W3C home > Mailing lists > Public > www-svg@w3.org > January 2011

Re: [css3-images] Reconsider 'auto' value for object-fit

From: R. Masters <grick23@gmail.com>
Date: Thu, 27 Jan 2011 10:55:30 -0800
Message-ID: <AANLkTinRo=YrsyiQcdeC4oDVcGtHywQ1J5H4r5rGAX20@mail.gmail.com>
To: Helder Magalh„es <helder.magalhaes@gmail.com>
Cc: Simon Pieters <simonp@opera.com>, Simon Fraser <smfr@me.com>, "www-style@w3.org" <www-style@w3.org>, Philip Jšgenstedt <philipj@opera.com>, Leif Arne Storset <lstorset@opera.com>, "L. David Baron" <dbaron@dbaron.org>, Erik Dahlstrom <ed@opera.com>, www-svg@w3.org
Hi, this is my first post on this list so I'll start by saying: Hi my
name is Rick Masters and I am the co-leader of the SVG Web project,
which brings SVG to IE 6- 8 using flash.

Pardon me if this message is out of place, but it appears that this
thread is bringing up the same issue or a very similar issue to one
that I have been working on.

As part of the SVG Web project, I needed to code a SVG sizing strategy
for IE since it obviously did not have one. This led to a lot of
research to determine how exactly SVG sizing behavior works across
browsers and what behavior should be coded for IE. Turns out there
were significant inconsistencies and I had to pick a browser behavior
that seemed "most correct", based mostly on my own opinion. I
mentioned the inconsistencies to folks at SVG Open 2009 but there
seemed to be little awareness of a problem.

Fast forward over a year, and not much has changed except that I was
recently able to find time to revisit the issue. I have spent time
creating reproducable test cases and a test harness that can
illustrate the problem easily for folks who want to see it first hand.
I also wrote up my observations and conclusions (with a link to my
online test harness) here:


The goal is figure out, for the divergences that I illustrated with
screen shots, which browser is behaving correctly? Are the browsers
that are not behaving correctly aware of the divergence? Have they
made an explicit decision to behave that way? I express my preferred
behavior in my write up, and unfortunately, I am worried that some of
the "correct" behaviors are the ones that are actually undesirable
(like scroll bars on objects), which perhaps is a justification for
intentional divergence. I can only speculate because I haven't been
part of the conversations.

This the most serious SVG standardization issue that I ran into during
my recent 2 years of serious SVG research and implementation work. I
would hope and respectfully request that it be a very high priority of
the Working Group to resolve this  basic deployment issue. Frankly, I
cannot imagine what could be more important, but that's just my

I should also say that I really appreciate the efforts of the SVG WG. Thank you!

Rick Masters
SVG Web Project

On Thu, Jan 27, 2011 at 2:28 AM, Helder Magalh„es
<helder.magalhaes@gmail.com> wrote:
> Hi everyone,
>> Bitmaps in <img> and <object> traditionally behave as 'fill', while SVG does
>> not (even without preserveAspectRatio). "respect preserveAspectRatio" below
>> is supposed to mean "repsect the preserveAspectRatio rules in the SVG spec
>> even if that attribute is absent". Note that 'meet' is the default value for
>> preserveAspectRatio, which is like object-fit:contain. If no viewBox is
>> provided or can be synthesized, for <object> and <svg> the traditional
>> behavior is like object-fit:none; object-position:top left.
>> See http://software.hixie.ch/utilities/js/live-dom-viewer/saved/807
>> Looking now, it seems that we still don't have interop in this area. IIRC,
>> Opera is compliant with the SVG spec. Chrome seems to always use 'fill' for
>> img and always cause an iframe-like effect for SVG in object.
> Could this be related with recent improvements? WebKit did nicely fix
> the annoying SVG bug 48462 [1] through it's underlying bug 10687 [2]
> in the latest few months. Anyway, I couldn't "force" it to work by no
> combination of "object, svg { overflow:hidden }".
>> Firefox is
>> more like Opera but disagrees with the no-viewBox case.
> I get a consistent result (in the remaining "SVG without viewBox in
> object" case, that is) between Firefox 4 nightly and Opera by adding
> "overflow:hidden;" to the img/object stylesheet in Firefox...
> In sum: could the overflow behavior be underspecified for these
> embedding cases? (SVG in image, SVG in object, inline SVG in HTML,
> etc.) I recall recent discussion on www-svg regarding at least the
> inline use-case.
> Cheers,
> †Helder
> --
> Helder M. A. Magalh„es
> http://heldermagalhaes.com/
> [1] https://bugs.webkit.org/show_bug.cgi?id=48462
> [2] https://bugs.webkit.org/show_bug.cgi?id=10687
Received on Thursday, 27 January 2011 21:51:06 UTC

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