[Webkit-unassigned] [Bug 103725] getBBox() return wrong bounding box in <use> tag

Mon Dec 3 16:40:29 PST 2012

https://bugs.webkit.org/show_bug.cgi?id=103725

--- Comment #4 from Philip Rogers <pdr at google.com>  2012-12-03 16:42:54 PST ---
(In reply to comment #3)
> (In reply to comment #2)
> > Shouldn't it print 
> > {height: 100, width: 100, y: 50, x: 50}
> > instead?
> > 
> > Since we are getting the bbox on <use>.
> > It can also link to an external file, which from a usage point of view, is a encapsulated container?
> > I also notice that <use> width and height attribute does not force a resize on the child content.
> > Am I using <use> wrongly?
> 
> Re-opening because there seems to be some confusion about this.
> 
> For the record, here's how the major browsers are currently working:
> Chrome Canary - {height: 100, width: 100, y: 100, x: 100}
> Firefox Nightly - {height: 100, width: 100, y: 100, x: 100}
> IE10 - {height: 100, width: 100, y: 100, x: 100}
> Opera next: {height: 100, width: 100, y: 150, x: 150}
> 
> It looks like Cr/FF/IE are returning the bbox of the referenced element whereas Opera is returning the bbox of the the rendered content. I think Opera might be the most intuitive. I do not think {height: 100, width: 100, y: 50, x: 50} makes sense.
> 
> In particular, we (Chrome, IE) seem inconsistent in the multiple-use case:
> <html>
> <body>
> <svg width="500" height="500">
>   <rect id="rect" x="0" y="0" width="100" height="100" opacity="0.5" fill="green"/>
>   <use id="use" xlink:href="#rect" x="50" y="50" />
>   <use id="use2" xlink:href="#use" x="200" y="200" />
> </svg>
> <script>
>   console.log(document.getElementById('rect').getBBox());
>   console.log(document.getElementById('use').getBBox());
>   console.log(document.getElementById('use2').getBBox());
> </script>
> </body>
> </html>
> 
> @Dirk, should we be adding the x,y offset from the <use> attributes in returning the bbox?
> Relevant spec: http://www.w3.org/TR/SVG/single-page.html#types-__svg__SVGLocatable__getBBox

Dirk on irc/#ksvg set me straight. This comes down to transforms on the current element not contributing to the bbox. When the <use> tree is built, we effectively replace <use> with <g> with all attributes except x,y,width,height. Therefore, these results make sense after all and Cr/FF/IE are consistent.

I'll file a bug against Opera.

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