Re: [Docutils-users] configuration file for PDF

[Paul T. <pau...@gm...>]

On 1/9/11 9:42 PM, Roberto Alsina wrote:
>    From what kind of file does FO take that? A INI file? If yes, then if
> you are using the section for [PDF] or [FO] you probably don't have
> enough structure to describe the document style. For example, you
> probably want to set the space-before for block quotes different than
> for normal paragraphs.
>
> If you do that by using a space-before and a blockquote-space-before
> then I expect an explicit stylesheet to be roughly 20 times longer than
> rst2pdf's, since on a PDF you don't have defaults as in HTML's CSS,
> exact sizes are more important, and I have learned people really really
> like things to be styled just like they want them.
>
> rst2pdf supports multiple styles (for example, for different parts of
> the document) and supports multiple stylesheets (they are read in order
> and can modify each other, similar to how CSS does it), with the
> addition of style inheritace. Then it uses that to generate a dictionary
> of reportlab styles.
>
> I think the style-loading code is about 2000 LOC, and it was a pain to
> get right (I am pretty sure it's not really right :-)
>
> But hey, if you create a useful stylesheet for FO I can probably create
> something to convert it to rst2pdf's format. I just don't see the gain
> for either project yet.
>
>
I'm not sure what an INI file is. (Though I just came across this when 
looking at the documentation for ConfigParser.) I am going to use the 
same format as the docutils.conf file, meaning python's ConfigParser 
will read the file. Yes, the file could be long, but it goes very 
straightforward in XSLFO:

[FO]

[FO]
default-paragraph.space-before = 12pt
block-paragraph.space-before = 12pt
block-paragraph.space-before = 12pt
block-paragraph.start-indent = 6pt
block-paragraph.end-indent = 6pt
#end config file

The code to parse this is:

# start python code
import sys
import ConfigParser
stylesheet = 
'/Library/svn/trunk/sandbox/paultremblay/xsl_fo/docutils_to_fo.xsl'
config = ConfigParser.RawConfigParser()
config.read('config.txt')
opts =  config.items('FO')


def make_attribute_set(the_name, the_dict):
     sys.stdout.write('<xsl:attribute-set name="%s">\n' % (the_name))
     the_keys = the_dict.keys()
     the_keys.sort()
     for the_key in the_keys:
         sys.stdout.write(' <xsl:attribute name="%s">' % (the_key))
         sys.stdout.write(the_dict[the_key])
         sys.stdout.write('</xsl:attribute>\n')
     sys.stdout.write('</xsl:attribute-set>\n\n')
sys.stdout.write("""
<xsl:stylesheet
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
     xmlns:fo="http://www.w3.org/1999/XSL/Format"
     version="1.1"
 >
<xsl:import href="%s"/>
     """ % (stylesheet))

opts_dict = {}
for pair_tupple in opts:
     first = pair_tupple[0]
     second = pair_tupple[1]
     the_class, att = first.split('.')
     class_exists = opts_dict.get(the_class)
     if not class_exists:
         opts_dict[the_class] = {}
     opts_dict[the_class][att] = second

the_keys = opts_dict.keys()
the_keys.sort()
for the_key in the_keys:
     make_attribute_set(the_key, opts_dict[the_key])

sys.stdout.write('\n</xsl:stylesheet>')

# end python code

Here is the result

<xsl:stylesheet
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
     xmlns:fo="http://www.w3.org/1999/XSL/Format"
     version="1.1"
 >
<xsl:import 
href="/Library/svn/trunk/sandbox/paultremblay/xsl_fo/docutils_to_fo.xsl"/>
<xsl:attribute-set name="block-paragraph">
<xsl:attribute name="end-indent">6pt</xsl:attribute>
<xsl:attribute name="space-before">12pt</xsl:attribute>
<xsl:attribute name="start-indent">6pt</xsl:attribute>
</xsl:attribute-set>

<xsl:attribute-set name="default-paragraph">
<xsl:attribute name="space-before">12pt</xsl:attribute>
</xsl:attribute-set>


</xsl:stylesheet>

<!--END OF STYLESHEET-->

That took me only about 20 minutes to write, but it produces a very 
readable stylesheet. Anyone who understand XSLFO can read that right 
off. A user can pass almost an infinite number of pairs to the 
config.txt file, and still get a readable stylesheet to process. The 
only problem is when a user passes a bad pair, but one can check this 
with a dictionary, and anyway, an end user would be somewhat responsible 
for such a mistake.

I think inheritance is more important in HTML than XSLFO. For a PDF 
file, users often plod along, fiddling to get each thing right. An HTML 
file is generated on the fly and is constantly changing.