transformations in SVG

Yesterday we were talking about where transform would appear:
-- DOM
-- XCF
-- ApsAttr in metafile

Secondary but obviously related question was whether it would be:
-- Style Property
-- ApsAttr

Benoit suggested that we needed to start nailing down the technical 
mathematical details before we could ask and answer questions like, "What 
is the effect of successive bind-by-id elements carrying 'transform'?"

I volunteered to supply a link to the SVG chapter that deals with a lot of 
this stuff, as a resource and reference for our own use.  Here is the 
chapter [1]:

[1] http://www.w3.org/TR/SVG11/coords.html

It's worth a read.

Caveat:  IMO, there is lots in here that is irrelevant to WebCGM, and I'm 
not sure that I like the model of presenting and explaining 
transformation.  But there is also useful stuff, like the matrix 
equivalents of the primitive transform operations (translate, rotate, 
scale, see 7.5), use and manipulation of the normalized form (3x3 matrices 
instead of 2x3), etc.

Observation:  What we do for transform, if 2.1 is going to become a W3C 
REC, will need to be compatible with SVG in our usual sense:  we can map 
WebCGM into SVG (at least).  For example, in the object tree, nested 
objects which each carry an individual transform better combine into a 
composite transform in the same way as nested <g> in SVG.  Right?

More later,
-Lofton.

Received on Thursday, 17 January 2008 22:09:48 UTC