SVG backend - handle font weight as integer (#30960)

steveberardi · timhoffm · web-flow · commit 3a1df7d67ef4 · 2026-01-14T12:28:51.000-05:00
* weight is int

* comments

* test

* docstring

* Update lib/matplotlib/backends/backend_svg.py

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;

* revert

---------

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -1134,7 +1134,8 @@ def _draw_text_as_text(self, gc, x, y, s, prop, angle, ismath, mtext=None):
                 font_style['font-style'] = prop.get_style()
             if prop.get_variant() != 'normal':
                 font_style['font-variant'] = prop.get_variant()
-            weight = fm.weight_dict[prop.get_weight()]
+            weight = prop.get_weight()
+            weight = fm.weight_dict.get(weight, weight)  # convert to int
             if weight != 400:
                 font_style['font-weight'] = f'{weight}'
 
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -748,7 +748,7 @@ def get_variant(self):
 
     def get_weight(self):
         """
-        Set the font weight.  Options are: A numeric value in the
+        Get the font weight.  Options are: A numeric value in the
         range 0-1000 or one of 'light', 'normal', 'regular', 'book',
         'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold',
         'heavy', 'extra bold', 'black'
diff --git a/lib/matplotlib/tests/test_backend_svg.py b/lib/matplotlib/tests/test_backend_svg.py
@@ -74,7 +74,8 @@ def test_bold_font_output():
     ax.plot(np.arange(10), np.arange(10))
     ax.set_xlabel('nonbold-xlabel')
     ax.set_ylabel('bold-ylabel', fontweight='bold')
-    ax.set_title('bold-title', fontweight='bold')
+    # set weight as integer to assert it's handled properly
+    ax.set_title('bold-title', fontweight=600)
 
 
 @image_comparison(['bold_font_output_with_none_fonttype.svg'])
@@ -84,7 +85,8 @@ def test_bold_font_output_with_none_fonttype():
     ax.plot(np.arange(10), np.arange(10))
     ax.set_xlabel('nonbold-xlabel')
     ax.set_ylabel('bold-ylabel', fontweight='bold')
-    ax.set_title('bold-title', fontweight='bold')
+    # set weight as integer to assert it's handled properly
+    ax.set_title('bold-title', fontweight=600)
 
 
 @check_figures_equal(extensions=['svg'], tol=20)
