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gtkmm2.4-doc-2.12.7-1mdv2008.1.x86_64.rpm

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<title>Chapter 18. Printing</title>
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<tr><th colspan="3" align="center">Chapter 18. Printing</th></tr>
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<div class="titlepage"><div><div><h2 class="title">
<a name="sec-printing"></a>Chapter 18. Printing</h2></div></div></div>
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<p><b>Table of Contents</b></p>
<ul>
<li><span class="sect1"><a href="ch18.html#sec-printoperation">PrintOperation</a></span></li>
<li><span class="sect1"><a href="ch18s02.html">Page setup</a></span></li>
<li><span class="sect1"><a href="ch18s03.html">Rendering text</a></span></li>
<li><span class="sect1"><a href="ch18s04.html">Asynchronous operations</a></span></li>
<li><span class="sect1"><a href="ch18s05.html">Export to PDF</a></span></li>
<li><span class="sect1"><a href="ch18s06.html">Extending the print dialog</a></span></li>
<li><span class="sect1"><a href="ch18s07.html">Preview</a></span></li>
<li><span class="sect1"><a href="ch18s08.html">Example</a></span></li>
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<th align="left">Note</th>
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<tr><td align="left" valign="top"><p>Printing support is available in <span class="application">gtkmm</span> version 2.10 and later.</p></td></tr>
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<p>
At the application development level, <span class="application">gtkmm</span>'s printing API
provides dialogs that are consistent across applications and allows us of Cairo's common drawing API, with Pango-driven text rendering. In the implementation of this common API, platform-specific backends and printer-specific drivers are used.
</p>
<div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="sec-printoperation"></a>PrintOperation</h2></div></div></div>
<p>
The primary object is <code class="classname">Gtk::PrintOperation</code>, allocated
for each print operation. To handle page drawing connect to its signals,
or inherit from it and override the default virtual signal handlers.
<code class="classname">PrintOperation</code> automatically handles all the settings
affecting the print loop.
</p>
<div class="sect2" lang="en">
<div class="titlepage"><div><div><h3 class="title">
<a name="sec-printoperation-signals"></a>Signals</h3></div></div></div>
<p>
The <code class="function">PrintOperation::run()</code> method starts the print loop, 
during which various signals are emitted:

</p>
<div class="itemizedlist"><ul type="disc">
<li><p>
      <code class="literal">begin_print</code>:
      You must handle this signal, because this is where you
      create and set up a <code class="classname">Pango::Layout</code> using the
      provided <code class="classname">Gtk::PrintContext</code>, and break up your
      printing output into pages.
    </p></li>
<li><p>
      <code class="literal">paginate</code>: Pagination is potentially slow so if you
      need to monitor it you can call the
      <code class="function">PrintOperation::set_show_progress()</code> method and
      handle this signal.
    </p></li>
<li>
<p>
      For each page that needs to be rendered, the following signals
      are emitted:
      </p>
<div class="itemizedlist"><ul type="circle">
<li><p>
	    <code class="literal">request_page_setup</code>: Provides a
	    <code class="classname">PrintContext</code>, page number and
	    <code class="classname">Gtk::PageSetup</code>. Handle this signal if you
	    need to modify page setup on a per-page basis.
	  </p></li>
<li><p>
	    <code class="literal">draw_page</code>: You must handle this signal, which provides a
	    <code class="classname">PrintContext</code> and a page number.
	    The <code class="classname">PrintContext</code> should be used 
	    to create a <code class="classname">Cairo::Context</code> into which
	    the provided page should be drawn. To render text, iterate over
	    the <code class="classname">Pango::Layout</code> you created in the
	    <code class="literal">begin_print</code> handler.
	  </p></li>
</ul></div>
<p>
    </p>
</li>
<li><p>
      <code class="literal">end_print</code>: A handler for it is a safe place to free
      any resources related to a <code class="classname">PrintOperation</code>.
      If you have your custom class that inherits from
      <code class="classname">PrintOperation</code>, it is naturally simpler to do it
      in the destructor.
    </p></li>
<li><p>
      <code class="literal">done</code>: This signal is emitted when printing is finished, meaning when the
      print data is spooled. Note that the provided 
      <code class="literal">Gtk::PrintOperationResult</code> may indicate that
      an error occurred. In any case you probably want to notify the user
      about the final status.
    </p></li>
<li><p>
      <code class="literal">status_changed</code>: Emitted whenever a print job's
      status changes, until it is finished. Call the 
      <code class="function">PrintOperation::set_track_print_status()</code> method to
      monitor the job status after spooling. To see the status, use
      <code class="function">get_status()</code> or
      <code class="function">get_status_string()</code>.
    </p></li>
</ul></div>
<p>

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<a class="ulink" href="../../reference/html/classGtk_1_1PrintOperation.html" target="_top">Reference</a>
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