Re: DOCBOOK-APPS: What's the most appropriate (and futureproof) way tostyle the FO?

[Tobias Reif <tobiasreif at pinkjuice dot com>]

Hi

Bob Stayton wrote:

> Norm might want to answer this too, but
> I believe the mechanisms are meant to be combined, in
> a hierarchical manner.  The titlepage.templates
> mechanism establishes the default values, and the
> propery attribute-sets provide the runtime flexibility.

But some stuff can only be set in the titlepage AFAICS.


> As you know,

I did not know that.

> editing a copy of titlepage.templates.xml
> and regenerating titlepage.templates.xsl is not something
> you want to do very often.

It needs to be done each time I want to change more than one style 
property for which there is no option param or option param attribute set.

Again: Styling is the most basic customization, and it should be as 
painless and as lightweight as possible IMHO.

When I generate XHTML, I get the basic styling from the base/default CSS 
 of the browser (actually I'm using my own, but that's optional); then 
I can add styling and override the defaults in a very flexible, simple, 
quick, and painless way, by inserting any number of stylesheets in the 
cascade, below the base style. That's how I'd like to do it with the FO 
XSLTs. Not so much redundancy and different places and mechanisms, 
editing my own small files not the provided one, subset / override only 
the relevant parts instead of copying the whole 1KLOC shebang (in the 
case of the FO titlepage), etc.

> It can be used to set
> properties, but think of them as the new default properites.

This would only be possible if I could override all of them in some 
other way or file, which is not possible AFAICS. I have to deal with the 
titlepage mechanism for many stylings, so it makes no difference if they 
are called "new defaults" or not.


> It is important to retain the ability to change properties
> at run time, using parameters and attribute-sets.

Sounds good; but since this is not possible for all properties, the more 
static nature of the titlepage mechanism seems to have the problem you 
describe: it is not flexible and dynamic enough.


> Since the attribute-set properties appear in an fo:block
> nested inside the fo:block from the titlepage template,
> it can override the defaults.

Can all properties set in the titlepage be overridden? This seems to be 
a requirement for all this to work out well.


> Here is where the properties come from in your first example
> above:
>
> 1.  From attribute-set 'section.titlepage.recto.style' in
> fo/titlepage.xsl:
>
>   <fo:block
>      keep-together="always"
>
> 2. From titlepage.templates.xml:
>
>      margin-left="-4pc"
>      font-family="sans-serif">
>
> 3. From <xsl:template match="section/title|..." mode="titlepage.mode">
> in fo/sections.xsl:
>
>     <fo:block keep-with-next.within-column="always">
>
> 4. From attribute-set 'section.title.properties' in 
> fo/param.xsl:
>
>    <fo:block font-family="sans-serif" font-weight="bold"
>      keep-with-next.within-column="always" space-before.minimum="0.8em"
>      space-before.optimum="1.0em" space-before.maximum="1.2em">
>  
> 5. From attribute-set 'section.title.level1.properties' in
> fo/param.xsl (not included in your example):
>
>     <fo:block font-size="20.736pt">

Thank you very much for taking the time to explain this.

But doesn't the length of this explanation show that styling FO 
currently is quite complex, inflexible, confusing, and very tedious?

Again: Your FO XSLTs sure are very useful already, but I see alot of 
room for improvement where the life of the user (who is styling and 
customizing output) can be made much easier.


> In your case, you can make the change to font-weight=100
> without regenerating titlepage.templates.xsl.  The
> attribute-set 'section.title.properties' in fo/param.xsl
> sets properties for all section title levels, while
> 'section.title.level1.properties' adds properties specific
> to sect1 level headings.  Change the font-weight
> in 'section.title.properties' from 'bold' to '100', and it will
> apply to all section title levels.

Yes, but there were stylings where I was told that the only only way to 
achieve them is to edit (my copy of the) titlepage.


> I can't say how 'futureproof" these various mechanisms are.
> It kind of seems like there are too many places
> to set properties,

Absolutely.

> but I believe some of that is the result of
> stylesheet evolution, rather than by design.

Probably.


> So perhaps these will be consolidated a bit in the future.

Consolidation would be one of many measures and strategies which would 
improve the styling experience.

With all my (hopefully constructive) criticism I don't want to make your 
life harder, but instead make those of the users (including me) easier :)

Tobi

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