Re: [Gnash-dev] Coordinate system discussion cont'd

[Bastiaan Jacques]

On Tue, 6 May 2008, Udo Giacomozzi wrote:

> Since pictures say more than 1000 words I made a little
> illustration - and guess what in which format ;)

Nice picture!

> The central CS (coordinate system) is the one in which the graphics
> are defined, which is in TWIPS. Starting from this CS there are a few
> global matrices* that translate to the other CS. The translation
> between local and global coordinates is a different discussion and
> has been solved with world_matrix anyway.

Actually, I think we should take the opportunity to resolve some
ambiguity with regards to the word "world". In the renderer, I believe
it's used to convert various coordinate systems (e.g. SWF def.) to renderer
coordinates and vice versa. So (I think) world here means coordinates in
TWIPS, with renderer matrix applied. However, in libgeometry, I believe
world means something different namely, in a Range2d world means "contains
all possible points". In the character class, there are the
get_world_{matrix,cxform} methods and I don't know what world means in
that context.

So I'd definitely like to either clearly document the differences, or,
even better, use world to describe only a single thing.

Bastiaan