bugGNU Octave - Bugs: bug #31596, Printing plots with non-ASCII...


bug #31596: Printing plots with non-ASCII characters wrong

Submitter:  None
Submitted:  Tue 09 Nov 2010 11:18:06 AM UTC
Category:  Plotting Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Fixed Assigned to:  None
Originator Name:  José Luis García Pallero Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * dev
Operating System:  * GNU/Linux
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Fri 15 Jul 2016 03:26:30 PM UTC, comment #9: 

In the development version of Octave (which will be released as Octave 4.2), printing with TeX markup using the qt toolkit works correctly. That is not what this bug report was about.

I think this stale bug is no longer relevant, since it was originally about printing with UTF-8 characters using the gnuplot toolkit. I can print UTF-8 characters using gnuplot with the "epscairo" and "pngcairo" devices, and svg works as always.

There still appears to be some shortcomings with printing UTF-8 characters using the OpenGL based toolkits (qt and fltk), but that should probably be filed as a new bug if it's not already reported.

Please reopen if I missed something, but closing as fixed.

Mike Miller <mtmiller>
Project Administrator
Fri 15 Jul 2016 01:48:00 PM UTC, comment #8: 

Another update to reflect the situation with Octave 4.0.3 under Windows 7 64bit using the qt toolkit:

The attached script 'plotWithGreekLabel.m' uses

xlabel ("\\Omega")
ylabel ("Ω")

to generate the greek capital letter omega as axis labels. Neither of the two versions works for all output formats:

  • The x label shows up correctly on screen, but as 'Omega' in the eps and png and as '\Omega' in the svg.
  • The y label is an shown as two different glyphs (00CE and 00A9) on screen, as one or two undefined glyphs in eps and png and correctly in svg.

(file #37892, file #37893, file #37895)

Martin Kunz <mkunz>
Fri 28 Mar 2014 01:28:26 AM UTC, comment #7: 

Updating title to reflect the current situation. Plotting correctly displays non-ASCII characters with both gnuplot and fltk but printing to a file does not show the right characters.

Mike Miller <mtmiller>
Project Administrator
Fri 30 Aug 2013 02:09:22 PM UTC, comment #6: 

The following changeset implements multibyte support in the Freetype-based renderer:


This does not consider printing and PS generation, though. However, I'm wondering whether this is even supported in the gnuplot backend.

Michael Goffioul <goffioul>
Fri 30 Aug 2013 12:54:44 AM UTC, comment #5: 

I'm willing to take a look at this, and decode the provided string manually to unicode. However, there's a catch, as the decoding will be dependent on the current locale (for LC_CTYPE).

So let's say that you're using UTF-8 (which is my case under Linux), then to code the degree symbol properly, you'd have to use

char([194 176])

instead of


as reported in another bug. Is this desirable?

Michael Goffioul <goffioul>
Thu 29 Aug 2013 08:15:57 PM UTC, comment #4: 

The missing glyph warning no longer occurs.  However, Unicode characters still produce 2 glyphs in the output display rather than the single desired glyph.

Rik <rik5>
Project Administrator
Mon 31 Oct 2011 01:57:10 AM UTC, comment #3: 

I can confirm this is still present in version 3.4.3. Any non-ASCII Unicode character can't be rendered and will always throw a "ft_render: skipping missing glyph for character `X'"

Joaquín Ignacio Aramendía <samsagax>
Thu 31 Mar 2011 05:46:22 PM UTC, comment #2: 

The warning

"ft_render: skipping missing glyph for character"

even appears when using a font that actually has the glyph in question. It appears, for example, when issuing

text(0.5, 0.5, "H°H", "fontname", "DejaVuSans")

the sign between the "H" being Unicode Character 'DEGREE SIGN' (U+00B0).

Interestingly, when using gnuplot as graphics_toolkit actually two glyphs are displayed between the H's.

Muhali <muhali>
Fri 12 Nov 2010 10:32:21 AM UTC, comment #1: 

The warning message 'ft_render...' not only appears in version 3.3.53 when I try to plot non-english characters. If I try to put a title containing a newline character as

title(sprintf('One line\nAnd another'));

I obtain

warning: ft_render: skipping missing glyph for character `

But the plot is done right
Octave 3.2.4 in the same computer doesn't emits the warning

José Luis García Pallero <jgpallero>
Tue 09 Nov 2010 11:18:06 AM UTC, original submission:  

I'm using Octave testing 3.3.53 and I have a minor problem with plot command. If I try to set xlabel() or ylabel() text containing non english characters (á, Á, etc.) If I try to execute this (for example)

plot(randn(3),';En las antípodas;');
ylabel('todo es idéntico');
xlabel('a lo autóctono');

I obtain warning warnings saying:

warning: ft_render: skipping missing glyph for character `�'

I'm working in Debian GNU/Linux unstable and my plot backend is
gnuplot 4.4 patchlevel 0.

In Octave 3.2.4 I can put non english characters without problems.



(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:

Attached Files
file #37896:  greekScreenshot.png added by mkunz (37KiB - image/png)
file #37892:  plotWithGreekLabel.m added by mkunz (284B - text/plain)
file #37893:  greek.eps added by mkunz (91KiB - application/postscript)
file #37894:  greek.png added by mkunz (8KiB - image/png)
file #37895:  greek.svg added by mkunz (7KiB - image/svg+xml)


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by mkunz (Updated the item)
  • -email is unavailable- added by mtmiller (Posted a comment)
  • -email is unavailable- added by rik5 (Posted a comment)
  • -email is unavailable- added by burkart
  • -email is unavailable- added by samsagax (Posted a comment)
  • -email is unavailable- added by samsagax
  • -email is unavailable- added by muhali (Posted a comment)
  • -email is unavailable- added by jgpallero (Posted a comment)
  • -email is unavailable- added by None (Submitted the item)

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    Follow 13 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2016-07-15 mtmiller StatusConfirmed Fixed
        Open/ClosedOpen Closed
    2016-07-15 mkunz Attached File- Added greekScreenshot.png, #37896
    2016-07-15 mkunz Attached File- Added plotWithGreekLabel.m, #37892
        Attached File- Added greek.eps, #37893
        Attached File- Added greek.png, #37894
        Attached File- Added greek.svg, #37895
    2014-03-28 mtmiller CategoryInterpreter Plotting
        StatusNone Confirmed
        SummaryPlotting non-english characters wrong Printing plots with non-ASCII characters wrong
    2013-08-29 rik5 Release3.3.53 dev
    2012-03-20 burkart Carbon-Copy- Added burkart
    2011-10-31 samsagax Carbon-Copy- Added samsagax

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