Make manual volume breaking work properly

[bertfrees]

Manual volume breaking is a feature that Joel has implemented right before he left on vacation and there hasn't been time to debug it properly.

E.g. it currently doesn't work in combination with table of contents: brailleapps/dotify#212. Also, Joel has mentioned the current implementation might not work when there are a lot of manual break points. I think Mischa even had problems with just a couple of break points.

I can have a look at this myself but should ideally discuss this with Joel. We can already start with creating some unit tests.

+1 from:

• Nota: Enhanced volume breaking snaekobbi/pipeline-mod-nota#23

[egli]

Apparently Joel is going to work on this

[joeha480]

I have implemented this, and it is staged right now. dotify.formatter.impl:2.7.0

[bertfrees]

Thanks @joeha480! Looks good so far.

I checked that the TOC issue is fixed. I also tested with more than one manual break point, and also with a combination of manual and automatic volume breaking (break-before="volume" + sheets-in-volume-max +volume-keep-priority).

Mischa will do some further testing now.

[mixa72]

With my test, manual volume breaking only works without TOC. In combination with TOC the transformation fails.

[bertfrees]

Hi Mischa, Christian needs to deploy this first. Sorry for the confusion!

[mixa72]

Never mind.

[bertfrees]

@mixa72 We're wondering which behavior you would prefer. I'll explain with an example. Let's say there are 120 sheets, and the maximum number of sheets per volume is set to 50. Normally (if there are no other constraints) the system would split the book into 3 volumes of 40 sheets (40, 40, 40). Now if you insert a manual break point at sheet 90:

• would you like the system to adjust the other breaks so that the overall layout is optimized again taking into account the new constraint (this would result in 45, 45, 30)
• or would you like the other breaks to remain untouched? (this would result in 40, 40, 10, 30)

[mixa72]

Very good question. I think both ways of volume splitting are completely plausible and legitimate, but I'd prefer 45, 45, 30. (In my opinion the "full" division into volumes on the basis of 40 sheets per volume should no longer be relevant once you've inserted a manual break point).
Anyway, I'll avoid combining manual and automatic volume breaking since I'm not very strong at maths.

[bertfrees]

OK. 45, 45, 30 is what the current implementation will do, actually.

[mixa72]

Touché! Great.

[bertfrees]

Moved upstream: daisy/pipeline-mod-braille@05a27df...9aaa1b0

[mixa72]

See example, line 701:
The first chapter after the volume breaking (#B ELEUSIUS F@HRT LIFT) should start on a recto (odd braille page number), but it appears on a verso (even braille page number). The recto is empty instead.
I tried to force a page break in the CSS with page-break-after: always:

brl|volume[brl|grade='#{$contraction-grade}'] {
   display:block;
   volume-break-before:always;
   page-break-after: always;
}

It appears to have no effect though.
en_ex.zip

[bertfrees]

Blank pages fixed in sbsdev/pipeline@85e10c4

[bertfrees]

Mischa reported another bug with blank pages. See the private email with the DNA.xml test book. I have fixed it in sbsdev/pipeline@5e56065.