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Use glyph indices for font tracking in vector formats #30335

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16 changes: 8 additions & 8 deletions lib/matplotlib/_mathtext.py
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@

if T.TYPE_CHECKING:
from collections.abc import Iterable
from .ft2font import CharacterCodeType, Glyph
from .ft2font import CharacterCodeType, Glyph, GlyphIndexType


ParserElement.enable_packrat()
Expand Down Expand Up @@ -87,7 +87,7 @@ class VectorParse(NamedTuple):
width: float
height: float
depth: float
glyphs: list[tuple[FT2Font, float, CharacterCodeType, float, float]]
glyphs: list[tuple[FT2Font, float, GlyphIndexType, float, float]]
rects: list[tuple[float, float, float, float]]

VectorParse.__module__ = "matplotlib.mathtext"
Expand Down Expand Up @@ -132,7 +132,7 @@ def __init__(self, box: Box):
def to_vector(self) -> VectorParse:
w, h, d = map(
np.ceil, [self.box.width, self.box.height, self.box.depth])
gs = [(info.font, info.fontsize, info.num, ox, h - oy + info.offset)
gs = [(info.font, info.fontsize, info.glyph_id, ox, h - oy + info.offset)
for ox, oy, info in self.glyphs]
rs = [(x1, h - y2, x2 - x1, y2 - y1)
for x1, y1, x2, y2 in self.rects]
Expand Down Expand Up @@ -214,7 +214,7 @@ class FontInfo(NamedTuple):
fontsize: float
postscript_name: str
metrics: FontMetrics
num: CharacterCodeType
glyph_id: GlyphIndexType
glyph: Glyph
offset: float

Expand Down Expand Up @@ -375,7 +375,8 @@ def _get_info(self, fontname: str, font_class: str, sym: str, fontsize: float,
dpi: float) -> FontInfo:
font, num, slanted = self._get_glyph(fontname, font_class, sym)
font.set_size(fontsize, dpi)
glyph = font.load_char(num, flags=self.load_glyph_flags)
glyph_id = font.get_char_index(num)
glyph = font.load_glyph(glyph_id, flags=self.load_glyph_flags)

xmin, ymin, xmax, ymax = (val / 64 for val in glyph.bbox)
offset = self._get_offset(font, glyph, fontsize, dpi)
Expand All @@ -397,7 +398,7 @@ def _get_info(self, fontname: str, font_class: str, sym: str, fontsize: float,
fontsize=fontsize,
postscript_name=font.postscript_name,
metrics=metrics,
num=num,
glyph_id=glyph_id,
glyph=glyph,
offset=offset
)
Expand Down Expand Up @@ -427,8 +428,7 @@ def get_kern(self, font1: str, fontclass1: str, sym1: str, fontsize1: float,
info1 = self._get_info(font1, fontclass1, sym1, fontsize1, dpi)
info2 = self._get_info(font2, fontclass2, sym2, fontsize2, dpi)
font = info1.font
return font.get_kerning(font.get_char_index(info1.num),
font.get_char_index(info2.num),
return font.get_kerning(info1.glyph_id, info2.glyph_id,
Kerning.DEFAULT) / 64
return super().get_kern(font1, fontclass1, sym1, fontsize1,
font2, fontclass2, sym2, fontsize2, dpi)
Expand Down
2 changes: 1 addition & 1 deletion lib/matplotlib/_text_helpers.py
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
class LayoutItem:
ft_object: FT2Font
char: str
glyph_idx: GlyphIndexType
glyph_index: GlyphIndexType
x: float
prev_kern: float

Expand Down
27 changes: 14 additions & 13 deletions lib/matplotlib/backends/_backend_pdf_ps.py
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Expand Up @@ -20,27 +20,27 @@ def _cached_get_afm_from_fname(fname):
return AFM(fh)


def get_glyphs_subset(fontfile, characters):
def get_glyphs_subset(fontfile, glyphs):
"""
Subset a TTF font
Subset a TTF font.

