dviread: Ignore font maps for subset TrueType w/o encoding.

As noted in the pdftex manual,

> The *encodingfile* field may be omitted if you are sure that the font
> resource has the correct built-in encoding. In general this option is
> highly recommended, and it is *required* when subsetting a TrueType
> font.

This can be confirmed in a similar way to the previous commits, though
instead of ignoring the line, pdflatex quits while attempting to embed
the font.

Author: QuLogic

lib/matplotlib/dviread.py

@@ -884,6 +884,7 @@ def _parse_and_cache_line(self, line):
         if not line or line.startswith((b" ", b"%", b"*", b";", b"#")):
             return
         tfmname = basename = special = encodingfile = fontfile = None
+        is_subsetted = is_t1 = is_truetype = False
         matches = re.finditer(br'"([^"]*)(?:"|$)|(\S+)', line)
         for match in matches:
             quoted, unquoted = match.groups()
@@ -902,6 +903,7 @@ def _parse_and_cache_line(self, line):
                         encodingfile = word
                     else:
                         fontfile = word
+                        is_subsetted = True
                 elif tfmname is None:
                     tfmname = unquoted
                 elif basename is None:
@@ -919,12 +921,15 @@ def _parse_and_cache_line(self, line):
 
         # Verify some properties of the line that would cause it to be ignored
         # otherwise.
-        is_t1 = False
         if fontfile is not None:
-            if not fontfile.endswith((b".ttf", b".ttc", b".otf"):
+            if fontfile.endswith((b".ttf", b".ttc")):
+                is_truetype = True
+            elif not fontfile.endswith(b".otf"):
                 is_t1 = True
         elif basename is not None:
             is_t1 = True
+        if is_truetype and is_subsetted and encodingfile is None:
+            return
         if not is_t1 and ("slant" in effects or "extend" in effects):
             return
         if abs(effects.get("slant", 0)) > 1:

lib/matplotlib/tests/baseline_images/dviread/test.map

@@ -15,12 +15,19 @@ TeXfontA PSfontA2
 % Check SlantFont/ExtendFont
 %
 % Options are only allowed on T1 fonts (3 TrueType, 1 bitmap, and 1 T1 below).
-TeXfontB PSfontB1 "-0.1 SlantFont 1.2 ExtendFont" <fontB1.ttf
-TeXfontB PSfontB2 "-0.1 SlantFont" <fontB1.ttc
-TeXfontB PSfontB3 "1.2 ExtendFont" <fontB1.otf
+TeXfontB PSfontB1 "-0.1 SlantFont 1.2 ExtendFont" <fontB1.enc <fontB1.ttf
+TeXfontB PSfontB2 "-0.1 SlantFont" <fontB2.enc <fontB2.ttc
+TeXfontB PSfontB3 "1.2 ExtendFont" <fontB3.enc <fontB3.otf
 TeXfontB "0.1 SlantFont 1.2 ExtendFont"
 % Also, only within range ±1 / ±2.
 TeXfontB PSfontB4 "1.1 SlantFont 1.2 ExtendFont"
 TeXfontB PSfontB5 "0.1 SlantFont 2.2 ExtendFont"
 % This is the only one that works:
 TeXfontB PSfontB6
+%
+% Invalid TrueType entry.
+%
+% Must have encodingfile if subsetted.
+TeXfontC PSfontC1 <fontC1.ttf
+TeXfontC PSfontC2 <fontC2.ttc
+TeXfontC PSfontC3 <fontC3.ttf <8r.enc

lib/matplotlib/tests/test_dviread.py

@@ -50,6 +50,9 @@ def test_PsfontsMap(monkeypatch):
     # Slant/Extend only works for T1 fonts.
     entry = fontmap[b'TeXfontB']
     assert entry.psname == b'PSfontB6'
+    # Subsetted TrueType must have encoding.
+    entry = fontmap[b'TeXfontC']
+    assert entry.psname == b'PSfontC3'
     # Missing font
     with pytest.raises(KeyError, match='no-such-font'):
         fontmap[b'no-such-font']