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Implement a custom DCT filter callback for lossless transforms

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2011-09-17 00:18:31 +00:00
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@@ -77,10 +77,39 @@ Data Fields</h2></td></tr>
<tr><td class="mdescLeft">&#160;</td><td class="mdescRight">One of the <a class="el" href="group___turbo_j_p_e_g.html#ga2de531af4e7e6c4f124908376b354866">transform operations</a>. <a href="#a2525aab4ba6978a1c273f74fef50e498"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structtjtransform.html#ac0e74655baa4402209a21e1ae481c8f6">options</a></td></tr>
<tr><td class="mdescLeft">&#160;</td><td class="mdescRight">The bitwise OR of one of more of the <a class="el" href="group___turbo_j_p_e_g.html#ga9c771a757fc1294add611906b89ab2d2">transform options</a>. <a href="#ac0e74655baa4402209a21e1ae481c8f6"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">int(*&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structtjtransform.html#a3b9280f092324befdf4da07ac085d9dd">customFilter</a> )(short *coeffs, <a class="el" href="structtjregion.html">tjregion</a> arrayRegion, <a class="el" href="structtjregion.html">tjregion</a> planeRegion, int componentIndex, int transformIndex)</td></tr>
<tr><td class="mdescLeft">&#160;</td><td class="mdescRight">A callback function that can be used to modify the DCT coefficients after they are losslessly transformed but before they are transcoded to a new JPEG file. <a href="#a3b9280f092324befdf4da07ac085d9dd"></a><br/></td></tr>
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<hr/><a name="details" id="details"></a><h2>Detailed Description</h2>
<div class="textblock"><p>Lossless transform. </p>
</div><hr/><h2>Field Documentation</h2>
<a class="anchor" id="a3b9280f092324befdf4da07ac085d9dd"></a><!-- doxytag: member="tjtransform::customFilter" ref="a3b9280f092324befdf4da07ac085d9dd" args=")(short *coeffs, tjregion arrayRegion, tjregion planeRegion, int componentIndex, int transformIndex)" -->
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<td class="memname">int(* <a class="el" href="structtjtransform.html#a3b9280f092324befdf4da07ac085d9dd">tjtransform::customFilter</a>)(short *coeffs, <a class="el" href="structtjregion.html">tjregion</a> arrayRegion, <a class="el" href="structtjregion.html">tjregion</a> planeRegion, int componentIndex, int transformIndex)</td>
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<p>A callback function that can be used to modify the DCT coefficients after they are losslessly transformed but before they are transcoded to a new JPEG file. </p>
<p>This allows for custom filters or other transformations to be applied in the frequency domain.</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table class="params">
<tr><td class="paramname">coeffs</td><td>pointer to an array of DCT coefficients. (NOTE: this pointer is not guaranteed to be valid once the callback returns, so applications wishing to hand off the DCT coefficients to another function or library should make a copy of them within the body of the callback.) </td></tr>
<tr><td class="paramname">arrayRegion</td><td>region structure containing the width and height of the DCT coefficient array as well as its offset relative to the component plane. TurboJPEG implementations may choose to split each component plane into multiple DCT coefficient arrays and call the callback function once for each array. </td></tr>
<tr><td class="paramname">planeRegion</td><td>region structure containing the width and height of the component plane to which this DCT coefficient array belongs </td></tr>
<tr><td class="paramname">componentIndex</td><td>the component plane to which this DCT coefficient array belongs (Y, Cb, and Cr are, respectively, 0, 1, and 2 in typical JPEG images.) </td></tr>
<tr><td class="paramname">transformIndex</td><td>the transformed image to which this DCT coefficient array belongs</td></tr>
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<dl class="return"><dt><b>Returns:</b></dt><dd>0 if the callback was successful, or -1 if an error occurred. </dd></dl>
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<a class="anchor" id="a2525aab4ba6978a1c273f74fef50e498"></a><!-- doxytag: member="tjtransform::op" ref="a2525aab4ba6978a1c273f74fef50e498" args="" -->
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<hr class="footer"/><address class="footer"><small>Generated on Mon Jul 11 2011 22:02:02 for TurboJPEG by&#160;
<hr class="footer"/><address class="footer"><small>Generated on Fri Sep 16 2011 19:05:46 for TurboJPEG by&#160;
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