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anntzeranntzer
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Move PostScript Type3 subsetting to pure python.
... similarly to the change for pdf, but easier because there are no baseline images for which we need to provide bug-level backcompat :-) Drop the FontInfo metadata (which is explicitly optional in the PostScript spec) to avoid having to figure out the correct encoding (which can be quite obscure). Replace the implementation of the `_sc` command from `7 -1 roll{setcachedevice}{pop pop pop pop pop pop}ifelse` to a plain `setcachedevice` (as I cannot see any case where the "other" branch is taken). Drop the splitting of long commands using `exec` (`_e`) -- this is only needed for level-1 postscript, which has a small fixed stack size; we output level-2 postscript (per backend_version) and I guess level-1 is rarely in use nowadays anyways (probably the feature could be added back if there's really demand for it, but let's not get ahead of ourselves). Previously, some composite characters would be output in a "compressed" form (e.g., accented characters would be recorded as "draw the accent, then run the charproc for the unaccented character"). This is lost, but I'd guess outputting .ps.gz is better if compression really matters.
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+181
-22
lines changed

4 files changed

+181
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lines changed

‎lib/matplotlib/backends/backend_ps.py

Lines changed: 84 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -25,8 +25,8 @@
2525
_Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
2626
GraphicsContextBase, RendererBase)
2727
from matplotlib.cbook import is_writable_file_like, file_requires_unicode
28-
from matplotlib.font_manager import is_opentype_cff_font, get_font
29-
from matplotlib.ft2font import LOAD_NO_HINTING
28+
from matplotlib.font_manager import get_font
29+
from matplotlib.ft2font import LOAD_NO_HINTING, LOAD_NO_SCALE
3030
from matplotlib._ttconv import convert_ttf_to_ps
3131
from matplotlib.mathtext import MathTextParser
3232
from matplotlib._mathtext_data import uni2type1
@@ -134,6 +134,77 @@ def _move_path_to_path_or_stream(src, dst):
134134
shutil.move(src, dst, copy_function=shutil.copyfile)
135135

136136

137+
def _font_to_ps_type3(font_path, glyph_ids):
138+
font = get_font(font_path, hinting_factor=1)
139+
140+
preamble = """
141+
%!PS-Adobe-3.0 Resource-Font
142+
%%Creator: Converted from TrueType to Type 3 by Matplotlib.
143+
20 dict begin
144+
/_d {{bind def}} bind def
145+
/_m {{moveto}} _d
146+
/_l {{lineto}} _d
147+
/_ce {{closepath eofill}} _d
148+
/_c {{curveto}} _d
149+
/_sc {{setcachedevice}} _d
150+
/_e {{exec}} _d
151+
/FontName /{font_name} def
152+
/PaintType 0 def
153+
/FontMatrix [{inv_units_per_em} 0 0 {inv_units_per_em} 0 0] def
154+
/FontBBox [{bbox}] def
155+
/FontType 3 def
156+
/Encoding [{encoding}] def
157+
/CharStrings {num_glyphs} dict dup begin
158+
/.notdef 0 def
159+
""".format(font_name=font.postscript_name,
160+
inv_units_per_em=1 / font.units_per_EM,
161+
bbox=" ".join(map(str, font.bbox)),
162+
encoding=" ".join("/{}".format(font.get_glyph_name(glyph_id))
163+
for glyph_id in glyph_ids),
164+
num_glyphs=len(glyph_ids) + 1)
165+
postamble = """
166+
end readonly def
167+
168+
/BuildGlyph {
169+
exch begin
170+
CharStrings exch
171+
2 copy known not {pop /.notdef} if
172+
true 3 1 roll get exec
173+
end
174+
}_d
175+
176+
/BuildChar {
177+
1 index /Encoding get exch get
178+
1 index /BuildGlyph get exec
179+
}_d
180+
181+
FontName currentdict end definefont pop
182+
"""
183+
184+
entries = []
185+
for glyph_id in glyph_ids:
186+
g = font.load_glyph(glyph_id, LOAD_NO_SCALE)
187+
v, c = font.get_path()
188+
entries.append(
189+
"/%(name)s{%(bbox)s _sc\n" % {
190+
"name": font.get_glyph_name(glyph_id),
191+
"bbox": " ".join(map(str, [g.horiAdvance, 0, *g.bbox])),
192+
}
193+
+ _path.convert_to_string(
194+
# Convert back to TrueType's internal units (1/64's).
195+
# (Other dimensions are already in these units.)
196+
Path(v * 64, c), None, None, False, None, 0,
197+
# No code for quad Beziers triggers auto-conversion to cubics.
198+
# Drop intermediate closepolys (relying on the outline
199+
# decomposer always explicitly moving to the closing point
200+
# first).
201+
[b"_m", b"_l", b"", b"_c", b""], True).decode("ascii")
202+
+ "_ce}_d"
203+
)
204+
205+
return preamble + "\n".join(entries) + postamble
206+
207+
137208
class RendererPS(_backend_pdf_ps.RendererPDFPSBase):
138209
"""
139210
The renderer handles all the drawing primitives using a graphics
@@ -932,22 +1003,18 @@ def print_figure_impl(fh):
9321003
# Can't use more than 255 chars from a single Type 3 font.
9331004
if len(glyph_ids) > 255:
9341005
fonttype = 42
935-
# The ttf to ps (subsetting) support doesn't work for
936-
# OpenType fonts that are Postscript inside (like the STIX
937-
# fonts). This will simply turn that off to avoid errors.
938-
if is_opentype_cff_font(font_path):
939-
raise RuntimeError(
940-
"OpenType CFF fonts can not be saved using "
941-
"the internal Postscript backend at this "
942-
"time; consider using the Cairo backend")
9431006
fh.flush()
944-
try:
945-
convert_ttf_to_ps(os.fsencode(font_path),
946-
fh, fonttype, glyph_ids)
947-
except RuntimeError:
948-
_log.warning("The PostScript backend does not "
949-
"currently support the selected font.")
950-
raise
1007+
if fonttype == 3:
1008+
fh.write(_font_to_ps_type3(font_path, glyph_ids))
1009+
else:
1010+
try:
1011+
convert_ttf_to_ps(os.fsencode(font_path),
1012+
fh, fonttype, glyph_ids)
1013+
except RuntimeError:
1014+
_log.warning(
1015+
"The PostScript backend does not currently "
1016+
"support the selected font.")
1017+
raise
9511018
print("end", file=fh)
9521019
print("%%EndProlog", file=fh)
9531020

