There has been some PDF export improvements with version:1.4.0, maybe you should give it a try on http://demo.redmine.org or http://m.redmine.org?
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
See #8753.
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
I have created issue.
https://github.com/naitoh/rbpdf/issues/3
--------------------------------------------------------------------------------
I released rbpdf 1.18.3 gem.
Persian support was fixed by rbpdf 1.18.3.
please use DejaVuSans font.

# please bundle update
<pre>
bundle update rbpdf
</pre>
# set DejaVuSans font.
** config/locales/fa.yml
<pre>
general_pdf_fontname: DejaVuSans
</pre>
# use Persian locale
--------------------------------------------------------------------------------
I update rbpdf to 1.18.3
I changed general_pdf_fontname to "DejaVuSans"
I used Persian locale (fa_IR.UTF-8)
but, I get same error.

--------------------------------------------------------------------------------
m mahdi wrote:
> I update rbpdf to 1.18.3
> I changed general_pdf_fontname to "DejaVuSans"
> I used Persian locale (fa_IR.UTF-8)
> but, I get same error.

Sorry, additional procedure.
Please restart Redmine.

* result
!Persian_pdf.png!

Persian is a locale in RTL.
But, you seem to be using a locale in LTR.

!error_gantt.png !
--------------------------------------------------------------------------------
Thanks for your reply.
After restart Redmine, PDF export was correct.
But, task history is incorrect yet.

!task_history.png!

*Also the "DejaVuSans" font is not appropriate for Persian and Arabic language. Please change font to Arial, Tahoma or "times new roman"*

--------------------------------------------------------------------------------
DejaVuSans Arabic and Persian language weren't supported by Italic font.

Please use pdf_Arabic_Persian.patch. (for Remine 2.6 and trunk)

* result
!Persian_pdf2.png!
--------------------------------------------------------------------------------
m mahdi wrote:
> After restart Redmine, PDF export was correct.

No, the exported PDF is not correct yet despite the improvement. The problem is all characters are joined to their previous characters, even when they must not be joined.
--------------------------------------------------------------------------------
Ebrahim Mohammadi wrote:
>
> No, the exported PDF is not correct yet despite the improvement. The problem is all characters are joined to their previous characters, even when they must not be joined.

Yes, The font is not correct. The font not suitable for Persian and Arabic text.
--------------------------------------------------------------------------------
I'm not sure font is the problem. DejaVu fonts work well with Persian. I think something else is wrong.
--------------------------------------------------------------------------------
Ebrahim Mohammadi wrote:
> I'm not sure font is the problem. DejaVu fonts work well with Persian.

Yes, I think so, too.

> I think something else is wrong.

I released rbpdf 1.18.4 gem.
I fixed many Arabic and Persian PDF export's problem by rbpdf 1.18.4.

# please bundle update
<pre>
bundle update rbpdf
</pre>
# set DejaVuSans font.
** config/locales/fa.yml
<pre>
general_pdf_fontname: DejaVuSans
</pre>
** config/locales/ar.yml
<pre>
general_pdf_fontname: DejaVuSans
</pre>
# Please use pdf.rb_r13778.diff patch. (for Remine 2.6 and trunk)
# Please restart Redmine.
# Please use Arabic or Persian locale
# Please export PDF
--------------------------------------------------------------------------------
Jun NAITOH wrote:
> Ebrahim Mohammadi wrote:
> > I'm not sure font is the problem. DejaVu fonts work well with Persian.
>
> Yes, I think so, too.
>
> > I think something else is wrong.
>
> I released rbpdf 1.18.4 gem.
> I fixed many Arabic and Persian PDF export's problem by rbpdf 1.18.4.
>
> # please bundle update
> [...]
> # set DejaVuSans font.
> ** config/locales/fa.yml
> [...]
> ** config/locales/ar.yml
> [...]
> # Please use pdf.rb_r13778.diff patch. (for Remine 2.6 and trunk)
> # Please restart Redmine.
> # Please use Arabic or Persian locale
> # Please export PDF
Thanks Jun.
It was correct and works well.

--------------------------------------------------------------------------------
m mahdi wrote:

> Thanks Jun.
> It was correct and works well.

Thank you very much for your confirmation!

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Sorry, I cannot show italic correctly.

* Ruby 1.8.7
* Ruby 1.9.3
* Ruby 2.1.5

!web.png!
!pdf.png!

--------------------------------------------------------------------------------
Previous note is on 2.6-stable r13840 applying note 15.
--------------------------------------------------------------------------------
Toshi MARUYAMA wrote:
> Sorry, I cannot show italic correctly.

Sorry, pdf.rb_r13778.diff has problem.
DejaVuSans Arabic and Persian language weren't supported by Italic font.

I fixed so as not to use an italic style by pdf.rb_r13857.patch.

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Fixed in 2.6-stable r13984, thanks.
--------------------------------------------------------------------------------

relates,Closed,8753,PDF export for Hebrew is reversed
relates,Closed,13575,Graphic characters not exported
relates,Closed,13781,CJK(Chinese/Japanese/Korean) characters are not shown in PDF on non CJK locales
relates,Closed,16040,problem in exporting Arabic text to csv
relates,Closed,18586,Arabic PDF
duplicates,Closed,18504,PDF export for arabic and persian language doesn't work