Re: [Adobe-source-devel] Adam and Eve

[Sean P. <sp...@ad...>]

Moving the conversation to the developer list -

> Seriously, I
> am more interested with the dynamic/data-driven nature of
> GUI description. My interest lies in dynamic layouting and
> its binding to application code; again in a declarative form.
> I've written such a GUI framework before, heavily influenced by
> Fresco.

Very cool - the basic model we're following is:

Define the various Concepts involved in UI - write the UI components  
as models of these concepts. We're using type erasure techniques (see  
the regular_object library) to provide runtime polymorphism with  
value semantics and without imposing inheritance hierarchies on the  
individual types.

We currently have three Concepts governing a "widget" -

Controller - a controller allows you to monitor it by registering a  
function to be called. A call to the function is a request to change  
a model (in MVC terms - not generic terms - terminology gets  
confusing!). We've started to adopt a PropertyModel as the MVC model.  
A controller can also be notified that it is disconnected when it can  
not have any effect on the model. A controller has an associated  
model_type which it can manipulate.

View - a view has a single function, display() which is called with a  
model_type (also an associated type for a View). Controller and View  
are separate concepts - calling display() on a View does not end up  
invoking the Controller monitor function.

Placeable - a Placable object can be measured (providing an extents  
struct) and can be placed within a coordinate space.

Placable objects connect to the layout library (Eve).
Controllers and Views connect to the property model library (Adam).

> I'm just starting to play around with ASL and I am not quite
> sure as to what extent ASL will cover. For example, I am also
> quite interested with vector based (scalable) GUIs. I'm sure
> Adobe has its own vector graphics engine. Will such an engine
> be available with ASL? Right now, I'm particularly interested
> with anti-grain (http://www.antigrain.com/). It would be interesting
> to have a vector based extension for the Eve layout engine.

Adobe has a few vector based libraries (key ones for rendering PDF  
and Flash). I've yet to convince either team to open source their  
efforts, however, Flash is fairly programmable through the Flex  
product - but the programming happens in ActionScript (a variant of  
JavaScript) - but one possibility is to port the libraries to  
ActionScript. My understanding is that Flex components provide a rich  
enough geometry to be used effectively with something like the layout  
library.

I'd also be interested in integration with antigrain (I've been  
keeping my eye on the project, just haven't had the bandwidth to do  
anything). We have an image widget which ties our Generic Image  
Library (a raster library) into the rest but having something like  
antigrain rendering into a GIL image and adding an event model for  
interaction would let us extend the libraries into document content.

Long term - I'm interested in building out all the parts needed for a  
generic application - so we've got a lot of opportunity and a long  
way to go.

Sean