RE: IE11 reporting incorrect scale for touch width/height

There is some variance from device to device as digitizer manufacturers haven’t standardized on the sensitivity level for this metric.  Touch geometry is also not currently a part of the Windows Hardware Certification Kit [1]. But I wouldn’t expect values that small.

I’m looking into whether we do have a scaling problem in IE.  Digitizer resolutions don’t necessarily match the screen resolutions. So it’s possible there’s an issue there. There’s also DPI scaling to account for as well.  Also keep in mind that there is no such thing as a physical unit in CSS and browsers optimize scaling  for consistent apparent visual size, not consistent physical size. I was under the impression we validated all this for width/height when we updated IE11, but I’ll double check.

I wouldn’t be too concerned about sites compensating for IE. Geometry hasn’t been used much in the wild yet and there are Windows devices that do report appropriately sized widths and heights. I don’t believe there’s a consistent offset or anything that a site might compensate for.

I’ll report back with what I find.

-Jacob

[1] http://msdn.microsoft.com/en-us/library/windows/hardware/jj124227.aspx


From: Rick Byers [mailto:rbyers@google.com]
Sent: Friday, January 17, 2014 1:11 PM
To: Jacob Rossi; Asir Vedamuthu Selvasingh (MS OPEN TECH)
Cc: public-pointer-events@w3.org
Subject: IE11 reporting incorrect scale for touch width/height

Hi,
On IE11 on my SurfaceRT, the reported width and height values seem way too small to be correct in terms of CSS pixels (as specified by the standard and MSDN document).  Eg. with  http://www.rbyers.net/eventTest.html I typically see values of width/height=1, but with a really fat finger I can get values up to 5.

Is this just a bug in IE or the Surface?  Are any other devices known to properly support touch dimensions with pointer events?  Any known web sites that use this information?

I ask because I'm a little nervous to have Polymer+Chrome accurately report width/height values if there are sites already compensating for the scale in IE not matching the documentation.

Thanks,
   Rick