On Jan 8, 2011, at 9:23 PM, crjw wrote:
SVG syntax allows lengths to be specified with one of the following units: px, em, ex, pt, pc, cm, mm, and in. The SVG spec defines 1in=90px. Thus one thousandth of an inch can be spcified as 0.09, .09px, 0.001in, or 0.0254000mm. You may find when you specify units other than pixels that Inkscape will silently convert to pixels; this is a good thing because not all programs honor the 1in=90px standard. Firefox will assume 1in=96px.
Not quite.
The SVG spec defines the size of a px to be user agent dependent, but with a *default* of 90 DPI. Or 96 DPI. It depends on when the spec was referenced.
In any case, this value is only a suggested default for when the viewing software does not have any other information to go by.