[Plplot-devel] Possible Windows development agendas for the next 6 months

[Alan W. I. <Ala...@gm...>]

This post is Windows-centric so it is principally directed to our
developers with access to Windows (Arjen, Phil, and Jim).

I have decided that the release of 5.16.0 should be near December 1st this
year to stick close to the 6-month-long release cycle that worked so well for
the 5.15.0 release.

MinGW-w64/MSYS2 (MSYS2 for short), Cygwin, and MSVC are the three
Windows platforms that are of interest to us, and I would like to
summarize here some comments I have made before for each of these
platforms since that information is so relevant to the Windows
development plans for PLplot that I will be discussing below.

* MSYS2.  This is our primary Windows platform since it supplies most
   of the free software libraries in Windows native form (i.e., no link
   to msys2.dll that turns executables/libraries into non-native form)
   that provide PLplot with its power and *always* (since there is no X
   wrapper implemented for MSYS2) displays results efficiently using
   native Windows display functionality.  Because of this capability
   interactive comprehensive testing on this platform should be
   reasonably quick, but nobody has actually tried that yet.  On the
   other hand, for 5.15.0 Arjen supplied good noninteractive
   comprehensive test results (see
   <https://sourceforge.net/p/plplot/wiki/Testing_Reports/>) for this
   platform which demonstrate its excellent quality (at least for the
   noninteractive case) for the needs of our Windows users.

* Cygwin.  This is a secondary platform for us because all Cygwin
   libraries are non-native (i.e., linked to cygwin.dll to give
   non-native behaviour) and some of its free software display
   libraries (IIRC wxwidgets is a definite example of this issue, and
   pango/cairo and Qt may also have the same display issue) have been
   packaged incorrectly (in my view) to perform their display via a
   slow/inefficient X wrapper for Windows display rather than the
   direct Windows display capability that is available for all of these
   free software display libraries.  As a result, Arjen has found via
   one attempt in the past that *interactive* comprehensive testing on
   Cygwin is effectively impossible because the X-wrapped display
   functionality is so incredibly slow.

* MSVC is generally a low priority for us since ABI issues limit what
   free software libraries can be used on this platform so as a result
   PLplot is quite weak on this platform.  The exception, of course, is
   Phil has gotten our wxwidgets components to work with a wxwidgets
   library he downloaded? or built? on this platform that apparently
   was ABI compatible with the MSVC compiler.  Also, in the past Arjen
   has had success adding both library power and bash
   power to this platform by putting MSYS2 libraries and bash on
   his PATH.  But that mode is likely too complex for users so is
   only likely useful for the important comprehensive testing of this platform
   that can be done by knowledgeable PLplot developers.

@Arjen, Phil, and Jim:

I acknowledge all of you have told me in the past about your severe
family and job time constraints that leaves very little time for
PLplot, but having said that, I nevertheless assume all of you will
still have at least some time to work on PLplot during this 6-month
release cycle so during that precious limited time for PLplot you
should set good priorities.  Here are my ideas about what your
individual PLplot priorities should be, but, of course, if you prefer
other PLplot priorities for yourself during this next 6 months, please
let me know what those are!

@Arjen:

Here are the priorities I believe you should have in reverse priority
order.  Of course, if you think these priorities should be reordered
or there are more important ones that I forgot, please let me know.

1. Although Cygwin is of secondary importance some users do attempt to
    use PLplot on this platform.  Therefore, I think your immediate
    priority for this release cycle should be to finish up your
    comprehensive testing efforts on Cygwin that you tried to complete
    before the 5.15.0 release.  Time is of the essence (which is my
    motivation for giving this effort a high priority) since although
    you did not complete this effort in time for the 5.15.0 release, it
    is almost as good to complete it as soon as possible after the
    5.15.0 release to reassure Windows users (with finalized results
    mentioned at
    <https://sourceforge.net/p/plplot/wiki/Testing_Reports/>) that
    at least noninteractive PLplot-5.15.0 is as good on Cygwin as it is on MSYS2.

2. Update all our MSYS2-related wiki pages based on your recent good
    experiences with this platform. I think this project will take
    advantage of your good English technical writing skills, and
    up-to-date wiki information will also be extremely useful in
    helping both Phil and Jim to get started with this platform (see
    their priorities below).

3. Be prepared (via at least one preliminary testing effort this summer) to
    "turn the crank" to replicate your current good MSYS2 comprehensive
    test just before we release 5.16.0 on or near December 1st.

4. Comprehensively test the MSVC platform?  I put a question mark by
    that priority since this platform is not of primary importance to
    us.  Nevertheless, just to remind you, you were able to create a
    good comprehensive test of this platform a long time ago by putting
    native MSYS2 libraries and MSYS2 bash on your PATH (to add PLplot
    power and especially bash testing power to the otherwise low-power
    MSVC platform), and it "would be nice" if you can replicate that
    good MSVC result again for 5.16.0.

5. Package PLplot on Cygwin??  This is an even lower "would be nice"
    priority.  However, See remarks about why there is a need for this
    packaging effort that I recently made at
    <https://sourceforge.net/p/plplot/feature-requests/16/>.

@Phil:

Here are the priorities I believe you should have in reverse priority
order.  Of course, if you think these priorities should be reordered
or there are more important ones that I forgot, please let me know.

