iZinked/TWPUtil/libdir/JMagix/doc-src/xdocs/docs/faq.xml

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<!DOCTYPE faqs PUBLIC "-//APACHE//DTD FAQ V2.0//EN"
 "http://forrest.apache.org/dtd/faq-v20.dtd">

<!--
 Copyright (c) 2010-2010 by Bernhard Bablok (bablokb@users.sourceforge.net)

 $Revision: 1.2 $
 $Author: bablokb $
-->

<faqs>
    <title>im4java Frequently Asked Questions</title>

  <faqsection id="general">
    <title>General Questions</title>
    <faq id="jni">
      <question>
	What exactly do you mean with <em>JNI-hazard</em>?
      </question>
      <answer>
        <p>
	  Running native code using JNI from within java always
	  imposes additional risks. The JVM is no longer sandboxed, so
	  there 
	  might be some security issues. In addition, there could be
	  errors like memory leaks or memory corruption within the
	  JNI-layer (JMagick) or within the native code (ImageMagick).
	</p>
	<p>
	  This is especially dangerous for long running processes
	  (typically web-application-servers). Memory corruption or a
	  segmentation fault (maybe triggered by a intentionally
	  manipulated image) might bring down the whole server.
	</p>
	<p>
	  On the other side, in reality the situation is not as bad as
	  it sounds above. JMagick is well tested, and for standard
	  use-cases it prooves to be very stable.
	</p>
	<p>
	  Some additional information is available on the
	  JMagick-users mailing list where <a href="ext:jumljni">this
	    topic</a> has been discussed to some detail.
	</p>
      </answer>
    </faq>

    <faq id="winconvert">
      <question>
        The library does not use ImageMagicks <code>convert</code>
	command, but the one supplied by Microsoft. What can I do?
      </question>
      <answer>
        <p>
	  Read the Developer's Guide, section <a
	    href="dev-guide.html#environment">Setting up the
	    Environment</a>. 
        </p>
      </answer>
    </faq>

    <faq id="cmdoption">
      <question>
	The program xxx supports option <code>-foo</code>, but im4java
	does not. Why? And what can I do about it?
      </question>
      <answer>
        <p>
	  Keeping up with actively devolped tools is not easy, im4java
	  will always lag behind in the support of new commandline
	  options. But adding support for a new option is
	  straightforward: 
	</p>
	  <ol>
	    <li>Download the source-distribution of im4java.</li>
	    <li>Edit the file <code>input/XXXinterface.txt</code> and
	      add your new option. The syntax of the file should be
	      clear.
	    </li>
	    <li>Run <code>make src jar</code>. That's it!</li>
	    <li>Post the diff of <code>input/XXXinterface.txt</code>
	      on the jmagick-users mailing-list. I will add it to the
	      next version of im4java.
	    </li>
	  </ol>
      </answer>
    </faq>

    <faq id="exception">
      <question>
	Running my code just throws a
	<code>CommandException</code>. What can I do?
      </question>
      <answer>
        <p>
	  In case there is a CommandException, you should always print
	  the associated error-text:
	</p>
	<source>
	  try {
            ...
          } catch (CommandException ce) {
            ce.printStackTrace();
            ArrayList&lt;String&gt; cmdError = ce.getErrorText();
            for (String line:cmdError) {
              System.err.println(line);
            }
          } catch (Exception e) {
            e.printStackTrace();
          }
	</source>
	<p>The error-text ist the stderr of the used
	  command. Hopefully it tells you why it failed.
	</p>
      </answer>
    </faq>
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  </faqsection>

  <faqsection id="implementation">
    <title>Implementation related</title>
    <faq id="meta">
      <question>
        To be asked.
      </question>
      <answer>
        <p>To be answered.
        </p>
      </answer>
    </faq>
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  </faqsection>
</faqs>