From fc59f3529c07974eaca3c8613d5d7c1cba91a0ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jouni=20K=2E=20Sepp=C3=A4nen?= <jks@iki.fi>
Date: Thu, 30 Jul 2020 17:38:44 +0300
Subject: [PATCH 01/29] Proof of concept: Type42 subsetting in pdf

---
 lib/matplotlib/backends/backend_pdf.py | 47 +++++++++++++++++++-------
 lib/matplotlib/testing/conftest.py     |  1 +
 setup.py                               |  1 +
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index ec6154234e5d..218ae560515c 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -15,11 +15,13 @@
 import os
 import re
 import struct
+import tempfile
 import time
 import types
 import warnings
 import zlib
 
+from fontTools import subset
 import numpy as np
 from PIL import Image
 
@@ -36,7 +38,7 @@
 import matplotlib.type1font as type1font
 import matplotlib.dviread as dviread
 from matplotlib.ft2font import (FIXED_WIDTH, ITALIC, LOAD_NO_SCALE,
-                                LOAD_NO_HINTING, KERNING_UNFITTED)
+                                LOAD_NO_HINTING, KERNING_UNFITTED, FT2Font)
 from matplotlib.mathtext import MathTextParser
 from matplotlib.transforms import Affine2D, BboxBase
 from matplotlib.path import Path
@@ -1209,6 +1211,17 @@ def embedTTFType42(font, characters, descriptor):
             wObject = self.reserveObject('Type 0 widths')
             toUnicodeMapObject = self.reserveObject('ToUnicode map')
 
+            print(f"SUBSET {filename} characters: {''.join(chr(c) for c in characters)}")
+            fontdata = self.getSubset(filename, ''.join(chr(c) for c in characters))
+            print(f'SUBSET {filename} {os.stat(filename).st_size} -> {len(fontdata)}')
+
+            # reload the font object from the subset
+            # (all the necessary data could probably be obtained directly using fontLib.ttLib)
+            with tempfile.NamedTemporaryFile(suffix='.ttf') as tmp:
+                tmp.write(fontdata)
+                tmp.seek(0,0)
+                font = FT2Font(tmp.name)
+
             cidFontDict = {
                 'Type': Name('Font'),
                 'Subtype': Name('CIDFontType2'),
@@ -1233,21 +1246,12 @@ def embedTTFType42(font, characters, descriptor):
 
             # Make fontfile stream
             descriptor['FontFile2'] = fontfileObject
-            length1Object = self.reserveObject('decoded length of a font')
             self.beginStream(
                 fontfileObject.id,
                 self.reserveObject('length of font stream'),
-                {'Length1': length1Object})
-            with open(filename, 'rb') as fontfile:
-                length1 = 0
-                while True:
-                    data = fontfile.read(4096)
-                    if not data:
-                        break
-                    length1 += len(data)
-                    self.currentstream.write(data)
+                {'Length1': len(fontdata)})
+            self.currentstream.write(fontdata)
             self.endStream()
-            self.writeObject(length1Object, length1)
 
             # Make the 'W' (Widths) array, CidToGidMap and ToUnicode CMap
             # at the same time
@@ -1396,6 +1400,25 @@ def embedTTFType42(font, characters, descriptor):
         elif fonttype == 42:
             return embedTTFType42(font, characters, descriptor)
 
+    @classmethod
+    def getSubset(self, fontfile, characters):
+        """Read TTF font from the given file and subset it for the given characters.
+
+        Returns a serialization of the subset font as bytes."""
+
+        options = subset.Options(glyph_names=True, recommended_glyphs=True)
+        options.drop_tables += ['FFTM']
+        font = subset.load_font(fontfile, options)
+        try:
+            subsetter = subset.Subsetter(options=options)
+            subsetter.populate(text=characters)
+            subsetter.subset(font)
+            fh = BytesIO()
+            font.save(fh, reorderTables=False)
+            return fh.getvalue()
+        finally:
+            font.close()
+
     def alphaState(self, alpha):
         """Return name of an ExtGState that sets alpha to the given value."""
 
diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
index f35eddf96b00..ca6aae3635a8 100644
--- a/lib/matplotlib/testing/conftest.py
+++ b/lib/matplotlib/testing/conftest.py
@@ -19,6 +19,7 @@ def pytest_configure(config):
         ("markers", "pytz: Tests that require pytz to be installed."),
         ("markers", "network: Tests that reach out to the network."),
         ("filterwarnings", "error"),
+        #("filterwarnings", "error"),  # fontTools.subset raises a pointless DeprecationWarning
     ]:
         config.addinivalue_line(key, value)
 
diff --git a/setup.py b/setup.py
index 8fcc3ad9bceb..37370068c4d8 100644
--- a/setup.py
+++ b/setup.py
@@ -325,6 +325,7 @@ def make_release_tree(self, base_dir, files):
     ],
     install_requires=[
         "cycler>=0.10",
+        "fonttools>=4.13.0,<5.0",
         "kiwisolver>=1.0.1",
         "numpy>=1.17",
         "packaging>=20.0",

From a632b256b560169761ac0d6bcab502f32b503fae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jouni=20K=2E=20Sepp=C3=A4nen?= <jks@iki.fi>
Date: Sat, 1 Aug 2020 18:46:50 +0300
Subject: [PATCH 02/29] flake8

---
 lib/matplotlib/backends/backend_pdf.py | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 218ae560515c..98bb30e4213c 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -1211,15 +1211,21 @@ def embedTTFType42(font, characters, descriptor):
             wObject = self.reserveObject('Type 0 widths')
             toUnicodeMapObject = self.reserveObject('ToUnicode map')
 
-            print(f"SUBSET {filename} characters: {''.join(chr(c) for c in characters)}")
-            fontdata = self.getSubset(filename, ''.join(chr(c) for c in characters))
-            print(f'SUBSET {filename} {os.stat(filename).st_size} -> {len(fontdata)}')
+            print(f"SUBSET {filename} characters: "
+                  f"{''.join(chr(c) for c in characters)}")
+            fontdata = self.getSubset(
+                filename,
+                ''.join(chr(c) for c in characters)
+            )
+            print(f'SUBSET {filename} {os.stat(filename).st_size}'
+                  f' ↦ {len(fontdata)}')
 
             # reload the font object from the subset
-            # (all the necessary data could probably be obtained directly using fontLib.ttLib)
+            # (all the necessary data could probably be obtained directly
+            # using fontLib.ttLib)
             with tempfile.NamedTemporaryFile(suffix='.ttf') as tmp:
                 tmp.write(fontdata)
-                tmp.seek(0,0)
+                tmp.seek(0, 0)
                 font = FT2Font(tmp.name)
 
             cidFontDict = {
@@ -1402,9 +1408,11 @@ def embedTTFType42(font, characters, descriptor):
 
     @classmethod
     def getSubset(self, fontfile, characters):
-        """Read TTF font from the given file and subset it for the given characters.
+        """
+        Read TTF font from the given file and subset it for the given characters.
 
