></tr><tr><td>
<p></p>
<table cellpadding=3 border=0>
<tr valign=top><td><b>y</b></td><td>
<p>The pixel's y&nbsp;coordinate.</p>
</td></tr>
<tr valign=top><td><b>x</b></td><td>
<p>The pixel's x&nbsp;coordinate.</p>
</td></tr>
<tr valign=top><td><b>user</b></td><td>
<p>User-supplied data that is passed to the callback.</p>
</td></tr>
</table>
</td></tr></table>
<table align=center width="87%" cellpadding=5><tr bgcolor="#EEEEFF"><td><em><b>return</b></em></td></tr><tr><td>
<p>1&nbsp;if the pixel is &lsquo;set