PGF: Fix inconsistent options for \documentclass

This could cause a mismatch between lengths when measuring vs.
producing output for things that depend on the font size setting at
the beginning of the document, e.g. unicode-math.

Use \documentclass{article} without options here, which defaults to
a font size of 10pt (same as the matplotlib rc default for
font.size).

Author: Socob

lib/matplotlib/backends/backend_pgf.py

@@ -28,6 +28,8 @@
 _log = logging.getLogger(__name__)
 
 
+DOCUMENTCLASS = r"\documentclass{article}"
+
 # Note: When formatting floating point values, it is important to use the
 # %f/{:f} format rather than %s/{} to avoid triggering scientific notation,
 # which is not recognized by TeX.
@@ -185,7 +187,7 @@ class LatexManager:
     @staticmethod
     def _build_latex_header():
         latex_header = [
-            r"\documentclass{article}",
+            DOCUMENTCLASS,
             # Include TeX program name as a comment for cache invalidation.
             # TeX does not allow this to be the first line.
             rf"% !TeX program = {mpl.rcParams['pgf.texsystem']}",
@@ -814,7 +816,7 @@ def print_pdf(self, fname_or_fh, *, metadata=None, **kwargs):
             self.print_pgf(tmppath / "figure.pgf", **kwargs)
             (tmppath / "figure.tex").write_text(
                 "\n".join([
-                    r"\documentclass[12pt]{article}",
+                    DOCUMENTCLASS,
                     r"\usepackage[pdfinfo={%s}]{hyperref}" % pdfinfo,
                     r"\usepackage[papersize={%fin,%fin}, margin=0in]{geometry}"
                     % (w, h),
@@ -924,7 +926,7 @@ def _write_header(self, width_inches, height_inches):
         pdfinfo = ','.join(
             _metadata_to_str(k, v) for k, v in self._info_dict.items())
         latex_header = "\n".join([
-            r"\documentclass[12pt]{article}",
+            DOCUMENTCLASS,
             r"\usepackage[pdfinfo={%s}]{hyperref}" % pdfinfo,
             r"\usepackage[papersize={%fin,%fin}, margin=0in]{geometry}"
             % (width_inches, height_inches),