Re: Re: about your concept

On Thu, 22 Jul 2004, Ulrik Mikaelsson wrote:

> Maybe it would be possible to abstract server-side behaviors, such as
> "scrollable", or "clickable" and provide template-based reactions to those
> events, as well as a "custom" behavior which would pass on events to the
> client?

Interesting idea.  It would tie in quite well with the theme engine having
a concept of "clickable thing", "labelling thing", and so on.

> XML is a great language for many purposes, but perhaps we should also consider
> a format like EBML, or some own proprietary protocol to keep bandwidth-usage
> down to a minimum.

The "proprietary" protocol could be as simple as Y remote object method
calls in the right sequence.

> This sounds EXACTLY like OpenGL displays-lists. And they have proven to work
> quite well over the years. Except for the time when my Nvidia-card refused to
> store anything, including the damn lists, in video memory and just puked all
> over my screen. ;) Just add a LITTLE more flexibility to the display
> list-concept and we've got something that works. ;)

I'm not sure display-lists buy us anything useful.  Display lists work for
gfx cards because the rendering pipeline is usually a lot faster than the
cpu can send polys over the agp bus.  I don't think we'll have the same
problem for custom widgets (or, indeed, canvases in general).  It might be
an idea to throw together a prototype to see what happens.

> I'm afraid there might be one slight problem more, though. Widgets may contain
> other widgets. (At least I think they should?) How do we solve layouting of
> widgets embedded in a custom widget? Behaviour? Client-feedback? That will
> probably require some thinking. ;)

It has to be client feedback, since anything else can be obtained with the
correct layout widget layered over the top of your canvas.  In fact, I'm
tempted to say canvases can't have widgets inside them, but you can
arrange:

  +-- LayerLayout
      +-- FixedLayout
      |   +-- Widget A
      |   +-- Widget B
      +-- Canvas

Which means you can draw on the canvas, and place widgets anywhere over
it.

Regards,

  Mark.
-- 
|| Mark Thomas
|| efaref.net
||
|| My favorite mythical creature? The honest politician.