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[Bug]: Background of rotated png is rendered black #29300

@maederan201

Description

@maederan201

Bug summary

If I rotate an image, the background of its bounding box is rendered black when rendering as .pdf or .png

Code for reproduction

import matplotlib.pyplot as plt
from matplotlib.transforms import Affine2D
import numpy as np

img = np.random.random((100, 20, 3))

tr_rotate = Affine2D().rotate_deg_around(0 / 2, 0 / 2, 45)
tr_translate = Affine2D().translate(250, 250)

fig, ax = plt.subplots()

ax.imshow(
    img,
    transform=tr_rotate + ax.transData,
    clip_on=False,
)

ax.imshow(
    img,
    transform=tr_translate + ax.transData,
    clip_on=False,
)

ax.set_xlim(-250, 500)
ax.set_ylim(-250, 500)

fig.savefig("MWE.png")

Actual outcome

Image

Expected outcome

Transparent Bounding Box

Additional information

In the past this was possible, however I don't know which version of matplotlib was used...

Operating system

KDE Neon

Matplotlib Version

3.9.2

Matplotlib Backend

tkagg

Python version

3.12.3

Jupyter version

No response

Installation

pip

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