Plots with ipywidgets.interact do not respect retina/HiDPI settings

[ianholst]

Environment data

• VS Code version: 1.105.1
• Jupyter Extension version: 2025.9.1
• Python Extension version: 2025.16.0
• OS: Windows
• Python and/or Anaconda version: 3.12.0
• Type of virtual environment used: none
• Jupyter server running: local

Expected behaviour

When setting the matplotlib retina option for HiDPI screens (%config InlineBackend.figure_format = "retina"), plots should appear the same size, but with extra resolution.

Actual behaviour

When showing a matplotlib plot normally, it uses the retina setting properly, but when it is part of an ipywidgets.interact, it does not.

The image displays twice as big as it should, and without the crisp image quality.

Steps to reproduce:

import matplotlib.pyplot as plt
import ipywidgets
%config InlineBackend.figure_format = "retina"

def plot(a):
    plt.figure(figsize=[2,2])
    plt.plot()
    plt.show()

plot(1)

ipywidgets.interact(plot, a=(0,1,0.1));

This was fixed for normal image display outside of ipywidgets after #7471, but I guess that fix didn't transfer to the widget display.