Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752477Ab0LIAGs (ORCPT ); Wed, 8 Dec 2010 19:06:48 -0500 Received: from mail-ww0-f42.google.com ([74.125.82.42]:59141 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963Ab0LIAGr (ORCPT ); Wed, 8 Dec 2010 19:06:47 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=hHHOVJefp+qjRjYMiATBjQio3QANkutZ2Sayzzop8QUOKEWp5F4GBYOKGNIKn+wAUy MivBMBGkX9UN4/Kglw1yLoaRbtb7aPwAYY+nIE7jd4t/j4ew8nW3PvonwbUaJrVKLRfv jRXBv4Eb3eEwrT9aFhDfqWgR90xD4lPua6Tlk= MIME-Version: 1.0 In-Reply-To: <20101208235805.GE15294@core.coreip.homeip.net> References: <1291721340-22652-1-git-send-email-rydberg@euromail.se> <4CFFC3C2.1080905@canonical.com> <20101208235805.GE15294@core.coreip.homeip.net> Date: Wed, 8 Dec 2010 16:06:45 -0800 Message-ID: Subject: Re: [PATCH] input: mt: Add an envelope tool type From: Ping Cheng To: Dmitry Torokhov Cc: Chase Douglas , Henrik Rydberg , Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2431 Lines: 56 On Wed, Dec 8, 2010 at 3:58 PM, Dmitry Torokhov wrote: > On Wed, Dec 08, 2010 at 03:43:51PM -0800, Ping Cheng wrote: >> On Wed, Dec 8, 2010 at 9:43 AM, Chase Douglas >> wrote: >> > On 12/07/2010 03:29 AM, Henrik Rydberg wrote: >> >> Some touch devices are capable of detecting the envelope or hull >> >> of the touches, but not the touches themselves. This patch adds >> >> the MT_TOOL_ENVELOPE touch type to be used for such devices. >> >> >> >> Signed-off-by: Henrik Rydberg >> >> --- >> >> Hi all, >> >> >> >> This patch represents an MT solution for those devices that can detect >> >> and report some effects of dual touch, but cannot report individual >> >> contacts. Synaptics and elantech are two examples. Having the drivers >> >> report the bounding rectangle of the touches is useful in userland, >> >> since the information makes it possible to implement zooming >> >> gestures. At the same time, it would be confusing to send these >> >> envelope points as fingers, since they clearly are not. As a remedy, >> >> introduce MT_TOOL_ENVELOPE, which tells applications that care about >> >> details that these are not real fingers, at the same time as it allows >> >> gesture applications based on MT data to function without >> >> modification. >> > >> > Is it assumed that the envelop has only two touches comprising it? Or is >> > it any number of touches? If it's any number of touches, how does one >> > know how many touches it is? >> >> Those are good questions. Specifying how many touches are in the >> envelop makes sense. It also covers rectangle as a special case of >> envelop. > > I have a feeling that trying to accomodate non-rectangular, No, we are not talking about non-rectangular shape here. Envelop is always a rectangle. By rectangle above, I meant 2 touches. An envelop that includes number of touches offers us more information than a rectangle does. Ping > more than 2 point shapes without using native MT data is over-engineering the > problem... Do we have examples other than older generation Elantechs and > Synaptics that need envelope notion? > > -- > Dmitry > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/