Regarding the serialization of Spiro control points
by Fred Brennan
Greetings,
I write from the FontForge project. Of particular interest to me is the Spiro
spline feature, which was originated around ten years ago by Raph Levien.
One thing I'd like to add, (which would benefit both our projects,) is the
ability of FontForge to understand the Inkscape Spiro serialization format.
However, there are several things about the format which to me as an outsider
appear to be defects serious enough that I have no idea how to even *import*
these splines correctly, much less export our Spiro splines to this format. I
would very much like to support the _de facto_ standard Inkscape has
originated of supporting Spiro in SVG, but I am lost.
George Williams, FontForge's original author, noticed this defect over eleven
years ago.[1] Things are virtually unchanged since then, I checked `git
blame`.
Spiro has five point types, not including beginning and ending points. They
are:
* G4 curve (o)
* G2 curve (c)
* Corner (v)
* Left Constraint ([)
* Right Constraint (])
The ASCII single letters are the normal method of Spiro serialization, as
championed by Raph Levien and by us in FontForge.
Inkscape seems to create what I will call a "pseudo-SVG path". So, it is not
really an SVG path, but rather is an SVG path which undergoes transformation
into the typical Spiro format. Inkscape stores this in the "original-d"
attribute.
So, given a Bezier spline with control points defined as (x, y, c1, c2),
Inkscape interprets a control point with only (x, y) to be a corner, meanwhile
a control point with all four is a G4 curve, and (x, y, c1, NULL) is a left
constraint while (x, y, NULL, c2) is a right constraint.
I can probably overcome this, although George Williams was right to be
skeptical of this format. There is no way I can see to define a G2 curve in
this strange "original-d" format.
Thus, this email. I write to ask a few things. I suppose first of all, what
are the chances that we can convince you guys to store Spiro splines in
plate[2] format, or another widely accepted Spiro serialization format?
Second, if we cannot convince you to do that, how do I export FontForge spiros
which contain G2 control points to Inkscape's original-d format? It's not
possible, yes? So should I just silently fail and save them as G4? The curves
will not be the same if I do that. Should I disallow export to SVG w/Spiro if
glyph contains G2 control point? That seems a steep cost that will just
confuse my users, so perhaps I should abandon the whole thing if it comes to
that.
Cordial regards,
Fredrick Brennan (@ctrlcctrlv)
[1]: https://narkive.com/63FADpG3.4
[2]: https://levien.com/garden/ppedit/README, section "Plate files"
1 year, 6 months
retirement
by NASA Jeff
you'll be pleased to hear i'm going into retirement for a good while. so no
SVG animation for now unless someone wants to continue where i left off.
this is to work on personal projects.
3 years, 1 month
Inkscape developer meetings
by Marc Jeanmougin
Hi all developers,
during recent discussions, we have been pondering the idea of regular
dev meetings, and discussing them again on the live today, we are
suggesting to hold them every eight days (so that if someone has an
agenda problem with a day of the week, it'll still be okay for most of
the meetings) .
The idea for these meetings would be to talk about the development of
Inkscape code informally, discuss bug reports we have been working on,
recently raised regressions, etc, so that we could help one another if
needed and get a wider sense of who is working on what area, and how
things are progressing overall with features or releases in mind.
Tentatively, we could hold a first meeting on August 6th 5pm UTC (24h
before next board meeting ?)
If you have any remarks about this, feel free to voice them :)
Thanks everyone!
--
Marc
3 years, 2 months
Hackfest 2020: Developer Day
by Martin Owens
Dear Developers,
This coming Saturday we are continuing are hackfest sessions with our
developer day. If you are a developer, please come along at any point
during the day starting at 4PM UTC and ending at 10PM UTC.
There will be a meeting to talk about Inkscape's development
specifically will be at 5PM UTC hosted by Thomas Holder, one item to
talk about is if the developer team should meet once a month like other
teams do.
The rest of the day we will be looking at merge requests together.
Going through some code and doing some presentation style hacking.
Expect a lot of screen sharing!
Let me know if you have anything specific you'd like to present before
Saturday.
Thanks everyone!
Best Regards, Martin Owens
Hackfest Organiser
3 years, 2 months
gitlab.com gold group features
by Marc Jeanmougin
Hi all,
this is a short "what do you think about this?" message about gitlab.
Current state of things : we currently use gitlab on their "gold" plan
which does include proprietary extensions to the free software gitlab
core (those features are scoped labels, multiple assignees, related
issues (/duplicates), multiple issues boards, exceptions to protected
branches, push rules, merge approvals).
By "just asking", we could also have access to group-level gold
features, such as Epics which are like meta-issues to track releases or
big feature plans ( https://docs.gitlab.com/ee/user/group/epics/ ) and
Group milestones (instead of having per-project milestones)
The question is simple : should we ?
(Pro : we get access to it; Cons : it's asking to use proprietary
features, which is not something we usually do)
--
Marc
3 years, 2 months
Hackfest Today! 4PM UTC Leadership/Board day
by Martin Owens
Dear Develoeprs, Users and everyone,
Today is the first experimental online hackfest day.
Go here to join: https://digimedia1.r2.enst.fr/b/vec-tz3-fi9
Today we'll join joining teams and talking about what responsibilities
different parts of the project do or should have as well as hosting a
"Meet the board" meeting at 5PM UTC.
Hope to see you all there!
Next week: UX and design day!
Best Regards, Martin Owens
3 years, 2 months
PDF and patents, feel free to ignore this if it's touchy.
by NASA Jeff
Hi,
I'm currently writing an import filter to import free flow pdf text into
Scribus for editing but i'm aware that there's no free pdf editor worth
it's salt because pdf is patent encumbered. as a result all pdf editors
that let you edit free flow pdf text are quite expensive and the free
versions often limited by watermarks. anyhow, i hope i've avoided any
patent issues as layout and fonts used bare no resemblance to anything pdf
uses as I aggregate all the text and use Scribus's quite advanced layout
engine to do the bulk of the heavy lifting with some
vaguely intelligent aggregation code to aggregate the text in the filter.
anyhow,
can anyone give me a heads up on pdf and patents?
3 years, 2 months
