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Bug 28385 - Follow current SVG behavior for transforms interaction with object bounding box units
Summary: Follow current SVG behavior for transforms interaction with object bounding b...
Alias: None
Product: CSS
Classification: Unclassified
Component: Transforms (show other bugs)
Version: unspecified
Hardware: All All
: P2 normal
Target Milestone: ---
Assignee: Simon Fraser
QA Contact: public-css-bugzilla
Depends on:
Reported: 2015-03-31 17:40 UTC by Amelia Bellamy-Royds
Modified: 2017-01-13 18:15 UTC (History)
6 users (show)

See Also:


Description Amelia Bellamy-Royds 2015-03-31 17:40:16 UTC
In the CSS transforms module, the section "User Coordinate space" has the following statement:

> In particular the patternUnits, gradientUnits and maskUnits 
> attributes don’t affect the user coordinate system used for
> transformations [SVG11].

- last published working draft
- current editor's draft

Although the draft spec references SVG 1.1, this would be a *breaking change* from current SVG behavior.  The SVG definition used for gradientTransform and patternTransform is as follows:

> This additional transformation matrix is post-multiplied to 
> (i.e., inserted to the right of) any previously defined 
> transformations, including the implicit transformation necessary 
> to convert from object bounding box units to user space.


Unless there is an overwhelming reason to change this, I would recommend that the CSS transforms text be updated to state the transformation applies in the user coordinate system in effect for the element's contents, including any implicit transformations created by patternUnits, gradientUnits, or maskUnits.

( This text is a duplicate of a note sent to the email list: )
Comment 1 Simon Fraser 2017-01-13 18:15:27 UTC