3. Quickstart

In this example, a plot is produced with Matplotlib and saved as PyPDF-file using the pypdfplot backend.

First, create a new python file and call it e.g. example.py.

To produce a PyPDF-file, all you have to do is import the pypdfplot backend by adding the line import pypdfplot.backend before importing Matplotlib:

import pypdfplot.backend
import matplotlib.pyplot as plt
import numpy as np

x = np.arange(-10,20,0.1)
y = x**2

plt.plot(x,y)
plt.savefig('example.pdf')

After running this script, the file example.py will have been removed and replaced by a new file example.pdf:

_images/example_plot.png

As can be seen in the “Attachments” column on the left, the orginal example.py generating script is embedded in the PDF file.

The script can be accessed by renaming example.pdf back to example.py and opening it in a text editor:

#%PDF-1.4 24 0 obj << /Type /EmbeddedFile /Length        690 >> stream
import pypdfplot.backend
import matplotlib.pyplot as plt
import numpy as np

x = np.arange(-10,20,0.1)
y = x**2

plt.plot(x,y)
plt.savefig('example.pdf')

"""
--- Do not edit below ---
endstream
endobj
1 0 obj

<< ... >>

startxref
9567
%%EOF
0000010174 LF
PyPDF-1.0
"""

It can be seen that after saving the plot with the pypdfplot backend, a commented line was added at the first line and a large comment block was appended at the end of the file. These comments contain all the necessary data for displaying the PDF and should not be altered directly by the user.

To update the plot, the user should instead modify the generating Python script and the PDF will be updated after running the script again!

For example, let’s add another plot, e.g. a sine function:

#%PDF-1.4 24 0 obj << /Type /EmbeddedFile /Length        690 >> stream
import pypdfplot.backend
import matplotlib.pyplot as plt
import numpy as np

x = np.arange(-10,20,0.1)
y1 = x**2
y2 = 100*np.sin(x)

plt.plot(x,y1)
plt.plot(x,y2)
plt.savefig('example.pdf')

"""
--- Do not edit below ---
endstream
endobj
1 0 obj

<< ... >>

startxref
9567
%%EOF
0000010174 LF
PyPDF-1.0
"""

After running example.py, the file is again replaced by our updated example.pdf:

_images/example_plot2.png