A collection of use cases for column-span: <integer>

[JayPanoz]

Since we’re using columns extensively for ebooks, and I’m documenting needs for different languages and their typography, I may come across use cases for the multicol/overflow spec.

Please feel free to use this issue to add use cases to this collection. I believe it will be a collective effort to document those use cases and do some triage.

I’ll start with the processing of column spanning headings in japanese. There are Requirements for Japanese Text Layout with a lot of illustrations. The most interesting is the note though:

In multi-column books, the top level heading for the start page usually spans all columns designed in the kihon-hanmen. In common magazines, the title of the start page of an article usually spans all columns designed in the kihon-hanmen.

Top level heading can be considered <h1> on a web page kihon-hanmen, the text area in the viewport. In other words, if you have a column-count of 2 and columns overflow, there is currently no way to have a column-span of 2 as well.

There are also examples where <h2>, <h3>, <h4>, etc. span a specific number of columns.

Although not discussed explicitly, there are other examples of column-span in Hangul (see illustrations at the end of this section) and Chinese (see the last note of section 4.1.1).

There are of course examples in latin languages but my main focus being CJK at the moment, I guess it’s worth mentioning that in Japanese, this is quite a clear requirement.

[JayPanoz]

And while I’m at it, another use case would be a “featured article” spanning 2 columns in such a layout (Codepen Spark)

[rachelandrew]

Thanks for this - I'm very keen to see examples of non horizontal-tb layouts because I know that is where I lack experience.

The thing with column-span: is I'd like to collect examples of how that works in other media. As we don't skip over the spanning element the content is going to break into columns above the span but then the last column for example runs full length. How does that tend to work in existing patterns? Are they doing the multicol before and after the spanner then continue on the full height one afterwards? That seems to be what your first example shows. Collecting lots of use cases around those patterns would be helpful as it's a L2 thing again, but I get asked about this all the time so it would be good to build up a collection of good use cases then we can try and solve it.

[rachelandrew]

David Storey pointed out on Twitter that Opera Reader did implement prefixed column-span: integer http://www.wiumlie.no/2012/reader/

[JayPanoz]

Oh yes, that is definitely the tricky part.

You could say there is such an example in the JLREQ, see figure 4.48, where the subheading spans the last column. But the last column on the page. On the other hand, one can assume that the same process is used on the last page of the section/chapter.

BTW, there are also examples in horizontal-tb that are not Japanese-specific. See fig. 2.15 (illustrations) or fig. 4.112 (tables, which happens to be a huge issue in ebooks when we fake a spread). And the same issue would apply… the concept of anchoring might be a hint for illustrations and tables though.

I would say that Opera probably solved those requirements back in the Presto days. But with the help of paged overflow.

To be fair, those are complex issues that we’ve been trying to solve for a long time, see EPUB Adaptive Layout demoes which prolyfill a spec Reading Systems never implemented. It’s quite brutal if we compare it to what we’re currently achieving with columns.