Re: [NTG-context] EPUB woes

20 Nov 2013

      Hi Mica,

Am 19.11.2013 um 22:39 schrieb Mica Semrick :
...
Keith,
Maybe you should explore an XML format that can be transformed directly to epub. You'd also be able to write a style sheet with ConTeXt that would out put a PDF as well. I think TEI-Lite is a good starting point.
   While XML is one approach and using XML-Styles and DocBook I could even do without ConTeXt completely. Yet, from a general
   user standpoint this way of marking up ebooks is tedious. XML has become the standard for storing all kinds of data. A a storage
   format it is great and allows for conversion to other formats for ages to come. YET, one has to know what XML is how to use it
   how to make tools to process it. That is something that I would not like to enforce on the average author.
Since you can make your own commands in ConTeXt, it will never be able to intelligently map all commands on to simple HTML.
   How true. That is the problem with any system that is and can handle more complex structures than a simpler system.
   That is why any module geared to creating ebooks has to only allow what is needed and can be done in any EREADER, 
   (notice I wrote reader not / Book or EPub!)
My Idea is to use the Lua capabilities of ConTeXt to get the job done.
	I will try to exemplify.

	suggest MWE:
	\usemodule[ebook]

	\setupcss[…]{…}% see comment #1

	\setupmapping[…]{…} % used for when author has his/her own ideas #2

	%normal ConTeXt sets see comment #3

	% possibly set a mode or set externally

	\starttext
		\startebook
			\chapter… %see comment #4
				\startparagraph{leftmargin=20%, …] % see comment #5
				% text
				\stopparagraph
				\starttable…
				\stoptable
				…
                \stopebook
	\stoptext

OK, this pretty much looks like standard ConTeXt
Comments:
	1) Here is where the author can define the CSS he wants
	    It will integrated into the CSS used for the ebook

	2) The author can setup how the ebook commands are mapped to
	     ConTeXt commands

	3) Here are setups for the  NORMAL ConTeXt commands for producing PDFs

	4)  if mode is PDF command is mapped to normal ConTeXt injected into stream
	     if mode ebook, gather information for spine, etc, start a new file for the chapter
	     start writing to this file as HTML 

	5)  if in mode PDF map to ConTeXt command, whereby the leftmargin is used as the
             basis for the calculation .2\textwidth or if you wish

This approach is ebook centric. Allows for rapid prototyping and proofing of the ebook using a PDF
This approach alleviates the need to attempt to dumb down ConTeXt markup. 
Through the use mappings te author has the possibility of producing a higher quality PDF if wanted.
The system could be designed to produce a file with the ConTeXt commands that can be edited for even
higher quality PDFs of printed versions. 

There could be even XML or whatever mode in the ebook module.

Another advantage would be is that we are a module that will produce HTML out of a ConTeXt styled syntax
that can be directly converted to a PDF directly, without worrying about lose of formatting or using tools over
which features are supported or not. This is a straight forward approach.

True, enough, ConTeXt is not designed to be a  HTML editor. 

It is a matter of design policy! The philosophy of going from TeX/ConTeXt centric to HTML is IMHO far inferior than
going from HTML/ebook centric to ConTeXt. One can always make things more intricate/complicated and taking something
complicated and morphing onto a less sophisticated system.

What one has to keep in mind is that ConTeXt "renders" to PDF and that is what is not needed when producing a ebook.
The rendering is done by the ereader. ConTeXt does have any information about screen size or  orientation. ConTeXt is built upon 
a page morphology. ebooks are not! So any decent approach has to keep this in mind.

regards
	Keith.
...
On Mon, Nov 18, 2013 at 10:12 AM, Keith J. Schultz  wrote:
Am 18.11.2013 um 16:33 schrieb Hans Hagen :
...
On 11/18/2013 4:11 PM, Keith J. Schultz wrote:
...
Hi Hans,
Am 18.11.2013 um 13:21 schrieb Hans Hagen :
...
On 11/18/2013 10:00 AM, Keith J. Schultz wrote:
...
2) Now, what a EPub-READER must implement to handle is very
       little. There are HARDLY ANY provisions that a certified EPuB-READER has
             to implement any particular engine or features therein to display/render
       the information contain in the EPub-file/wrapper.
right, and I'm not going to waste time on it till i have a decent ebook reader that behaves well
  The point you are missing is that the ereaders are behaving well. They are following the epub
         standard, and that to the letter of the standard. The problem is that the standard does not
  enforce any particular implementation. If you look at the slow progress of the standard that
  actually requires a full implementation of the HTML5 standard. That  wait will very long.
sure, and every time i see an epub novel i realize that for something like that one really can stick to rather dumb html ... the point is that one cannot expect context to output simple everywhere accepted html from complex rendered input ...
I agree fully. But, Since there are those that wish to produce epubs aka ebooks, they should not be doing complex
  layout. One can always go from simple to complicated in needed, if there were commands dedicated to epub/ebooks/html.
  As I had pointed out in my last post below.
...
...
Furthermore, ereaders are made by companies more interested in profits than spending a few Euros
  more to put decent HTML engines into their readers. Why they do not do that is beyond me!
...
...
...
3. Modify the way in which ConTeXt generates the XML files. Ideally, I should be able to write something like
  Would be nice if there where commands in ConTeXt or a module for defining what should go into the CSS and a
  mode "epub" where the ConTeXt commands are converted to suitible HTML5 structures that are suitiable for
  most ereaders.
      Features:
                       1) margins in percentages
                       2) font sizes based on em
                 3) a new file for every chapter optional for sections user defined
  Just a few. Lots more can be found in any decent documentation on writing ebooks.
context outputs xml and as a bonus provides a css too ... one can always convert that xml to his/her ebooks liking .. maybe at some point the mtx-epub script will do that
I always to like to look at programming as modular and would think that a epub/ebook module would be nice that maps
  there are commands for layingout ebooks. these commands can then be mapped back to standard context commands.
in that case code in xml and either processit by context or transform it into something ebooks can render
...
For some interested in producing a epub then can use the conventions for producing ebooks and ConTeXt can provide the
  math conversions to regular page dimensions used in PDFs for proofing or creating a printed version. It would also make the
  creation of EPubs from ConTeXt a simple parsing exercise.
so far i had no projects where epub was needes so it has a low priority and i still read paper books (or when i would have ebooks i wouldn't need to render them) ... pdfs views quite well on e.g. nexus 7 devices and i assume the upcoming sony high res ebook will also do pdf well
Well I did start the discussion. Just offer my 2 Euro cents worth. Especially, since it comes up every now and then.
  Furthermore, I there was a simple way to create epubs/books with ConTeXt more would use this feature.
I have used up enough of or time.
regards
  Keith.
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If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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archive  : http://foundry.supelec.fr/projects/contextrev/
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