After talking with @eunue I realised that the way I'd first
implemented the box/grid "pack" API was simply too complicated.
I had tried to make it possible to change the layout function
at runtime, like good old evas box, but since there are no function
pointers in EO the final design was really convoluted.
If someone really needs to change the layout of a box at runtime,
just create your own subclass, or unpack all items and repack them
in a new box.
Note: there are still some issues with the layout params & flow
- Children are now contents
- Efl.Pack_Layout is now a separate class and
merges Pack_Engine.
- Removed dumb class Efl.Pack_Item
- Updated docs
- Added pack_ or grid_ prefixes to some methods
This reuses the Evas.Box code, since we are still using the
box internally. The flow layout function is far from perfect
(it works well only with items of same height).
This shows how to use specific layouts provided by EFL.
So, since we don't have function pointers, all the solutions
to reimplementing the layout function are quite convoluted:
1. use events
2. reimplement layout func
3. use an extra object
4. use a generic class (non instanciated)
Promises don't apply here (layout will run multiple times).
Problems:
1. Multiple event callbacks will be called, resulting in
potential performance impact, extra events, etc...
Also, there is no way to define standard implementations
that would be provided by the framework.
2. Reimplementation of a function requires extra EO work
(create an EO class, etc...), doesn't allow on-the-fly
change of the layout method.
3. Probably the best solution is to have an object implementing
the layout. But this means creating an extra object along
with the container.
4. To avoid the extra object, use a class, and reimplement
a @class function. This unfortunately requires extra
EO work.
Solution 4. has been selected, but it's not very nice...
This should be the only linear packing container.
This replaces: evas box and elm box.
Edje box needs to be kept around for compatibility,
but it stays an EDC object only (for apps).
Lots of things are still to be fleshed out in this
box implementation:
- Simplify smart object / elm widget code
- Maybe stop using evas object box altogether
- Implement other layout strategies
@feature
Jean-Philippe Andre
Tom Hacohen