Handle file-like objects instead of saving

aitikgupta · aitikgupta · commit 3c17311936b5 · 2021-07-14T12:37:35.000+05:30
diff --git 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
@@ -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
@@ -1193,22 +1194,19 @@ 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'),
@@ -1237,8 +1235,8 @@ 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
@@ -965,20 +965,22 @@ 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
                             # along with updated glyph_ids
                             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,
