[Pixman] Plan to release final development version before stable branch

[Oded Gabbay]

On Mon, Dec 21, 2015 at 6:50 PM, Bill Spitzak <spitzak at gmail.com> wrote:
> I suspect I will need to check the X server version, actually. That seems to
> be what the other tests are doing.
>
> My main concern is to figure out *which* version this (will) happen in. I am
> hoping this can be known before code release so Cairo can be updated to use
> it at the same time.
>
Don't worry, you will full visibility into which version this code
will get into.
If I had to guess right now, I would say 0.35.2, which is the stable
release of the next development tree. Estimated time is March-April
2016

Oded

> On Sun, Dec 20, 2015 at 5:58 AM, Oded Gabbay <oded.gabbay at gmail.com> wrote:
>>
>> On Wed, Dec 16, 2015 at 4:41 AM, Bill Spitzak <spitzak at gmail.com> wrote:
>> >
>> >
>> > On Tue, Dec 15, 2015 at 1:29 AM, Oded Gabbay <oded.gabbay at gmail.com>
>> > wrote:
>> >>
>> >> On Sat, Dec 12, 2015 at 9:10 PM, Bill Spitzak <spitzak at gmail.com>
>> >> wrote:
>> >> >
>> >> >
>> >> > On Sat, Dec 12, 2015 at 10:37 AM, Oded Gabbay <oded.gabbay at gmail.com>
>> >> > wrote:
>> >> >>
>> >> >> On Sat, Dec 12, 2015 at 8:34 PM, Bill Spitzak <spitzak at gmail.com>
>> >> >> wrote:
>> >> >> > On Fri, Dec 11, 2015 at 4:15 AM, Oded Gabbay
>> >> >> > <oded.gabbay at gmail.com>
>> >> >> > wrote:
>> >> >> >>
>> >> >> >> On Thu, Dec 10, 2015 at 11:19 PM, Bill Spitzak
>> >> >> >> <spitzak at gmail.com>
>> >> >> >> wrote:
>> >> >> >> > Can you include my patches to fix the filtering? They have been
>> >> >> >> > posted
>> >> >> >> > for a
>> >> >> >> > long time now.
>> >> >> >> >
>> >> >> >> > The last patch makes GOOD/BEST use filtering for scaling images
>> >> >> >> > down.
>> >> >> >> > This
>> >> >> >> > matches the current Cairo behavior and would allow Cairo to use
>> >> >> >> > the
>> >> >> >> > pixman
>> >> >> >> > backend rather than doing an image fallback for any image
>> >> >> >> > scaling
>> >> >> >> > smaller
>> >> >> >> > than .75. It also contains a bunch of minor optimizaion and
>> >> >> >> > filter
>> >> >> >> > selection
>> >> >> >> > tweaks that makes the output somewhat better than current
>> >> >> >> > Cairo.
>> >> >> >> >
>> >> >> >> Hi Bill,
>> >> >> >>
>> >> >> >> Unfortunately, I don't see anyone reviewed your patches, and from
>> >> >> >> what
>> >> >> >> I heard, those are quite significant changes.
>> >> >> >>
>> >> >> >> It's a shame you didn't bring this up when I did the first
>> >> >> >> development
>> >> >> >> release 4 months ago. Then we had enough time to check and test
>> >> >> >> it.
>> >> >> >> I'm quite hesitant of including such changes right before the
>> >> >> >> final
>> >> >> >> development version, even with a review.
>> >> >> >
>> >> >> >
>> >> >> > I did send email on May 22, 2015, in response to your comments.
>> >> >>
>> >> >> That's strange, because I only started working on pixman during June
>> >> >> of
>> >> >> 2015...
>> >> >
>> >> >
>> >> > You are right. That was just a general email I sent trying to get
>> >> > somebody
>> >> > to look at the patches. Searching in the history I found 3 of these.
>> >> >
>> >> >>
>> >> >>
>> >> >>
>> >> >> >
>> >> >> >> I suggest that you try to contact one of pixman's veterans
>> >> >> >> (Soren,
>> >> >> >> Siarhei, Matt, Pekka, Ben) offline and ask them nicely to at
>> >> >> >> least
>> >> >> >> skim over the patches and give a high-level opinion about the
>> >> >> >> series.
>> >> >> >
>> >> >> >
>> >> >> > These were discussed with Soren before. He disagreed with my
>> >> >> > previous
>> >> >> > version because I changed to a single filter calculation rather
>> >> >> > than
>> >> >> > his
>> >> >> > pair of filters being convoluted. This version preserves the pair
>> >> >> > of
>> >> >> > filters, with some fixes of bugs that caused artifacts in the
>> >> >> > resulting
>> >> >> > filters. I'm sending email directly in case they are not reading
>> >> >> > the
>> >> >> > pixman
>> >> >> > list.
>> >> >>
>> >> >> Could you send me those emails ?
>> >> >
>> >> >
>> >> > I forwarded the big one from him and my response. The patches I have
>> >> > had
>> >> > since then I believe address his concerns and preserve the 2-filter
>> >> > convolution api, they are just bug fixes and some efficiency changes.
>> >> >>
>> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> Also, check if you need to rebase the patches against current
