Issue 1:
Hi there,

I am trying to find out if it is possible to add vectors based off of quiver in matplotlib and animate this via matplotlib animation.

I was able to use quiver to create static graphs of vector addtion.

I am trying to duplicate the animation style here from this link:

https://www.physics.mun.ca/~jjerrett/vector/vector.html

But i saw on stackoverflow that at one point it was not possible to position vectors

then they said it can, see this link:

https://stackoverflow.com/questions/17758942/is-it-possible-to-update-matplotlib-quiver-position-coordinates-in-an-animation?rq=1

So to explain details of my program, it asks user to input 2 vectors.

Then the 2 vectors, the tails, are placed at the origin.

Then need to move one of the vector tails to the tip of the other vector in order to do vector addition.

And then draw arrow from origin to the final point.

Hope you can let me know.

P.

Issue 2:
Saving vector graphic figures with certain characters in LaTeX will fail. Here I tried to use the \textmu character. Could it be related to #8068?

Code for reproduction

Here I'm saving to PostScript. It gives an error that I think is the most informative and points to some problems with ghostscript. Outputs for SVG and PDF below.

import matplotlib
matplotlib.rcParams['text.usetex'] = True
import matplotlib.pyplot as plt

fig = plt.figure()
ax = fig.add_subplot(111)
ax.set_ylabel(r'\textmu')
plt.savefig('fig.ps')

Output - PS

Traceback (most recent call last):
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_ps.py", line 1520, in gs_distill
report = subprocess.check_output(command, stderr=subprocess.STDOUT)
File "/usr/lib/python3.6/subprocess.py", line 336, in check_output
**kwargs).stdout
File "/usr/lib/python3.6/subprocess.py", line 418, in run
output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['gs', '-dBATCH', '-dNOPAUSE', '-r6000', '-sDEVICE=ps2write', '-sPAPERSIZE=letter', '-sOutputFile=/tmp/tmpt8w23igm.ps', '/tmp/tmpt8w23igm']' returned non-zero exit status 1.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "Untitled.py", line 8, in <module>
plt.savefig('fig.ps')
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/pyplot.py", line 701, in savefig
res = fig.savefig(*args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/figure.py", line 1834, in savefig
self.canvas.print_figure(fname, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backend_bases.py", line 2267, in print_figure
**kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_ps.py", line 910, in print_ps
return self._print_ps(outfile, 'ps', *args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_ps.py", line 937, in _print_ps
**kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_ps.py", line 1359, in _print_figure_tex
rotated=psfrag_rotated)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_ps.py", line 1525, in gs_distill
'\n\n' % exc.output.decode("utf-8")))
RuntimeError: ghostscript was not able to process your image.
Here is the full report generated by ghostscript:
GPL Ghostscript 9.22 (2017-10-04)
Copyright (C) 2017 Artifex Software, Inc. All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
Error: /undefined in --get--
Operand stack:
--nostringval-- --dict:9/18(ro)(L)-- 112 --dict:13/13(L)-- --dict:13/13(L)-- base
Execution stack:
%interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 2015 1 3 %oparray_pop 2014 1 3 %oparray_pop 1998 1 3 %oparray_pop 1884 1 3 %oparray_pop --nostringval-- %errorexec_pop .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- %finish_stringwidth --nostringval-- --nostringval-- 14 8 0 --nostringval-- (pdf_text_enum_t) %op_show_continue --nostringval--
Dictionary stack:
--dict:986/1684(ro)(G)-- --dict:1/20(G)-- --dict:82/200(L)-- --dict:5/6(ro)(L)-- --dict:180/300(L)-- --dict:44/200(L)-- --dict:8/17(L)-- --dict:51/90(L)--
Current allocation mode is local
Last OS error: No such file or directory
Current file position is 58919
GPL Ghostscript 9.22: Unrecoverable error, exit code 1

Output - SVG, PDF

Traceback (most recent call last):
File "Untitled.py", line 8, in <module>
plt.savefig('fig.svg')
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/pyplot.py", line 701, in savefig
res = fig.savefig(*args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/figure.py", line 1834, in savefig
self.canvas.print_figure(fname, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backend_bases.py", line 2267, in print_figure
**kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_svg.py", line 1193, in print_svg
return self._print_svg(filename, svgwriter, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_svg.py", line 1248, in _print_svg
self.figure.draw(renderer)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/figure.py", line 1299, in draw
renderer, self, artists, self.suppressComposite)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/image.py", line 138, in _draw_list_compositing_images
a.draw(renderer)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/axes/_base.py", line 2437, in draw
mimage._draw_list_compositing_images(renderer, self, artists)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/image.py", line 138, in _draw_list_compositing_images
a.draw(renderer)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/axis.py", line 1147, in draw
self.label.draw(renderer)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/artist.py", line 55, in draw_wrapper
return draw(artist, renderer, *args, **kwargs)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/text.py", line 762, in draw
mtext=mtext)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_svg.py", line 1150, in draw_tex
self._draw_text_as_path(gc, x, y, s, prop, angle, ismath="TeX")
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/backends/backend_svg.py", line 950, in _draw_text_as_path
return_new_glyphs_only=True)
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/textpath.py", line 335, in get_glyphs_tex
font_bunch = self.tex_font_map[dvifont.texname]
File "/home/mirek/.local/lib/python3.6/site-packages/matplotlib/dviread.py", line 850, in __getitem__
result = self._font[texname]
KeyError: b'tcss3583'

For PDF it's nearly identical; the last line reads:

KeyError: b'tcss1000'

In case of PS and SVG, no file is produced. In case of PDF, a corrupted file results. Saving to raster formats and inline previews in jupyter notebook work fine.

Matplotlib version

Operating system: Debian 10

Matplotlib version: 2.1.1

Python version: 3.6.4

Matplotlib from pip. Both Matplotlib and LaTeX are installed in userspace