1. Deal with <https://sourceforge.net/p/plplot/patches/34/>.

2. Become familiar with our primary Windows platform, MSYS2.  You have
    already told me off-list that you would be willing to do this, and
    I think this release cycle would be an excellent time for you to
    achieve this goal not only for your own personal benefit (because this
    really is a powerful PLplot platform) but also to ease the testing
    burden carried by Arjen right now and also to eventually extend the
    scope of his current testing (i.e., by including interactive tests
    in the comprehensive test script that you run).
    See <https://sourceforge.net/p/plplot/wiki/Testing_PLplot/> for the details
    concerning testing PLplot including how to run the comprehensive test script.

    A very good source of information for the MSYS2 platform is
    <https://github.com/msys2/msys2/wiki> and links you can follow from
    there that should make it easy to install the basic version of this
    platform and enhance it by using the pacman installer to install
    all the native Windows libraries provided by MSYS2 that provide
    extra power to PLplot.  For example, pango/cairo, Qt, and wxwidgets
    libraries already provide good noninteractive results (or have the
    potential to do so in the wxwidgets case, remember the wxpng device
    driver) and should potentially also provide rapid, high-quality
    interactive results for comprehensive tests.

3. This one is a cross-platform issue rather than just limited to
    Windows.  Fix the wxwidgets device so that its display event loop
    checks to see whether the plot commands in the buffer have been
    extended and adds those plot commands to the display of the plot
    whenever such an extension occurs rather than waiting until the
    buffer of all plot commands for a given page is complete before
    running all those plot commands.  This fundamental improvement for
    new wxwidgets should bring the new wxwidgets device in line with
    the old wxwidgets device as well as the wincairo (or xcairo on
    Linux) and qtwidget interactive devices.  For all those other
    interactive device alternatives the -np (no pause) option works
    properly, and the 17th example displays like a video as the plot
    unfolds rather than just plotting the final plot for the page.
    (You should be able to prove this for yourself by trying the
    wincairo and qtwidget devices on MSYS2 for example 17).  In sum,
    this fundamental change to the new wxwidgets device needs to be
    done before it can gain those same good -np and 17th example
    display results showed by the other interactive devices.

4. Help with packaging PLplot for MSYS2?  Of course, Arjen could
    likely be able to do this instead of you, but it is a good way to
    take some of the load off him, and it should not be that big a
    burden for you since packaging on this platform is really simple.

    See my recent comments at
    <https://sourceforge.net/p/plplot/feature-requests/16/> concerning
    the importance of such binary packaging.  I should add here that my
    old estimate of binary package use of PLplot (via the fraction of
    Debian users that used it actively each month on Debian) was very
    roughly 100000 users when you apply that fraction to an estimate
    of the free software desktops in the world while downloaders of our source code typically
    are only ~5000 per release according to SF statistics.  So that
    comparison is quite rough, but the important point is binary package
    users of PLplot far outweigh those who build PLplot from source which
    is why I view binary packaging to be so important
    for PLplot.

    From the MSYS2 wiki reference above, you can discover that
    packaging for MSYS2 is really quite simple, and there is already a
    very good start on that at
    <https://github.com/msys2/MINGW-packages/tree/master/mingw-w64-plplot>
    to help you further.  However, if you just look at the PKGBUILD
    file there you should notice some problematic configuration issues
    (relying on the gd library and associated png and jpeg device
    drivers that have been deprecated for a very long time, and
    dropping (!) the high-quality qt device driver that is working so
    well for Arjen).  So once you are familiar with building PLplot on
    MSYS2, you should be able to give Alex (the primary MSYS2 developer
    and also the author of the PLplot package for that platform) some
    good advice (through patches to that PKGBUILD file and testing the
    effect of those changes on the plplot binary package results) about
    how to substantially improve that PLplot package.

@Jim:

Here are the priorities I believe you should have in reverse priority
order.  Of course, if you think these priorities should be reordered
or there are more important ones that I forgot, please let me know.

1. Phil has already told me he is willing to give MSYS2 a try so
    I hope you are in as well during this release cycle.  See topic
    2. in my remarks to him.

2. Deal with <https://sourceforge.net/p/plplot/bugs/195/>.  My feeling
    is there is a reasonable chance you can replicate this guy's Cygwin
    issue on MSYS2 (since MSYS2 is a fork of Cygwin), and if that
    proves to be the case, that should provide some essential help
    to your effort to fix this bug.

3. If the wingdi device is anything like my memory of the wingcc
    device results long ago when I was testing that device on Wine, it
    has problems with the -np option and example 17.  See topic 3 in my
    remarks to Phil about a similar issue for the wxwidgets device and
    the MSYS2 interactive device comparisons he can use to discover the
    correct behaviour of all interactive devices.  And if you verify
    this bug for wingdi on MSYS2, it would be great if you could also
    come up with a fix for it.  But I would not bother with fixing
    wingcc in this regard since I hope we will be able to retire that device
    driver soon (see below).

4. Enhance the wingdi device so it can properly handle UTF-8 text?
    This is the obvious and long-discussed next step for this device that would allow us
    to permanently retire wingcc so I hope you have some time during
    this release cycle to finish off this topic.

@ Arjen, Phil, and Jim:

Don't take what I said too seriously above because my Windows experience
is from quite a while ago on the Wine platform with MinGW/MSYS (as opposed
to the modern alternative to that ancient platform, MinGW-w64/MSYS2).
But I do hope to stir up some discussion from you three PLplot developers
with access to Windows.  So I am looking forward to your individual
replies to my remarks above.

Alan
__________________________
Alan W. Irwin

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.org); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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