[erlang-questions] ErlGuten

Tue Sep 25 22:06:09 CEST 2018

I am doing a prettifying pass now:

   - Adding function specs
   - Converting text specs to normal -spec specs
   - Adding named types where they make sense
   - Replacing tabs with spaces
   - Running Dialyzer on it, and fixing types so it makes sense
   - ... that sort of thing.

Can't promise when it will be finished, a day or two, or 3 weeks. You'll
have a pull request when its done. Will be a MASSIVE changeset but no
actual logic affected.

On Tue, 25 Sep 2018 at 18:51, <lloyd@REDACTED> wrote:

> Hi Theepan,
>
> Other than display in my demo PDF, I haven't worked much with images.
>
> The issues you've run across seem serious. Getting at the root of the
> problems will likely involve a deep dive into both the PDF reference
> manuals and core ErlGuten source code.
>
> As I noted in my earlier email, ErlGuten source code is very challenging.
> It would benefit significantly from re-write, possibly refactoring in some
> cases and definitely systematic documentation of functions and parameters.
>
> I'm not confident that my skills are up to this. My take is that it would
> require some amount of community effort to put ErlGuten/erlpress_core on a
> solid, maintainable base. I would dearly love to see this happen.
>
> Is there a CS major or intern out there with time to take on the
> challenges?
>
> Joe showed us the way and I, for one, am deeply grateful. Given that PDF
> is a significant standard in the print media world, Erlang deserves to have
> a world-class library and suite of tools to generate PDF documents and
> decode them back into Erlang structures.
>
> This will take community effort.
>
> All the best,
>
> Lloyd
>
>
>
>
>
> -----Original Message-----
> From: "Theepan" <vasdeveloper@REDACTED>
> Sent: Monday, September 24, 2018 7:27pm
> To: "Lloyd Prentice" <lloyd@REDACTED>
> Cc: "Erlang Questions Mailing List" <erlang-questions@REDACTED>, "Joe
> Armstrong" <erlang@REDACTED>
> Subject: Re: [erlang-questions] ErlGuten
>
> Wanted to add to the issues the reasons --
>
> ** When some JPEG image is embedded into the PDF, it turns out dark in the
> generated PDF file [Happens due to CYMK color profile.]
> ** When some PNG file is embedded, it takes too long (unto 5 minutes) to
> generate the PDF file. Debugging shows that the delay is on defilter(Method
> , Line1, Line2, Offset, Width, Iter) of eg_pdf_image module.[Happens due to
> Alpha channel presence]
>
>
>
> On Tue, Sep 25, 2018 at 4:45 AM Theepan <vasdeveloper@REDACTED> wrote:
>
> > Thanks Lloyd for your detailed explanation on what has been done, and
> your
> > vision for the library. However we are already using ErlGuten in one of
> our
> > production systems, and the issues is mainly with the images.
> >
> > I will definitely keep an eye on the development of erlpress_core in the
> > future, as you seem enthusiastic about making it a lively library.
> >
> > The issues we have are:
> >
> > ** When some JPEG image is embedded into the PDF, it turns out dark in
> the
> > generated PDF file
> > ** When some PNG file is embedded, it takes too long (unto 5 minutes) to
> > generate the PDF file. Debugging shows that the delay is on defilter(
> > Method, Line1, Line2, Offset, Width, Iter) of eg_pdf_image module.
> >
> > Did you come acrsoss this?
> >
> > Best,
> > Theepan
> >
> >
> >
> >
> >
> > On Tue, Sep 25, 2018 at 2:56 AM <lloyd@REDACTED> wrote:
> >
> >> Hi Theepan,
> >>
> >> 1. If you look at ErlGuten source, you'll see that function
> documentation
> >> is fairly minimal and many parameters have single character names with
> >> little to no documentation. This makes maintenance and revision very
> >> difficult. I consider the core ErlGuten modules diamonds-in-the-rough.
> >>
> >> I also found the high-level page make-up functions provided by Hugh and
> >> Carl limited with respect to professional page make-up and, to me at
> least,
> >> a bit confusing.
> >>
> >> But erlpress_core owes a deep debt and much gratitude to the ErlGuten
> >> lineage.
> >>
> >> erlpress_core is based on Joe's font-handling, justification, and XML
> >> parsing code with few if any changes. But it provides map structures to
> >> represent nearly all of the PDF objects represented in eg_pdf_op.erl.
> These
> >> map structures incorporate many default parameters so generating PDF
> >> documents is syntactically simple and consistent without sacrificing
> >> expressive flexibility. You can easily customize display by
> instantiating
> >> map parameters with your own values.
> >>
> >> You can see most of the PDF objects currently supported by
> erlpress_core,
> >> including boxed text, justification options, and various line and text
> >> objects, demonstrated in ep_show_n_tell.pdf and the source in
> >> ep_show_n_tell.erl.
> >>
> >> If you look at the map definitions of the various PDF objects, you'll
> see