-        Returns a serialization of the subset font as bytes."""
+        Returns a serialization of the subset font as bytes.
+        """
 
         options = subset.Options(glyph_names=True, recommended_glyphs=True)
         options.drop_tables += ['FFTM']

From 501b30e42f282419bb4993b22b22f44e7d624190 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jouni=20K=2E=20Sepp=C3=A4nen?= <jks@iki.fi>
Date: Sat, 1 Aug 2020 18:55:54 +0300
Subject: [PATCH 03/29] Filter out just the py23 warning

---
 lib/matplotlib/testing/conftest.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
index ca6aae3635a8..d0aa85367529 100644
--- a/lib/matplotlib/testing/conftest.py
+++ b/lib/matplotlib/testing/conftest.py
@@ -19,7 +19,8 @@ def pytest_configure(config):
         ("markers", "pytz: Tests that require pytz to be installed."),
         ("markers", "network: Tests that reach out to the network."),
         ("filterwarnings", "error"),
-        #("filterwarnings", "error"),  # fontTools.subset raises a pointless DeprecationWarning
+        ("filterwarnings",
+         "ignore:.*The py23 module has been deprecated:DeprecationWarning"),
     ]:
         config.addinivalue_line(key, value)
 

From a5d527ae88099946c5c71c0d6b4608524f1df032 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jouni=20K=2E=20Sepp=C3=A4nen?= <jks@iki.fi>
Date: Sat, 1 Aug 2020 19:06:34 +0300
Subject: [PATCH 04/29] More flake8

---
 lib/matplotlib/backends/backend_pdf.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 98bb30e4213c..c61d2517297e 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -1409,8 +1409,9 @@ def embedTTFType42(font, characters, descriptor):
     @classmethod
     def getSubset(self, fontfile, characters):
         """
-        Read TTF font from the given file and subset it for the given characters.
+        Subset a TTF font
 
+        Reads the named fontfile and restricts the font to the characters.
         Returns a serialization of the subset font as bytes.
         """
 

From 8493184838d4beadb61894621f1af95a6530e323 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sun, 13 Jun 2021 14:32:39 +0530
Subject: [PATCH 05/29] Implement subsetting for PS backend

---
 lib/matplotlib/backends/backend_ps.py | 38 ++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index ef98eba4c38a..7ab6ea6e50a5 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -7,16 +7,18 @@
 from enum import Enum
 import functools
 import glob
-from io import StringIO
+from io import BytesIO, StringIO, TextIOWrapper
 import logging
 import math
 import os
 import pathlib
+import tempfile
 import re
 import shutil
 from tempfile import TemporaryDirectory
 import time
 
+from fontTools import subset
 import numpy as np
 
 import matplotlib as mpl
@@ -27,7 +29,7 @@
     GraphicsContextBase, RendererBase)
 from matplotlib.cbook import is_writable_file_like, file_requires_unicode
 from matplotlib.font_manager import get_font
-from matplotlib.ft2font import LOAD_NO_HINTING, LOAD_NO_SCALE
+from matplotlib.ft2font import LOAD_NO_HINTING, LOAD_NO_SCALE, FT2Font
 from matplotlib._ttconv import convert_ttf_to_ps
 from matplotlib.mathtext import MathTextParser
 from matplotlib._mathtext_data import uni2type1
@@ -954,8 +956,36 @@ def print_figure_impl(fh):
                         fh.write(_font_to_ps_type3(font_path, glyph_ids))
                     else:
                         try:
-                            convert_ttf_to_ps(os.fsencode(font_path),
-                                              fh, fonttype, glyph_ids)
+                            _log.debug(
+                                f"SUBSET {font_path} characters: "
+                                f"{''.join(chr(c) for c in chars)}"
+                            )
+                            fontdata = getSubset(
+                                font_path, "".join(chr(c) for c in chars)
+                            )
+                            _log.debug(
+                                f"SUBSET {font_path} "
+                                f"{os.stat(font_path).st_size} "
+                                f"↦ {len(fontdata)}"
+                            )
+
+                            # give ttconv a subsetted font
+                            # along with updated glyph_ids
+                            with tempfile.NamedTemporaryFile(
+                                suffix=".ttf"
+                            ) as tmp:
+                                tmp.write(fontdata)
+                                tmp.seek(0, 0)
+                                font = FT2Font(tmp.name)
+                                glyph_ids = [
+                                    font.get_char_index(c) for c in chars
+                                ]
+                                convert_ttf_to_ps(
+                                    os.fsencode(tmp.name),
+                                    fh,
+                                    fonttype,
+                                    glyph_ids,
+                                )
                         except RuntimeError:
                             _log.warning(
                                 "The PostScript backend does not currently "

From b61744be90af2c48698e68c3af93ea1dd45910a1 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Tue, 15 Jun 2021 21:41:27 +0530
Subject: [PATCH 06/29] Move getSubset to common pdf/ps backend

---
 lib/matplotlib/backends/_backend_pdf_ps.py | 25 ++++++++++++++++++++
 lib/matplotlib/backends/backend_pdf.py     | 27 +---------------------
 lib/matplotlib/backends/backend_ps.py      |  5 ++--
 3 files changed, 28 insertions(+), 29 deletions(-)

diff --git a/lib/matplotlib/backends/_backend_pdf_ps.py b/lib/matplotlib/backends/_backend_pdf_ps.py
index 780e79bf71b8..8f13ad63f22e 100644
--- a/lib/matplotlib/backends/_backend_pdf_ps.py
+++ b/lib/matplotlib/backends/_backend_pdf_ps.py
@@ -2,8 +2,11 @@
 Common functionality between the PDF and PS backends.
 """
 
