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Bug 20220 - hwTimestamp should be interoperable with the high resolution time spec

From: Jacob Rossi <Jacob.Rossi@microsoft.com>
Date: Tue, 18 Dec 2012 06:14:44 +0000
To: "public-pointer-events@w3.org" <public-pointer-events@w3.org>, "Rick Byers (rbyers@google.com)" <rbyers@google.com>
CC: "flackr@google.com" <flackr@google.com>, Jatinder Mann <jmann@microsoft.com>, Travis Leithead <travis.leithead@microsoft.com>
Message-ID: <ecf69e712e3e4005a91223cf710cd767@BN1PR03MB021.namprd03.prod.outlook.com>
Hey Rick,

Looking at this issue [1], I agree that DOMHighResTimeStamp is probably the right units for this.

The important nuance to hwTimestamp is that it represents the time at which the *hardware* reported the event, not the time the event is dispatched. I believe timeStamp is the latter (Olli may correct me). Hardware times, as opposed to message times, let you calculate the time between two interactions (e.g. down, up) as opposed to the time between handling the events for the interactions. It's a subtle difference, but on slower devices or sites with long running scripts it can make a difference.

I'm not sure if Rob meant hardware time or event handling time in his statement below:
"the monotonic system time responsible for the creation of the DOM event" [2]

Since not all DOM events result from hardware, I'm not sure how we would define this globally (e.g. "systemTime" on Event).

-Jacob

[1] https://www.w3.org/Bugs/Public/show_bug.cgi?id=20220
[2] http://lists.w3.org/Archives/Public/public-web-perf/2012Oct/0046.html
[3] http://html5labs.interoperabilitybridges.com/dom4events/
Received on Tuesday, 18 December 2012 06:16:06 UTC

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