n a blended color according to the current <a href="command-line-options.html#interpolate">-interpolate</a> setting.</p>

<p>A position outside the boundary of the image retrieves a value dictated by the <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> option setting.</p>

<p>Specify <samp>u.r</samp> to specify the red channel of the current image. If you don't specify a channel qualifier, you get the current channel. Use <samp>mean.this</samp> to set the output channel to the mean of ju