Yes- it is a bit of work to write a good, feature complete backend. You might be able to whip up something more limited quite quickly however. It really depends on the complexity of the protocol. The cost of the backend is inversely proportional to the cost of the scanner.<br>
<br>allan<br><br><div class="gmail_quote">On Tue, Jul 24, 2012 at 7:46 PM, Clyde Shappee <span dir="ltr"><<a href="mailto:clydeshappee@yahoo.com" target="_blank">clydeshappee@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td style="font:inherit" valign="top">It sounds to me like a backend is an awful lot of work. My scanner is a real orphan -- perhaps that is why it sold for $19.<br>
<br>The author at <a href="http://www.chmil.org/hp4600linux/" target="_blank">http://www.chmil.org/hp4600linux/</a> mentions the "<span style="font-size:12px">banding/color correction into the executable</span>", a problem that I am aware of under Windows. This was a nasty problem to fix and I forget now how it was done, but it was a trick and one likely not doable in software. It is a shame as this scanner stand vertical on the desktop and you can see through it... That is why I purchased it.<br>
<br>Maybe I will look for a more Linux compatible scanner and throw money rather than time on the problem.<br><br><br><br>--- On <b>Tue, 7/24/12, Paul Newall <i><<a href="mailto:p.newalls@ntlworld.com" target="_blank">p.newalls@ntlworld.com</a>></i></b> wrote:<br>
<blockquote style="border-left:2px solid rgb(16,16,255);margin-left:5px;padding-left:5px"><br>From: Paul Newall <<a href="mailto:p.newalls@ntlworld.com" target="_blank">p.newalls@ntlworld.com</a>><div class="im"><br>
Subject: Re: [sane-devel] Newbie questions<br></div><div class="im">To: <a href="mailto:clydes@theworld.com" target="_blank">clydes@theworld.com</a><br>Cc: "Sane Developers" <<a href="mailto:sane-devel@lists.alioth.debian.org" target="_blank">sane-devel@lists.alioth.debian.org</a>><br>
</div>Date: Tuesday, July 24, 2012, 3:20 PM<div><div class="h5"><br><br><div>I have been through the process of writing a backend myself in the last year.<br>The things that I found particularly difficult were:<br>1. The sane build system, using automake. I'd never seen automake before and found it totally baffling. To get your new backend to compile with all the others requires a lot of edits to a lot of files.<br>
2. Getting other users to test my backend. I tried distributing a patch for the last official release of sane. This was generally a failure, maybe because I'd never made a patch before, or because most potential users have never compiled anything, never mind patching it first. Sane also requires a number of setup
actions as root, particularly to set permissions for usb scanners.<br>It was a long time before I got enough reports of sucessful users to feel confident enough to propose adding my backend to sane git.<br><br>Having said that, I certainly learnt an awful lot in a short time! I'm not really trying to put anyone off.<br>
<br>I think it would help beginner backend writers significantly to have one of the following:<br>a. A special empty backend distributed with sane backends that beginners could tinker with. It would already be included in the build system, so they can concentrate on writing the actual code. Then, when it's all working, they should rename it to a unique name before distribution.<br>
b. A patch, that adds a new backend to the build system. You would have to edit the patch to give this backend a unique name.<br>c. A script, that adds a new backend to the build system with an arbitrary name.<br><br>I think the best approach to distributing
test versions is to distribute a complete version of sane.<br>You still have to provide a lot of support to users on compiling and setting up sane.<br><br>Regards,<br>Paul<br><br>----- Original Message ----- From: "m. allan noah" <<a href="http://mc/compose?to=kitno455@gmail.com" target="_blank">kitno455@gmail.com</a>><br>
To: <<a href="http://mc/compose?to=clydes@theworld.com" target="_blank">clydes@theworld.com</a>><br>Cc: "Sane Developers" <<a href="http://mc/compose?to=sane-devel@lists.alioth.debian.org" target="_blank">sane-devel@lists.alioth.debian.org</a>><br>
Sent: Tuesday, July 24, 2012 1:57 AM<br>Subject: Re: [sane-devel] Newbie questions<br><br><br>> I suppose you have seen this:<br>> <br>> <a href="http://www.chmil.org/hp4600linux/" target="_blank">http://www.chmil.org/hp4600linux/</a><br>
> <br>> It might at give you some hints. For a proper starting
point, you<br>> would want to take a look at an existing backend, and find one that<br>> suits your programming style.<br>> <br>> Also, please learn to cut and past text, instead of attaching images<br>> of text. This will allow it to show up in the mailing list archives<br>
> and search engines...<br>> <br>> allan<br>> <br>> On Mon, Jul 23, 2012 at 7:56 PM, <<a href="http://mc/compose?to=clydes@theworld.com" target="_blank">clydes@theworld.com</a>> wrote:<br>>> Hello all,<br>
>> <br>>> Pardon me if I start out a little rough around the edges, but here goes.<br>>> <br>>> I'd like to write a back end for the HP 4670 scanner which is currently<br>>> not supported.<br>
>> <br>>> Attached is the output from the find scanners command.<br>>> <br>>> I am not a strong programmer, but rather and embedded hardware designer,<br>>> but know my way
around C and am willing to give this a go. (I've written<br>>> thousands of lines of assembler for just about every micro and a ton of<br>>> FORTRAN putting myself through college. There, I just dated myself!)<br>
>> <br>>> If I am successful in this endeavour, I can finally kiss Windows good bye<br>>> once and for all. The only reason I boot it any more is to use the<br>>> scanner.<br>>> <br>>> My questions to the group are:<br>
>> <br>>> 1.) Anyone out there started this effort on this scanner?<br>>> 2.) I believe the scanner is high level, so I am wondering if there is a<br>>> back end template to start from<br>>> 3.) Is there material I need to read to smarten up (read-mes, tutorials,<br>
>> web stuff, etc. on how these things work?<br>>> 4.) If anyone has friendly advice on how best to get started and tips on<br>>> etiquette here, I am all
ears.<br>>> <br>>> Clyde<br>>> Boston Metro Area<br>>> <br>>> --<br>>> sane-devel mailing list: <a href="http://mc/compose?to=sane-devel@lists.alioth.debian.org" target="_blank">sane-devel@lists.alioth.debian.org</a><br>
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