Re: transform as a presentation attribute

The relation between the unit px and local units did not change in SVG.
What was changed in CSS 2.1 is the relation between absolute units
and px. There are different interpretations of the wording, but because
absolute units are already defined by other organisations, 1px is fixed
to 1/96 inch (with 1 inch = 2.54 cm as usual). But in typical viewers px and
absolute units are presented rescaled somehow, therefore with CSS 2.1
absolute units become useless in practice. Presumably SVG 2 will adopt
this from CSS 2.1, this will apply as well. In practice viewers do it already
for documents written in SVG 1.x (and fail therefore typically for absolutely
scaled documents, if the screen does not have exactly a resolution of 96dpi - 
printers may do it better, but one has to take into account, that viewers can 
pass the obfuscation to the printer ;o)

The other thing changed in the CSS transform drafts and in the SVG 2 draft
is, that one can use units at all for transform, not just numbers with the
meaning of local units. 
Therefore effectively, if one uses 100% for width and height for the root
svg element and no units inside the document, the presentation remains
the same.

The joke to suggest to write transform="translate(200px, 200px)" 
instead of transform="translate (200 200)" has mainly the function to blow
up the source code and ensures, that older/current viewers will fail to 
interpret this.


Received on Wednesday, 25 June 2014 07:56:52 UTC