On Mon, Feb 11, 2019 at 9:58 AM Stephen Gallagher <sgallagh(a)redhat.com> wrote:
On Fri, Nov 16, 2018 at 7:18 PM Adam Williamson
> On Thu, 2018-09-20 at 08:33 -0400, Stephen Gallagher wrote:
> > There was a bug filed recently that indicated that printing was
> > broken on certain printers. As a result of that discussion, it became
> > apparent that there was no criteria for printing to work at all, which
> > seems like an oversight.
> > I discussed this briefly with Matthias Clasen this morning and he
> > agreed that this should be treated as blocking for Workstation.
> > I'd like to propose that we add the following criteria to Beta for Fedora
> > * Printing must work on at least one printer available to Fedora QA.
> > "Work" is defined as the output from the device matching a preview
> > shown on the GNOME print preview display. (Note that differences in
> > color reproduction are not considered "non-working".)
> > and this to Final for Fedora 30+:
> > * Printing must work on at least one printer using each of the
> > following drivers:
> > (I don't know which ones to specify here, but we ought to try to
> > figure out a cross-section that covers a large swath of our expected
> > user base).
> So as with the optical media proposal we had quite a lively discussion
> on this one, then it got stuck a bit. Stephen, can you take a look at
> all the followups and either restate or revise the proposal? Thanks!
Sorry that it's taken me so long to get back to this.
I think the feedback on this has been mostly positive on the Beta
criteria, but I'd like to tweak the phrasing a bit and see if this
comes off more favorable:
I'd like to propose that we add the following criteria to Beta for Fedora 30+:
* Printing must work on at least one printer available to Fedora QA.
"Work" is defined as the output from the device matching a preview
shown on the GNOME print preview display. (Note that differences in
color reproduction are not considered "non-working".)
Does the criterion pply strictly to the printing of text and line
art, or does it also apply to gross departures in photographs? If the
^minor differences in color reproduction are not considered "non-working"; or
^only major differences in color reproduction are considered "non-working"
Major defined as any of:
obvious and grossly incorrect scaling (e.g. +/- 20%)
color inversion, torqued primaries (white becomes black, black becomes
white; red becomes blue, blue becomes green, etc)
tone reproduction that obliterates relevant identifying detail in two
or more test images
With that language I'm trying to carve out only remarkable, WTF level,
bugs as blockers.
Next question is what applications to use for printing, since the
initiating application matters. What if there's a bug in just one
application? That shouldn't be a printing blocker (it might be a basic
functionality blocker for that application if it's included in default
installations). So I'd say pick two. Firefox and LibreOffice? Firefox
Next question, test document(s). European Color Initiative has several
test PDFs already prepared, perhaps the most applicable for our
purposes is the visual test (and a subset of it).And for font scaling
and reproduction, Ghent Working Group has test GWG 9.1 which tests
various encodings of TrueType, PostScript, and OpenType rendering.
Also, there's a suite of LibreOffice test files, and while I haven't
gone through it, I'm willing to bet there's one or two that'd serve as
a decent sanity tester (in any case I'm not proposing printing out
entire test suites):
The nice thing about standardized tests is the far lower risk of bugs
in the test file itself, and for sure the applicable developers are
familiar with them so as they get escalated, it eliminates the kick
back "how did you create this test file? can you attach it to the
and this to Final for Fedora 30+:
* Printing must work on at least one printer using each of the
- The built-in print-to-PDF driver
- The generic IPP driver
To clarify, this does not mean that all printers need to function
properly that use the IPP driver, just that at least one does (so we
know that printing as a whole is unbroken). Contrary to the first
proposal, we won't specify any particular hardware makes or models
that must work.
I agree with this. One possible sanity test:
1. "Print" the standardized test file to a PDF file (using the
built-in print to PDF driver)
2. Print both the resulting PDF from 1, and the original standardized
test file, to the designated IPP printer.
i.e. two physical prints on paper. And within some ballpark on
scaling, they should appear the same. Some of the subcriteria:
a. PDF file is created from test document
b. PDF file is viewable with the default PDF viewer
c. PDF file is printed
d. Test document is printed
e. minor differences aside: b, c, and d should not cause a WTF
reaction by a human