Tamil font is rendered in a wrong manner in matplotlib

[Pavan-RESTs]

I have been working on with a project in matplotlib.
I'm trying to display tamil texts in a pie chart.
I did downloaded and specified the appropriate font paths (In my case Brahmini, Noto sans tamil, Tiro, etc...)
Everything does render the tamil font but it is completely in a wrong manner.
Figure(1) is the actual rendering.
Figure(2) is the required rendering.

CODING

import matplotlib.pyplot as plt
from matplotlib.font_manager import FontProperties

font_path = r"Fonts\Tamil Font.TTF" //Replace with a tamil font path

tamil_font = FontProperties(fname=font_path) 

sizes = [25, 35, 20, 20]  
labels = ['எனக்கு ', 'மின்விசிறி', 'கலை', 'வாழைப்பழம்']  
colors = ['#ff9999','#66b3ff','#99ff99','#ffcc99']

fig, ax = plt.subplots()
wedges, texts, autotexts = ax.pie(sizes, colors=colors, autopct='%1.1f%%', startangle=90)

ax.axis('equal')

for i, autotext in enumerate(autotexts):
    autotext.set_text(labels[i])  
    autotext.set_color("black")  
    autotext.set_fontsize(12)  
    autotext.set_fontproperties(tamil_font)  

for text in texts:
    text.set_fontproperties(tamil_font)

plt.show()

[radarhere]

Hi. Do you have raqm installed?

>>> from PIL import features
>>> features.check("raqm")
True

[Pavan-RESTs]

No what is it's used for?

[radarhere]

Complex text rendering. It is "recommended for all non-English text". See #6018 (comment) for an instance where using Raqm has solved Tamil rendering in the past.

How did you install Pillow?

If you're a Windows user, I suggest looking at https://pillow.readthedocs.io/en/stable/installation/building-from-source.html

On Windows this requires compiling FriBiDi and installing fribidi.dll into a directory listed in the Dynamic-link library search order (Microsoft Learn) (fribidi-0.dll or libfribidi-0.dll are also detected).

[Pavan-RESTs]

I installed pillow in my conda environment using the command "pip install pillow".
But even though i upgrade my pillow version still it returns false for the checking the existence of raqm.

[radarhere]

What operating system are you using?

Could you uninstall Pillow, and then run pip install -v Pillow and show us the output?

[Pavan-RESTs]

I am using windows os

[radarhere]

Have you attempted placing fribidi in the correct location? Here is fribidi.dll from our recent Pillow 11.0.0 release for various architectures - fribidi.zip

https://pillow.readthedocs.io/en/stable/installation/building-from-source.html

On Windows this requires compiling FriBiDi and installing fribidi.dll into a directory listed in the Dynamic-link library search order (Microsoft Learn) (fribidi-0.dll or libfribidi-0.dll are also detected).

[Pavan-RESTs]

I have installed raqm and now i get true for the following code,

>>> from PIL import features
>>> features.check("raqm")

Now how do i enable or activate raqm to render text in matplotlib pie chart?

[radarhere]

Hmm. I would have expected the correct output from matplotlib once you had done that.

If matplotlib is still not working as you expect, does the following Pillow-only code work?

from PIL import Image, ImageDraw, ImageFont

font = ImageFont.truetype(r"Fonts\Tamil Font.TTF", 25)

im = Image.new("RGB", (250, 250))
draw = ImageDraw.Draw(im)

for i, text in enumerate(['எனக்கு ', 'மின்விசிறி', 'கலை', 'வாழைப்பழம்']):
    draw.text((20, 20+i*50), text, font=font, fill="white")
im.show()

[Pavan-RESTs]

The provided code does give the correct output but in matplotlib it is not outputting correctly

[radarhere]

Ok, so we are agreed that Pillow by itself is behaving correctly.

Can I ask - what led you to the conclusion that incorrect matplotlib output was caused by Pillow? Searching through the matplotlib main, I see no calls to truetype() or FreeTypeFont.

matplotlib/matplotlib#5941 (comment) says

Matplotlib uses its own basic text layout algorithm, rather than something like Pango, which can handle internationalized text. This is the main purpose of MEP14

MEP14 is https://matplotlib.org/devdocs/devel/MEP/MEP14.html

matplotlib/matplotlib#23082 indicates that using https://github.com/matplotlib/mplcairo might be the solution.

[Pavan-RESTs]

Can you please tell me indepth about setting up mpl cairo backend to overcome the issue