Re: [O] **: Re: [dev] About a beamer back-end

[Sebastien Vauban]

Hi Nicolas,

> "Sebastien Vauban" writes:
>
>>> - Sectioning and packages are extracted from `org-e-latex-classes'.
>>>   Since calling Beamer back-end is explicit, it can be applied on any
>>>   tex file, not only when that file starts with
>>>   "\documentclass{beamer}".  Additionally, an equivalent to
>>>   `org-beamer-use-parts' is unnecessary.
>>
>> I did not understand that one.
>
> At the moment, beamer exporter is hooked into regular latex exporter
> when latex class is "beamer".  This restriction is unnecessary when you
> consider beamer as an independent back-end (i.e. you can call beamer
> export even on your "article" setup).

Cool...

>> I'm wondering, though, how you support the special case of "beamer frame
>> level" set to 0, where we need to add the tag "B_frame" (in fact, the
>> property) to show where the frame really begins.
>
> Would you mind providing an example for that? I am not aware of that
> special case.

For sure, I'm willing to do so. Here an ECM of that feature:

--8<---------------cut here---------------start------------->8---
#+TITLE:     "Free" beamer frame level
#+OPTIONS:   H:3 num:t toc:t

#+startup: beamer
#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation,t]
#+BEAMER_HEADER_EXTRA: \usetheme{PaloAlto}\usecolortheme{default}
#+BEAMER_FRAME_LEVEL: 0

* Introduction

** Slide 1                                                           :B_frame:
   :PROPERTIES:
   :BEAMER_env: frame
   :END:

- =BEAMER_FRAME_LEVEL: 0= gives you some flexibility in deciding what is and
  isn't a frame.

- For example, this frame is directly located under the section
  "Introduction".

* Analysis

** Client

*** Slide 2                                                          :B_frame:
    :PROPERTIES:
    :BEAMER_env: frame
    :END:

- This frame is located under the section "Analysis", subsection "Client".

*** Slide 3                                                          :B_frame:
    :PROPERTIES:
    :BEAMER_env: frame
    :END:

- You explicitly have to say which headlines are a frame by setting the
  =BEAMER_env: frame= property.

** Supplier

*** Slide 4                                                          :B_frame:
    :PROPERTIES:
    :BEAMER_env: frame
    :END:

- This becomes visible through the =B_frame= tag (visual aid only).

* Conclusion

** Slide 5                                                           :B_frame:
   :PROPERTIES:
   :BEAMER_env: frame
   :END:

- This frame is directly located under the section "Conclusion".

- No need to create a (stupidly) redundant subsection called "Conclusion"...
--8<---------------cut here---------------end--------------->8---

>> I liked the fact we had 2 types of highlighting (bold, in black, and
>> alert, in red, in my case).
>>
>> I would say that, as Beamer has those 2 different highlightings, we should be
>> able to still support both. Is this a problem?
>
> Not really a problem, but Org limits text markup to six elements.  You
> can easily choose to use another one for bold (i.e. with filters),
> though.

Sorry to insist, but I don't think it's a good idea to suppress the
distinction between alert (generally mapped to @ in private Org
configurations) and bold (*).

If I follow your advice, to get back the bold, I would have to override
another symbol, like + for example.

Not mentioning the fact it won't be standard (if I ever distribute my Org
file), but I can't export my slides once to Beamer PDF, once to a standard
document PDF without seeing big differences in the interpretation of the
symbols.

While, on the contrary, if we have an apart symbol for alert (apart from bold,
as foreseen in Beamer), and if we include such a line for the standard PDF
export:

  \providecommand{\alert}[1]{\textbf{#1}}

or, better

  \providecommand{\alert}[1]{{\textcolor{red}{\bfseries{#1}}}}

we win on both sides (we can export to both Beamer and standard doc with both
bold and alert differentiated), don't we?

Best regards,
  Seb

-- 
Sebastien Vauban