Improve font weight guessing.

anntzer · anntzer · commit c546627519f6 · 2019-06-07T15:24:53.000+02:00
Previously, we would guess that "Times New Roman Bold" is a regular
weight font because its name contains the substring "Roman", even though
the font correctly sets the BOLD flag (FT_STYLE_FLAG_BOLD).  Invert the
logic to give priority to the flag, as its presence is clearly more
robust than a substring check.

`s.find(w) &gt;= 0` is just an obfuscated way to write `w in s`, so change
that.
diff --git a/doc/api/next_api_changes/2019-06-09-AL.rst b/doc/api/next_api_changes/2019-06-09-AL.rst
@@ -0,0 +1,6 @@
+Changes in font weight guessing
+```````````````````````````````
+
+Font weight guessing now first checks for the presence of the FT_STYLE_BOLD_FLAG
+before trying to match substrings in the font name.  In particular, this means
+that Times New Roman Bold is now correctly detected as bold, not normal weight.
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -395,12 +395,10 @@ def ttfFontProperty(font):
     else:
         variant = 'normal'
 
-    weight = next((w for w in weight_dict if sfnt4.find(w) >= 0), None)
-    if not weight:
-        if font.style_flags & ft2font.BOLD:
-            weight = 700
-        else:
-            weight = 400
+    if font.style_flags & ft2font.BOLD:
+        weight = 700
+    else:
+        weight = next((w for w in weight_dict if w in sfnt4), 400)
 
     #  Stretch can be absolute and relative
     #  Absolute stretches are: ultra-condensed, extra-condensed, condensed,
