in a Pandas DataFrame:

Right now I do not know other better option than first save the image and use it later.

I am doing something like that:

import matplotlib.pylab as plt
from reportlab.platypus import BaseDocTemplate, Image

for index, row in myDataFrame.iterrows():
    fig = plt.figure()
    plt.plot(row['Xvalues'], row['Yvalues'],'o', color='r')
    fig.savefig('figure_%s.png' % (row['ID']))
    plt.close(fig)

text = []
doc = BaseDocTemplate(pageName, pagesize=landscape(A4))

for f in listdir(myFolder):
    if f.endswith('png'):
        image1 = Image(f)
        text.append(image1)

doc.build(text)

回答1:

Here is the best solution provided by matplotlib itself:

from matplotlib.backends.backend_pdf import PdfPages
import matplotlib.pyplot as plt

with PdfPages('foo.pdf') as pdf:
    #As many times as you like, create a figure fig and save it:
    fig = plt.figure()
    pdf.savefig(fig)

    ....
    fig = plt.figure()
    pdf.savefig(fig)

Voilà

Find a full example here: multipage pdf matplotlib

回答2:

I think you can save the figure into a buffer using io.BytessIO and use that in platypus. Something like this perhaps?

import io
import matplotlib.pylab as plt
from reportlab.platypus import BaseDocTemplate, Image

buffers = []

for index, row in myDataFrame.iterrows():
    fig = plt.figure()
    plt.plot(row['Xvalues'], row['Yvalues'],'o', color='r')

    mybuffer = io.BytesIO()
    fig.savefig(mybuffer, format = 'pdf')
    mybuffer.seek(0)
    buffers.append(mybuffer)
    plt.close(fig)

text = []
doc = BaseDocTemplate(pageName, pagesize=landscape(A4))

doc.build(buffers)

回答3:

using my package autobasedoc https://pypi.org/project/autobasedoc/ your example would look like that:

from autobasedoc import autorpt as ar
from autobasedoc import autoplot as ap

@ap.autoPdfImg
def my_plot(index, row, canvaswidth=5): #[inch]
    fig, ax = ap.plt.subplots(figsize=(canvaswidth,canvaswidth))
    fig.suptitle(f"My simple plot {index}", fontproperties=fontprop)
    ax.plot(row['Xvalues'], row['Yvalues'],label=f"legendlabel{index}")
    return fig

doc = ar.AutoDocTemplate(pageName)

content = []

for index, row in myDataFrame.iterrows():
    content.append(my_plot(index, row))

doc.build(content)

来源：https://stackoverflow.com/questions/32608199/matplotlib-figure-to-pdf-without-saving

标签

python

pandas

matplotlib

reportlab