Re: Coordinate system stuff

Cameron McCormack:
> Second, the definition of “current transformation matrix” in the intro
> chapter says:
>   The current transformation matrix defines the mapping from the user
>   coordinate system into the viewport coordinate system.
>    —
> But in the Coordinates chapter, section 7.7.4 defines the CTM as
> including the user transform:
>   This [the CTM] is the product of all coordinate system transformations
>   that apply to an element, effectively mapping the element into a
>   coordinate system that is then transformed into device units by the
>   SVG user agent. 
>   …
>   With the above definitions for U, VB, and TS, the CTM for the
>   rectangle with xml:id="elt" is:
>     CTM(elt) = U.VB(root).TS(elt)
>              = U.VB(root). Txf(g-n).[...].Txf(g-0).Txf(elt)
>    —
> Should the CTM inclue the user transform or not?

After looking at this, I think it should, since the viewport coordinate
system is affected by the user transform (currentTranslate, etc.).  So
I’m closing ACTION-2168 with no changes to the spec.



Cameron McCormack ≝

Received on Thursday, 4 September 2008 04:51:57 UTC