Expand utility classes

[jason-fox]

You might want to consider this as part of #12 once #11 has landed.

It splits out as many hard-coded magic numbers into an <xsl:attribute-set> in the same fashion as the PDF transform

[infotexture]

Marked as Draft for now, as we'll want to rebase this onto develop now that #11 has been merged.

🤔 Not sure I get the intention of using attribute sets like in the PDF plug-in here.

I think it's good to make things easier to customize, but doesn't this just change the file in which the values must be changed?

[jason-fox]

I've had a rethink, and it looks like the existing DITA-OT mode="get-output-class" already provides most of what is needed. The utility-classes.xsl should hold the magic numbers so you can apply common bootstrap styling to bootstrap elements. For example making all your card elements w-50 or indenting the tabbed dialog or adding a background or changing the default Warning alert bootstrap icon to a bi-emoji-smilesmiley face 😄 (or changing all of them if you want to use a different icon set or ... etc.

The PR just collects all the relevant bootstrap CSS styles into one single file rather than scattering them across all the xsl stylesheets, which makes the values easier to maintain and update.

[jason-fox]

For example, the "default" DITA Bootstrap uses text-dark for all of the headers (this aligns with Bootstrap itself, since the bright blue looks very jarring. But the current DITA-OT documentation uses text-primary for all of the headers (since the dark blue looks much better.) It doesn't make sense to annotate every <title> DITA element with output-class="text-primary", it would be much easier to do this on the command line like:

./dita -f html5-bootstrap \
    -i ../plugins/dita-bootstrap/sample/document.ditamap \
    --bootstrap.css.header=text-primary

Example: Plugins for DITA Open Toolkit

Similarly you can change the margins and add a border on all vertical tabbed dialogs with:

./dita -f html5-bootstrap \
    -i ../plugins/dita-bootstrap/sample/document.ditamap \
    --bootstrap.css.tabs.vertical="border m-5"

Similarly, the "default" bootstrap uses rounded corners for boxes so the codeblocks should also be annotated with utility classes to provide rounded corners border rounded, but if the theme uses sharp corners, the rounded addition will be unnecessary:

./dita -f html5-bootstrap \
   -i ../plugins/dita-bootstrap/sample/document.ditamap \
   --bootstrap.css.codeblock=border

[infotexture]

Sorry this was stuck in the review queue for so long, but I think the ability to pass additional Bootstrap classes via CLI parameters is useful, so I'll merge this. 👍

We'll probably want to add a few more examples to the README based on #13 (comment), but I can handle that along with the other release prep tasks in #12.