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Bounding box of a group with a transformed child

From: Kari Pihkala <kari.pihkala@gmail.com>
Date: Mon, 26 May 2014 10:57:45 +0300
Message-ID: <CAE0t3MxnxWN2Vb8csxvWknaTbCVAQqY9VjMgGH7KTL5KqTUgrA@mail.gmail.com>
To: www-svg@w3.org
Hi!

I noticed a difference in bounding box calculation (getBBox()) in
Firefox and Safari and I'm not sure which one is correct.

The document has a rotated ellipse element in a group element:
<g id="e2">
    <ellipse id="e1" rx="50" ry="50" transform="translate(100,100) rotate(45)"/>
</g>

The resulting bboxes for e2 are:
Firefox: 50.011 50.011 99.976 99.976
Safari: 29.289 29.289 141.421 141.421

Here's jsfiddle to the doc, so you can see the results.
http://jsfiddle.net/AJYhX/1/

I read the specs about this and they talk about "tightest fitting
rectangle", so I assume Firefox is correct? The algorithm given in
SVG2 spec doesn't mention how transforms affect the union of child
bounding boxes, so I'm not sure about this.

http://www.w3.org/TR/SVG11/types.html#__svg__SVGLocatable__getBBox
http://www.w3.org/TR/SVG2/coords.html#BoundingBoxes

BR,
Kari
Received on Monday, 26 May 2014 07:58:14 UTC

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