+from io import BytesIO
 import functools
 
+from fontTools import subset
+
 import matplotlib as mpl
 from .. import font_manager, ft2font
 from ..afm import AFM
@@ -16,6 +19,28 @@ def _cached_get_afm_from_fname(fname):
         return AFM(fh)
 
 
+def getSubset(self, fontfile, characters):
+    """
+    Subset a TTF font
+
+    Reads the named fontfile and restricts the font to the characters.
+    Returns a serialization of the subset font as bytes.
+    """
+
+    options = subset.Options(glyph_names=True, recommended_glyphs=True)
+    options.drop_tables += ['FFTM']
+    font = subset.load_font(fontfile, options)
+    try:
+        subsetter = subset.Subsetter(options=options)
+        subsetter.populate(text=characters)
+        subsetter.subset(font)
+        fh = BytesIO()
+        font.save(fh, reorderTables=False)
+        return fh.getvalue()
+    finally:
+        font.close()
+
+
 class CharacterTracker:
     """
     Helper for font subsetting by the pdf and ps backends.
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index c61d2517297e..40dffc408715 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -8,20 +8,17 @@
 from datetime import datetime
 from enum import Enum
 from functools import total_ordering
-from io import BytesIO
 import itertools
 import logging
 import math
 import os
 import re
 import struct
-import tempfile
 import time
 import types
 import warnings
 import zlib
 
-from fontTools import subset
 import numpy as np
 from PIL import Image
 
@@ -1213,7 +1210,7 @@ def embedTTFType42(font, characters, descriptor):
 
             print(f"SUBSET {filename} characters: "
                   f"{''.join(chr(c) for c in characters)}")
-            fontdata = self.getSubset(
+            fontdata = _backend_pdf_ps.getSubset(
                 filename,
                 ''.join(chr(c) for c in characters)
             )
@@ -1406,28 +1403,6 @@ def embedTTFType42(font, characters, descriptor):
         elif fonttype == 42:
             return embedTTFType42(font, characters, descriptor)
 
-    @classmethod
-    def getSubset(self, fontfile, characters):
-        """
-        Subset a TTF font
-
-        Reads the named fontfile and restricts the font to the characters.
-        Returns a serialization of the subset font as bytes.
-        """
-
-        options = subset.Options(glyph_names=True, recommended_glyphs=True)
-        options.drop_tables += ['FFTM']
-        font = subset.load_font(fontfile, options)
-        try:
-            subsetter = subset.Subsetter(options=options)
-            subsetter.populate(text=characters)
-            subsetter.subset(font)
-            fh = BytesIO()
-            font.save(fh, reorderTables=False)
-            return fh.getvalue()
-        finally:
-            font.close()
-
     def alphaState(self, alpha):
         """Return name of an ExtGState that sets alpha to the given value."""
 
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 7ab6ea6e50a5..db52f9a90f65 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -7,7 +7,7 @@
 from enum import Enum
 import functools
 import glob
-from io import BytesIO, StringIO, TextIOWrapper
+from io import StringIO, TextIOWrapper
 import logging
 import math
 import os
@@ -18,7 +18,6 @@
 from tempfile import TemporaryDirectory
 import time
 
-from fontTools import subset
 import numpy as np
 
 import matplotlib as mpl
@@ -960,7 +959,7 @@ def print_figure_impl(fh):
                                 f"SUBSET {font_path} characters: "
                                 f"{''.join(chr(c) for c in chars)}"
                             )
-                            fontdata = getSubset(
+                            fontdata = _backend_pdf_ps.getSubset(
                                 font_path, "".join(chr(c) for c in chars)
                             )
                             _log.debug(

From 44739429644caa5a0e6db22a35c210dcac3d99e2 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Tue, 15 Jun 2021 22:15:45 +0530
Subject: [PATCH 07/29] Handle file-like objects instead of saving

---
 lib/matplotlib/backends/_backend_pdf_ps.py |  6 +++---
 lib/matplotlib/backends/backend_pdf.py     | 18 ++++++++----------
 lib/matplotlib/backends/backend_ps.py      | 10 ++++++----
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/lib/matplotlib/backends/_backend_pdf_ps.py b/lib/matplotlib/backends/_backend_pdf_ps.py
index 8f13ad63f22e..97b396c28dbd 100644
--- a/lib/matplotlib/backends/_backend_pdf_ps.py
+++ b/lib/matplotlib/backends/_backend_pdf_ps.py
@@ -19,12 +19,12 @@ def _cached_get_afm_from_fname(fname):
         return AFM(fh)
 
 
-def getSubset(self, fontfile, characters):
+def getSubset(fontfile, characters):
     """
     Subset a TTF font
 
     Reads the named fontfile and restricts the font to the characters.
-    Returns a serialization of the subset font as bytes.
+    Returns a serialization of the subset font as file-like object.
     """
 
     options = subset.Options(glyph_names=True, recommended_glyphs=True)
@@ -36,7 +36,7 @@ def getSubset(self, fontfile, characters):
         subsetter.subset(font)
         fh = BytesIO()
         font.save(fh, reorderTables=False)
-        return fh.getvalue()
+        return fh
     finally:
         font.close()
 
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 40dffc408715..70833bff5be8 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -8,6 +8,7 @@
 from datetime import datetime
 from enum import Enum
 from functools import total_ordering
+from io import BytesIO
 import itertools
 import logging
 import math
@@ -1208,22 +1209,19 @@ def embedTTFType42(font, characters, descriptor):
             wObject = self.reserveObject('Type 0 widths')
             toUnicodeMapObject = self.reserveObject('ToUnicode map')
 
-            print(f"SUBSET {filename} characters: "
-                  f"{''.join(chr(c) for c in characters)}")
+            _log.debug(f"SUBSET {filename} characters: "
+                       f"{''.join(chr(c) for c in characters)}")
             fontdata = _backend_pdf_ps.getSubset(
                 filename,
                 ''.join(chr(c) for c in characters)
             )
-            print(f'SUBSET {filename} {os.stat(filename).st_size}'
-                  f' ↦ {len(fontdata)}')
+            _log.debug(f'SUBSET {filename} {os.stat(filename).st_size}'
+                       f' ↦ {fontdata.getbuffer().nbytes}')
 