>> >> >> >> pixman
>> >> >> >> and if so, maybe send the series again. It might stir up a
>> >> >> >> discussion.
>> >> >> >
>> >> >> >
>> >> >> > The patches applied to the newest version without any conflicts
>> >> >> > and
>> >> >> > my
>> >> >> > test
>> >> >> > programs still work. I have resent them to the pixman mailing
>> >> >> > list.
>> >> >> >>
>> >> >>
>> >> >> Great!
>> >> >>
>> >> >> >>
>> >> >> >> I'm willing to review them in terms of correctness and code
>> >> >> >> style,
>> >> >> >> but
>> >> >> >> I'm not veteran enough in pixman to give an opinion on the
>> >> >> >> underlying
>> >> >> >> changes (which is the most important issue).
>> >> >> >
>> >> >> >
>> >> >> > Anything would be great.
>> >> >> >
>> >> >> > I believe these work well and have been using them for a while.
>> >> >> > This
>> >> >> > would
>> >> >> > allow the removal of redundant code in Cairo, and would allow
>> >> >> > 2-pass
>> >> >> > filtering to be done at some point in the future, which would
>> >> >> > really
>> >> >> > improve
>> >> >> > pixman performance.
>> >> >> >
>> >> >> ok, I'll try to take a look next week or so.
>> >> >>
>> >> >> Oded
>> >> >
>> >> >
>> >>
>> >> Hi Bill,
>> >>
>> >> I read most of the emails you sent me and I cleared time tomorrow to
>> >> review your patches.
>> >>
>> >> Having said that, IMHO, I believe it would be too risky to merge them
>> >> into the final development release. This is due to a combination of
>> >> two things:
>> >>
>> >> A. This release, although it is a "development release" is used by
>> >> current distributions (fedora 22,23, ubuntu, debian). That's because
>> >> there was a big gap in the release schedule earlier this year.
>> >>
>> >> B. The changes here affect users of pixman and cairo, by changing the
>> >> way pixman behaves. So even if your patches are perfect, and the
>> >> result is a better pixman, we need to give time to users (and to
>> >> cairo) to adapt to it. This can only be done in master branch, not in
>> >> stable branches.
>> >>
>> >> So, what I intend to do is to:
>> >>
>> >> A. Review your patches and if necessary, ask you to fix issues.
>> >>
>> >> B. Assuming no objection will be made by other pixman developers
>> >> during the next couple of weeks, I will merge the patch series into
>> >> master *after* I branch out the 0.34 release.
>> >>
>> >> That way, the patch series will be included in the future development
>> >> releases that will be packaged inside "testing" distributions, such as
>> >> fedora rawhide and debian unstable, and thus we will have time to
>> >> receive feedback from users about the changes.
>> >>
>> >> I hope this is accepted by you and by everyone else. If not, please
>> >> tell
>> >> me.
>> >>
>> >> Thanks,
>> >>
>> >>        Oded
>> >
>> >
>> > I am fine with this all being for the next release and will be happy to
>> > answer any questions.
>> >
>> > I would like to know what a compile-time test for whether libpixman is
>> > this
>> > next release or not, and a run-time test to see if X (using both xlib
>> > and
>> > xcb) is using this next release of pixman. This will allow code to be
>> > added
>> > to Cairo to automatically send the filtering to pixman when possible,
>> > and
>> > hopefully get that added at the same time this is supported in the
>> > pixman
>> > release.
>> >
>> >
>> >
>>
>> For compile time, you can check PIXMAN_VERSION_MAJOR/MINOR/MICRO in
>> pixman-version.h
>>
>> For run-time, check pixman_version() in pixman.c:
>>
>> /**
>>  * pixman_version:
>>  *
>>  * Returns the version of the pixman library encoded in a single
>>  * integer as per %PIXMAN_VERSION_ENCODE. The encoding ensures that
>>  * later versions compare greater than earlier versions.
>>  *
>>  * A run-time comparison to check that pixman's version is greater than
>>  * or equal to version X.Y.Z could be performed as follows:
>>  *
>>  * <informalexample><programlisting>
>>  * if (pixman_version() >= PIXMAN_VERSION_ENCODE(X,Y,Z)) {...}
>>  * </programlisting></informalexample>
>>  *
>>  * See also pixman_version_string() as well as the compile-time
>>  * equivalents %PIXMAN_VERSION and %PIXMAN_VERSION_STRING.
>>  *
>>  * Return value: the encoded version.
>>  **/
>>
>> I don't know, however, if X server exports this function through its
>> API. You will need to check with them.
>>
>> Oded
>
>