dip-ExternalInterface.html

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  <title>dip::ExternalInterface class | DIPlib | a library for quantitative image analysis</title>
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        <h1>
          <div class="m-doc-include m-thin m-right-m m-text-right">
<a href="imagetype.html" class="m-doc">Image</a> module<br/><span class="m-code m-thin">#include <a href="file--diplib-h.html">"diplib.h"</a></span>          </div>

          <span class="m-breadcrumb"><a href="dip.html">dip</a>::<wbr/></span>ExternalInterface <span class="m-thin">class</span>        </h1>
        <p>Support for external interfaces.</p>
        <div class="m-index m-block m-default">
          <h3>Contents</h3>
          <ul>
            <li>
              Reference
              <ul>
                <li><a href="#derived-classes">Derived classes</a></li>
                <li><a href="#function-members">Functions</a></li>
              </ul>
            </li>
          </ul>
        </div>
          <p>Software using <em>DIPlib</em> might want to control how the image data is allocated. Such software
should derive a class from this one, and assign a pointer to it into each of the images that
it creates, through <a href="dip-Image.html#dip-Image-SetExternalInterface-dip-ExternalInterface-P"><code>dip::Image::SetExternalInterface</code></a>. The caller will maintain ownership of
the interface.</p>
<p>See <a href="dip-Image.html#external_interface">Define an image&rsquo;s allocator</a> for details on how to use the external interfaces.</p>
        <section id="derived-classes">
          <h2>Derived classes</h2>
          <dl class="m-doc">
                          <dt>
              class <a href="dip-AlignedAllocInterface.html" class="m-doc">dip::<wbr />AlignedAllocInterface</a>
            </dt>
            <dd><a href="dip-ExternalInterface.html"><code>dip::ExternalInterface</code></a> that allocates aligned data. <a href="dip-AlignedAllocInterface.html#dip-AlignedAllocInterface">more...</a></dd>
                          <dt>
              class <a href="dip_opencv-ExternalInterface.html" class="m-doc">dip_opencv::<wbr />ExternalInterface</a>
            </dt>
            <dd>This class is the <a href="dip-ExternalInterface.html"><code>dip::ExternalInterface</code></a> for the <em>OpenCV</em> interface. <a href="dip_opencv-ExternalInterface.html#dip_opencv-ExternalInterface">more...</a></dd>
                          <dt>
              class <a href="dml-MatlabInterface.html" class="m-doc">dml::<wbr />MatlabInterface</a>
            </dt>
            <dd>This class is the <a href="dip-ExternalInterface.html"><code>dip::ExternalInterface</code></a> for the <em>MATLAB</em> interface. <a href="dml-MatlabInterface.html#dml-MatlabInterface">more...</a></dd>
          </dl>
        </section>
        <section id="function-members">
          <h2>Functions</h2>
          <dl class="m-doc">
                          <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#dip-ExternalInterface-AllocateData-void-PL-dip-DataType--UnsignedArray-CL-IntegerArray-L-dip-Tensor-CL-dip-sint-L" class="m-doc">AllocateData</a>(</span><span class="m-doc-wrap">void*&amp; origin,
              <a href="dip-DataType.html" class="m-doc">dip::DataType</a> dataType,
              <a href="supporttypes.html#dip-UnsignedArray" class="m-doc">dip::UnsignedArray</a> const&amp; sizes,
              <a href="supporttypes.html#dip-IntegerArray" class="m-doc">dip::IntegerArray</a>&amp; strides,
              <a href="dip-Tensor.html" class="m-doc">dip::Tensor</a> const&amp; tensor,
              <a href="supporttypes.html#dip-sint" class="m-doc">dip::sint</a>&amp; tensorStride) -&gt; <a href="imagetype.html#dip-DataSegment" class="m-doc">dip::DataSegment</a> <span class="m-label m-flat m-warning">pure virtual</span></span>
            </dt>
