Bug summary

When using theStroke path effect with a large linewidth, there are artefacts appearing here and there in the form of "wholes" in the outline.

Code for reproduction

importmatplotlib.pyplotaspltfrommatplotlibimportpatheffectsfig,ax=plt.subplots(1,1)text=ax.text(.5,.5,'-x.',color='red',ha='center',va='center',size=20)text.set_path_effects([patheffects.Stroke(linewidth=30,foreground='black'),patheffects.Normal()])fig.savefig("this_produces_artefacts.png")fig.savefig("this_is_fine.svg")

Actual outcome

Expected outcome

Additional information

The artefacts only appear when using the QtAgg backend or exporting as png. However, the output when using SVG is fine.

The artefacts only appear when the stroke linewidth becomes large enough for the outline of one letter to overlap with the outline of another.

Operating system

Arch

Matplotlib Version

3.7.1

Matplotlib Backend

QtAgg

Python version

3.10.10

Jupyter version

No response

Installation

conda