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


A few observers have helped this working group and others identify these anomalies and interoperability issues.  Since we last shipped a preview of Internet Explorer we have done a bit of refactoring to align to the letter of the spec. What we owe back (and I am working on this now) is our findings and supporting tests.  

These emails and other have not gone unnoticed and have contributed greatly to our understanding of what web developers face and how to fix it. 

So thanks :)

Patrick Dengler
Senior Program Manager
Internet Explorer

-----Original Message-----
From: [] On Behalf Of R. Masters
Sent: Thursday, January 27, 2011 10:56 AM
To: Helder Magalh„es
Cc: Simon Pieters; Simon Fraser;; Philip Jšgenstedt; Leif Arne Storset; L. David Baron; Erik Dahlstrom;
Subject: Re: [css3-images] Reconsider 'auto' value for object-fit

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 opinion.

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 <> 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
>> 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
> [1]
> [2]

Received on Friday, 28 January 2011 16:36:14 UTC