Re: ES SVG lib? (was Re: Eights SVG)

On Dec 30, 2004, at 8:26 PM, Mike Sugarbaker wrote:

> Is it time to start thinking about a standard set of scripts to
> provide to Volity UI writers? I'm thinking of basic things like
> generating combo boxes, draggable things and drag targets, simple
> sprites (on the level of "here are the shapes in your walk animation,
> flip through them when i tell you 'walk' and stop when i tell you
> 'stop'"), grids (automagically spec out either a chessboard-like thing
> or an RPG inventory-like thing, or a grid layout for something else
> entirely)...

My focus on finishing the core protocol, and cheering on the Javolin 
hackers as they push its first releases out the door, has prevented me 
from spending a lot of time thinking about how UIs are actually made, 
even though they're actually at least as important to actual gameplay 
as all the other stuff. (I made an exception to finish the Eights SVG 
so that Javolin would have multiple working examples, at least one of 
which was less lame than rock-paper-scissors.)

I have assumed (or, rather, dreamed) from the start that "someday" 
there would exist a whole application suite just for creating UI files 
and shared UI-component libraries. The first steps towards this ideal 
are little reusable patterns just of the sort you describe above.

> A casual cruise through google world has surprisingly not revealed any
> ECMAScript libraries for simple UI widgets, although it seems like
> such an obvious project that I could be wrong. Plenty for generating
> SVG from Java and such, but nothing in pure ES. Such a library seems
> both useful for Volity and likely to catch on with other projects as
> well.

I agree. I believe that one reason few examples exist is that SVG has 
yet to find its killer app, and it's mainly been used so far in very 
specialized projects. One of the "problems" with our approach is that 
we are, in fact, blazing trails -- very few projects are trying to make 
SVG act so general and flexible as Volity demands, though I believe 
this flexibility is inherent to SVG.

> I don't have a completely firm grasp on SVG yet, but I do know the
> DOM, and I feel up to this if I can get time. Are there any
> Volity-specific needs that I'm overlooking?

I would *love* to see some work towards this end, especially as a 
parallel effort with the Frivolity and Javolin sub-projects. Let's talk 
about it, if you want to try making a project out of this; I can 
provide help with SVG and the like, as well as coordination with the 
rest of the Volity project. Would anyone else be interested in helping 
with this?

Knowing the DOM is half the battle at least, and I can say from 
experience that Batik/Rhino, the SVG/ES library combination that 
Javolin uses, seems to support it quite thoroughly; I don't think that, 
in programming the Eights UI, anything I tried DOM-wise failed to work 
exactly as I expected it to. You may notice that much of the display 
work in that file involves just creating, destroying, and moving around 
many SVG <use> elements that point to various <symbol> elements which 
the file hard-codes.

Ah, here is Batik's full confession of DOM support: 
http://xml.apache.org/batik/SVGDOMstatus.html

An aside (and a caveat): one thing that Batik _doesn't_ support -- at 
least until until 2.0, which we're not gonna wait for -- is SMIL-based 
animation. Andy and I knew this from the start and decided long ago 
that we could live without SMIL at first, especially since basic 
animation can be achieved through clever ECMAScripting, via 
setInterval() and related methods listed here: 
http://xml.apache.org/batik/scriptingFeatures.html I'm also not sure 
what Batik's sound support is like. I would like a little sound 
support, and unlike animation, this is something we could probably work 
around with clever client programming... but this is a discussion for 
later.

--
   Jason McIntosh             jmac <at> jmac.org
Somerville, MA, USA       http://www.jmac.org

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