Replace maxdict with lru_cache #52
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Requires an update to matplotlib-pyodide before it will work: pyodide/matplotlib-pyodide#52
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| self.mathtext_parser = MathTextParser("bitmap") | ||
| self._get_font_helper = lru_cache(maxsize=50)(self._get_font_helper) |
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What's the difference between adding a lru_cache decorator on top of self._get_font_helper, or re-defining a variable like this?
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Two things:
- Decorating the method makes one shared cache across all class instances, this makes a per-instance cache. It actually might make more sense to have a shared cache here but I don't understand what's going on well enough to know.
- The cache holds a strong reference to the arguments of the function including the
selfargument so if you decorate the method directly then instances can be kept alive by the cache. This instead makes a reference loop but the gc will collect it.
It would probably be better to shift this to a top level or static method and use a shared cache.
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I guess the main concern is that the font objects appear to be mutable. I wonder if there is a good way to copy them so we can avoid mutating cache entries...
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I see. Thanks for the explanation!
Matplotlib removed maxdict:
https://matplotlib.org/stable/api/prev_api_changes/api_changes_3.6.0.html#miscellaneous-internals
I asked about this on the matplotlib discourse:
https://discourse.matplotlib.org/t/matplotlib-pyodide-font-caching-with-maxdict-and-lru-cache/24260