W3C home > Mailing lists > Public > www-svg@w3.org > February 2013

Re: Clarification on object bounding box specification

From: Dirk Schulze <dschulze@adobe.com>
Date: Wed, 13 Feb 2013 15:20:42 -0800
To: Philip Rogers <pdr@google.com>
CC: "www-svg@w3.org" <www-svg@w3.org>
Message-ID: <373DB15E-2F9B-4EC3-B91E-2591E922551C@adobe.com>

On Feb 13, 2013, at 1:28 PM, Philip Rogers <pdr@google.com> wrote:

> www-svg,
> 
> The following wording is currently in the spec:
> "Keyword objectBoundingBox should not be used when the geometry of the applicable element has no width or no height, such as the case of a horizontal or vertical line, even when the line has actual thickness when viewed due to having a non-zero stroke width since stroke width is ignored for bounding box calculations. When the geometry of the applicable element has no width or height and objectBoundingBox is specified, then the given effect (e.g., a gradient or a filter) will be ignored."
> 
> For patterns/gradients, this is not intuitive. A horizontal line has an empty bounding box and will not be stroked with a pattern. A slightly rotated line will be stroked with a pattern.

I think you do not mean rotation, since a transform does not affect the OBB.

> 
> Opera, IE10*, and Chrome* all follow the spec's wording.
> Firefox does not, and renders the stroked, horizontal patterned line.
> 
> I think Firefox's implementation is the most intuitive for end users and I would like to propose we align on their interpretation of the spec.
> 
> Testcase: http://philbit.com/emptyPattern.svg
> Chrome bug: https://code.google.com/p/chromium/issues/detail?id=175779

I do not see a difference across browsers. All browser display a green blue patterned stroke. I think this wording was added because of problems with gradients and calculating the gradient user space. I might be wrong about that.

Greetings,
Dirk

> 
> Philip
> 
> 
> * Both IE10 and WebKit have a similar bug where the pattern shows up after a relayout.
Received on Wednesday, 13 February 2013 23:21:38 GMT

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