Method _get_box_metrics

lib/matplotlib/backends/backend_pgf.py:328–357

Get the width, total height and descent (in TeX points) for a TeX command's output in the current LaTeX environment.

(self, tex)

        return self._get_box_metrics(_escape_and_apply_props(text, prop))

    def _get_box_metrics(self, tex):
        """
        Get the width, total height and descent (in TeX points) for a TeX
        command's output in the current LaTeX environment.
        """
        # This method gets wrapped in __init__ for per-instance caching.
        self._stdin_writeln(  # Send textbox to TeX & request metrics typeout.
            # \sbox doesn't handle catcode assignments inside its argument,
            # so repeat the assignment of the catcode of "^" and "%" outside.
            r"{\catcode`\^=\active\catcode`\%%=\active\sbox0{%s}"
            r"\typeout{\the\wd0,\the\ht0,\the\dp0}}"
            % tex)
        try:
            answer = self._expect_prompt()
        except LatexError as err:
            # Here and below, use '{}' instead of {!r} to avoid doubling all
            # backslashes.
            raise ValueError("Error measuring {}\nLaTeX Output:\n{}"
                             .format(tex, err.latex_output)) from err
        try:
            # Parse metrics from the answer string.  Last line is prompt, and
            # next-to-last-line is blank line from \typeout.
            width, height, offset = answer.splitlines()[-3].split(",")
        except Exception as err:
            raise ValueError("Error measuring {}\nLaTeX Output:\n{}"
                             .format(tex, answer)) from err
        w, h, o = float(width[:-2]), float(height[:-2]), float(offset[:-2])
        # The height returned from LaTeX goes from base to top;
        # the height Matplotlib expects goes from bottom to top.
        return w, h + o, o


@functools.lru_cache(1)