Asp Forum - What's the best way to write a Textile-to-PDF::Writer converter?

Andreas Semt

1/16/2005 6:51:00 PM

Hello list!

I am relative new to Ruby, so i ask:
What's the best way to develop a *pure* Ruby Textile-to-PDF::Writer
converter? I use the Soks Wiki (http://rubyforge.org/proj... by
Tom Counsell) for documentation purpose on work (on a W2K Pro Box). This
wiki saves the page content in flat text files in the Textile Markup
language, so i want a converter to generate PDF files from these Textile
files. Austin Ziegler has a RubyForge project
(http://rubyforge.org/projects...) for writing PDF files in Ruby.
So all parts of my imaginary pure Ruby Textile-to-PDF::Writer converter
are there, however i wonder how to use them?

Thanks for any help or suggestions!

Greetings,
Andreas

7 Answers

Austin Ziegler

1/16/2005 8:32:00 PM

On Mon, 17 Jan 2005 03:51:29 +0900, Andreas Semt <as@computer-leipzig.de> wrote:
> I am relative new to Ruby, so i ask:
> What's the best way to develop a *pure* Ruby Textile-to-PDF::Writer
> converter? I use the Soks Wiki (http://rubyforge.org/proj... by
> Tom Counsell) for documentation purpose on work (on a W2K Pro Box). This
> wiki saves the page content in flat text files in the Textile Markup
> language, so i want a converter to generate PDF files from these Textile
> files. Austin Ziegler has a RubyForge project
> (http://rubyforge.org/projects...) for writing PDF files in Ruby.
> So all parts of my imaginary pure Ruby Textile-to-PDF::Writer converter
> are there, however i wonder how to use them?

I don't know, offhand, but if you want to definitely do this and
contribute it to PDF::Writer, I will happily work with you on that --
this has been part of a goal of PDF::Writer (the specification of a
better formatting language than the simple one that I support right
now).

My problem is mostly that I don't really know Textile, and I'm deep in
the middle of Text::Format, with a bit of review of a new port of
Text::Reform. After that, I *must* work on Diff::LCS and Ruwiki again,
but I also need to get a PDF::Writer release out the door that
captures a font fix that I made last week (so you definitely want the
CVS HEAD version of PDF::Writer).

By contributing something like this to PDF::Writer, I will also make
sure that as the API for PDF::Writer changes (and I promise that it
will), the converter is kept up to date.

-austin
--
Austin Ziegler * halostatue@gmail.com
* Alternate: austin@halostatue.ca

John Labovitz

1/16/2005 9:04:00 PM

On Jan 16, 2005, at 12:32 PM, Austin Ziegler wrote:
> On Mon, 17 Jan 2005 03:51:29 +0900, Andreas Semt
> <as@computer-leipzig.de> wrote:
>> I am relative new to Ruby, so i ask:
>> What's the best way to develop a *pure* Ruby Textile-to-PDF::Writer
>> converter?
> I don't know, offhand, but if you want to definitely do this and
> contribute it to PDF::Writer, I will happily work with you on that --
> this has been part of a goal of PDF::Writer (the specification of a
> better formatting language than the simple one that I support right
> now).

(This is mostly a response to Andreas; it probably won't be news to
Austin.)

I've been using PDF::Writer to do some graphical charting, so I'm not
so familiar with its text processing. But I'll take a guess on how to
do this.

When you use the #ez_text method, the text you pass in can be a big
block of text, possibly spanning multiple pages. The text can have
HTML-like markup. The text processing code in PDF::Writer will
apparently handle all the details of wrapping lines, spacing
paragraphs, and breaking pages. So for a first pass (assuming you
don't need to control page breaks), you might work on a simple
Textile-to-ez_text converter.

If you haven't seen it, you should look at RedCloth, which is an
implementation of a Textile-to-HTML converter. It doesn't appear to be
very extensible -- its HTML generation seems all wrapped up in the
parsing -- but at only 1000 lines of code, maybe it would be a good
thing to build on.

