Advanced Text Wraps

[dbolack-ab]

In channel yesterday there was discussion of the need/value of additional prepackaged text wraps. This dovetails with #3126 which was in response to user issue #380.

Most of these will probably be static classes. A few may need to be mustache functions ( I use the term macro in my PR but the difference is negligible ) where the invocation does both (class or style) injection and some manipulation based on either the invocation and/or the tag the mustache applies to.

We should be dutiful to ensure that where classes are used the classes live in the blank theme unless absolutely wed to another theme.

Consensus for inclusion:

• list items to be added later.

Lastly, we should have a nice tutorial document demonstrating each of these and any similar techniques that do not warrant inclusion.

[dbolack-ab]

I'm going to start with the referenced PR.

$swl and $swl are mustache macro/functions that take the form of function-floating_point_value to inject style attribute values into the <img> tag before the mustache.

eg: $swl-0.5

This uses shape-outside to generate a text wrap shape based on the transparency of source image and sets a wrap threshold based on the floating point value. Lastly, it floats the image right or left ( r or l in the name ) as that is a requirement for shape-outside.

Note that at this time we may switch from shape-margin-threshold to shape-margin, which takes an explicit size in CSS units.