Reads the named fontfile and restricts the font to the characters.
Reads the named fontfile and restricts the font to the glyphs.

Parameters
----------
fontfile : str
Path to the font file
characters : str
Continuous set of characters to include in subset
glyphs : set[int]
Set of glyph IDs to include in subset.

Returns
-------
fontTools.ttLib.ttFont.TTFont
An open font object representing the subset, which needs to
be closed by the caller.
"""

options = subset.Options(glyph_names=True, recommended_glyphs=True)
options = subset.Options(glyph_names=True, recommended_glyphs=True,
retain_gids=True)

# Prevent subsetting extra tables.
options.drop_tables += [
Expand Down Expand Up @@ -71,7 +71,7 @@ def get_glyphs_subset(fontfile, characters):

font = subset.load_font(fontfile, options)
subsetter = subset.Subsetter(options=options)
subsetter.populate(text=characters)
subsetter.populate(gids=glyphs)
subsetter.subset(font)
return font

Expand All @@ -97,10 +97,10 @@ def font_as_file(font):

class CharacterTracker:
"""
Helper for font subsetting by the pdf and ps backends.
Helper for font subsetting by the PDF and PS backends.

Maintains a mapping of font paths to the set of character codepoints that
are being used from that font.
Maintains a mapping of font paths to the set of glyphs that are being used from that
font.
"""

def __init__(self):
Expand All @@ -110,10 +110,11 @@ def track(self, font, s):
"""Record that string *s* is being typeset using font *font*."""
char_to_font = font._get_fontmap(s)
for _c, _f in char_to_font.items():
self.used.setdefault(_f.fname, set()).add(ord(_c))
glyph_index = _f.get_char_index(ord(_c))
self.used.setdefault(_f.fname, set()).add(glyph_index)

def track_glyph(self, font, glyph):
"""Record that codepoint *glyph* is being typeset using font *font*."""
"""Record that glyph index *glyph* is being typeset using font *font*."""
self.used.setdefault(font.fname, set()).add(glyph)


Expand Down
10 changes: 5 additions & 5 deletions lib/matplotlib/backends/backend_cairo.py
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@

import functools
import gzip
import itertools
import math

import numpy as np
Expand Down Expand Up @@ -248,13 +249,12 @@ def _draw_mathtext(self, gc, x, y, s, prop, angle):
if angle:
ctx.rotate(np.deg2rad(-angle))

for font, fontsize, idx, ox, oy in glyphs:
for (font, fontsize), font_glyphs in itertools.groupby(
glyphs, key=lambda info: (info[0], info[1])):
ctx.new_path()
ctx.move_to(ox, -oy)
ctx.select_font_face(
*_cairo_font_args_from_font_prop(ttfFontProperty(font)))
ctx.select_font_face(*_cairo_font_args_from_font_prop(ttfFontProperty(font)))
ctx.set_font_size(self.points_to_pixels(fontsize))
ctx.show_text(chr(idx))
ctx.show_glyphs([(idx, ox, -oy) for _, _, idx, ox, oy in font_glyphs])

for ox, oy, w, h in rects:
ctx.new_path()
Expand Down
78 changes: 38 additions & 40 deletions lib/matplotlib/backends/backend_pdf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -960,9 +960,9 @@ def writeFonts(self):
else:
# a normal TrueType font
_log.debug('Writing TrueType font.')
chars = self._character_tracker.used.get(filename)
if chars:
fonts[Fx] = self.embedTTF(filename, chars)
glyphs = self._character_tracker.used.get(filename)
if glyphs:
fonts[Fx] = self.embedTTF(filename, glyphs)
self.writeObject(self.fontObject, fonts)

def _write_afm_font(self, filename):
Expand Down Expand Up @@ -1136,9 +1136,8 @@ def _get_xobject_glyph_name(self, filename, glyph_name):
end
end"""

def embedTTF(self, filename, characters):
def embedTTF(self, filename, glyphs):
"""Embed the TTF font from the named file into the document."""

font = get_font(filename)
fonttype = mpl.rcParams['pdf.fonttype']