--
John Labovitz
Macintosh support, research, and software development
John Labovitz Consulting, LLC
johnl@johnlabovitz.com | +1 503.949.3492 |
www.johnlabovitz.com/consulting

Christian Metts

1/16/2005 10:57:00 PM

On Mon, 17 Jan 2005 03:51:29 +0900, Andreas Semt <as@computer-leipzig.de> wrote:
> Hello list!
>
> I am relative new to Ruby, so i ask:
> What's the best way to develop a *pure* Ruby Textile-to-PDF::Writer
> converter? I use the Soks Wiki (http://rubyforge.org/proj... by
> Tom Counsell) for documentation purpose on work (on a W2K Pro Box). This
> wiki saves the page content in flat text files in the Textile Markup
> language, so i want a converter to generate PDF files from these Textile
> files.

I think it would make more sense to work on an HTML to PDF writer.
It's an extra-step from textile, but it shouldn't slow you down any,
and will be more useful.

From there you can also work on CSS support. Which would give you the
ability to control colors, font and quite a bit of other formatting.
There is even CSS for supporting page-breaks[1]. I'm not suggesting
you write a full pure-ruby CSS parser (I wouldn't wish that on anyone)
but you should be able to get a specific sub-set that would be
particularly useful for PDFing.

[1]: http://www.w3.org/TR/REC-CSS2/page.html#p...

Anyway, just a thought.

-- Xian

Andreas Semt

1/17/2005 2:01:00 PM

John Labovitz wrote:
> On Jan 16, 2005, at 12:32 PM, Austin Ziegler wrote:
>>
>> I don't know, offhand, but if you want to definitely do this and
>> contribute it to PDF::Writer, I will happily work with you on that --
>> this has been part of a goal of PDF::Writer (the specification of a
>> better formatting language than the simple one that I support right
>> now).
>

Hello Austin!

I want just a little converter for my Soks content, no big deal. However
i could (later) expand this little converter to a more general tool for
converting Textile-to-PDF using PDF::Writer.

>
> (This is mostly a response to Andreas; it probably won't be news to
> Austin.)
>
> I've been using PDF::Writer to do some graphical charting, so I'm not so
> familiar with its text processing. But I'll take a guess on how to do
> this.
>
> When you use the #ez_text method, the text you pass in can be a big
> block of text, possibly spanning multiple pages. The text can have
> HTML-like markup. The text processing code in PDF::Writer will
> apparently handle all the details of wrapping lines, spacing paragraphs,
> and breaking pages. So for a first pass (assuming you don't need to
> control page breaks), you might work on a simple Textile-to-ez_text
> converter.

Hello John!

Thanks for that hint. However "ez_text" does not support formatting of
any kind (for example: bold, italic, ...). So i will use other methods.

> If you haven't seen it, you should look at RedCloth, which is an
> implementation of a Textile-to-HTML converter. It doesn't appear to be
> very extensible -- its HTML generation seems all wrapped up in the
> parsing -- but at only 1000 lines of code, maybe it would be a good
> thing to build on.
>

Yes, it's a good starting point. "redcloth.rb" and Austin Ziegler's
"readme.rb" example will guide me ;-)

Greetings,
Andreas

> --
> John Labovitz
> Macintosh support, research, and software development
> John Labovitz Consulting, LLC
> johnl@johnlabovitz.com | +1 503.949.3492 | www.johnlabovitz.com/consulting
>
>
>
>

John Labovitz

1/17/2005 6:15:00 PM

On Jan 17, 2005, at 6:00 AM, Andreas Semt wrote:

> Thanks for that hint. However "ez_text" does not support formatting of
> any kind (for example: bold, italic, ...). So i will use other
> methods.

Ah. #ez_text supports "callbacks" for formatting, but #add_text (in
the base class) *does* support and formatting.

--
John Labovitz
Macintosh support, research, and software development
John Labovitz Consulting, LLC
johnl@johnlabovitz.com | +1 503.949.3492 |
www.johnlabovitz.com/consulting

Andreas Semt

1/17/2005 6:48:00 PM

Austin Ziegler wrote:

