textpath encoding #12928

anntzer · 2018-12-03T16:49:51Z

PR Summary

Consider the following example.

import matplotlib.pyplot as plt
plt.rcParams['text.usetex'] = True
plt.rcParams['text.latex.preamble'] = r'\usepackage{siunitx}'
plt.rcParams['text.hinting_factor'] = 1
plt.text(.5, .5, r'$\si{\degree}$')
plt.text(.5, .4, r'ff\textwon')
plt.gca().set_axis_off()
plt.savefig('/tmp/plot.svg')
plt.savefig('/tmp/plot.pdf')
plt.savefig('/tmp/plot.png')
plt.show()

In the svg output, one sees that the \degree and \textwon characters
(which come from a different font that the ff ligature) are now
correctly loaded, but at a too small size -- this still needs to be
fixedn but is already better than not loading the glyphs at all.
(pdf and png output are unaffected.)

Supersedes #8286, #8415 (from which a test is taken).
Fixes part of #8068, #8280 (the glyph-loading part; the sizing issue is a bug this PR newly exposes).

Likely the bad font sizing has something to do with the use, in textpath.py of self.FONT_SCALE rather than prop.get_size_in_points()/dvifont.size...

PR Checklist

Has Pytest style unit tests
Code is Flake 8 compliant
New features are documented, with examples if plot related
Documentation is sphinx and numpydoc compliant
Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
Documented in doc/api/api_changes.rst if API changed in a backward-incompatible way

anntzer · 2018-12-04T10:38:07Z

lib/matplotlib/textpath.py

+            # If psfonts.map specifies no encoding, the indices directly map to
+            # the font's builtin charmap (see the pdftex manual, section 6.1
+            # -- Map files); so don't use the FreeType-synthesized charmap but
+            # the native ones (we can't directly identify it but it's typically


See also http://lists.nongnu.org/archive/html/freetype/2018-12/msg00001.html.

anntzer · 2018-12-06T23:48:47Z

Very empirically, it looks like glyphs are correctly sized (across multiple of font sizes) with

diff --git i/lib/matplotlib/textpath.py w/lib/matplotlib/textpath.py
index 8ef6187bd..d306e82c8 100644
--- i/lib/matplotlib/textpath.py
+++ w/lib/matplotlib/textpath.py
@@ -315,7 +315,7 @@ class TextToPath(object):
 
             if char_id not in glyph_map:
                 font.clear()
-                font.set_size(self.FONT_SCALE, self.DPI)
+                font.set_size(self.FONT_SCALE ** 2 / dvifont.size, self.DPI)
                 # See comments in _get_ps_font_and_encoding.
                 if enc is not None:
                     index = font.get_name_index(enc[glyph])

which doesn't look completely nuts, but I haven't tracked down all the resizings either.

jklymak

Not clear on all details, but this seems to work...

anntzer · 2019-03-04T20:57:17Z

rebased

tacaswell · 2019-04-02T03:19:54Z

lib/matplotlib/textpath.py

-                    glyph0 = font.load_char(charcode, flags=ft2font_flag)
+                # See comments in _get_ps_font_and_encoding.
+                if enc is not None:
+                    index = font.get_name_index(enc[glyph])


this used to handle the case where glyph not in enc where as this looks like it will now raise KeyError. Is this a change we want to make?

Restored handling of glyph not in enc (in the last commit). Not sure why I removed this in the first place.

tacaswell

modulo the question about changing .get -> [].

Consider the following example. import matplotlib.pyplot as plt plt.rcParams['text.usetex'] = True plt.rcParams['text.latex.preamble'] = r'\usepackage{siunitx}' plt.rcParams['text.hinting_factor'] = 1 plt.text(.5, .5, r'$\si{\degree}$') plt.text(.5, .4, r'ff\textwon') plt.gca().set_axis_off() plt.savefig('/tmp/plot.svg') plt.savefig('/tmp/plot.pdf') plt.savefig('/tmp/plot.png') plt.show() In the svg output, one sees that the \degree and \textwon characters (which come from a different font that the ff ligature) are now correctly loaded, *but* at a too small size -- this still needs to be fixed. (pdf and png output are unaffected.)

…928-on-v3.1.x Backport PR #12928 on branch v3.1.x (textpath encoding)

anntzer added backend: svg topic: text/usetex labels Dec 3, 2018

anntzer added this to the v3.1 milestone Dec 3, 2018

anntzer force-pushed the textpath-encoding branch 2 times, most recently from 04dfa60 to 83f2d64 Compare December 3, 2018 20:41

anntzer commented Dec 4, 2018

View reviewed changes

anntzer force-pushed the textpath-encoding branch 2 times, most recently from 533b875 to 2077dc9 Compare December 7, 2018 14:57

jklymak approved these changes Mar 4, 2019

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anntzer force-pushed the textpath-encoding branch from 2077dc9 to 976e779 Compare March 4, 2019 20:57

tacaswell reviewed Apr 2, 2019

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tacaswell approved these changes Apr 2, 2019

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anntzer force-pushed the textpath-encoding branch from 976e779 to 51436bf Compare April 2, 2019 09:35

anntzer and others added 4 commits April 2, 2019 13:54

Added test encoding issue in SVG backend

88e1b53

Fix the cherry-picked test.

c5f2bbe

Properly warn when glyph is not in encoding.

722de6f

anntzer force-pushed the textpath-encoding branch from 51436bf to 722de6f Compare April 2, 2019 11:54

tacaswell merged commit a2277af into matplotlib:master Apr 2, 2019

meeseeksmachine pushed a commit to meeseeksmachine/matplotlib that referenced this pull request Apr 2, 2019

Backport PR matplotlib#12928: textpath encoding

4ffbeeb

meeseeksmachine mentioned this pull request Apr 2, 2019

Backport PR #12928 on branch v3.1.x (textpath encoding) #13841

Merged

anntzer deleted the textpath-encoding branch April 2, 2019 13:25

dstansby added a commit that referenced this pull request Apr 2, 2019

Merge pull request #13841 from meeseeksmachine/auto-backport-of-pr-12…

9f39678

…928-on-v3.1.x Backport PR #12928 on branch v3.1.x (textpath encoding)

This was referenced May 7, 2019

Saving polar plots with MiKTeX on Windows fails for some file formats #14146

Closed

Fix glyph loading in textpath. #14156

Merged

Fix glyph sizing in textpath. #14159

Draft

This was referenced Jul 5, 2019

ENH: try to use unicode charmap before ADOBE_STANDARD in textpath #8286

Closed

Fixed Issue #8068 - SVG encoding #8415

Closed

QuLogic mentioned this pull request Apr 7, 2023

svg backend has limited encoding support with usetex #8068

Closed

ksunden mentioned this pull request Apr 9, 2023

Trouble saving svg file when plot contains special characters #8280

Closed

anntzer mentioned this pull request Mar 22, 2025

[Bug]: Saving as an SVG and PDF produce different outputs with Latex characters, with wrong character sizing #29791

Open

anntzer mentioned this pull request Apr 1, 2025

Fix loading of Type1 "native" charmap. #29843

Merged

5 tasks

anntzer mentioned this pull request May 23, 2025

Use fix-cm instead of type1cm. #30100

Open

5 tasks

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textpath encoding #12928

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