Re: [boost] [gui] The Big Picture

From: E. Gladyshev (eegg_at_[hidden])
Date: 2004-12-29 15:22:19

Reece Dunn wrote:
> Hi All,
> 
> We have different people with different needs and ideas as to what 
> constitutes a UI system. The general concensus is that the resulting 
> library should be designed independant of any target implementation and 
> should support general platforms such as text-based systems. It is also 
> advisable to allow interaction with a target platform to allow for 
> platform-specific user code if required.
> 
> There are several layers to a (G)UI library:
> [1]  The platform independant layer.
> [2]  The geometry layer - unit type, point, size, rect.
> [3]  The base graphics layer - fonts, canvas, pens, images, etc.
> [4]  The event handling layer - event loop, events, event handlers.
> [5]  The UI object layer - frames, forms, widgets, lightweight objects, 
> etc.
> 
> Each of these layers is conceptually independant, but builds on top of 
> the other. Should there be a separate library for each of these layers 
> (Boost.Platform, Boost.Geometry, Boost.Graphics, Boost.Events and 
> Boost.UIObject)?
> 
> The design for the UI object layer must be able to support:
> *  native-based UI objects that are dynamically constructed.
> *  native-based UI objects taken from pre-built elements, e.g. objects 
> on a form.
> *  lightweight UI objects that are not native-based.
> *  custom drawn native-based UI objects (either dynamically constructed 
> or from pre-constructed objects), in essence a hybrid of native-based 
> and lightweight UI objects.
> 
> All of these UI object forms need to be supported, including bindings to 
> different platforms/APIs. I see the basic UI object heirarchy as:
> 
>    ui::object
>       ui::frame
>          ui::form
>          ui::main_frame
>          ui::popup
>          ...
>       ui::widget
>          ui::textfield
>          ui::textarea
>          ui::button
>          ui::grid
>          ui::table
>          ...
>       ui::layout_manager
>          ui::flow_layout
>          ...

Oh boy, it looks like another MFC to me.
Such single object derived hierarchies
usually don't work well. They are hardly
scalable.

Eugene