             # reload the font object from the subset
             # (all the necessary data could probably be obtained directly
             # using fontLib.ttLib)
-            with tempfile.NamedTemporaryFile(suffix='.ttf') as tmp:
-                tmp.write(fontdata)
-                tmp.seek(0, 0)
-                font = FT2Font(tmp.name)
+            font = FT2Font(fontdata)
 
             cidFontDict = {
                 'Type': Name('Font'),
@@ -1252,8 +1250,8 @@ def embedTTFType42(font, characters, descriptor):
             self.beginStream(
                 fontfileObject.id,
                 self.reserveObject('length of font stream'),
-                {'Length1': len(fontdata)})
-            self.currentstream.write(fontdata)
+                {'Length1': fontdata.getbuffer().nbytes})
+            self.currentstream.write(fontdata.getvalue())
             self.endStream()
 
             # Make the 'W' (Widths) array, CidToGidMap and ToUnicode CMap
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index db52f9a90f65..3124e223df92 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -965,7 +965,7 @@ def print_figure_impl(fh):
                             _log.debug(
                                 f"SUBSET {font_path} "
                                 f"{os.stat(font_path).st_size} "
-                                f"↦ {len(fontdata)}"
+                                f"↦ {fontdata.getbuffer().nbytes}"
                             )
 
                             # give ttconv a subsetted font
@@ -973,12 +973,14 @@ def print_figure_impl(fh):
                             with tempfile.NamedTemporaryFile(
                                 suffix=".ttf"
                             ) as tmp:
-                                tmp.write(fontdata)
-                                tmp.seek(0, 0)
-                                font = FT2Font(tmp.name)
+                                font = FT2Font(fontdata)
                                 glyph_ids = [
                                     font.get_char_index(c) for c in chars
                                 ]
+                                tmp.write(fontdata.getvalue())
+                                tmp.seek(0, 0)
+                                # TODO: allow convert_ttf_to_ps
+                                # to input file objects (BytesIO)
                                 convert_ttf_to_ps(
                                     os.fsencode(tmp.name),
                                     fh,

From 24219b9e3a24de05690f9214e823abd7fc29d71e Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Tue, 15 Jun 2021 22:26:56 +0530
Subject: [PATCH 08/29] Fix doc and warning

---
 lib/matplotlib/testing/conftest.py | 2 --
 src/_ttconv.cpp                    | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
index d0aa85367529..f35eddf96b00 100644
--- a/lib/matplotlib/testing/conftest.py
+++ b/lib/matplotlib/testing/conftest.py
@@ -19,8 +19,6 @@ def pytest_configure(config):
         ("markers", "pytz: Tests that require pytz to be installed."),
         ("markers", "network: Tests that reach out to the network."),
         ("filterwarnings", "error"),
-        ("filterwarnings",
-         "ignore:.*The py23 module has been deprecated:DeprecationWarning"),
     ]:
         config.addinivalue_line(key, value)
 
diff --git a/src/_ttconv.cpp b/src/_ttconv.cpp
index daa9f2639e55..635f7c7bcfde 100644
--- a/src/_ttconv.cpp
+++ b/src/_ttconv.cpp
@@ -164,7 +164,7 @@ static PyMethodDef ttconv_methods[] =
         "font data will be written to.\n"
         "fonttype may be either 3 or 42.  Type 3 is a \"raw Postscript\" font. "
         "Type 42 is an embedded Truetype font.  Glyph subsetting is not supported "
-        "for Type 42 fonts.\n"
+        "for Type 42 fonts within this module (needs to be done externally).\n"
         "glyph_ids (optional) is a list of glyph ids (integers) to keep when "
         "subsetting to a Type 3 font.  If glyph_ids is not provided or is None, "
         "then all glyphs will be included.  If any of the glyphs specified are "

From 525760ec1cfa06a82c42394a2403b22f7dc2e68f Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sat, 19 Jun 2021 02:57:21 +0530
Subject: [PATCH 09/29] Change function doc and context

---
 lib/matplotlib/backends/_backend_pdf_ps.py | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/lib/matplotlib/backends/_backend_pdf_ps.py b/lib/matplotlib/backends/_backend_pdf_ps.py
index 97b396c28dbd..207e6e2527e5 100644
--- a/lib/matplotlib/backends/_backend_pdf_ps.py
+++ b/lib/matplotlib/backends/_backend_pdf_ps.py
@@ -19,26 +19,33 @@ def _cached_get_afm_from_fname(fname):
         return AFM(fh)
 
 
-def getSubset(fontfile, characters):
+def get_glyphs_subset(fontfile, characters):
     """
     Subset a TTF font
 
     Reads the named fontfile and restricts the font to the characters.
     Returns a serialization of the subset font as file-like object.
+
+    Parameters
+    ----------
+    symbol : str
+        Path to the font file
+    characters : str
+        Continuous set of characters to include in subset
     """
 
     options = subset.Options(glyph_names=True, recommended_glyphs=True)
+
+    # prevent subsetting FontForge Timestamp table
     options.drop_tables += ['FFTM']
-    font = subset.load_font(fontfile, options)
-    try:
+
+    with subset.load_font(fontfile, options) as font:
         subsetter = subset.Subsetter(options=options)
         subsetter.populate(text=characters)
         subsetter.subset(font)
         fh = BytesIO()
         font.save(fh, reorderTables=False)
         return fh
-    finally:
-        font.close()
 
 
 class CharacterTracker:

From 0d751175e82a363121bc644db66bbd85d5069424 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sat, 19 Jun 2021 03:00:35 +0530
Subject: [PATCH 10/29] Log the correct way

---
 lib/matplotlib/backends/backend_pdf.py | 17 ++++++++++-------
 lib/matplotlib/backends/backend_ps.py  | 12 ++++++------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 70833bff5be8..4d38040d29b9 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -1209,14 +1209,17 @@ def embedTTFType42(font, characters, descriptor):
             wObject = self.reserveObject('Type 0 widths')
             toUnicodeMapObject = self.reserveObject('ToUnicode map')
 
-            _log.debug(f"SUBSET {filename} characters: "
-                       f"{''.join(chr(c) for c in characters)}")
-            fontdata = _backend_pdf_ps.getSubset(
-                filename,
-                ''.join(chr(c) for c in characters)
+            _log.debug(
+                "SUBSET %s characters: %s",
+                filename, "".join(chr(c) for c in characters)
+            )
+            fontdata = _backend_pdf_ps.get_glyphs_subset(
+                filename, "".join(chr(c) for c in characters)
+            )
+            _log.debug(
+                "SUBSET %s %d ↦ %d", filename,
+                os.stat(filename).st_size, fontdata.getbuffer().nbytes
             )
-            _log.debug(f'SUBSET {filename} {os.stat(filename).st_size}'
-                       f' ↦ {fontdata.getbuffer().nbytes}')
 