Expand All @@ -1153,7 +1152,7 @@ def cvt(length, upe=font.units_per_EM, nearest=True):
else:
return math.ceil(value)

def embedTTFType3(font, characters, descriptor):
def embedTTFType3(font, glyphs, descriptor):
"""The Type 3-specific part of embedding a Truetype font"""
widthsObject = self.reserveObject('font widths')
fontdescObject = self.reserveObject('font descriptor')
Expand Down Expand Up @@ -1200,15 +1199,13 @@ def get_char_width(charcode):
# Make the "Differences" array, sort the ccodes < 255 from
# the multi-byte ccodes, and build the whole set of glyph ids
# that we need from this font.
glyph_ids = []
differences = []
multi_byte_chars = set()
for c in characters:
ccode = c
gind = font.get_char_index(ccode)
glyph_ids.append(gind)
charmap = {gind: ccode for ccode, gind in font.get_charmap().items()}
for gind in glyphs:
glyph_name = font.get_glyph_name(gind)
if ccode <= 255:
ccode = charmap.get(gind)
if ccode is not None and ccode <= 255:
differences.append((ccode, glyph_name))
else:
multi_byte_chars.add(glyph_name)
Expand All @@ -1222,7 +1219,7 @@ def get_char_width(charcode):
last_c = c

# Make the charprocs array.
rawcharprocs = _get_pdf_charprocs(filename, glyph_ids)
rawcharprocs = _get_pdf_charprocs(filename, glyphs)
charprocs = {}
for charname in sorted(rawcharprocs):
stream = rawcharprocs[charname]
Expand Down Expand Up @@ -1259,7 +1256,7 @@ def get_char_width(charcode):

return fontdictObject

def embedTTFType42(font, characters, descriptor):
def embedTTFType42(font, glyphs, descriptor):
"""The Type 42-specific part of embedding a Truetype font"""
fontdescObject = self.reserveObject('font descriptor')
cidFontDictObject = self.reserveObject('CID font dictionary')
Expand All @@ -1269,9 +1266,8 @@ def embedTTFType42(font, characters, descriptor):
wObject = self.reserveObject('Type 0 widths')
toUnicodeMapObject = self.reserveObject('ToUnicode map')

subset_str = "".join(chr(c) for c in characters)
_log.debug("SUBSET %s characters: %s", filename, subset_str)
with _backend_pdf_ps.get_glyphs_subset(filename, subset_str) as subset:
_log.debug("SUBSET %s characters: %s", filename, glyphs)
with _backend_pdf_ps.get_glyphs_subset(filename, glyphs) as subset:
fontdata = _backend_pdf_ps.font_as_file(subset)
_log.debug(
"SUBSET %s %d -> %d", filename,
Expand Down Expand Up @@ -1319,11 +1315,11 @@ def embedTTFType42(font, characters, descriptor):
cid_to_gid_map = ['\0'] * 65536
widths = []
max_ccode = 0
for c in characters:
ccode = c
gind = font.get_char_index(ccode)
glyph = font.load_char(ccode,
flags=LoadFlags.NO_SCALE | LoadFlags.NO_HINTING)
charmap = {gind: ccode for ccode, gind in font.get_charmap().items()}
for gind in glyphs:
glyph = font.load_glyph(gind,
flags=LoadFlags.NO_SCALE | LoadFlags.NO_HINTING)
ccode = charmap[gind]
widths.append((ccode, cvt(glyph.horiAdvance)))
if ccode < 65536:
cid_to_gid_map[ccode] = chr(gind)
Expand Down Expand Up @@ -1361,11 +1357,10 @@ def embedTTFType42(font, characters, descriptor):
(len(unicode_groups), b"\n".join(unicode_bfrange)))

