Merge pull request matplotlib#21752 from anntzer/pdfstream

Add a helper for directly output pdf streams.

Author: timhoffm

lib/matplotlib/backends/backend_pdf.py

@@ -848,6 +848,11 @@ def endStream(self):
             self.currentstream.end()
             self.currentstream = None
 
+    def outputStream(self, ref, data, *, extra=None):
+        self.beginStream(ref.id, None, extra)
+        self.currentstream.write(data)
+        self.endStream()
+
     def _write_annotations(self):
         for annotsObject, annotations in self._annotations:
             self.writeObject(annotsObject, annotations)
@@ -1052,13 +1057,10 @@ def createType1Descriptor(self, t1font, fontfile):
 
         self.writeObject(fontdescObject, descriptor)
 
-        self.beginStream(fontfileObject.id, None,
-                         {'Length1': len(t1font.parts[0]),
-                          'Length2': len(t1font.parts[1]),
-                          'Length3': 0})
-        self.currentstream.write(t1font.parts[0])
-        self.currentstream.write(t1font.parts[1])
-        self.endStream()
+        self.outputStream(fontfileObject, b"".join(t1font.parts[:2]),
+                          extra={'Length1': len(t1font.parts[0]),
+                                 'Length2': len(t1font.parts[1]),
+                                 'Length3': 0})
 
         return fontdescObject
 
@@ -1181,13 +1183,13 @@ def get_char_width(charcode):
             charprocs = {}
             for charname in sorted(rawcharprocs):
                 stream = rawcharprocs[charname]
-                charprocDict = {'Length': len(stream)}
+                charprocDict = {}
                 # The 2-byte characters are used as XObjects, so they
                 # need extra info in their dictionary
                 if charname in multi_byte_chars:
-                    charprocDict['Type'] = Name('XObject')
-                    charprocDict['Subtype'] = Name('Form')
-                    charprocDict['BBox'] = bbox
+                    charprocDict = {'Type': Name('XObject'),
+                                    'Subtype': Name('Form'),
+                                    'BBox': bbox}
                     # Each glyph includes bounding box information,
                     # but xpdf and ghostscript can't handle it in a
                     # Form XObject (they segfault!!!), so we remove it
@@ -1196,9 +1198,7 @@ def get_char_width(charcode):
                     # value.
                     stream = stream[stream.find(b"d1") + 2:]
                 charprocObject = self.reserveObject('charProc')
-                self.beginStream(charprocObject.id, None, charprocDict)
-                self.currentstream.write(stream)
-                self.endStream()
+                self.outputStream(charprocObject, stream, extra=charprocDict)
 
                 # Send the glyphs with ccode > 255 to the XObject dictionary,
                 # and the others to the font itself
@@ -1266,12 +1266,9 @@ def embedTTFType42(font, characters, descriptor):
 
             # Make fontfile stream
             descriptor['FontFile2'] = fontfileObject
-            self.beginStream(
-                fontfileObject.id,
-                self.reserveObject('length of font stream'),
-                {'Length1': fontdata.getbuffer().nbytes})
-            self.currentstream.write(fontdata.getvalue())
-            self.endStream()
+            self.outputStream(
+                fontfileObject, fontdata.getvalue(),
+                extra={'Length1': fontdata.getbuffer().nbytes})
 
             # Make the 'W' (Widths) array, CidToGidMap and ToUnicode CMap
             # at the same time
@@ -1330,10 +1327,9 @@ def embedTTFType42(font, characters, descriptor):
             rawcharprocs = _get_pdf_charprocs(filename, glyph_ids)
             for charname in sorted(rawcharprocs):
                 stream = rawcharprocs[charname]
-                charprocDict = {'Length': len(stream)}
-                charprocDict['Type'] = Name('XObject')
-                charprocDict['Subtype'] = Name('Form')
-                charprocDict['BBox'] = bbox
+                charprocDict = {'Type': Name('XObject'),
+                                'Subtype': Name('Form'),
+                                'BBox': bbox}
                 # Each glyph includes bounding box information,
                 # but xpdf and ghostscript can't handle it in a
                 # Form XObject (they segfault!!!), so we remove it
@@ -1342,27 +1338,17 @@ def embedTTFType42(font, characters, descriptor):
                 # value.
                 stream = stream[stream.find(b"d1") + 2:]
                 charprocObject = self.reserveObject('charProc')
-                self.beginStream(charprocObject.id, None, charprocDict)
-                self.currentstream.write(stream)
-                self.endStream()
+                self.outputStream(charprocObject, stream, extra=charprocDict)
 
                 name = self._get_xobject_glyph_name(filename, charname)
                 self.multi_byte_charprocs[name] = charprocObject
 
             # CIDToGIDMap stream
             cid_to_gid_map = "".join(cid_to_gid_map).encode("utf-16be")
-            self.beginStream(cidToGidMapObject.id,
-                             None,
-                             {'Length': len(cid_to_gid_map)})
-            self.currentstream.write(cid_to_gid_map)
-            self.endStream()
+            self.outputStream(cidToGidMapObject, cid_to_gid_map)
 
             # ToUnicode CMap
-            self.beginStream(toUnicodeMapObject.id,
-                             None,
-                             {'Length': unicode_cmap})
-            self.currentstream.write(unicode_cmap)
-            self.endStream()
+            self.outputStream(toUnicodeMapObject, unicode_cmap)
 
             descriptor['MaxWidth'] = max_width