Cannot export to html when matplotlib axis is negative.

[apwebber]

• esparto version: 4.1.0
• Python version: 3.9.7
• Operating System: Windows 10

Description

Cannot export to html when matplotlib axis is negative. I get the error:

UnicodeEncodeError: 'charmap' codec can't encode character '\u2212' in position 13531 character maps to

What I Did

import unittest
import matplotlib.pyplot as plt
import esparto

class TestNegativeChar(unittest.TestCase):
    
    def test_no_negative_char(self):
        
        fig, ax = plt.subplots()
        x = [1,2,3,4,5]
        y = [1,0.5, 0, 1, 2]
        ax.plot(x, y)
        
        page = esparto.Page(title="Test")
        page["Plot"] = fig
        page.save_html("test-fig.html")
    
    def test_negative_char(self):
        """This fails
        
        UnicodeEncodeError: 'charmap' codec can't encode character '\u2212' in position 13531: character maps to <undefined>
        """
        
        fig, ax = plt.subplots()
        x = [1,2,3,4,5]
        y = [-1,-0.5, 0, 1, 2]
        ax.plot(x, y)
        
        page = esparto.Page(title="Test")
        page["Plot"] = fig
        page.save_html("test-fig.html")

[domvwt]

Thanks for reporting this. I've tried to reproduce on my machine but I was able to run the following code successfully:

import matplotlib.pyplot as plt

import esparto


def test_no_negative_char():

    fig, ax = plt.subplots()
    x = [1,2,3,4,5]
    y = [1,0.5, 0, 1, 2]
    ax.plot(x, y)

    page = esparto.Page(title="Test")
    page["Plot"] = fig
    page.save_html("test-fig-01.html")

def test_negative_char():
    """This fails

    UnicodeEncodeError: 'charmap' codec can't encode character '\u2212' in position 13531: character maps to <undefined>
    """

    fig, ax = plt.subplots()
    x = [1,2,3,4,5]
    y = [-1,-0.5, 0, 1, 2]
    ax.plot(x, y)

    page = esparto.Page(title="Test")
    page["Plot"] = fig
    page.save_html("test-fig-02.html")

if __name__ == "__main__":
    test_no_negative_char()
    test_negative_char()

This makes me think it's a Windows OS specific issue as I've been developing and testing in a Linux environment.

Could you share the full error message so I can pinpoint where the error is occurring?

[domvwt]

One other thing, could you try setting the figure format to PNG as an interim solution?

from esparto import options

options.matplotlib.notebook_format = "png"
options.matplotlib.html_output_format = "png"

[apwebber]

Hi domvwt

I have a fix that works on my machine.

In esparto/publish/output.py, line 69

    if filepath:
        Path(filepath).write_text(html_rendered)

Specifying the encoding fixes this for me:

    if filepath:
        Path(filepath).write_text(html_rendered, encoding='utf-8')

This is the full error message I was getting:

File "C:\Users\*\AppData\Local\Programs\Python\Python39\lib\contextlib.py", line 79, in inner
    return func(*args, **kwds)
  File "C:\Users\*\Envs\lab-progress-env\lib\site-packages\esparto\design\layout.py", line 482, in save_html
    html = publish_html(
  File "C:\Users\*\Envs\lab-progress-env\lib\site-packages\esparto\publish\output.py", line 70, in publish_html
    Path(filepath).write_text(html_rendered)
  File "C:\Users\*\AppData\Local\Programs\Python\Python39\lib\pathlib.py", line 1286, in write_text
    return f.write(data)
  File "C:\Users\*\AppData\Local\Programs\Python\Python39\lib\encodings\cp1252.py", line 19, in encode
    return codecs.charmap_encode(input,self.errors,encoding_table)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u2212' in position 13531: character maps to <undefined>

[apwebber]

Although a funny side effect of the above fix is that the page icon is now random letters:

<link href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>📊</text></svg>" rel="icon">

[domvwt]

What if we replace the text with this 📊?

This is on line 7 of https://github.com/domvwt/esparto/blob/main/esparto/resources/jinja/base.html.jinja.

[apwebber]

Yes that works :)

[domvwt]

Great, thanks for making the fix!

If you can make a pull request with your changes I'll merge and make a new release.

[domvwt]

I've made a develop branch that you can use as the base - I think you'll need to fork the repository first if you haven't already.