             # reload the font object from the subset
             # (all the necessary data could probably be obtained directly
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 3124e223df92..dd470ed62138 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -956,16 +956,16 @@ def print_figure_impl(fh):
                     else:
                         try:
                             _log.debug(
-                                f"SUBSET {font_path} characters: "
-                                f"{''.join(chr(c) for c in chars)}"
+                                "SUBSET %s characters: %s", font_path,
+                                ''.join(chr(c) for c in chars)
                             )
-                            fontdata = _backend_pdf_ps.getSubset(
+                            fontdata = _backend_pdf_ps.get_glyphs_subset(
                                 font_path, "".join(chr(c) for c in chars)
                             )
                             _log.debug(
-                                f"SUBSET {font_path} "
-                                f"{os.stat(font_path).st_size} "
-                                f"↦ {fontdata.getbuffer().nbytes}"
+                                "SUBSET %s %d ↦ %d", font_path,
+                                os.stat(font_path).st_size,
+                                fontdata.getbuffer().nbytes
                             )
 
                             # give ttconv a subsetted font

From f5eebbb8d35f42365ce92c153e57a39698a6d4fb Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sat, 19 Jun 2021 03:02:04 +0530
Subject: [PATCH 11/29] Add fonttools min version for testing

---
 requirements/testing/minver.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/requirements/testing/minver.txt b/requirements/testing/minver.txt
index 395a1d3e26c0..385de6d2dba0 100644
--- a/requirements/testing/minver.txt
+++ b/requirements/testing/minver.txt
@@ -7,3 +7,4 @@ packaging==20.0
 pillow==6.2.0
 pyparsing==2.2.1
 python-dateutil==2.7
+fonttools==4.13.0

From 91417cde7ff2b5af5a365d5e0e4618def360fa42 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sun, 20 Jun 2021 00:42:02 +0530
Subject: [PATCH 12/29] Add fonttools in test workflow

---
 .github/workflows/tests.yml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 64508593e238..c9e34bef1874 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -145,8 +145,7 @@ jobs:
 
           # Install dependencies from PyPI.
           python -m pip install --upgrade $PRE \
-            cycler kiwisolver numpy packaging pillow pyparsing python-dateutil \
-            setuptools-scm \
+            cycler fonttools kiwisolver numpy pillow pyparsing python-dateutil setuptools-scm \
             -r requirements/testing/all.txt \
             ${{ matrix.extra-requirements }}
 

From aca3bb53286a80d0dfe35361f25e254bc3176171 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 03:54:06 +0530
Subject: [PATCH 13/29] Use ASCII characters for logging

---
 lib/matplotlib/backends/backend_pdf.py | 2 +-
 lib/matplotlib/backends/backend_ps.py  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 4d38040d29b9..ee1bd3673ce0 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -1217,7 +1217,7 @@ def embedTTFType42(font, characters, descriptor):
                 filename, "".join(chr(c) for c in characters)
             )
             _log.debug(
-                "SUBSET %s %d ↦ %d", filename,
+                "SUBSET %s %d -> %d", filename,
                 os.stat(filename).st_size, fontdata.getbuffer().nbytes
             )
 
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index dd470ed62138..b22137702fe8 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -963,7 +963,7 @@ def print_figure_impl(fh):
                                 font_path, "".join(chr(c) for c in chars)
                             )
                             _log.debug(
-                                "SUBSET %s %d ↦ %d", font_path,
+                                "SUBSET %s %d -> %d", font_path,
                                 os.stat(font_path).st_size,
                                 fontdata.getbuffer().nbytes
                             )

From 265a563afe83cb71768d45dbcbdc7150ac30fc80 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 05:58:06 +0530
Subject: [PATCH 14/29] Add unit test for get_glyphs_subset

---
 lib/matplotlib/tests/test_backend_pdf.py | 34 +++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
index 384b88250c7f..353c8bd3525d 100644
--- a/lib/matplotlib/tests/test_backend_pdf.py
+++ b/lib/matplotlib/tests/test_backend_pdf.py
@@ -10,7 +10,14 @@
 
 import matplotlib as mpl
 from matplotlib import dviread, pyplot as plt, checkdep_usetex, rcParams
-from matplotlib.backends.backend_pdf import PdfPages
+from matplotlib.cbook import _get_data_path
+from matplotlib.ft2font import FT2Font
+
+# Weird py23 deprecation warning from fonttools
+with pytest.warns(DeprecationWarning):
+    from matplotlib.backends._backend_pdf_ps import get_glyphs_subset
+    from matplotlib.backends.backend_pdf import PdfPages
+
 from matplotlib.testing.decorators import check_figures_equal, image_comparison
 
 
@@ -339,3 +346,28 @@ def test_kerning():
     s = "AVAVAVAVAVAVAVAV€AAVV"
     fig.text(0, .25, s, size=5)
     fig.text(0, .75, s, size=20)
+
+
+def test_glyphs_subset():
+    fpath = str(_get_data_path("fonts/ttf/DejaVuSerif.ttf"))
+    chars = "these should be subsetted!"
+
+    # non-subsetted FT2Font
+    nosubfont = FT2Font(fpath)
+    nosubfont.set_text(chars)
+
+    # subsetted FT2Font
+    subfont = FT2Font(get_glyphs_subset(fpath, chars))
+    subfont.set_text(chars)
+
+    nosubcmap = nosubfont.get_charmap()
+    subcmap = subfont.get_charmap()
+
+    # all unique chars must be available in subsetted font
+    assert set(chars).issuperset(set([chr(key) for key in subcmap.keys()]))
+
+    # subsetted font's charmap should have less (or equal) entries
+    assert len(subcmap) <= len(nosubcmap)
+
+    # since both objects are assigned same characters
+    assert subfont.get_num_glyphs() == nosubfont.get_num_glyphs()

From 2193caa5c1f5780339ccee6b6def0c005be57d14 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 06:00:50 +0530
Subject: [PATCH 15/29] Remove seek()

