ISSUE-2073 (constrained transformations): inverse and constrained transformations [Last Call: SVG 1.2 Tiny ]

ISSUE-2073 (constrained transformations): inverse and constrained transformations [Last Call: SVG 1.2 Tiny ]

http://www.w3.org/Graphics/SVG/WG/track/issues/2073

Raised by: Doug Schepers
On product: Last Call: SVG 1.2 Tiny 

Dr. Olaf Hoffmann
<http://lists.w3.org/Archives/Public/www-svg/2008Sep/0123.html>:
[[
the section 7.7 about constrained transformations mentions
several times the inverse of the CTM. Obviously this does
not always exist (if the determinant is zero).
Is it really intended, that this inverse matrix is used by 
implementations to get the desired effect or is it expected, 
that the effect is gained with other methods (what should be 
always possible even without using the not always existing 
inverse matrix, because the document contains much more 
information about the transformations than only the CTM)?

But if it is really expected, that the inverse matrix
is used, what is the expected behaviour, if it does not exist,
for example for a short time within an animation or due to
some tricky things using the vector-effect non-scaling-stroke.
To mention this would be important especially for authors,
because then they have to compute and avoid such situations.
If another method is used, they do not really have to care.
]]

Received on Sunday, 28 September 2008 02:08:15 UTC