gr.Plot does not work with matplotlib plots properly anymore

[asigalov61]

Describe the bug

Hey Gradio Team,

I just wanted to let you know that the latest gradio version does not seem to be working properly with Matplotlib plots/figures.

Previous gradio versions (i.e 5.5) seem to work fine.

 

Have you searched existing issues? 🔎

• I have searched and found no existing issues

Reproduction

import gradio as gr

with gr.Blocks() as demo:

  test_plot = gr.Plot()
  
  test_btn = gr.Button("Test", variant="primary")

  test_btn .click(test_fn, inputs=[], outputs=[test,plot])

demo.launch()

I use the following code to create Matplotlib plot:

def test_fn()

  fig, ax = plt.subplots()
  plt.close(fig)
  
  return fig

==================================================================

I managed to make it work like so:

I used gr.Image instead of gr.Plot

and for matplotlib part:

def test_fn():

  fig, ax = plt.subplots()

  import io
  from PIL import Image
  
  out_fig = io.BytesIO()
  fig.savefig(out_fig, format='png')
  out_fig.seek(0)
  img = Image.open(out_fig)
  return img

So there is some kinda issue between latest gradio and matplotlib when it comes to gr.Plot.

Please fix it. I would really appreciate it.

Thank you.

Sinceerly,

Alex

Screenshot

No response

Logs

======================================================================
Traceback (most recent call last):
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/queueing.py", line 624, in process_events
    response = await route_utils.call_process_api(
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/route_utils.py", line 323, in call_process_api
    output = await app.get_blocks().process_api(
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/blocks.py", line 2025, in process_api
    data = await self.postprocess_data(block_fn, result["prediction"], state)
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/blocks.py", line 1831, in postprocess_data
    prediction_value = block.postprocess(prediction_value)
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/components/plot.py", line 138, in postprocess
    out_y = processing_utils.encode_plot_to_base64(value, self.format)
  File "/home/ubuntu/.local/lib/python3.10/site-packages/gradio/processing_utils.py", line 158, in encode_plot_to_base64
    plt.savefig(output_bytes, format=fmt)
  File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 3019, in savefig
    self.canvas.print_figure(fname, **kwargs)
  File "/usr/lib/python3/dist-packages/matplotlib/backend_bases.py", line 2259, in print_figure
    canvas = self._get_output_canvas(backend, format)
  File "/usr/lib/python3/dist-packages/matplotlib/backend_bases.py", line 2188, in _get_output_canvas
    raise ValueError(
ValueError: Format 'webp' is not supported (supported formats: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg, svgz, tif, tiff)

System Info

Matplotlib version: 3.5.1

========================================================

Gradio Environment Information:
------------------------------
Operating System: Linux
gradio version: 5.6.0
gradio_client version: 1.4.3

------------------------------------------------
gradio dependencies in your environment:

aiofiles: 23.2.1
anyio: 4.6.2.post1
audioop-lts is not installed.
fastapi: 0.115.5
ffmpy: 0.4.0
gradio-client==1.4.3 is not installed.
httpx: 0.27.2
huggingface-hub: 0.26.2
jinja2: 3.0.3
markupsafe: 2.0.1
numpy: 1.21.5
orjson: 3.10.11
packaging: 21.3
pandas: 1.3.5
pillow: 9.0.1
pydantic: 2.10.1
pydub: 0.25.1
python-multipart==0.0.12 is not installed.
pyyaml: 5.4.1
ruff: 0.8.0
safehttpx: 0.1.1
semantic-version: 2.10.0
starlette: 0.41.3
tomlkit==0.12.0 is not installed.
typer: 0.13.1
typing-extensions: 4.12.2
urllib3: 1.26.5
uvicorn: 0.32.1
authlib; extra == 'oauth' is not installed.
itsdangerous; extra == 'oauth' is not installed.





gradio_client dependencies in your environment:

fsspec: 2024.3.1
httpx: 0.27.2
huggingface-hub: 0.26.2
packaging: 21.3
typing-extensions: 4.12.2
websockets: 12.0

Severity

I can work around it