Handle precedingseparator with CSS

[bertfrees]

Currently it is handled with XSLT: see handle-precedingseparator.xsl. In order to handle this in CSS a new CSS feature would be needed, e.g. an ::outside pseudo-element.

[bertfrees]

To do:

• Update braille CSS spec: Pseudo-elements braillespecs/braille-css#33
• Implement: Implement ::outside pseudo-element daisy/pipeline-mod-braille#131

[bertfrees]

I've chosen an easier solution which does not require any new CSS features:

p.precedingseparator {
    $separator-width: 6;
    text-indent: 0;
    &::before {
        content: "\A"                                              /* empty line */
                 repeat("\A0", ($page-width - $separator-width)/2) /* centering */
                 repeat("⠒", $separator-width) "\A"                /* separator */
                 "\A"                                              /* empty line */
                 "\A0 ";                                           /* text indent */
        white-space: pre-line;
        text-transform: none;
        hyphens: initial;
    }
}

Note that this only works for positive text-indents.

The "::outside pseudo-element" path can be explored later but for now I don't really see a good reason to go there. Maybe when some more use cases appear.

[bertfrees]

Moved upstream: daisy/pipeline-mod-braille@cb448df

[mixa72]

It appears that I can't combine: class="precedingseparator noindent"

Is it possible to add a rule for the combination?

p.precedingseparator.noindent {
    $separator-width: 6;
    text-indent: 0;
    &::before {
        content: "\A"                                            /* empty line */
                 repeat(" ", ($page-width - $separator-width)/2) /* centering */
                 repeat("⠒", $separator-width) "\A"              /* separator */
                 "\A";                                            /* empty line */
        white-space: pre-line;
        text-transform: none;
        hyphens: initial;
    }
}

does not work though.

[egli]

Whether or not this is implemented in css or xslt doesn't really matter. What is important is that the user

1. can combine the precedingseparator class attribute with other class attributes like noindent or even brl:class
2. can define the separator (would be nice if this could be defined in css)

[bertfrees]

OK. The current solution is really the worst. It's a ugly workaround, it's not simpler than the XSLT solution and it can't make the corner cases work. So let's go back to the XSLT solution and make everything work, and then we can see if a real CSS is needed to make it configurable enough.

[bertfrees]

Defining the separator could be done in CSS if we handle it like in EPUB, namely by converting a <p class="precedingseparator"> into a <hr class="separator"/> followed by a normal <p> (with XSLT) and then apply this CSS:

$separator-width: 6;

hr.separator {
    display: block;
    text-align: center;
    margin: 1 0;
    &::before {
        content: repeat("⠒", $separator-width);
        text-transform: none;
        hyphens: initial;
    }
}

I don't think an hr is valid DTBook so maybe I'll use a div.