DAISY3 import, large DTBook XML => single XHTML document, super slow CSS Column pagination (700+ "pages")

[danielweck]

There seems to be a huge "paint" bottleneck on MacOS (not tested on Windows and Linux, but expect the same) in Electron / Chromium.
To be investigated and fixed in r2-navigator-js.

[danielweck]

The source DTBook XML weighs in at 2.8 MB

[danielweck]

Note that a common approach is to convert each DTBook input XML file to several fragmented XHTML5 documents, based on front matter, body matter and rear matter, but also (and more importantly) by splitting the body matter into level1 sections (in the sample DAISY book I am using to stress-test Thorium, the body matter itself is 2.6MB)
That being said, this approach can break CSS selectors, and the splitting algorithm must usually account for multiple SMIL files per DTBook file (in my test book: 16 SMILs)

[danielweck]

Side note: the DOM conversion from DTBook to XHTML5 takes a long time (r2-shared-js), hopefully import performance can be improved too.