Support not embedding glyphs in svg mathtests.

anntzer · anntzer · commit 740235060519 · 2022-06-12T01:18:05.000+02:00
diff --git a/lib/matplotlib/testing/compare.py b/lib/matplotlib/testing/compare.py
@@ -214,6 +214,21 @@ def __del__(self):
             self._tmpdir.cleanup()
 
 
+class _SVGWithMatplotlibFontsConverter(_SVGConverter):
+    """
+    A SVG converter which explicitly adds the fonts shipped by Matplotlib to
+    Inkspace's font search path, to better support `svg.fonttype = "none"`
+    (which is in particular used by certain mathtext tests).
+    """
+
+    def __call__(self, orig, dest):
+        if not hasattr(self, "_tmpdir"):
+            self._tmpdir = TemporaryDirectory()
+            shutil.copytree(cbook._get_data_path("fonts/ttf"),
+                            Path(self._tmpdir.name, "fonts"))
+        return super().__call__(orig, dest)
+
+
 def _update_converter():
     try:
         mpl._get_executable_info("gs")
@@ -235,6 +250,7 @@ def _update_converter():
 #: extension to png format.
 converter = {}
 _update_converter()
+_svg_with_matplotlib_fonts_converter = _SVGWithMatplotlibFontsConverter()
 
 
 def comparable_formats():
@@ -284,7 +300,14 @@ def convert(filename, cache):
                 return str(newpath)
 
         _log.debug("For %s: converting to png.", filename)
-        converter[path.suffix[1:]](path, newpath)
+        convert = converter[path.suffix[1:]]
+        if path.suffix == ".svg":
+            contents = path.read_text()
+            if 'style="font:' in contents:
+                # for svg.fonttype = none, we explicitly patch the font search
+                # path so that fonts shipped by Matplotlib are found.
+                convert = _svg_with_matplotlib_fonts_converter
+        convert(path, newpath)
 
         if cache_dir is not None:
             _log.debug("For %s: caching conversion result.", filename)
diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
@@ -116,7 +116,11 @@
     r'$\left(X\right)_{a}^{b}$',  # github issue 7615
     r'$\dfrac{\$100.00}{y}$',  # github issue #1888
 ]
-# 'Lightweight' tests test only a single fontset (dejavusans, which is the
+# 'svgastext' tests switch svg output to embed text as text (rather than as
+# paths).
+svgastext_math_tests = [
+]
+# 'lightweight' tests test only a single fontset (dejavusans, which is the
 # default) and only png outputs, in order to minimize the size of baseline
 # images.
 lightweight_math_tests = [
@@ -199,6 +203,24 @@ def test_mathtext_rendering(baseline_images, fontset, index, text):
              horizontalalignment='center', verticalalignment='center')
 
 
+@pytest.mark.parametrize('index, text', enumerate(svgastext_math_tests),
+                         ids=range(len(svgastext_math_tests)))
+@pytest.mark.parametrize(
+    'fontset', ['cm', 'stix', 'stixsans', 'dejavusans', 'dejavuserif'])
+@pytest.mark.parametrize('baseline_images', ['mathtext0'], indirect=True)
+@image_comparison(
+    baseline_images=None,
+    savefig_kwarg={'metadata': {  # Minimize image size.
+        'Creator': None, 'Date': None, 'Format': None, 'Type': None}})
+def test_mathtext_rendering_svgastext(baseline_images, fontset, index, text):
+    mpl.rcParams['mathtext.fontset'] = fontset
+    mpl.rcParams['svg.fonttype'] = 'none'  # Minimize image size.
+    fig = plt.figure(figsize=(5.25, 0.75))
+    fig.patch.set(visible=False)  # Minimize image size.
+    fig.text(0.5, 0.5, text,
+             horizontalalignment='center', verticalalignment='center')
+
+
 @pytest.mark.parametrize('index, text', enumerate(lightweight_math_tests),
                          ids=range(len(lightweight_math_tests)))
 @pytest.mark.parametrize('fontset', ['dejavusans'])