            <dd>Allocates the data for an image. <a href="#dip-ExternalInterface-AllocateData-void-PL-dip-DataType--UnsignedArray-CL-IntegerArray-L-dip-Tensor-CL-dip-sint-L">more...</a></dd>
                          <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#dip-ExternalInterface-Name-C" class="m-doc">Name</a>(</span><span class="m-doc-wrap">) const -&gt; <a href="supporttypes.html#dip-String" class="m-doc">dip::String</a> <span class="m-label m-flat m-warning">virtual</span></span>
            </dt>
            <dd>Overriding the <code>Name</code> function allows the user to find out what the external interface attached
to an image is.</dd>
          </dl>
        </section>
        <section>
          <h2>Function documentation</h2>
                        <section class="m-doc-details" id="dip-ExternalInterface-AllocateData-void-PL-dip-DataType--UnsignedArray-CL-IntegerArray-L-dip-Tensor-CL-dip-sint-L"><div>
            <h3>
              <span class="m-doc-return"><a href="imagetype.html#dip-DataSegment" class="m-doc">dip::DataSegment</a> </span>
              <span class="m-doc-name"><a href="#dip-ExternalInterface-AllocateData-void-PL-dip-DataType--UnsignedArray-CL-IntegerArray-L-dip-Tensor-CL-dip-sint-L" class="m-doc-self">AllocateData</a></span>(
<span class="m-doc-arg">void*&amp; origin, </span><span class="m-doc-arg"><a href="dip-DataType.html" class="m-doc">dip::DataType</a> dataType, </span><span class="m-doc-arg"><a href="supporttypes.html#dip-UnsignedArray" class="m-doc">dip::UnsignedArray</a> const&amp; sizes, </span><span class="m-doc-arg"><a href="supporttypes.html#dip-IntegerArray" class="m-doc">dip::IntegerArray</a>&amp; strides, </span><span class="m-doc-arg"><a href="dip-Tensor.html" class="m-doc">dip::Tensor</a> const&amp; tensor, </span><span class="m-doc-arg"><a href="supporttypes.html#dip-sint" class="m-doc">dip::sint</a>&amp; tensorStride</span>) <span class="m-label m-warning">pure virtual</span>            </h3>
            <p>Allocates the data for an image.</p>
<p>This function is called when <a href="dip-Image.html#dip-Image-Forge"><code>dip::Image::Forge</code></a> is called on an image with this
external interface. It should be overridden by a function that will allocate space
according to <code>dataType</code>, <code>sizes</code> and <code>tensor.Elements()</code>.
<code>strides</code> and <code>tensorStride</code> might have been set by the user before calling forging,
and should be honored if possible.</p>
<p>The function is required to set <code>strides</code>,
<code>tensorStride</code> and <code>origin</code>, and return a <a href="imagetype.html#dip-DataSegment"><code>dip::DataSegment</code></a> that owns the
allocated data segment. <code>origin</code> does not need to be the same pointer as
stored in the returned <a href="imagetype.html#dip-DataSegment"><code>dip::DataSegment</code></a>. For example, the latter can point
to a container object (e.g. <code>std::vector</code>), and <code>origin</code> can point to data
owned by the container object (e.g. <code>std::vector::data()</code>).</p>
<p>There are two possible failure modes:</p>
<ol>
<li>The function can throw an exception, which will not be caught, and causes the call to <code>Forge</code> to fail.</li>
<li>The function can return a <code>nullptr</code>, which tells <code>Forge</code> to use the default allocator instead.</li>
</ol>
          </div></section>
                        <section class="m-doc-details" id="dip-ExternalInterface-Name-C"><div>
            <h3>
              <span class="m-doc-return"><a href="supporttypes.html#dip-String" class="m-doc">dip::String</a> </span>
              <span class="m-doc-name"><a href="#dip-ExternalInterface-Name-C" class="m-doc-self">Name</a></span>(
) const <span class="m-label m-warning">virtual</span>            </h3>
            <p>Overriding the <code>Name</code> function allows the user to find out what the external interface attached
to an image is.</p>
          </div></section>
        </section>
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