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72 wiersze
3.4 KiB
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<!-- received="Thu Jul 29 19:41:11 1999 PDT" -->
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<!-- sent="Thu, 29 Jul 1999 19:58:49 -0700" -->
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<!-- name="Stephen Williams" -->
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<!-- email="steve@icarus.com" -->
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<!-- subject="scanners that do jpeg compression" -->
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<!-- id="199907300258.TAA13262@icarus.com" -->
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<title>sane-devel: scanners that do jpeg compression</title>
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<h1>scanners that do jpeg compression</h1>
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<b>Stephen Williams</b> (<a href="mailto:steve@icarus.com"><i>steve@icarus.com</i></a>)<br>
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<i>Thu, 29 Jul 1999 19:58:49 -0700</i>
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<p>
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<ul>
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<li> <b>Messages sorted by:</b> <a href="date.html#219">[ date ]</a><a href="index.html#219">[ thread ]</a><a href="subject.html#219">[ subject ]</a><a href="author.html#219">[ author ]</a>
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<li> <b>Next message:</b> <a href="0220.html">Didier Carlier: "Re: SANE & exposure times"</a>
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<li> <b>Previous message:</b> <a href="0218.html">Nick Lamb: "Re: SANE & exposure times"</a>
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</ul>
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I have a whole bunch of high-performance scanners that are just<br>
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screaming for SANE drivers. Some are color, some are grayscale.<br>
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All can produce many views (i.e. color and binary) of the same image,<br>
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and all compressed the image in hardware.<br>
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<p>
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I see that SANE is going to have some troubles with these scanners.<br>
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It is reasonable to expect the driver to decompress these images and<br>
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present them to the default application as RGB images, but I would like<br>
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to write SANE applications that can receive these images as JFIF streams.<br>
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The program may save them to disk, or preview the image, or both, but I<br>
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would like to give a JFIF aware application the JFIF frame.<br>
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<p>
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For the particular scanners I have in mind, it is imperative that the<br>
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image not be decompressed/recompressed unless it is to be displayed<br>
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or passed on to non-compression aware applications. Otherwise, there is<br>
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simply no chance of getting the 180PPM that some of these scanners can<br>
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operate at.<br>
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<p>
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To accomplish this I can see obviously that I can create a driver<br>
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option that enables JFIF frames. However, if the user does this, I do<br>
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not see how to communicate with the application that the comming frame<br>
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is JFIF. The scan_get_parameters result includes the format, and I see<br>
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no way to express that the image is arriving compressed.<br>
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<p>
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TWAIN supports compression of frames, as does Pixel Translations Pixtools.<br>
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<p>
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So, what's a high performance scanner producer to do?<br>
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<pre>
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--
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Steve Williams "The woods are lovely, dark and deep.
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<a href="mailto:steve@icarus.com">steve@icarus.com</a> But I have promises to keep,
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<a href="mailto:steve@picturel.com">steve@picturel.com</a> and lines to code before I sleep,
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<a href="http://www.picturel.com">http://www.picturel.com</a> And lines to code before I sleep."
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<p>
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<p>
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<p>
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<pre>
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--
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Source code, list archive, and docs: <a href="http://www.mostang.com/sane/">http://www.mostang.com/sane/</a>
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</pre>
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<p>
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<ul>
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<!-- next="start" -->
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<li> <b>Next message:</b> <a href="0220.html">Didier Carlier: "Re: SANE & exposure times"</a>
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<li> <b>Previous message:</b> <a href="0218.html">Nick Lamb: "Re: SANE & exposure times"</a>
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<!-- nextthread="start" -->
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<!-- reply="end" -->
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</ul>
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