> >> how to customize display.
> >>
> >> At some point if would be good to re-write the base Erlguten modules
> with
> >> more explicit function and parameter documentation, but I'm not up to
> that
> >> at this point. But, anyone looking for a challenge is free to jump in.
> >>
> >> I'm currently working on tables and text flow across pages (think
> reports
> >> and book chapters). Hope to deliver these features plus much code
> polishing
> >> in the next release coming "real soon now."
> >>
> >> High on my wish/to-do list are:
> >>
> >> -- Easy-to_use page-grid design functions
> >> -- Imposition (printing multiple page impressions on a single sheet of
> >> paper stock)
> >> -- Articles and beads (think text jumping across  columns and pages)
> >> -- Easy-to-use and expressive page make-up functions
> >> -- Example templates for various print formats
> >> -- Markdown input
> >> -- Support of TTF and OTF fonts
> >>
> >> Joe Armstrong expressed the following goal when he first announced
> >> ErlGuten:
> >>
> >> "Better than TeX."
> >>
> >> That's a tall order, yet to be realized. My hope is that erlpress will
> >> move the ball further down the field.
> >>
> >> 2. I haven't done anything with image formats beyond what you'll find in
> >> eg_pdf_image.erl. I'd welcome work in that direction.
> >>
> >> 3. erlpress_core is still at Version 0.01. It's just out. I'm working
> >> toward sufficient functionality and stability to support a web
> application
> >> that we have currently under development.
> >>
> >> 4. I developed erlpress_core on Erlang/OTP 19. It does require support
> >> for maps.
> >>
> >> I see the erlpress_core library as a valuable library for embedding PDF
> >> generation into Erlang applications and as the basis for many exciting
> >> Erlang-based print production tools.
> >>
> >> So, Treepan, I appreciate your interest and would welcome your
> >> involvement in testing and feature development.
> >>
> >> I would jump for joy if some Erlang guru were to step forward take on
> the
> >> TTF/OTF support issue. I've done some research and have a few ideas on
> how
> >> expanded font support might be accomplished, but have too little time
> over
> >> the next several months to dig into it.
> >>
> >> Incidentally, in my previous post my iPad decided it was smarter than me
> >> and erroneously corrected my GitHUb address.it should be
> >> writersglen/erlPress_core.
> >>
> >> My intention is to bag the camel case in my next release with luck in a
> >> week or two so it should look like writersglen/erlpress_core.
> >>
> >> All the best,
> >>
> >> Lloyd
> >>
> >>
> >> -----Original Message-----
> >> From: "Theepan" <vasdeveloper@REDACTED>
> >> Sent: Monday, September 24, 2018 3:59pm
> >> To: lloyd@REDACTED
> >> Cc: "Erlang Questions Mailing List" <erlang-questions@REDACTED>, "Joe
> >> Armstrong" <erlang@REDACTED>
> >> Subject: Re: [erlang-questions] ErlGuten
> >>
> >> Hi Lloyd,
> >>
> >> Thank you for your response. I have some quick clarifications --
> >>
> >> * What are the major improvements made on the source ErlGuten? Did you
> >> improve support to different image formats? Any critical bugs fixed?
> >> * Is erlPress_core used in commercial applications, specifically of high
> >> throughput types?
> >> * What is the minimum erlang/OTP version required?
> >>
> >> Best,
> >> Theepan
> >>
> >>
> >>
> >>
> >>
> >>
> >> On Mon, Sep 24, 2018 at 6:36 AM Lloyd R. Prentice <
> lloyd@REDACTED>
> >> wrote:
> >>
> >> > Hi Thepan,
> >> >
> >> > I’ve undertaken a major revision of ErlGuten called erlPress_core—
> >> > announced it on Erlang questions several weeks ago.  It’s available
> from
> >> > GitHub as Writersglen/erlPress_core. I think you’ll find it much more
> >> > accessible than the ErlGutens.
> >> >
> >> > I’ve since been polishing up the code and adding a few new features.
> >> After
> >> > the launch I learned that camel case is not conventional usage when it
> >> > comes to the names of Erlang applications and libraries. So I plan to
> >> > release the updated version as erlpress_core. With smooth sailing I
> >> hope to
> >> > release sometime this week or next.
> >> >
> >> > All the best,
> >> >
> >> > Lloyd
> >> >
> >> > Sent from my iPad
> >> >
> >> > On Sep 23, 2018, at 8:30 PM, Theepan <vasdeveloper@REDACTED> wrote:
> >> >
> >> >
> >> > Hi Team,
> >> >
> >> > I see many forks of ErlGuten. Which one is the latest, most stable and
> >> > widely used?
> >> >
> >> > https://github.com/richcarl/erlguten
> >> > https://github.com/CarlWright/NGerlguten
> >> > https://github.com/hwatkins/erlguten/commits/master
> >> >
> >> > Best,
> >> > Theepan
> >> >
> >> >
> >> > _______________________________________________
> >> > erlang-questions mailing list
> >> > erlang-questions@REDACTED
> >> > http://erlang.org/mailman/listinfo/erlang-questions
> >> >
> >> >
> >>
> >>
> >>
>
>
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