> On Mon, 17 Jan 2005 03:51:29 +0900, Andreas Semt <as@computer-leipzig.de> wrote:
>
>>I am relative new to Ruby, so i ask:
>>What's the best way to develop a *pure* Ruby Textile-to-PDF::Writer
>>converter? I use the Soks Wiki (http://rubyforge.org/proj... by
>>Tom Counsell) for documentation purpose on work (on a W2K Pro Box). This
>>wiki saves the page content in flat text files in the Textile Markup
>>language, so i want a converter to generate PDF files from these Textile
>>files. Austin Ziegler has a RubyForge project
>>(http://rubyforge.org/projects...) for writing PDF files in Ruby.
>>So all parts of my imaginary pure Ruby Textile-to-PDF::Writer converter
>>are there, however i wonder how to use them?
>
>
> I don't know, offhand, but if you want to definitely do this and
> contribute it to PDF::Writer, I will happily work with you on that --
> this has been part of a goal of PDF::Writer (the specification of a
> better formatting language than the simple one that I support right
> now).
>
> My problem is mostly that I don't really know Textile, and I'm deep in
> the middle of Text::Format, with a bit of review of a new port of
> Text::Reform. After that, I *must* work on Diff::LCS and Ruwiki again,
> but I also need to get a PDF::Writer release out the door that
> captures a font fix that I made last week (so you definitely want the
> CVS HEAD version of PDF::Writer).
>
> By contributing something like this to PDF::Writer, I will also make
> sure that as the API for PDF::Writer changes (and I promise that it
> will), the converter is kept up to date.
>
> -austin

Hello Austin!

a question to your "readme.rb" example file: In the "data.txt" file you say:
--- snip ---
# can be used within the text with gleeful abandon
--- snap ---

Could you *please* explain how you parse these "bold" and "italic" tags
in the "readme.rb" file? I have not discovered it yet :-(

John Labovitz wrote:

> Ah. #ez_text supports "callbacks" for formatting, but #add_text (in the base class) *does* support and formatting.

Hello John!

Thanks ... will use the #add_text method.

Greetings,
Andreas

Austin Ziegler

1/17/2005 7:43:00 PM

On Tue, 18 Jan 2005 03:47:41 +0900, Andreas Semt
<as@computer-leipzig.de> wrote:
> Austin Ziegler wrote:
>> On Mon, 17 Jan 2005 03:51:29 +0900, Andreas Semt
>> <as@computer-leipzig.de > wrote:
>>> I am relative new to Ruby, so i ask: What's the best way to
>>> develop a *pure* Ruby Textile-to-PDF::Writer converter? I use
>>> the Soks Wiki (http://rubyforge.org/proj... by Tom
>>> Counsell) for documentation purpose on work (on a W2K Pro Box).
>>> This wiki saves the page content in flat text files in the
>>> Textile Markup language, so i want a converter to generate PDF
>>> files from these Textile files. Austin Ziegler has a RubyForge
>>> project (http://rubyforge.org/projects... ) for writing
>>> PDF files in Ruby. So all parts of my imaginary pure Ruby
>>> Textile-to-PDF::Writer converter are there, however i wonder how
>>> to use them?
>> I don't know, offhand, but if you want to definitely do this and
>> contribute it to PDF::Writer, I will happily work with you on
>> that -- this has been part of a goal of PDF::Writer (the
>> specification of a better formatting language than the simple one
>> that I support right now).
>>
>> My problem is mostly that I don't really know Textile, and I'm
>> deep in the middle of Text::Format, with a bit of review of a new
>> port of Text::Reform. After that, I *must* work on Diff::LCS and
>> Ruwiki again, but I also need to get a PDF::Writer release out
>> the door that captures a font fix that I made last week (so you
>> definitely want the CVS HEAD version of PDF::Writer).
>>
>> By contributing something like this to PDF::Writer, I will also
>> make sure that as the API for PDF::Writer changes (and I promise
>> that it will), the converter is kept up to date.
> Hello Austin!
>
> a question to your "readme.rb" example file: In the "data.txt"
> file you say: --- snip --- # can be used within
> the text with gleeful abandon --- snap ---
>
> Could you *please* explain how you parse these "bold" and "italic"
> tags in the "readme.rb" file? I have not discovered it yet :-(

Look at writer.rb:398 (set_current_font); it refers to
@current_text_state. This is set (currently) in
prvt_check_text_directive1 (line 646). It's an awful hack, but this
is what was in the original code. This is the sort of thing that I
hope to greatly improve in the future. That is to say that and
 are built into the writer and are only supported if the font(s)
involved support them. That latter restriction will probably always
be true, but ...

-austin
--
Austin Ziegler * halostatue@gmail.com
* Alternate: austin@halostatue.ca

comp.lang.ruby

What's the best way to write a Textile-to-PDF::Writer converter?

Andreas Semt

Austin Ziegler

John Labovitz

Christian Metts

Andreas Semt

John Labovitz

Andreas Semt

Austin Ziegler

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