---
 lib/matplotlib/backends/backend_ps.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index b22137702fe8..94699313b2f1 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -978,7 +978,6 @@ def print_figure_impl(fh):
                                     font.get_char_index(c) for c in chars
                                 ]
                                 tmp.write(fontdata.getvalue())
-                                tmp.seek(0, 0)
                                 # TODO: allow convert_ttf_to_ps
                                 # to input file objects (BytesIO)
                                 convert_ttf_to_ps(

From 5661f0d56ca074258066328a7048c92bb32949eb Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 06:31:29 +0530
Subject: [PATCH 16/29] Add prefix to subsetted font names according to PDF
 spec

---
 lib/matplotlib/backends/backend_pdf.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index ee1bd3673ce0..defa57f44813 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -13,7 +13,9 @@
 import logging
 import math
 import os
+import random
 import re
+import string
 import struct
 import time
 import types
@@ -768,6 +770,13 @@ def newTextnote(self, text, positionRect=[-100, -100, 0, 0]):
                    }
         self.pageAnnotations.append(theNote)
 
+    def _get_subsetted_psname(self, ps_name):
+        # first three characters as MPL
+        prefix = "MPL"
+        # rest 3 random characters
+        rand = ''.join(random.choice(string.ascii_uppercase) for x in range(3))
+        return prefix + rand + "+" + ps_name
+
     def finalize(self):
         """Write out the various deferred objects and the pdf end matter."""
 
@@ -1360,7 +1369,8 @@ def embedTTFType42(font, characters, descriptor):
 
         # Beginning of main embedTTF function...
 
-        ps_name = font.postscript_name.encode('ascii', 'replace')
+        ps_name = self._get_subsetted_psname(font.postscript_name)
+        ps_name = ps_name.encode('ascii', 'replace')
         ps_name = Name(ps_name)
         pclt = font.get_sfnt_table('pclt') or {'capHeight': 0, 'xHeight': 0}
         post = font.get_sfnt_table('post') or {'italicAngle': (0, 0)}

From d0d766fe3e39f2615fa5b1d34c1c162316fac649 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 10:03:10 +0530
Subject: [PATCH 17/29] Use charmap for prefix

---
 lib/matplotlib/backends/backend_pdf.py | 28 ++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index defa57f44813..991f3b1bed70 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -13,10 +13,10 @@
 import logging
 import math
 import os
-import random
 import re
 import string
 import struct
+import sys
 import time
 import types
 import warnings
@@ -770,12 +770,21 @@ def newTextnote(self, text, positionRect=[-100, -100, 0, 0]):
                    }
         self.pageAnnotations.append(theNote)
 
-    def _get_subsetted_psname(self, ps_name):
-        # first three characters as MPL
-        prefix = "MPL"
-        # rest 3 random characters
-        rand = ''.join(random.choice(string.ascii_uppercase) for x in range(3))
-        return prefix + rand + "+" + ps_name
+    def _get_subsetted_psname(self, ps_name, charmap):
+        def toStr(n, base):
+            if n < base:
+                return string.ascii_uppercase[n]
+            else:
+                return (
+                    toStr(n // base, base) + string.ascii_uppercase[n % base]
+                )
+
+        # encode to string using base 26
+        hashed = hash(frozenset(charmap.keys())) % ((sys.maxsize + 1) * 2)
+        prefix = toStr(hashed, 26)
+
+        # get first 6 characters from prefix
+        return prefix[:6] + "+" + ps_name
 
     def finalize(self):
         """Write out the various deferred objects and the pdf end matter."""
@@ -1369,7 +1378,10 @@ def embedTTFType42(font, characters, descriptor):
 
         # Beginning of main embedTTF function...
 
-        ps_name = self._get_subsetted_psname(font.postscript_name)
+        ps_name = self._get_subsetted_psname(
+            font.postscript_name,
+            font.get_charmap()
+        )
         ps_name = ps_name.encode('ascii', 'replace')
         ps_name = Name(ps_name)
         pclt = font.get_sfnt_table('pclt') or {'capHeight': 0, 'xHeight': 0}

From 5ea7f1bea766ca2f44c0323aa909e4880d903ec0 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 24 Jun 2021 10:09:10 +0530
Subject: [PATCH 18/29] Update fonttools requirements

---
 requirements/testing/minver.txt | 2 +-
 setup.py                        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/requirements/testing/minver.txt b/requirements/testing/minver.txt
index 385de6d2dba0..578cd205f9b5 100644
--- a/requirements/testing/minver.txt
+++ b/requirements/testing/minver.txt
@@ -7,4 +7,4 @@ packaging==20.0
 pillow==6.2.0
 pyparsing==2.2.1
 python-dateutil==2.7
-fonttools==4.13.0
+fonttools==4.22.0
diff --git a/setup.py b/setup.py
index 37370068c4d8..c72e13623c2d 100644
--- a/setup.py
+++ b/setup.py
@@ -325,7 +325,7 @@ def make_release_tree(self, base_dir, files):
     ],
     install_requires=[
         "cycler>=0.10",
-        "fonttools>=4.13.0,<5.0",
+        "fonttools>=4.22.0",
         "kiwisolver>=1.0.1",
         "numpy>=1.17",
         "packaging>=20.0",

From 17873f392d44bd9dd73939d3fddb196dd6e6f105 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Wed, 7 Jul 2021 12:54:34 +0530
Subject: [PATCH 19/29] Drop PfEd table

---
 lib/matplotlib/backends/_backend_pdf_ps.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/backends/_backend_pdf_ps.py b/lib/matplotlib/backends/_backend_pdf_ps.py
index 207e6e2527e5..15a5578461cc 100644
--- a/lib/matplotlib/backends/_backend_pdf_ps.py
+++ b/lib/matplotlib/backends/_backend_pdf_ps.py
@@ -36,8 +36,8 @@ def get_glyphs_subset(fontfile, characters):
 
     options = subset.Options(glyph_names=True, recommended_glyphs=True)
 
-    # prevent subsetting FontForge Timestamp table
-    options.drop_tables += ['FFTM']
+    # prevent subsetting FontForge Timestamp and other tables
+    options.drop_tables += ['FFTM', 'PfEd']
 
     with subset.load_font(fontfile, options) as font:
         subsetter = subset.Subsetter(options=options)

