Merge pull request matplotlib#30334 from QuLogic/ttc-loading

Add support for loading all fonts from collections

Author: ksunden

doc/release/next_whats_new/ttc_fonts.rst

@@ -0,0 +1,18 @@
+Support for loading TrueType Collection fonts
+---------------------------------------------
+
+TrueType Collection fonts (commonly found as files with a ``.ttc`` extension) are now
+supported. Namely, Matplotlib will include these file extensions in its scan for system
+fonts, and will add all sub-fonts to its list of available fonts (i.e., the list from
+`~.font_manager.get_font_names`).
+
+From most high-level API, this means you should be able to specify the name of any
+sub-font in a collection just as you would any other font. Note that at this time, there
+is no way to specify the entire collection with any sort of automated selection of the
+internal sub-fonts.
+
+In the low-level API, to ensure backwards-compatibility while facilitating this new
+support, a `.FontPath` instance (comprised of a font path and a sub-font index, with
+behaviour similar to a `str`) may be passed to the font management API in place of a
+simple `os.PathLike` path. Any font management API that previously returned a string path
+now returns a `.FontPath` instance instead.

lib/matplotlib/backends/_backend_pdf_ps.py

@@ -42,7 +42,7 @@ def get_glyphs_subset(fontfile: str, glyphs: set[GlyphIndexType]) -> TTFont:
 
     Parameters
     ----------
-    fontfile : str
+    fontfile : FontPath
         Path to the font file
     glyphs : set[GlyphIndexType]
         Set of glyph indices to include in subset.
@@ -80,8 +80,7 @@ def get_glyphs_subset(fontfile: str, glyphs: set[GlyphIndexType]) -> TTFont:
         'xref',  # The cross-reference table (some Apple font tooling information).
     ]
     # if fontfile is a ttc, specify font number
-    if fontfile.endswith(".ttc"):
-        options.font_number = 0
+    options.font_number = fontfile.face_index
 
     font = subset.load_font(fontfile, options)
     subsetter = subset.Subsetter(options=options)
@@ -267,11 +266,12 @@ def track_glyph(self, font: FT2Font, chars: str | CharacterCodeType,
             charcode = chars
             chars = chr(chars)
 
-        glyph_map = self.glyph_maps.setdefault(font.fname, GlyphMap())
+        font_path = font_manager.FontPath(font.fname, font.face_index)
+        glyph_map = self.glyph_maps.setdefault(font_path, GlyphMap())
         if result := glyph_map.get(chars, glyph):
             return result
 
-        subset_maps = self.used.setdefault(font.fname, [{}])
+        subset_maps = self.used.setdefault(font_path, [{}])
         use_next_charmap = (
             # Multi-character glyphs always go in the non-0 subset.
             len(chars) > 1 or

lib/matplotlib/backends/backend_pdf.py

@@ -32,7 +32,7 @@
     RendererBase)
 from matplotlib.backends.backend_mixed import MixedModeRenderer
 from matplotlib.figure import Figure
-from matplotlib.font_manager import get_font, fontManager as _fontManager
+from matplotlib.font_manager import FontPath, get_font, fontManager as _fontManager
 from matplotlib._afm import AFM
 from matplotlib.ft2font import FT2Font, FaceFlags, LoadFlags, StyleFlags
 from matplotlib.transforms import Affine2D, BboxBase
@@ -894,8 +894,10 @@ def fontName(self, fontprop, subset=0):
         as the filename of the font.
         """
 
-        if isinstance(fontprop, str):
+        if isinstance(fontprop, FontPath):
             filenames = [fontprop]
+        elif isinstance(fontprop, str):
+            filenames = [FontPath(fontprop, 0)]
         elif mpl.rcParams['pdf.use14corefonts']:
             filenames = _fontManager._find_fonts_by_props(
                 fontprop, fontext='afm', directory=RendererPdf._afm_font_dir
@@ -935,7 +937,7 @@ def writeFonts(self):
             _log.debug('Embedding Type-1 font %s from dvi.', dvifont.texname)
             fonts[pdfname] = self._embedTeXFont(dvifont)
         for (filename, subset), Fx in sorted(self._fontNames.items()):
-            _log.debug('Embedding font %s:%d.', filename, subset)
+            _log.debug('Embedding font %r:%d.', filename, subset)
             if filename.endswith('.afm'):
                 # from pdf.use14corefonts
                 _log.debug('Writing AFM font.')
@@ -986,10 +988,11 @@ def _embedTeXFont(self, dvifont):
 
