Re: GtkCanvas requirements?

[Federico Mena Quintero <federico ximian com>]

El dom, 22-04-2007 a las 22:26 +0100, Damon Chaplin escribi�> So basically it is all kinds of data visualization and manipulation, and
> the occasional animation. Plus some WYSIWYG stuff to be printed.

For the record, I fully trust Damon to do the right thing for the
programmatic side of the canvas.  Many moons ago he had the thankless
job of implementing Evolution's calendar views on top of GnomeCanvas, so
he's quite familiar with the problems which someone using the canvas may
encounter.

Now for the other use-case... in GNOME we don't have much experience
with loading SVG-like things and then manipulating them (think Flash).
Maybe we can find someone with Flash experience to comment on what API
would be helpful to them?

> I spent quite a while reading through the Piccolo docs before writing
> GooCanvas, but I'm afraid I didn't like it that much. The API is
> horribly complicated:

Heh.  But remember that it was developed by academia, after all ;)

Things that I liked from Piccolo:

- The animation scheduler.  You can say "when this bit of the animation
is done, start this other one".

- Being able to animate based on object properties.  "Modify the 'size'
property from 2.5 to 7.0, while you change the 'position' property from
<a> to <b>, all during 300 milliseconds".

- Having a concept of "scale" for zoomable UIs.

- They actually implemented nontrivial zoomable UIs that work (a
calendar, an image catalog, some PDA stuff).  It would be instructive to
see how these programs use the underlying APIs.

  Federico