‎lib/matplotlib/tests/baseline_images/test_backend_ps/type3.eps

Lines changed: 90 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,90 @@
1+
%!PS-Adobe-3.0 EPSF-3.0
2+
%%BeginProlog
3+
/mpldict 8 dict def
4+
mpldict begin
5+
/m { moveto } bind def
6+
/l { lineto } bind def
7+
/r { rlineto } bind def
8+
/c { curveto } bind def
9+
/cl { closepath } bind def
10+
/box {
11+
m
12+
1 index 0 r
13+
0 exch r
14+
neg 0 r
15+
cl
16+
} bind def
17+
/clipbox {
18+
box
19+
clip
20+
newpath
21+
} bind def
22+
23+
%!PS-Adobe-3.0 Resource-Font
24+
%%Creator: Converted from TrueType to Type 3 by Matplotlib.
25+
20 dict begin
26+
/_d {bind def} bind def
27+
/_m {moveto} _d
28+
/_l {lineto} _d
29+
/_ce {closepath eofill} _d
30+
/_c {curveto} _d
31+
/_sc {setcachedevice} _d
32+
/_e {exec} _d
33+
/FontName /DejaVuSans def
34+
/PaintType 0 def
35+
/FontMatrix [0.00048828125 0 0 0.00048828125 0 0] def
36+
/FontBBox [-2090 -948 3673 2524] def
37+
/FontType 3 def
38+
/Encoding [/I] def
39+
/CharStrings 2 dict dup begin
40+
/.notdef 0 def
41+
/I{604 0 201 0 403 1493 _sc
42+
201 1493 _m
43+
403 1493 _l
44+
403 0 _l
45+
201 0 _l
46+
201 1493 _l
47+
48+
_ce}_d
49+
end readonly def
50+
51+
/BuildGlyph {
52+
exch begin
53+
CharStrings exch
54+
2 copy known not {pop /.notdef} if
55+
true 3 1 roll get exec
56+
end
57+
}_d
58+
59+
/BuildChar {
60+
1 index /Encoding get exch get
61+
1 index /BuildGlyph get exec
62+
}_d
63+
64+
FontName currentdict end definefont pop
65+
end
66+
%%EndProlog
67+
mpldict begin
68+
18 180 translate
69+
576 432 0 0 clipbox
70+
gsave
71+
0 0 m
72+
576 0 l
73+
576 432 l
74+
0 432 l
75+
cl
76+
1.000 setgray
77+
fill
78+
grestore
79+
0.000 setgray
80+
/DejaVuSans findfont
81+
12.000 scalefont
82+
setfont
83+
gsave
84+
288.000000 216.000000 translate
85+
0.000000 rotate
86+
0.000000 0 m /I glyphshow
87+
grestore
88+
89+
end
90+
showpage

‎lib/matplotlib/tests/test_backend_ps.py

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -133,3 +133,8 @@ def test_partial_usetex(caplog):
133133
plt.savefig(io.BytesIO(), format="ps")
134134
assert caplog.records and all("as if usetex=False" in record.getMessage()
135135
for record in caplog.records)
136+
137+
138+
@image_comparison(["type3.eps"])
139+
def test_type3_font():
140+
plt.figtext(.5, .5, "I")

‎lib/matplotlib/tests/test_font_manager.py

Lines changed: 2 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -120,11 +120,8 @@ def test_find_ttc():
120120

121121
fig, ax = plt.subplots()
122122
ax.text(.5, .5, "\N{KANGXI RADICAL DRAGON}", fontproperties=fp)
123-
fig.savefig(BytesIO(), format="raw")
124-
fig.savefig(BytesIO(), format="svg")
125-
fig.savefig(BytesIO(), format="pdf")
126-
with pytest.raises(RuntimeError):
127-
fig.savefig(BytesIO(), format="ps")
123+
for fmt in ["raw", "svg", "pdf", "ps"]:
124+
fig.savefig(BytesIO(), format=fmt)
128125

129126

130127
def test_find_invalid(tmpdir):

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