From 9837733de6474c877ea825c7e4aeadbbe970e6d5 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Mon, 12 Jul 2021 13:34:13 +0530
Subject: [PATCH 20/29] flush before reading the contents back from tmp file

---
 lib/matplotlib/backends/backend_ps.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 94699313b2f1..1f37a30c748f 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -978,6 +978,8 @@ def print_figure_impl(fh):
                                     font.get_char_index(c) for c in chars
                                 ]
                                 tmp.write(fontdata.getvalue())
+                                tmp.flush()
+
                                 # TODO: allow convert_ttf_to_ps
                                 # to input file objects (BytesIO)
                                 convert_ttf_to_ps(

From f5097311c2238e9dc758acacd18c744bebd10c71 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Mon, 12 Jul 2021 13:35:35 +0530
Subject: [PATCH 21/29] Fix testing for subsetting

---
 lib/matplotlib/testing/conftest.py       |  2 ++
 lib/matplotlib/tests/test_backend_pdf.py | 11 ++++-------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
index f35eddf96b00..d0aa85367529 100644
--- a/lib/matplotlib/testing/conftest.py
+++ b/lib/matplotlib/testing/conftest.py
@@ -19,6 +19,8 @@ def pytest_configure(config):
         ("markers", "pytz: Tests that require pytz to be installed."),
         ("markers", "network: Tests that reach out to the network."),
         ("filterwarnings", "error"),
+        ("filterwarnings",
+         "ignore:.*The py23 module has been deprecated:DeprecationWarning"),
     ]:
         config.addinivalue_line(key, value)
 
diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
index 353c8bd3525d..bd9ab6fcb2de 100644
--- a/lib/matplotlib/tests/test_backend_pdf.py
+++ b/lib/matplotlib/tests/test_backend_pdf.py
@@ -12,11 +12,8 @@
 from matplotlib import dviread, pyplot as plt, checkdep_usetex, rcParams
 from matplotlib.cbook import _get_data_path
 from matplotlib.ft2font import FT2Font
-
-# Weird py23 deprecation warning from fonttools
-with pytest.warns(DeprecationWarning):
-    from matplotlib.backends._backend_pdf_ps import get_glyphs_subset
-    from matplotlib.backends.backend_pdf import PdfPages
+from matplotlib.backends._backend_pdf_ps import get_glyphs_subset
+from matplotlib.backends.backend_pdf import PdfPages
 
 from matplotlib.testing.decorators import check_figures_equal, image_comparison
 
@@ -350,7 +347,7 @@ def test_kerning():
 
 def test_glyphs_subset():
     fpath = str(_get_data_path("fonts/ttf/DejaVuSerif.ttf"))
-    chars = "these should be subsetted!"
+    chars = "these should be subsetted! 1234567890"
 
     # non-subsetted FT2Font
     nosubfont = FT2Font(fpath)
@@ -364,7 +361,7 @@ def test_glyphs_subset():
     subcmap = subfont.get_charmap()
 
     # all unique chars must be available in subsetted font
-    assert set(chars).issuperset(set([chr(key) for key in subcmap.keys()]))
+    assert set(chars).issubset(set([chr(key) for key in subcmap.keys()]))
 
     # subsetted font's charmap should have less (or equal) entries
     assert len(subcmap) <= len(nosubcmap)

From a362601c934f3bd1eabd3c234d7870d19d99ac06 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Mon, 12 Jul 2021 13:53:07 +0530
Subject: [PATCH 22/29] Add whatsnew entry for Type42 subsetting

---
 doc/users/next_whats_new/subsetting.rst | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 doc/users/next_whats_new/subsetting.rst

diff --git a/doc/users/next_whats_new/subsetting.rst b/doc/users/next_whats_new/subsetting.rst
new file mode 100644
index 000000000000..89c33f58d371
--- /dev/null
+++ b/doc/users/next_whats_new/subsetting.rst
@@ -0,0 +1,22 @@
+Type 42 Subsetting is now enabled for PDF/PS backends
+-----------------------------------------------------
+
+`~matplotlib.backends.backend_pdf` and `~matplotlib.backends.backend_ps` now use
+a unified Type 42 font subsetting interface, with the help of `fontTools <https://fonttools.readthedocs.io/en/latest/>`_
+
+Set `~matplotlib.RcParams`'s *fonttype* value as ``42`` to trigger this workflow:
+
+.. code-block::
+
+    # for PDF backend
+    plt.rcParams['pdf.fonttype'] = 42
+
+    # for PS backend
+    plt.rcParams['ps.fonttype'] = 42
+
+
+    fig, ax = plt.subplots()
+    ax.text(0.4, 0.5, 'subsetted document is smaller in size!')
+
+    fig.savefig("document.pdf")
+    fig.savefig("document.ps")

From 57267a3187b4a08b30c0c63705b7328d029c4bd7 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sat, 17 Jul 2021 23:09:19 +0530
Subject: [PATCH 23/29] Fix subset tests

---
 lib/matplotlib/tests/test_backend_pdf.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
index bd9ab6fcb2de..8e16eb2b7b94 100644
--- a/lib/matplotlib/tests/test_backend_pdf.py
+++ b/lib/matplotlib/tests/test_backend_pdf.py
@@ -361,10 +361,10 @@ def test_glyphs_subset():
     subcmap = subfont.get_charmap()
 
     # all unique chars must be available in subsetted font
-    assert set(chars).issubset(set([chr(key) for key in subcmap.keys()]))
+    assert set(chars) == set(chr(key) for key in subcmap.keys())
 
-    # subsetted font's charmap should have less (or equal) entries
-    assert len(subcmap) <= len(nosubcmap)
+    # subsetted font's charmap should have less entries
+    assert len(subcmap) < len(nosubcmap)
 
     # since both objects are assigned same characters
     assert subfont.get_num_glyphs() == nosubfont.get_num_glyphs()

From 7571055ea1160ff33e4cb2e7415962da616fef62 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Sun, 18 Jul 2021 19:16:13 +0530
Subject: [PATCH 24/29] Add PS test for multiple fonttypes

