sane-project-website/old-archive/1998-10/0214.html

118 wiersze
5.2 KiB
HTML

<!-- received="Tue Oct 20 11:04:37 1998 PDT" -->
<!-- sent="Tue, 20 Oct 1998 22:02:03 +0200 (MEST)" -->
<!-- name="becka@rz.uni-duesseldorf.de" -->
<!-- email="becka@rz.uni-duesseldorf.de" -->
<!-- subject="Re: your mail" -->
<!-- id="m0zVhyl-000CEkC@hades.beck-sw.de" -->
<!-- inreplyto="199810200110.UAA08128@dfw-ix16.ix.netcom.com" -->
<title>sane-devel: Re: your mail</title>
<h1>Re: your mail</h1>
<a href="mailto:becka@rz.uni-duesseldorf.de"><i>becka@rz.uni-duesseldorf.de</i></a><br>
<i>Tue, 20 Oct 1998 22:02:03 +0200 (MEST)</i>
<p>
<ul>
<li> <b>Messages sorted by:</b> <a href="date.html#214">[ date ]</a><a href="index.html#214">[ thread ]</a><a href="subject.html#214">[ subject ]</a><a href="author.html#214">[ author ]</a>
<!-- next="start" -->
<li> <b>Next message:</b> <a href="0215.html">Dr. Andreas Bolsch: "Pixels vs. Bytes per Line"</a>
<li> <b>Previous message:</b> <a href="0213.html">Thomas Kluge: "Casio QV-11"</a>
<li> <b>In reply to:</b> <a href="0212.html">jbnivoit@ix.netcom.com: "(no subject)"</a>
<!-- nextthread="start" -->
<li> <b>Next in thread:</b> <a href="0217.html">Jean-Baptiste Nivoit: "Re: your mail"</a>
<li> <b>Reply:</b> <a href="0217.html">Jean-Baptiste Nivoit: "Re: your mail"</a>
<!-- reply="end" -->
</ul>
<!-- body="start" -->
Hi !<br>
<p>
<i>&gt; i just purchased a Casio QV-11 camera the other day and got</i><br>
<p>
<i>&gt; load CAM pictures directly into the GIMP). Now i think i read in the </i><br>
<i>&gt; SANE doc that JPEG was not supported yet... i don't see the point of</i><br>
<i>&gt; translating a JPEG file into a bitmap that SANE can handle, since most</i><br>
<i>&gt; often users might convert the result to JPEG in the end anyway..</i><br>
<p>
Yes. If it hasn't been removed, there was an entry in the "TODO" file<br>
or something that stated that for a while.<br>
Oh - just found it again in "LEVEL2".<br>
<p>
BTW: David - could you correct my EMail address in there ?<br>
The one stated there isn't valid on the internet, just within my intranet.<br>
<a href="mailto:becka@ggi-project.org">becka@ggi-project.org</a> is.<br>
<p>
<i>&gt; So here are basically the questions:</i><br>
<i>&gt; - how hard is it to write a backend? what's a good place to</i><br>
<i>&gt; start (which one is the simplest ?) ?</i><br>
<p>
I once wrote the pnm backend to serve as some kind of reference<br>
implementation. In your case, this might be a good place to start, as<br>
effectively the camera is more like an "external image library" than like<br>
a scanner, so it does make sense to start from the pnm backend.<br>
<p>
I'd say it isn't too hard, if you have the actual communications code.<br>
The SANE interface itself is pretty simple, once you have grasped how<br>
this option stuff works.<br>
<p>
<i>&gt; - when will there be JPEG support in the SANE interface? i guess</i><br>
<i>&gt; other camera (such as the Kodak ones?) also use a format</i><br>
<i>&gt; that's close to JPEG...</i><br>
<p>
We should finally add that.<br>
<p>
My idea about adding it would be to increase the version number, which<br>
can be queried at sane_init() time.<br>
<p>
If the frontend finds a sufficiently high version, it would assume<br>
that the SANE_Parameters struct is extended by a few fields like:<br>
<p>
SANE_String mime_type;<br>
SANE_String suggested_filename;<br>
<p>
This would effectively take care of all possible fileformats.<br>
<p>
The frontend code would have to be changed a bit like this:<br>
<p>
if (strcmp(param.mimetype,"application/SANE"))<br>
save_directly_to_file(<br>
make_path_suitable_for_host_os(<br>
param.suggested_filename)));<br>
else <br>
do_the_same_as_before();<br>
<p>
This would also take care of the second suggestion in the file to use SANE<br>
for arbitrary datatypes.<br>
<p>
File size could be handled in a compatible way, by setting bytes_per_line<br>
and lines accordingly, that is usually to something like fsize(),1 or<br>
1,fsize().<br>
<p>
This would only be a minor modification to frontends and backends<br>
(even old frontends would handle new-style data somewhat correctly, <br>
if they would save it to a file directly without trying to convert/<br>
interpret it first). Most of our current front-ends afaik do a very<br>
simplistic "convert to pnm" which could easily be undone afterwards <br>
by a small script that simply removes the header.<br>
<p>
CU, Andy<br>
<p>
<pre>
--
= Andreas Beck | Email : &lt;<a href="mailto:andreas.beck@ggi-project.org">andreas.beck@ggi-project.org</a>&gt; =
<p>
<pre>
--
Source code, list archive, and docs: <a href="http://www.mostang.com/sane/">http://www.mostang.com/sane/</a>
To unsubscribe: echo unsubscribe sane-devel | mail <a href="mailto:majordomo@mostang.com">majordomo@mostang.com</a>
</pre>
<!-- body="end" -->
<p>
<ul>
<!-- next="start" -->
<li> <b>Next message:</b> <a href="0215.html">Dr. Andreas Bolsch: "Pixels vs. Bytes per Line"</a>
<li> <b>Previous message:</b> <a href="0213.html">Thomas Kluge: "Casio QV-11"</a>
<li> <b>In reply to:</b> <a href="0212.html">jbnivoit@ix.netcom.com: "(no subject)"</a>
<!-- nextthread="start" -->
<li> <b>Next in thread:</b> <a href="0217.html">Jean-Baptiste Nivoit: "Re: your mail"</a>
<li> <b>Reply:</b> <a href="0217.html">Jean-Baptiste Nivoit: "Re: your mail"</a>
<!-- reply="end" -->
</ul>