Closes#1669.
If there are further issues, please open a new, targeted issue on the
tracker. Some notes on the further issues you gestured at:
Data URIs are indeed dereferenced, but why is this a problem?
(The function being used to fetch from URLs is used for many different
formats. Preserving data URIs would make sense in EPUBs, but not
for e.g. PDF output. And by dereferencing we can get a smaller,
more efficient EPUB, with the data stored as bytes in a file rather
than encoded in textual representation.)
"absolute uris are not recognized" -- I assume that is the problem
just fixed. If not, please open a new issue.
"relative uris are resolved (wrongly) like file paths" -- can you
give an example?
`<base>` tag is ignored. Yes. I didn't know about the base tag. Could
you open a new issue just for this?
This function can be used to sanitize reference labels so that
they do not contain any of the illegal characters \#[]",{}%()|= .
Currently only Links have their labels sanitized, because they
are the only Elements that use passed labels.
We previously took the old relationship names of the headers and footer in
secptr. That led to collisions. We now make a map of availabl names in the
relationships file, and then rename in secptr.
Graphics in `\section`/`\subsection` etc titles need to be `\protect`ed.
This adds a state value and manually turns it on before every invocation
of `sectionHeader` and manually turns it off after. Using a writer value
and applying `local` would probably be cleaner, but this fits with the
current style.
When we encounter one of the polyglot header styles, we want to remove
that from the par styles after we convert to a header. To do that, we
have to keep track of the style name, and remove it appropriately.
We're just keeping a list of header formats that different languages use
as their default styles. At the moment, we have English, German, Danish,
and French. We can continue to add to this.
This is simpler than parsing the styles file, and perhaps less
error-prone, since there seems to be some variations, even within a
language, of how a style file will define headers.
When users number their headers, Word understands that as a single item
enumerated list. We make the assumption that such a list is, in fact, a header.