         # Reduce the font to only the glyphs used in the document, get the encoding
         # for that subset, and compute various properties based on the encoding.
-        charmap = self._character_tracker.used[dvifont.fname][0]
+        font_path = FontPath(dvifont.fname, dvifont.face_index)
+        charmap = self._character_tracker.used[font_path][0]
         chars = {
             # DVI type 1 fonts always map single glyph to single character.
-            ord(self._character_tracker.subset_to_unicode(dvifont.fname, 0, ccode))
+            ord(self._character_tracker.subset_to_unicode(font_path, 0, ccode))
             for ccode in charmap
         }
         t1font = t1font.subset(chars, self._get_subset_prefix(charmap.values()))
@@ -1241,12 +1244,12 @@ def embedTTFType42(font, subset_index, charmap, descriptor):
             wObject = self.reserveObject('Type 0 widths')
             toUnicodeMapObject = self.reserveObject('ToUnicode map')
 
-            _log.debug("SUBSET %s:%d characters: %s", filename, subset_index, charmap)
+            _log.debug("SUBSET %r:%d characters: %s", filename, subset_index, charmap)
             with _backend_pdf_ps.get_glyphs_subset(filename,
                                                    charmap.values()) as subset:
                 fontdata = _backend_pdf_ps.font_as_file(subset)
             _log.debug(
-                "SUBSET %s:%d %d -> %d", filename, subset_index,
+                "SUBSET %r:%d %d -> %d", filename, subset_index,
                 os.stat(filename).st_size, fontdata.getbuffer().nbytes
             )
 
@@ -2137,13 +2140,13 @@ def draw_mathtext(self, gc, x, y, s, prop, angle):
         for font, fontsize, ccode, glyph_index, ox, oy in glyphs:
             subset_index, subset_charcode = self.file._character_tracker.track_glyph(
                 font, ccode, glyph_index)
-            fontname = font.fname
+            font_path = FontPath(font.fname, font.face_index)
             self._setup_textpos(ox, oy, 0, oldx, oldy)
             oldx, oldy = ox, oy
-            if (fontname, subset_index, fontsize) != prev_font:
-                self.file.output(self.file.fontName(fontname, subset_index), fontsize,
+            if (font_path, subset_index, fontsize) != prev_font:
+                self.file.output(self.file.fontName(font_path, subset_index), fontsize,
                                  Op.selectfont)
-                prev_font = fontname, subset_index, fontsize
+                prev_font = font_path, subset_index, fontsize
             self.file.output(self._encode_glyphs([subset_charcode], fonttype),
                              Op.show)
         self.file.output(Op.end_text)
@@ -2338,7 +2341,9 @@ def output_singlebyte_chunk(kerns_or_chars):
                     item.ft_object, item.char, item.glyph_index)
                 if (item.ft_object, subset) != prev_font:
                     output_singlebyte_chunk(singlebyte_chunk)
-                    ft_name = self.file.fontName(item.ft_object.fname, subset)
+                    font_path = FontPath(item.ft_object.fname,
+                                         item.ft_object.face_index)
+                    ft_name = self.file.fontName(font_path, subset)
                     self.file.output(ft_name, fontsize, Op.selectfont)
                     self._setup_textpos(item.x, 0, 0, prev_start_x, 0, 0)
                     prev_font = (item.ft_object, subset)