---
 lib/matplotlib/tests/test_backend_ps.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lib/matplotlib/tests/test_backend_ps.py b/lib/matplotlib/tests/test_backend_ps.py
index b1ea2cd1736d..07eb0382010b 100644
--- a/lib/matplotlib/tests/test_backend_ps.py
+++ b/lib/matplotlib/tests/test_backend_ps.py
@@ -207,3 +207,18 @@ def test_type42_font_without_prep():
     mpl.rcParams["mathtext.fontset"] = "stix"
 
     plt.figtext(0.5, 0.5, "Mass $m$")
+
+
+@pytest.mark.parametrize('fonttype', ["3", "42"])
+def test_fonttype(fonttype):
+    mpl.rcParams["ps.fonttype"] = fonttype
+    fig, ax = plt.subplots()
+
+    ax.text(0.25, 0.5, "Forty-two is the answer to everything!")
+
+    buf = io.BytesIO()
+    fig.savefig(buf, format="ps")
+
+    test = b'/FontType ' + bytes(f"{fonttype}", encoding='utf-8') + b' def'
+
+    assert re.search(test, buf.getvalue(), re.MULTILINE)

From 1630ad90d11d1c5c718f3adb80229b2b35d42043 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Mon, 19 Jul 2021 14:08:09 +0530
Subject: [PATCH 25/29] Use TemporaryDirectory instead of NamedTemporaryFile

---
 lib/matplotlib/backends/backend_ps.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 1f37a30c748f..7cdab6c6a053 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -970,20 +970,21 @@ def print_figure_impl(fh):
 
                             # give ttconv a subsetted font
                             # along with updated glyph_ids
-                            with tempfile.NamedTemporaryFile(
-                                suffix=".ttf"
-                            ) as tmp:
+                            with TemporaryDirectory() as tmpdir:
+                                tmpfile = os.path.join(tmpdir, "tmp.ttf")
                                 font = FT2Font(fontdata)
                                 glyph_ids = [
                                     font.get_char_index(c) for c in chars
                                 ]
-                                tmp.write(fontdata.getvalue())
-                                tmp.flush()
+
+                                with open(tmpfile, 'wb') as tmp:
+                                    tmp.write(fontdata.getvalue())
+                                    tmp.flush()
 
                                 # TODO: allow convert_ttf_to_ps
                                 # to input file objects (BytesIO)
                                 convert_ttf_to_ps(
-                                    os.fsencode(tmp.name),
+                                    os.fsencode(tmpfile),
                                     fh,
                                     fonttype,
                                     glyph_ids,

From fa197d2dc9a15df2fa03da69ab7aa193a4c80c8f Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 22 Jul 2021 01:09:36 +0530
Subject: [PATCH 26/29] Add fontTools in dependencies.rst

---
 doc/devel/dependencies.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/devel/dependencies.rst b/doc/devel/dependencies.rst
index dff7a9b463b9..62453e5c18c9 100644
--- a/doc/devel/dependencies.rst
+++ b/doc/devel/dependencies.rst
@@ -22,6 +22,7 @@ reference.
 * `kiwisolver <https://github.com/nucleic/kiwi>`_ (>= 1.0.1)
 * `Pillow <https://pillow.readthedocs.io/en/latest/>`_ (>= 6.2)
 * `pyparsing <https://pypi.org/project/pyparsing/>`_ (>=2.2.1)
+* `fontTools <https://fonttools.readthedocs.io/en/latest/>`_ (>=4.22.0)
 
 
 .. _optional_dependencies:

From fe583dd2f8e46985b221b7860e746a923602e65c Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 22 Jul 2021 01:10:03 +0530
Subject: [PATCH 27/29] Add API changenote for new dependency

---
 doc/api/next_api_changes/development/20391-AG.rst | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 doc/api/next_api_changes/development/20391-AG.rst

diff --git a/doc/api/next_api_changes/development/20391-AG.rst b/doc/api/next_api_changes/development/20391-AG.rst
new file mode 100644
index 000000000000..37cc539c5ad2
--- /dev/null
+++ b/doc/api/next_api_changes/development/20391-AG.rst
@@ -0,0 +1,8 @@
+fontTools for type 42 subsetting
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A new dependency known as `fontTools <https://fonttools.readthedocs.io/>`_
+is integrated in with Maptlotlib 3.5
+
+It is designed to be used with PS/EPS and PDF documents; and handles
+Type 42 font subsetting.

From a95f2b6a4aba5be1bb6faf65f77189906c2b96a9 Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 22 Jul 2021 01:12:52 +0530
Subject: [PATCH 28/29] Rebase tests.yml for packaging

---
 .github/workflows/tests.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c9e34bef1874..28398cd1973e 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -145,7 +145,8 @@ jobs:
 
           # Install dependencies from PyPI.
           python -m pip install --upgrade $PRE \
-            cycler fonttools kiwisolver numpy pillow pyparsing python-dateutil setuptools-scm \
+            cycler fonttools kiwisolver numpy packaging pillow pyparsing \
+            python-dateutil setuptools-scm \
             -r requirements/testing/all.txt \
             ${{ matrix.extra-requirements }}
 

From 85f4377181609f3b705de69cd8dbd12aef75c73a Mon Sep 17 00:00:00 2001
From: Aitik Gupta <aitikgupta@gmail.com>
Date: Thu, 22 Jul 2021 19:22:40 +0530
Subject: [PATCH 29/29] Keep a reference to non-subsetted font for XObjects

---
 lib/matplotlib/backends/backend_pdf.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
index 991f3b1bed70..89afe92ce913 100644
--- a/lib/matplotlib/backends/backend_pdf.py
+++ b/lib/matplotlib/backends/backend_pdf.py
@@ -1239,6 +1239,9 @@ def embedTTFType42(font, characters, descriptor):
                 os.stat(filename).st_size, fontdata.getbuffer().nbytes
             )
 
+            # We need this ref for XObjects
+            full_font = font
+
             # reload the font object from the subset
             # (all the necessary data could probably be obtained directly
             # using fontLib.ttLib)
@@ -1325,10 +1328,10 @@ def embedTTFType42(font, characters, descriptor):
             glyph_ids = []
             for ccode in characters:
                 if not _font_supports_char(fonttype, chr(ccode)):
-                    gind = font.get_char_index(ccode)
+                    gind = full_font.get_char_index(ccode)
                     glyph_ids.append(gind)
 
-            bbox = [cvt(x, nearest=False) for x in font.bbox]
+            bbox = [cvt(x, nearest=False) for x in full_font.bbox]
             rawcharprocs = _get_pdf_charprocs(filename, glyph_ids)
             for charname in sorted(rawcharprocs):
                 stream = rawcharprocs[charname]