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<a name="libvips-generate"></a><div class="titlepage"></div>
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<td valign="top">
<h2><span class="refentrytitle"><a name="libvips-generate.top_of_page"></a>generate</span></h2>
<p>generate — calculate pixels and pixel buffers</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="libvips-generate.stability-level"></a><h2>Stability Level</h2>
Stable, unless otherwise indicated
</div>
<div class="refsynopsisdiv">
<a name="libvips-generate.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <vips/vips.h>
<span class="returnvalue">void</span> * (<a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()">*VipsStartFn</a>) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> (<a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()">*VipsGenerateFn</a>) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> (<a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()">*VipsStopFn</a>) (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">void</span> * <a class="link" href="libvips-generate.html#vips-start-one" title="vips_start_one ()">vips_start_one</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-stop-one" title="vips_stop_one ()">vips_stop_one</a> (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">void</span> * <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()">vips_start_many</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()">vips_stop_many</a> (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<a class="link" href="VipsImage.html" title="VipsImage"><span class="returnvalue">VipsImage</span></a> ** <a class="link" href="libvips-generate.html#vips-allocate-input-array" title="vips_allocate_input_array ()">vips_allocate_input_array</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code>...</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()">vips_image_generate</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-demand-hint-array" title="vips_demand_hint_array ()">vips_demand_hint_array</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> **in</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-demand-hint" title="vips_demand_hint ()">vips_demand_hint</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code>...</code></em>);
</pre>
</div>
<div class="refsect1">
<a name="libvips-generate.description"></a><h2>Description</h2>
<p>
These functions let you generate regions of pixels in an image
processing operation, and ask for regions of image to be calculated.
</p>
</div>
<div class="refsect1">
<a name="libvips-generate.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="VipsStartFn"></a><h3>VipsStartFn ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * (*VipsStartFn) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start a new processing sequence for this generate function. This allocates
per-thread state, such as an input region.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-start-one" title="vips_start_one ()"><code class="function">vips_start_one()</code></a>, <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>image being calculated</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a new sequence value</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsGenerateFn"></a><h3>VipsGenerateFn ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> (*VipsGenerateFn) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Fill <em class="parameter"><code>image->valid</code></em> with pixels. <em class="parameter"><code>seq</code></em> contains per-thread state, such as the
input regions.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()"><code class="function">vips_stop_many()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>region</code></em> :</span></p></td>
<td>
<a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> to fill</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsStopFn"></a><h3>VipsStopFn ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> (*VipsStopFn) (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop a processing sequence. This frees
per-thread state, such as an input region.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-stop-one" title="vips_stop_one ()"><code class="function">vips_stop_one()</code></a>, <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()"><code class="function">vips_stop_many()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-start-one"></a><h3>vips_start_one ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * vips_start_one (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start function for one image in. Input image is <em class="parameter"><code>a</code></em>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td>
<td>image to generate</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-stop-one"></a><h3>vips_stop_one ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_stop_one (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop function for one image in. Input image is <em class="parameter"><code>a</code></em>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-start-many"></a><h3>vips_start_many ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * vips_start_many (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start function for many images in. <em class="parameter"><code>a</code></em> is a pointer to
a <code class="literal">NULL</code>-terminated array of input images.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-allocate-input-array" title="vips_allocate_input_array ()"><code class="function">vips_allocate_input_array()</code></a>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td>
<td>image to generate</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-stop-many"></a><h3>vips_stop_many ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_stop_many (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop function for many images in. <em class="parameter"><code>a</code></em> is a pointer to
a <code class="literal">NULL</code>-terminated array of input images.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-allocate-input-array"></a><h3>vips_allocate_input_array ()</h3>
<pre class="programlisting"><a class="link" href="VipsImage.html" title="VipsImage"><span class="returnvalue">VipsImage</span></a> ** vips_allocate_input_array (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code>...</code></em>);</pre>
<p>
Convenience function --- make a <code class="literal">NULL</code>-terminated array of input images.
Use with <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>free array when this image closes</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>...</code></em> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated list of input images</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated array of images. Do not free the result.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-image-generate"></a><h3>vips_image_generate ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_image_generate (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Generates an image. The action depends on the image type.
</p>
<p>
For images opened with "p", <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a> just attaches the
start/generate/stop callbacks and returns.
</p>
<p>
For "t" images, memory is allocated for the whole image and it is entirely
generated using <a class="link" href="VipsThreadState.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>.
</p>
<p>
For "w" images, memory for a few scanlines is allocated and
<a class="link" href="VipsThreadState.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a> used to generate the image in small chunks. As each
chunk is generated, it is written to disc.
</p>
<p>
See also: <a class="link" href="VipsThreadState.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>, <a class="link" href="VipsImage.html#vips-image-new" title="vips_image_new ()"><code class="function">vips_image_new()</code></a>, <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>generate this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>start</code></em> :</span></p></td>
<td>start sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>generate</code></em> :</span></p></td>
<td>generate pixels with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stop</code></em> :</span></p></td>
<td>stop sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-demand-hint-array"></a><h3>vips_demand_hint_array ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_demand_hint_array (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> **in</code></em>);</pre>
<p>
Operations can set demand hints, that is, hints to the VIPS IO system about
the type of region geometry this operation works best with. For example,
operations which transform coordinates will usually work best with
<a class="link" href="VipsImage.html#VIPS-DEMAND-STYLE-SMALLTILE:CAPS"><code class="literal">VIPS_DEMAND_STYLE_SMALLTILE</code></a>, operations which work on local windows of
pixels will like <a class="link" href="VipsImage.html#VIPS-DEMAND-STYLE-FATSTRIP:CAPS"><code class="literal">VIPS_DEMAND_STYLE_FATSTRIP</code></a>.
</p>
<p>
VIPS uses the list of input images to build the tree of operations it needs
for the cache invalidation system. You have to call this function, or its
varargs friend <a class="link" href="libvips-generate.html#vips-demand-hint" title="vips_demand_hint ()"><code class="function">vips_demand_hint()</code></a>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-demand-hint" title="vips_demand_hint ()"><code class="function">vips_demand_hint()</code></a>, <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>image to set hint for</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>hint</code></em> :</span></p></td>
<td>hint for this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>in</code></em> :</span></p></td>
<td>array of input images to this operation</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-demand-hint"></a><h3>vips_demand_hint ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_demand_hint (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code>...</code></em>);</pre>
<p>
Build an array and call <a class="link" href="libvips-generate.html#vips-demand-hint-array" title="vips_demand_hint_array ()"><code class="function">vips_demand_hint_array()</code></a>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-demand-hint" title="vips_demand_hint ()"><code class="function">vips_demand_hint()</code></a>, <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>image to set hint for</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>hint</code></em> :</span></p></td>
<td>hint for this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>...</code></em> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated list of input images to this operation</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<div class="refsect1">
<a name="libvips-generate.see-also"></a><h2>See Also</h2>
image,
region
</div>
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