Re: [sane-devel] new Backenddriver
Johannes Meixner writes: > Hello, > > On Oct 19 21:51 Olaf Meeuwissen wrote (excerpt): >> Michael Rall writes: > ... >>> So basically my SANE Backend needs to call a Webservice >>> an will receive an Image as result. > ... >> ... I mentioned the pnm backend is because >> it reads an image from file. > > I have a - perhaps stupid - generic question: > > What is the reason for a SANE backend when one already > has an image as a file? Testing or demoing your super-duper new SANE frontend, perhaps? I for one have used such an approach in the past where it was not feasible to use a real scanner (because it was still on the drawing board or its firmware was only in the early stages of development ;-). > I assumed the reason for a SANE backend is to create > an image file in a known image data format from whatever > special bits of data that a scanner hardware can deliver. That has been and probably still is the main reason but anything you can come up with that is exposed via the SANE API is, by definition, a SANE backend. The dll and net backends are good examples. > For example when a network scanner can deliver an e-mail > with the scanned image(s) e.g. as JPEG or PDF attachment, > then I think there is no need for a SANE backend. > > In other words: When that Webservice cannot deliver > known image data formats but only whatever special bits > of data that need to be converted into a known image data > format, then I would understand a SANE backend for it. I have no idea what web service Michael needs/wants to capture in a SANE backend and whether that makes sense to begin. Trying to think up a not completely ridiculous scenario, what about a computationally intensive image rendering or post-processing service (i.e. SaaSS[1]). The whole system has been put somewhere on a VPC in the cloud and results are made available piecemeal via a websocket over HTTPS. Your old workflow used to let you do everything via an existing SANE frontend but now the, eh, "service" requires you pump the image into the cloud and pull results out of it again. [1] https://www.gnu.org/philosophy/who-does-that-server-really-serve.en.html Hope this helps, -- Olaf Meeuwissen, LPIC-2FSF Associate Member since 2004-01-27 GnuPG key: F84A2DD9/B3C0 2F47 EA19 64F4 9F13 F43E B8A4 A88A F84A 2DD9 Support Free Softwarehttps://my.fsf.org/donate Join the Free Software Foundation https://my.fsf.org/join -- sane-devel mailing list: sane-devel@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to sane-devel-requ...@lists.alioth.debian.org
Re: [sane-devel] new Backenddriver
Hello, On Oct 19 21:51 Olaf Meeuwissen wrote (excerpt): Michael Rall writes: ... So basically my SANE Backend needs to call a Webservice an will receive an Image as result. ... ... I mentioned the pnm backend is because it reads an image from file. I have a - perhaps stupid - generic question: What is the reason for a SANE backend when one already has an image as a file? I assumed the reason for a SANE backend is to create an image file in a known image data format from whatever special bits of data that a scanner hardware can deliver. For example when a network scanner can deliver an e-mail with the scanned image(s) e.g. as JPEG or PDF attachment, then I think there is no need for a SANE backend. In other words: When that Webservice cannot deliver known image data formats but only whatever special bits of data that need to be converted into a known image data format, then I would understand a SANE backend for it. Kind Regards Johannes Meixner -- SUSE LINUX GmbH - GF: Felix Imendoerffer, Jane Smithard, Graham Norton - HRB 21284 (AG Nuernberg) -- sane-devel mailing list: sane-devel@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to sane-devel-requ...@lists.alioth.debian.org
Re: [sane-devel] new Backenddriver
Hi Michael, Michael Rall writes: > Hello Everybody, > > my name is Michael Rall. I'm a freelancing Softwaredeveloper from Germany. > > For one of my projects I would like to create a SANE Backend for a > Web-Based ImageAquisition-Tool. > > So basically my SANE Backend needs to call a Webservice an will receive > an Image as result. > > What existing Backend would be the best/simplest starting point? Or > would a start from scratch be easier? I'm a quite experienced Developer, > but actually I haven't yet developed some Linux-Stuff. You could take a peek at the pnm backend (not built by default out of security/privacy concerns, IIRC), but if I were in your situation, I'd start mostly from scratch as "legacy" code might get in my way. Have a look at the doc/backend-writing.txt file (it's a bit dated perhaps) and the SANE API specification is required reading, of course. The reason I mentioned the pnm backend is because it reads an image from file. Your web-base image acquisition scenario is basically just one step up from a file:/// URL. I'd have a look at implementing something on top of a generic URL fetching library or tool and provide a backend option to set the URL. No idea on what other backend options you might want to provide though. Hope this helps (and makes any sense), -- Olaf Meeuwissen, LPIC-2FSF Associate Member since 2004-01-27 GnuPG key: F84A2DD9/B3C0 2F47 EA19 64F4 9F13 F43E B8A4 A88A F84A 2DD9 Support Free Softwarehttps://my.fsf.org/donate Join the Free Software Foundation https://my.fsf.org/join -- sane-devel mailing list: sane-devel@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to sane-devel-requ...@lists.alioth.debian.org
[sane-devel] new Backenddriver
Hello Everybody, my name is Michael Rall. I'm a freelancing Softwaredeveloper from Germany. For one of my projects I would like to create a SANE Backend for a Web-Based ImageAquisition-Tool. So basically my SANE Backend needs to call a Webservice an will receive an Image as result. What existing Backend would be the best/simplest starting point? Or would a start from scratch be easier? I'm a quite experienced Developer, but actually I haven't yet developed some Linux-Stuff. kind regards Michael Rall <>-- sane-devel mailing list: sane-devel@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to sane-devel-requ...@lists.alioth.debian.org