lib/matplotlib/backends/backend_pgf.py

@@ -38,9 +38,17 @@
 
 def _get_preamble():
     """Prepare a LaTeX preamble based on the rcParams configuration."""
-    font_size_pt = FontProperties(
-        size=mpl.rcParams["font.size"]
-    ).get_size_in_points()
+    def _to_fontspec():
+        for command, family in [("setmainfont", "serif"),
+                                ("setsansfont", "sans\\-serif"),
+                                ("setmonofont", "monospace")]:
+            font_path = fm.findfont(family)
+            path = pathlib.Path(font_path)
+            yield r"  \%s{%s}[Path=\detokenize{%s/}%s]" % (
+                command, path.name, path.parent.as_posix(),
+                f',FontIndex={font_path.face_index:d}' if path.suffix == '.ttc' else '')
+
+    font_size_pt = FontProperties(size=mpl.rcParams["font.size"]).get_size_in_points()
     return "\n".join([
         # Remove Matplotlib's custom command \mathdefault.  (Not using
         # \mathnormal instead since this looks odd with Computer Modern.)
@@ -63,15 +71,8 @@ def _get_preamble():
         *([
             r"\ifdefined\pdftexversion\else  % non-pdftex case.",
             r"  \usepackage{fontspec}",
-        ] + [
-            r"  \%s{%s}[Path=\detokenize{%s/}]"
-            % (command, path.name, path.parent.as_posix())
-            for command, path in zip(
-                ["setmainfont", "setsansfont", "setmonofont"],
-                [pathlib.Path(fm.findfont(family))
-                 for family in ["serif", "sans\\-serif", "monospace"]]
-            )
-        ] + [r"\fi"] if mpl.rcParams["pgf.rcfonts"] else []),
+            *_to_fontspec(),
+            r"\fi"] if mpl.rcParams["pgf.rcfonts"] else []),
         # Documented as "must come last".
         mpl.texmanager._usepackage_if_not_loaded("underscore", option="strings"),
     ])

lib/matplotlib/backends/backend_ps.py

@@ -94,7 +94,7 @@ def _font_to_ps_type3(font_path, subset_index, glyph_indices):
 
     Parameters
     ----------
-    font_path : path-like
+    font_path : FontPath
         Path to the font to be subsetted.
     subset_index : int
         The subset of the above font being created.
@@ -176,7 +176,7 @@ def _font_to_ps_type42(font_path, subset_index, glyph_indices, fh):
 
     Parameters
     ----------
-    font_path : path-like
+    font_path : FontPath
         Path to the font to be subsetted.
     subset_index : int
         The subset of the above font being created.
@@ -187,12 +187,8 @@ def _font_to_ps_type42(font_path, subset_index, glyph_indices, fh):
     """
     _log.debug("SUBSET %s:%d characters: %s", font_path, subset_index, glyph_indices)
     try:
-        kw = {}
-        # fix this once we support loading more fonts from a collection
-        # https://github.com/matplotlib/matplotlib/issues/3135#issuecomment-571085541
-        if font_path.endswith('.ttc'):
-            kw['fontNumber'] = 0
-        with (fontTools.ttLib.TTFont(font_path, **kw) as font,
+        with (fontTools.ttLib.TTFont(font_path.path,
+                                     fontNumber=font_path.face_index) as font,
               _backend_pdf_ps.get_glyphs_subset(font_path, glyph_indices) as subset):
             fontdata = _backend_pdf_ps.font_as_file(subset).getvalue()
             _log.debug(

lib/matplotlib/dviread.py

@@ -719,6 +719,10 @@ def fname(self):
         """A fake filename"""
         return self.texname.decode('latin-1')
 
+    @property
+    def face_index(self):  # For compatibility with FT2Font.
+        return 0
+
     def _get_fontmap(self, string):
         """Get the mapping from characters to the font that includes them.
 

lib/matplotlib/dviread.pyi

@@ -78,6 +78,8 @@ class DviFont:
     def widths(self) -> list[int]: ...
     @property
     def fname(self) -> str: ...
+    @property
+    def face_index(self) -> int: ...
     def resolve_path(self) -> Path: ...
     @property
     def subfont(self) -> int: ...