Hi@QuLogic, I think I might have found an issue with this commit. I'm not sure if this is the right forum (or if I should create an issue?). I suspect this commit is causing a memory usage growth, even after running the garbage collector. I've only tested it on Windows 10 with python3.11. Can you reproduce this behavior? Details below.

memory_usage_test.py

importgcfrommatplotlib.figureimportFigurefromnumpy.randomimportrandimportpsutildefplot(num_points):fig=Figure()ax=fig.add_subplot()ax.plot(rand(num_points))fig.clear()defdelta_mb_after_plot_and_gc(num_points):proc=psutil.Process()before_mb=proc.memory_info().rss/1e6plot(num_points)gc.collect()after_mb=proc.memory_info().rss/1e6delta_mb=after_mb-before_mbprint(f"plotting{num_points} points leaks{delta_mb:.3f} MB")defmain():gc.disable()delta_mb_after_plot_and_gc(100_000)delta_mb_after_plot_and_gc(1_000_000)delta_mb_after_plot_and_gc(10_000_000)if__name__=="__main__":main()

Running it against this commit and the previous commit (I found this commit via git bisect)

(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> git checkout 597554db667344c4c4ad026ec1c6dd5f4c688d8fHEAD is now at 597554db66 Add a pybind11 type caster for GCAgg and its requirements(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> python ..\memory_usage_test.pyplotting 100000 points leaks 1.978 MBplotting 1000000 points leaks 16.077 MBplotting 10000000 points leaks 159.719 MB(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> python ..\memory_usage_test.pyplotting 100000 points leaks 1.970 MBplotting 1000000 points leaks 16.081 MBplotting 10000000 points leaks 159.625 MB(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> git checkout a47e26bd8583f0fcacc1dd83c3f2ac39b1f7a091Previous HEAD position was 597554db66 Add a pybind11 type caster for GCAgg and its requirementsHEAD is now at a47e26bd85 Add a pybind11 type caster for agg::rgba(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> python ..\memory_usage_test.pyplotting 100000 points leaks 0.303 MBplotting 1000000 points leaks 0.041 MBplotting 10000000 points leaks -0.279 MB(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> python ..\memory_usage_test.pyplotting 100000 points leaks 0.197 MBplotting 1000000 points leaks 0.041 MBplotting 10000000 points leaks -0.311 MB

Environment Details

(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> python --versionPython 3.11.9(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> [System.Environment]::OSVersion.VersionMajor  Minor  Build  Revision-----  -----  -----  --------10     0      19045  0(mpl_venv) PS C:\Users\justi\projects\matplotlib_ref_cycle\matplotlib> pip freeze | findstr matplotlib-e git+https://github.com/justinjhendrick/matplotlib.git@a47e26bd8583f0fcacc1dd83c3f2ac39b1f7a091#egg=matplotlibmatplotlib-inline==0.1.7

Originally posted by@justinjhendrick in597554d