Problem with flow-with-text

[Sebastian Sauer]

Aloha,

===== Preamble =====

I am writing this to our mailinglist to have the discussion and a 
possible outcome of it achieved.

===== The problem =====

The textlayout-library hardcodes the position of each rootArea (aka page 
in Words) and that leads to problems with the flow-with-text implementation.

More concrete in KoTextDocumentLayout.cpp we do something like;
rootArea->setReferenceRect(0, size.width(), d->y, d->y + size.height());
d->y = rootArea->bottom() + qreal(50);

That means we assume the x-position is 0. This is not the case with 
facing pages (2 pages side-by-side - not done yet but it's a requirement 
I've still on my todo-list).

It's already a concrete problem with columns where we can have >1 
rootArea per page and there x-position==0 is just wrong.

Beside us assuming that there is only one column of pages we also 
hardcode the distance (50px) between them. That is wrong cause Words 
uses something different already (the configurable 
KWViewMode::ViewMap::distance) plus we may have additional space between 
pages (or to be more correct page-bodies) occupied by 
headers/footers/footnotes.

That means our referenceRect().top() has wrong values and we are 
applying those wrong values now, with the flow-with-text implementation, 
in FloatingAnchorStrategy::checkLayoutEnvironment as boundaries.

===== The Effect =====

It seems to work fine for the first page cause there we are indeed 
dealing with the correct values. But all following pages have wrong values.

That is the reason that at some documents anchored images which have 
flow-with-text=true have wrong positions now. As higher the page-number 
those images are on as more wrong is there position.

===== Solution =====

That is what I like to talk about. Personally I think;

1. We should apply a fast workaround first. That means disabling the 
FloatingAnchorStrategy::checkLayoutEnvironment logic for now till we 
have something that works as expected. I think the problem is to major 
to have it in the next Calligra releases. Instead it's imho better to 
not ship with support for flow-with-text till we have something that 
works as expected.

2. I think what we should do is to let the application define the proper 
positions and not hard.code it in the textlayout-lib.

3. The hard part is to keep those values synchronized. That means if the 
application does shape->setPosition() or shape->setSize then the 
referenceRect needs to be automatically adjusted. In the best case in a 
way that does not force additional "update-logic" in the application 
code. Maybe we can use the shape's model for it?

So, what do you think?