Function _text_metrics

lib/matplotlib/text.py:116–125

(text, fontprop, ismath, dpi)

        @functools.lru_cache(4096)
        # dpi is unused, but participates in cache invalidation (via the renderer).
        def _text_metrics(text, fontprop, ismath, dpi):
            # this should never happen under normal use, but this is a better error to
            # raise than an AttributeError on `None`
            if (local_renderer := renderer_ref()) is None:
                raise RuntimeError(
                    "Trying to get text metrics for a renderer that no longer exists.  "
                    "This should never happen and is evidence of a bug elsewhere."
                    )
            # do the actual method call we need and return the result
            return local_renderer.get_text_width_height_descent(text, fontprop, ismath)

        # stash the function for later use.
        _cache[input_renderer] = _text_metrics