sane-project-website/old-archive/1999-08/0093.html

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<title>sane-devel: Re: Starting a discussion about SANE and TWAIN...</title>
<h1>Re: Starting a discussion about SANE and TWAIN...</h1>
<b>Andreas Beck</b> (<a href="mailto:becka@rz.uni-duesseldorf.de"><i>becka@rz.uni-duesseldorf.de</i></a>)<br>
<i>Wed, 11 Aug 1999 19:31:25 +0200</i>
<p>
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Hello,<br>
<p>
<i>&gt; My name is Mark McLaughlin, and I am the current Chairperson</i><br>
<i>&gt; on the TWAIN Working Group Technical Sub-committee.  I am</i><br>
<i>&gt; sending this message to the manager for the SANE website in</i><br>
<i>&gt; the hope that it will reach the appropriate people.</i><br>
<p>
I think it did. Thank you for contacting us.<br>
<p>
<i>&gt; There is growing interest (as viewed on our mailing list) for</i><br>
<i>&gt; seeing TWAIN support on UNIX platforms, particularly on Linux.</i><br>
<i>&gt; This interest has finally reached a level where the TWAIN</i><br>
<i>&gt; Working Group feels it needs to investigate the possibility of</i><br>
<i>&gt; adding support for UNIX.</i><br>
<p>
This is good news. The original reason for the development of SANE was the<br>
lack of commercial drivers for the various Unix platforms we cover.<br>
<p>
If TWAIN would start an effort in this direction, this would mean setting a<br>
signal towards the manufacturers, that this is an interesting market worth<br>
developing drivers for.<br>
<p>
<i>&gt; We are interested in this because we believe there is an</i><br>
<i>&gt; opportunity to help developers of image capture systems</i><br>
<i>&gt; on UNIX, WIN32 and Macintosh platforms leverage their</i><br>
<i>&gt; code run on one or more or the alternate platforms.</i><br>
<p>
Yes. The variety of platforms on which SANE runs shows, that it is possible<br>
to easily write code that is portable across platforms, if you have a decent<br>
abstraction layer towards the hardware and towards the frontend (windowing<br>
system).<br>
<p>
<i>&gt; TWAIN has no intention of competing with SANE.  Rather we</i><br>
<i>&gt; wish to investigate a chance to employ the strengths of both</i><br>
<i>&gt; standards.  We are not against the idea of seeing SANE</i><br>
<i>&gt; running on WIN32 or Macintosh platforms, and if there are</i><br>
<i>&gt; ways we can help SANE achieve this we would be happy to</i><br>
<i>&gt; discuss them.  It is important that both groups benefit from any</i><br>
<i>&gt; interaction.</i><br>
<p>
Yes. I in deed see quite some possibilities for interaction ...<br>
<p>
The advantages/disatvantages of Twain vs. SANE  look to me like this:<br>
[please correct me on the Twain part, I am sure I am wrong in some places,<br>
 as my knowledge is second hand on that.]<br>
<p>
SANE					TWAIN<br>
separation of HW-driver (backend)	usually monolithic driver<br>
and user interface (frontend)<br>
<p>
network transparent operation using	normally not network transparent<br>
a special front- and backend<br>
<p>
User has choice of frontend		only single frontend per driver<br>
<p>
portable across many platforms		only Windows and MacOS<br>
<p>
API-internal hardware abstraction 	?<br>
layers.<br>
<p>
only three well known frontends		lots of colorful (though often<br>
					scanner-tied) frontends<br>
<p>
not very widespread			widespread, well known API<br>
<p>
small driver base			complete driver base.<br>
<p>
no existing ability to process		can transmit compressed data<br>
precompressed data.<br>
<p>
I think the best idea would be to take the good ideas from both standards<br>
and try to merge them in a way that ensures maximum interoperability.<br>
<p>
To achieve this I propose to:<br>
<p>
1. Enhance the functionality of the WinSANE package, which is trying to <br>
provide a SANE-&gt;Twain bridge in the sense, that it accesses a network-<br>
exported SANE device and presents it to the system as a TWAIN source.<br>
<p>
Using the cygwin tools and some minor hacking, this should allow SANE<br>
drivers to work on the Windows platform. I assume a similar solution could<br>
be worked out for the Mac.<br>
<p>
2. If my information is right, and a TWAIN driver does contain both the<br>
hardware driver and the GUI representation in one driver without a well<br>
defined interface between them, I propose that we work together on such an<br>
interface. I think SANE has shown a well working model (which can probably<br>
take a few enhancements), which could serve as a base.<br>
<p>
If we manage to assimilate our "intrafaces" that connect the HW driver to<br>
the GUI, we are pretty much set to mutually combine front- and backend<br>
drivers from both worlds, eventually using trivial glue layers, where things<br>
differ.<br>
<p>
I do see, that for most manufacturers there will not be a feel for needing<br>
to support multiple frontends for one single scanner. However I think it<br>
will both make writing drivers easier (as you can use a maybe not-so-pretty,<br>
but universal existing frontend while designing the backend, and then write <br>
the customized frontend), and allow for more flexibility for the user.<br>
<p>
Please do not take this personally, but I have seen a lot of TWAIN<br>
frontends, that are .. well very colorful, but pretty unuseable.<br>
While it might please some casual users to have the GUI designed like a<br>
car cockpit or a pinball game, it severely annoys me, when I have to wait<br>
for the bubble help over each button to pop up, as the only symbols you<br>
can guess what they are for are the brightness and contrast levers.<br>
For professional users that are interested in quick results rather than<br>
nifty look, a simple GUI is often more desireable.<br>
<p>
<p>
So I think the way to go would be to first make sure TWAIN gets an interface<br>
between frontend and backend, and we should as well define interfaces to<br>
well known transport layers like SCSI, parallel port, USB and serial port.<br>
<p>
This is what will make the drivers easily portable to Unixes. The main<br>
difference between OSes usually are the HAL and the GUI. The split driver<br>
model and the abovementioned interface-layers make sure that they are of no<br>
concern for the drivers themselves.<br>
<p>
Hardware driver layers for all OSes in questions need to be written, but<br>
that should be a minor effort.<br>
<p>
Frontend are GUI specific, so we expect the manufacturers to generally<br>
continue to only provide customized frontends for their main market only.<br>
However, as the above sketched scheme allows for arbitrary frontends, it<br>
will suffice to have backends available for all platforms, as the<br>
non-mainstream platforms can make use of generic frontends.<br>
<p>
3. While doing so enhance SANE with some lacking properties that can be done<br>
with TWAIN (like compressed data transfer).<br>
<p>
Comments, suggestions, questions, ... welcome.<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; =
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<li> <b>Next message:</b> <a href="0094.html">Hugo van der Kooij: "Re: a few questions"</a>
<li> <b>Previous message:</b> <a href="0092.html">Oliver Rauch: "Discussion about SANE and TWAIN..."</a>
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