- From: Jon Ferraiolo <jon.ferraiolo@adobe.com>
- Date: Tue, 11 Jan 2005 00:15:13 -0800
- To: Jonathan Watt <jonathan.watt@strath.ac.uk>, www-svg@w3.org
- Message-id: <6.1.1.1.2.20050111000843.051fba88@mailsj-v1.corp.adobe.com>
Jonathan, The key thing is that there are often two "current user coordinate systems" for a given element - the one before you process 'transform' or 'viewBox' and the one after you process the transformations associated with these attributes. Section 7.4 of the SVG 1.1 spec (http://www.w3.org/TR/SVG11/coords.html#EstablishingANewUserSpace) includes the following snippet in the first paragraph: ---------------------- The <file://coords.html#TransformAttribute>transform and <file://coords.html#ViewBoxAttribute>viewBox attributes transform user space coordinates and lengths on sibling attributes on the given element (see <file://coords.html#TransformAttributeEffectOnSiblingAttributes>effect of the transform attribute on sibling attributes and <file://coords.html#ViewBoxAttributeEffectOnSiblingAttributes>effect of the viewBox attribute on sibling attributes) and all of its descendants. ---------------------- and further on in the same section (if you follow the link to "effect of the transform attribute on sibling attributes): ---------------------- The transform attribute is applied to an element before processing any other coordinate or length values supplied for that element. In the element <rect x="10" y="10" width="20" height="20" transform="scale(2)"/> the x, y, width and height values are processed after the current coordinate system has been scaled uniformly by a factor of 2 by the transform attribute ---------------------- However, I agree that it makes sense to add some additional clarifications to the SVG spec. Jon At 09:19 AM 1/10/2005, Jonathan Watt wrote: >SVG WG, > >What is the "current user coordinate system" for an element defined as >(with emphesis on *current*, *user* and *element*)? Is it correct to say >that it's the coordinate system refered to by the element's "coordinate" >attributes (such as 'x' and 'y')? > >I'm specifically interested to know what the *current* user coordinate >system is for an 'svg' element. Is it the user coordinate system that the >element exists in (the one established by the 'svg' element's parent, and >to which it's "coordinate" attributes refer to)? Or is it the user space >it itself establishes via it's viewBox attribute? > >I don't believe this can be clearly answered from the contents of the specs. > >-Jonathan
Received on Tuesday, 11 January 2005 12:41:16 UTC