Bug#868360: cups-filters-core-drivers: driverless sets bizarre 600x2 resolution
On Sat 15 Jul 2017 at 19:40:04 +0000, brian m. carlson wrote:
> On Sat, Jul 15, 2017 at 08:16:19PM +0100, Brian Potkin wrote:
> > On Fri 14 Jul 2017 at 22:48:32 +0000, brian m. carlson wrote:
> >
> > > This does fix the problem. Since this printer supports PCL, I can also
> > > use the hpijs-pcl5c driver in the mean time.
> >
> > Is this a bug in Brother's printer? It looks like it is.
>
> It does look like a firmware bug to report this resolution. However,
> I think cups could improve upon its behavior in several ways:
>
> * Validate data. Nobody is going to print a two-pixel raster image, and
> cups should not accept it as a valid (and in this case, the only
> valid) option.
cups and cupsfilters have both accepted and fixed past bugs in their
implementation of driverless printing. In some cases cups has made
allowances for deficiencies in a manufacturer's implementaion of IPP
Everywhere. But where does it end?
Assuming this is a firmware bug, doesn't the vendor (who after all is
using a well defined standard) have the reponsibility, especially if
the issue is drawn to their attention by an affected user? If AirPrint
was involved you could well imagine they would jump to it.
> * Prefer PCL, PostScript, and PDF over PWG. People specifically buy
> printers that support the former languages. I've never heard of PWG
> raster format as a selling point.
The URF PDL is not a selling point; but Airprint is. PWG is (I think) a
requirement for Google Cloud Print. People may not have heard of either
raster format but it's all under the hood.
Many less costly printers nowadays do not have PCL, PostScript or PDF as
an accepted PDL, but they do have URF and/or PWG. It is a good avenue
for avoiding proprietary drivers and plugins.
> * Use the printer resolution instead of the PWG resolution when
> generating raster images. At the very least, these should be
> resolution options for configuration in addition to the PWG
> resolution.
Surely the printer resolution is what is returned by an IPP query?
Either that, or it is in a supplied PPD.
> * Stop suggesting driverless configurations as the recommended option if
> they're obviously broken or not going to work.
No bugs in PCL, PostScript or PDF interpreters? No bugs in PPDs? We
would end up not "recommending" anything. :)
--
Brian.
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