# Add XObjects for unsupported chars
glyph_ids = []
for ccode in characters:
if not _font_supports_glyph(fonttype, ccode):
gind = full_font.get_char_index(ccode)
glyph_ids.append(gind)
glyph_ids = [
gind for gind in glyphs
if not _font_supports_glyph(fonttype, charmap[gind])
]

bbox = [cvt(x, nearest=False) for x in full_font.bbox]
rawcharprocs = _get_pdf_charprocs(filename, glyph_ids)
Expand Down Expand Up @@ -1450,9 +1445,9 @@ def embedTTFType42(font, characters, descriptor):
}

if fonttype == 3:
return embedTTFType3(font, characters, descriptor)
return embedTTFType3(font, glyphs, descriptor)
elif fonttype == 42:
return embedTTFType42(font, characters, descriptor)
return embedTTFType42(font, glyphs, descriptor)

def alphaState(self, alpha):
"""Return name of an ExtGState that sets alpha to the given value."""
Expand Down Expand Up @@ -2215,28 +2210,32 @@ def draw_mathtext(self, gc, x, y, s, prop, angle):
oldx, oldy = 0, 0
unsupported_chars = []

font_charmaps = {}
self.file.output(Op.begin_text)
for font, fontsize, num, ox, oy in glyphs:
self.file._character_tracker.track_glyph(font, num)
for font, fontsize, glyph_index, ox, oy in glyphs:
self.file._character_tracker.track_glyph(font, glyph_index)
fontname = font.fname
if not _font_supports_glyph(fonttype, num):
if font not in font_charmaps:
font_charmaps[font] = {gind: ccode
for ccode, gind in font.get_charmap().items()}
ccode = font_charmaps[font].get(glyph_index)
if ccode is None or not _font_supports_glyph(fonttype, ccode):
# Unsupported chars (i.e. multibyte in Type 3 or beyond BMP in
# Type 42) must be emitted separately (below).
unsupported_chars.append((font, fontsize, ox, oy, num))
unsupported_chars.append((font, fontsize, ox, oy, glyph_index))
else:
self._setup_textpos(ox, oy, 0, oldx, oldy)
oldx, oldy = ox, oy
if (fontname, fontsize) != prev_font:
self.file.output(self.file.fontName(fontname), fontsize,
Op.selectfont)
prev_font = fontname, fontsize
self.file.output(self.encode_string(chr(num), fonttype),
self.file.output(self.encode_string(chr(ccode), fonttype),
Op.show)
self.file.output(Op.end_text)

for font, fontsize, ox, oy, num in unsupported_chars:
self._draw_xobject_glyph(
font, fontsize, font.get_char_index(num), ox, oy)
for font, fontsize, ox, oy, glyph_index in unsupported_chars:
self._draw_xobject_glyph(font, fontsize, glyph_index, ox, oy)

# Draw any horizontal lines in the math layout
for ox, oy, width, height in rects:
Expand Down Expand Up @@ -2274,7 +2273,7 @@ def draw_tex(self, gc, x, y, s, prop, angle, *, mtext=None):
seq += [['font', pdfname, dvifont.size]]
oldfont = dvifont
seq += [['text', x1, y1, [bytes([glyph])], x1+width]]
self.file._character_tracker.track(dvifont, chr(glyph))
self.file._character_tracker.track_glyph(dvifont, glyph)

# Find consecutive text strings with constant y coordinate and
# combine into a sequence of strings and kerns, or just one
Expand Down Expand Up @@ -2399,7 +2398,7 @@ def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
singlebyte_chunks[-1][2].append(item.char)
prev_was_multibyte = False
else:
multibyte_glyphs.append((item.ft_object, item.x, item.glyph_idx))
multibyte_glyphs.append((item.ft_object, item.x, item.glyph_index))
prev_was_multibyte = True
# Do the rotation and global translation as a single matrix
# concatenation up front
Expand All @@ -2409,7 +2408,6 @@ def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
-math.sin(a), math.cos(a),
x, y, Op.concat_matrix)
# Emit all the 1-byte characters in a BT/ET group.

self.file.output(Op.begin_text)
prev_start_x = 0
for ft_object, start_x, kerns_or_chars in singlebyte_chunks:
Expand Down
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