On Jan 29, 2013, at 11:10 AM, Benjamin De Kosnik <bkoz(a)redhat.com> wrote:
This is just scratching the surface. How are you going to evaluate
quality? I'm concerned about the rasterization changes, the filter
changes. Hopefully 1.6 may solve some of the image-quality regressions
I've been seeing.
Quality evaluation needs test targets/documents, and eyeballs. Many test targets are free
or easily produced and could be CC0 licensed or something reasonable. This is something
I've briefly discussed with Richard Hughes, and also participants in OpenICC, that are
needed not just for print, but also for display. Perhaps some OpenICC and OpenPrinting
collaboration is appropriate for acquiring test metrics.
Since CUPS itself doesn't rasterize, I don't expect you'd see changes in this
area; but if there are filter changes, or an application decides to produce PDF job
instead of PostScript, then it's possible, but probably not intended. If there are
features or effects that need to be performed on a job after the application has produced
the job, there are advantages to doing this on PDF than PostScript. But my expectation is
even applications that today still use PostScript, they would be subject to the pstopdf
filter, which in turn defers to Ghostscript on linux (Quartz2D by default on OS X) to turn
it into a PDF. Such normalization of postscript to pdf is something that's been going
on for many years, and is well tested (with many bug carcasses along the way).
4) In the past, I've found it difficult to debug cups filters step by
step. Especially with so many rasterization/filter changes.
Yes this is tedious. Figuring out the sequence for a job isn't so difficult. But in
case of problems, it would be useful to break the sequence, i.e. get access to the print
job in a particular state in between filters. I've got some material on how to do
this, for the purposes of troubleshooting the OS X print pipeline which of course uses
CUPS, but different print drivers, raster engine, and color management philosophy.
be updated? I would love it if issues like "what driver am I
could be re-integrated into the UI, or perhaps an admin level of the
ui. Also, "what filters did I run to get to this point of output" in a
This is useful. At least on OS X each PDF print job also has a job ticket. I think this is
a CUPS thing. Even once the job is complete, and the original document and raster files
are deleted, the job ticket remains and it should contain all of this information. Making
it more readable somehow might be useful.
5) integration with common printing dialog. (IMHO localhost:631).
I think integrating Fedora's print dialogs with the wider user
communities on macos and ubuntu would be very useful.
I'm not sure what common printing dialog refers to here. If it's the CPD,
that's dead as far as I know, unless it's been raised in the last 2 months.
As for using Mac OS as a model for print dialogs, I'm happy to discuss exactly what
areas I think this is useful and areas it's to be avoided. OS X for professional
printing is nothing short of a clusterf|ck. It has been a huge PITA for me for ~8 years.
Central to this problem is color, but also rather significantly is the UI/UX. We get *two*
print dialogs for every print job with such applications due to lack of integration
between the OS dialog and the application dialog. So we get an application dialog, and
then later get an OS dialog, and they each contain mutually exclusive features, or
settings that conflict between application and the OS. And the arbitration and assumption
for this is not great, and not well documented. And this is aside from the separate
interactions that occur with the print driver which does integrate with the OS dialog, but
can itself have settings that conflict with the OS, or the application.
The UI/UX part isn't much different on Windows, but the color management ideology is,
and that actually helps rather significantly for those who actually care about such
things. So the hopeful idea is to mimic the successes of these companies, and avoid the
mistakes. Should be easy. Ha!