Text rendering of some Persian characters has issues when converting SVG to PNG

Hi,

I am using Activiti Explorer 5.12.1, which uses batik transcoder 1.7 as a
library. When exporting bpmn models to png using Activiti Explorer, the
output has issues on characters "ی", "ک", "پ" and "گ". Note that theses
characters are part of the Persian character set of utf-8, and other
characters which are in the common set of Arabic and Persian character
sets, don't seem to have any problems.

I have *attached* a sample of one of my tests. The text in the box should
read

"ما کب گپ جیب جوب پا"

which is incorrectly shown as

"ما ک‌ب گ‌پ ج‌ی‌ب جوب پ‌ا"

I traced the problem in Activiti Explorer code to this small code snippet:

=======================
      InputStream svgStream = new
ByteArrayInputStream(modelForm.getFirstValue("svg_xml").getBytes("utf-8"));
      TranscoderInput input = new TranscoderInput(svgStream);

      PNGTranscoder transcoder = new PNGTranscoder();
      // Setup output
      ByteArrayOutputStream outStream = new ByteArrayOutputStream();
      TranscoderOutput output = new TranscoderOutput(outStream);

      // Do the transformation
      transcoder.transcode(input, output);
      final byte[] result = outStream.toByteArray();
=======================

It seems that the issues are coming from the PNGTranscoder not being able
to render persian text correctly. PNGTranscoder is part of Apache Batik
(org.apache.batik.transcoder.image.PNGTranscoder).

I have also created a very small eclipse project which does the same thing,
independent of any Activiti Explorer code, which helps a lot to debug the
problem. The project is attached.

More details:

OS: Ubuntu Linux 12.04 (3.2.0-44-generic #69-Ubuntu SMP Thu May 16 17:35:01
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux)

Java: java version "1.7.0_21"
OpenJDK Runtime Environment (IcedTea 2.3.9) (7u21-2.3.9-0ubuntu0.12.04.1)

Batik version used by Activiti Explorer (found in the MANIFEST.MF of the
jar file included): 1.7+r608262

Regards
-- 
Mostafa Mahdieh