[prev in list] [next in list] [prev in thread] [next in thread] 

List:       koffice-devel
Subject:    Re: koffice/libs/flake/tests
From:       Thorsten Zachmann <t.zachmann () zagge ! de>
Date:       2009-09-25 4:18:33
Message-ID: 200909250618.33764.t.zachmann () zagge ! de
[Download RAW message or body]

On Thu September 24 2009, Jan Hambrecht wrote:
> Thomas Zander wrote:
> So what we would need to do is when painting is to respect the shape
> hierarchy. So we have to sort the shapes on each level of the hierarchy.
> First sort all shapes by their z-Index. Start painting in that order.
> When painting a shape container, sort all of its children by their
> z-Index and start painting them. When painting a shape container, sort
> all of its children by their z-Index and start painting them...

Painting shapes by the hierarchy would make the painting code more complicated 
as then not only the shapes that are really need repainting but also their 
parents need to be taken into account. At the moment the painting algorithm is 
quite simple but it needs each object to have a unique z-index. However the z-
index needs to be unique whatever the painting algorithm will use a hierarchy 
or not as otherwise we will have the same behaviour as we have now that 
sometimes some shapes are above and sometimes below a shape with the same z-
index.

> That would ensure what you described above and would also make sure,
> z-Order inside a shape container is handled correctly.
> 
> > The 'if' has the comment; // we can't be under our parent.
> > Which illustrates this is the reason for it being there. I don't know if
> > this is the best solution, but its one that seemed to have worked so far.
> 
> Well obviously it does not work, otherwise we would not discuss these
> matters now, would we?
> 
> > If someone makes a patch that effectively removes that line I think we'll
> > have to do a lot of testing to make sure all code still works according
> > to the above design.
> 
> As written above, i think this line does not make sure that the above is
> working correctly.

The line does only work in one direction but not in the other e.g. not when 
raising objects. Also it does not work when you have a layer as a parent for 
the group and the shape as then both might return the same z-index.

I think there are two possibilities:

o Use a hierarchy when painting:
- more complicated paining algorithm
- it will no longer be possible to have something like the following: 
  layer 1: shape 1, shape 2
  layer 2: shape 3, shape 4
  and the following order:
  shape 1
  shape 3 
  shape 2
  shape 4
  which is possible right now and also allowed by the odf spec.
- in one hierarchy level the z-index needs to be unique 

o have a unique z-index over the full document.
- ordering is a bit more complicated for lower/raise

I think both ways need quite some work to implement.

Thorsten
_______________________________________________
koffice-devel mailing list
koffice-devel@kde.org
https://mail.kde.org/mailman/listinfo/koffice-devel
[prev in list] [next in list] [prev in thread] [next in thread]