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Interest in standard HTTP headers for specifying client display attributes?

From: Mark D. Wood <mdw@itc.kodak.com>
Date: Wed, 17 Sep 1997 15:27:53 -0400
Message-Id: <3.0.3.32.19970917152753.00b15d10@mailroom.itc.kodak.com>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Cc: mdw@itc.kodak.com

Microsoft currently provides in their various versions of Internet Explorer
the headers UA_COLOR and UA_PIXELS that give an indication of the color
depth supported by the client device and its screen resolution.  Microsoft
provides these headers in Internet Explorer 3 and 4, and also in the Pocket
Internet Explorer.  These headers are not standard; I would like to see
headers providing this type of information become standard.

These headers are useful for image rendering.  For example, certain image
formats, such as FlashPix and PhotoCD, contain multiple resolutions.  By
using the UA_PIXELS header, a web server can determine which resolution is
most appropriate to return to a device.  A thin client on a PDA might get a
64x64 resolution while a desktop might get a 512x512 image.

These headers certainly aren't perfect---a better header would tell me the
window size, which might be equivalent to the screen resolution on a PDA,
but most likely won't be on a desktop machine. So should a standard be
adopted, I would recommend including a UA_WINDOW_SIZE that did specify the
window dimensions.

Admittedly, this problem can be solved in more sophisticated ways but then
the solution is not likely to run on as many platforms.  For example, the
latest version of Javascript does provide access to window and screen size.
 But for Java-based applets, the Java security model limits the ability of
a applet to glean this type of information---unless someone knows a
workaround/extension here.  Adding a standard HTTP header will allow all
clients from thick to thin to readily make this information available to
servers.

Obviously, there are a wide range of client aspects that one might want to
know about, and it probably doesn't make sense to add HTTP headers for all
of them.  However, since images are pretty basic, adopting a standard here
would be useful.

Comments?  Discussion?

-Mark Wood
Received on Wednesday, 17 September 1997 12:34:04 EDT

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