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Diffstat (limited to 'doc/Devices.htm')
| -rw-r--r-- | doc/Devices.htm | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/doc/Devices.htm b/doc/Devices.htm index 5694b708e..60339dc3d 100644 --- a/doc/Devices.htm +++ b/doc/Devices.htm @@ -731,7 +731,8 @@ to 32760. <p>The <code>tiffsep</code> device (along with the <code>tiffscaled32</code> and <code>psdcmyk</code> devices) can perform rudimentary automatic bitmap -'trapping' on the final rendered bitmap. +'trapping' on the final rendered bitmap. This code is disabled by default; see +the <a href="trapping_patent_note">note</a> below as to why. <p>Trapping is a process whereby the output is adjusted to minimise the visual impact of offsets between each printed plane. Typically this involves @@ -741,8 +742,8 @@ revealed in the final printout if the different color plates do not exactly line up. <p>This trapping is controlled by 3 device parameters. Firstly the maximum -X and Y offsets are specified using <tt>-dTrapX=N</tt> and <tt>-dTrapY=N</tt> (where <tt>N</tt> is a -figure in pixels, before the downscaler is applied). +X and Y offsets are specified using <tt>-dTrapX=N</tt> and <tt>-dTrapY=N</tt> +(where <tt>N</tt> is a figure in pixels, before the downscaler is applied). <p>The final control is to inform the trapping process in what order inks should be processed, from darkest to lightest. For a typical CMYK device @@ -757,7 +758,27 @@ example: <blockquote><code> gs -sDEVICE=psdcmyk -dTrapX=2 -dTrapY=2 -o out.psd -c "<< [ 4 5 3 1 0 2 ] >> setpagedevice" -f examples\tiger.eps </code></blockquote> - + +<h4><a name="trapping_patent_note"></a>Trapping patents</h4> + +<p>Trapping is an technology area encumbered by many patents. Until +we can convince ourselves that our trapping code is not covered by +any of these patents, the functionality is disabled by default.</p> + +<p>It can be enabled by building with the <tt>ENABLE_TRAPPING</tt> +define, but before you do so you should convince yourself that +either:</p> + +<ul> +<li>The trapping code is not covered by any existing patent. +<li>Any patents that do cover the code are invalid in your +jurisdiction. +<li>That you have appropriate patent licenses for any patents + that do apply. +</ul> + +<p>You bear full responsibility for choosing to build with +<tt>ENABLE_TRAPPING</tt>. <h3><a name="fax"></a>FAX</h3> @@ -804,8 +825,9 @@ colors. <a href="#tiffsep">See the comments under the <tt>tiffsep</tt> and <tt> device about the maximum number of spot colors supported by Ghostscript</a> <p> -These devices support the same -dDownScaleFactor= ratios as <tt>tiffsep</tt>. <tt>tiffscaled32</tt> -supports the same trapping options as <tt>tiffsep</tt>. +These devices support the same -dDownScaleFactor= ratios as <tt>tiffsep</tt>. +<tt>psdcmyk</tt> supports the same trapping options as <tt>tiffsep</tt> +(but see <a href="trapping_patent_note">this note</a>). <p> NOTE: The PSD format is a single image per file format, so you must use the "%d" |