Sophie: vips-7.18.2-1mdv2010.0 i586

vips-7.18.2-1mdv2010.0.i586.rpm

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<title>IM_RENDER(3) manual page</title>
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<a href='#toc'>Table of Contents</a><p>

<h2><a name='sect0' href='#toc0'>Name</a></h2>
im_render, im_render_fade, im_cache - make image in the background 
<h2><a name='sect1' href='#toc1'>Synopsis</a></h2>
#include
&lt;vips/vips.h&gt; 
<p> int im_render_fade( IMAGE *in, IMAGE *out, IMAGE *mask,  <br>
  int width, int height, int max, <br>
 <br>
  int fps, int steps,<br>
 <br>
  int priority, <br>
 <br>
  void (*notify)( IMAGE *, Rect *, void * ), void *client );<br>
 
<p> int im_render( IMAGE *in, IMAGE *out, IMAGE *mask,  <br>
  int width, int height, int max, <br>
 <br>
  void (*notify)( IMAGE *, Rect *, void * ), void *client );<br>
 
<p> int im_cache( IMAGE *in, IMAGE *out,  <br>
  int width, int height, int max );<br>
 
<p> 
<h2><a name='sect2' href='#toc2'>Description</a></h2>
<a href='im_render_fade.3.html'><b>im_render_fade(3)</a>
 </b> behaves rather like  <a href='im_copy.3.html'><b>im_copy(3)</a>
 </b> between
images <b>in</b> and  <b>out,</b> except that it keeps a cache of computed pixels. This
cache is made of up to <b>max</b> tiles (a value of -1 for <b>max</b> means any number
of tiles), and each tile is of size <b>width</b> by <b>height</b> pixels. Each cache tile
is made with a call to  <a href='im_prepare_thread.3.html'><b>im_prepare_thread(3)</a>
,</b> so cache tile calculation
will be accelerated on multi-CPU machines. If image <b>in</b> represents a large
computation,  <a href='im_render_fade.3.html'><b>im_render_fade(3)</b></a>
 can save a lot of time. 
<p> If the <b>notify</b> parameter
points to a function, then tiles are not calculated immediately, but  are
added to a job list and calculated as CPU becomes available. When a tile
has been calculated, the notify function is passed the image which was
being cached, the area of the image which is now available, and a client
pointer. The notify function will be called by a background thread, so you
will usually need to implement some mechanism to interrupt your main thread
and update. 
<p> The <b>mask</b> image is a one band uchar image the same size as out,
which has 255 for every pixels which is in the cache and 0 everywhere else.
You should not read pixels from <b>mask</b> after  <b>out</b> has been closed. If mask
is NULL, then no mask image is written. 
<p> If  <b>steps </b> is greater than zero,
then pixels in mask are moved between 0 and 255 as tiles age in that many
steps. The <b>fps</b> parameter sets how many times per second the notify function
is called to indicate that an updated tile is ready. 
<p> If <b>priority </b> is zero,
then the render will only run when the system is idle, and only a few renders
will run at any time. Higher values will cause the render to happen more
quickly. 
<p> <a href='im_cache.3.html'><b>im_cache(3)</b></a>
 is a convenience function for <a href='im_render_fade.3.html'><b>im_render_fade(3)</b></a>
 that
caches image pixels synchronously. If you ask for an area not in the cache,
execution blocks until the area has been calculated. 
<p> <a href='im_render.3.html'><b>im_render(3)</b></a>
 is deprecated:
it is the old interface to the render function, before the <b>fps</b> and <b>steps</b>
parameters were added. 
<p> 
<h2><a name='sect3' href='#toc3'>Return Value</a></h2>
The function returns 0 on success, and
non-zero on error, setting im_error(). 
<h2><a name='sect4' href='#toc4'>See Also</a></h2>
<a href='im_prepare.3.html'>im_prepare(3)</a>
 
<h2><a name='sect5' href='#toc5'>Author</a></h2>
J Cupitt,
2003 <p>

<hr><p>
<a name='toc'><b>Table of Contents</b></a><p>
<ul>
<li><a name='toc0' href='#sect0'>Name</a></li>
<li><a name='toc1' href='#sect1'>Synopsis</a></li>
<li><a name='toc2' href='#sect2'>Description</a></li>
<li><a name='toc3' href='#sect3'>Return Value</a></li>
<li><a name='toc4' href='#sect4'>See Also</a></li>
<li><a name='toc5' href='#sect5'>Author</a></li>
</ul>
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