bugGNU Octave - Bugs: bug #56448, Backslashes in text objects break...


bug #56448: Backslashes in text objects break postscript export

Submitted by:  Georg Wiora <gwiora>
Submitted on:  Thu 06 Jun 2019 08:10:13 AM UTC  
Category:  Plotting with OpenGL Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Fixed Assigned to:  None
Originator Name:  gwiora Open/Closed:  Closed
Release:  5.1.0 Operating System:  Any

Add a New Comment (Rich Markup)

You are not logged in

Please log in, so followups can be emailed to you.


( Jump to the original submission)

Fri 07 Jun 2019 03:50:14 PM UTC, comment #9: 

@Georg: To place the plots correctly on the page use the "PaperPosition" property of the figure object.  Documentation is in the manual.  Also, in your original code, I see you using "-r300" which is an option associated with bitmap formats, but PostScript is a vector format and doesn't need that option.  As a quick placement option, you might want to try -bestfit or -fillpage options to print.  Documentation is below.

     When using a page-based format (PDF, PostScript, printer)
     ignore the "paperposition" property and have the plot occupy
     the entire page.  The option '-fillpage' will stretch the plot
     to occupy the page with 0.25 inch margins all around.  The
     option '-bestfit' will expand the plot to take up as much room
     as possible on the page *without* distorting the original
     aspect ratio of the plot.

Rik <rik5>
Project Administrator
Fri 07 Jun 2019 11:23:19 AM UTC, comment #8: 

@Georg: It is very strange that you don't see the warning ... In fact what is even more strange is that in your PS figure you obtain a "a" character instead of a "ä".
Anyway, can you file a new bug report about "-svgconvert" producing misplaced PDF together with a simple example? Please add your screen setup (resolution, number) since this may be relevant.
Also, for me PDF (with or without "-svgconvert" option) works very well with the -append option, as documented. Can you file another bug report about this?

Pantxo Diribarne <pantxo>
Project Member
Fri 07 Jun 2019 07:45:48 AM UTC, comment #7: 

Thank you for your hints and quick fix!

@Rik: I misinterpreted the 'convertsvg' option as another output device and specified it as '-dconvertsvg'. That failed. Using '-convertsvg' gives very nice output but the plot is now misplaced on the page (small problem :-)

@Pantxo: No I did not see this print warning.

Georg Wiora <gwiora>
Thu 06 Jun 2019 09:17:41 PM UTC, comment #6: 

@Pantxo: Great fix!  I applied it to stable so it will be part of the next bug fix release (5.2.0).

Marking as fixed and closing report.

Rik <rik5>
Project Administrator
Thu 06 Jun 2019 06:53:17 PM UTC, comment #5: 

The patch:

(file #47047)

Pantxo Diribarne <pantxo>
Project Member
Thu 06 Jun 2019 06:52:32 PM UTC, comment #4: 

I attached a one liner patch that fixes the issue.

@Georg: In your original example, you should be receiving a warning since you are trying to print a non ASCII character.

warning: print: only ASCII characters are supported for EPS and derived formats.

In that case "ä" will still be replaced by a blank space.

Pantxo Diribarne <pantxo>
Project Member
Thu 06 Jun 2019 05:37:43 PM UTC, comment #3: 

The option -svgconvert was part of the 5.1.0 release.  What is the error message when you execute the following?

plot (1:10, 'o-')
print -svgconvert tst.pdf

Rik <rik5>
Project Administrator
Thu 06 Jun 2019 03:47:02 PM UTC, comment #2: 

Thank you for your hints Rik! Unfortunately is svgconvert not available on windows and I need a multipage format. Otherwise i would use pdf output directly. But ps output seems the only one supporting 'append' option.

Georg Wiora <gwiora>
Thu 06 Jun 2019 03:30:27 PM UTC, comment #1: 

Confirmed.  A very simple example to reproduce is

ht = text (0.5, 0.5, "This is a backslash (\\).");
print -dpsc2 bslash.ps

This is not specific to Windows; I reproduced it on Linux using the code above.  The "interpreter" property is also a red herring as either "none" or "tex" have the same issue.  I believe this is going to be a problem with the gl2ps library.  We may be forced in Octave to work around it by filtering the output of gl2ps before we pass it to Ghostscript.

As a workaround for now you can go through svg and pdf formats which do work.  On a Linux machine which has the pdf2ps converter this sequence works

print -svgconvert bslash.pdf
system ("pdf2ps bslash.pdf")

(file #47046)

Rik <rik5>
Project Administrator
Thu 06 Jun 2019 08:10:13 AM UTC, original submission:  

Create a text with a backslash and display it with 'interpreter' 'none'. Postscript export looks broken then. I was using qt5 graphics on windows for this result.

% Postscript export bug octave 5.1.0

mytext = sprintf("this is _\\pm ä test:\nwith a linebreak\n and a %.3f number",pi)


fh = figure('name','my plot figure');

mytext2 = {"this is a_\\pm test:","with ä linebreak"}

fh2 = figure('name','my plot figure2');

print('-dpsc2', sprintf('-f%d',fh),'-r300','ps_export.ps');

print('-dpsc2', sprintf('-f%d',fh2),'-r300','-append','ps_export.ps');

Georg Wiora <gwiora>


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

Attach Files:

Attached Files
file #47047:  escape_backslash.patch added by pantxo (792B - text/x-patch)
file #47046:  tst_bslash.m added by rik5 (103B - text/x-matlab)
file #47043:  ps_export.ps added by gwiora (218KiB - application/postscript - Sample postscript output and test script)
file #47044:  PostscriptexportBug.m added by gwiora (718B - application/octet-stream - Sample postscript output and test script)


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by pantxo (Posted a comment)
  • -email is unavailable- added by rik5 (Updated the item)
  • -email is unavailable- added by gwiora (Submitted the item)

    Do you think this task is very important?
    If so, you can add your encouragement to it.
    This task has 0 encouragements so far.

    Only project members can vote.




    Follow 11 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-06-06 rik5 StatusPatch Submitted => Fixed
        Open/ClosedOpen => Closed
    2019-06-06 pantxo Attached File- => Added escape_backslash.patch, #47047
    2019-06-06 pantxo CategoryPlotting => Plotting with OpenGL
        StatusConfirmed => Patch Submitted
    2019-06-06 rik5 Attached File- => Added tst_bslash.m, #47046
        StatusNone => Confirmed
        Operating SystemMicrosoft Windows => Any
        SummaryBack slashes in text objects break postscript export => Backslashes in text objects break postscript export
    2019-06-06 gwiora Attached File- => Added ps_export.ps, #47043
        Attached File- => Added PostscriptexportBug.m, #47044

    Back to the top

    Powered by Savane 3.7