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Re: Drawing Tablets

From: Florian Bösch <pyalot@gmail.com>
Date: Fri, 3 Aug 2012 19:09:17 +0200
Message-ID: <CAOK8ODh7qepsSKtA34hkEAf-f6E617ztWtYPs4hQ082Q3oVLHg@mail.gmail.com>
To: Charles Pritchard <chuck@jumis.com>
Cc: "public-webapps@w3.org" <public-webapps@w3.org>
On Fri, Aug 3, 2012 at 6:54 PM, Charles Pritchard <chuck@jumis.com> wrote:

>  As I understand it, the browsers have mature event queues; and
> everything comes with a timestamp.
> We've got requestAnimationFrame as our primary loop for processing the
> queue.
>
> To clear a queue (so to speak), I believe one simple removes any
> associated handlers.
>
Yeah but that's not how it should work.
- Assuming requestAnimationFrame might be wrong in case that other events
are used to refresh either logic or simulation (such as when redraws only
happen upon input)
- Dispatching events individually makes it difficult to work out correlated
events, and since the device landscape changes constantly, it'd be easier
to adopt new devices for developers if they could do their own correllation
according to their needs. For that they need the buffer of queued events to
work trough them.
- Depending on the use there's a differing "granularities" that a developer
might want to implement. This is usually done by filtering the queue
according to the applications needs, if receiving events individually,
that'd just lead to the developer re-implementing the queue so he can
filter it at the appropriate time.

Are there any times when mouse emulation is not executed with a pen?
> As much as I've used my pen, it always "moves the mouse".
> Capture to area is something that's being handled for pointer events. I
> recently read that support for mouse capture is being contributed to
> webkit; it's at least, being actively authored.
> The capture model is based on the full screen request model.
>
The mouse emulation mode is appropriate when: 1) the tablet is used to
interact with a larger area containing interface elements AND 2) it is used
singularly AND 3) the screen dimensions match the tablet dimensions.

It is not appropriate when 1) the tablet is used to interact with a limited
area (such as a drawing surface) exclusively OR 2) the tablet is
used ambidexterity in conjunction with other pointing devices and/or
multiple pens OR 3) the screen dimensions do not match the tablet dimensions

Regarding #1, this situation arises naturally when drawing is engaged with
the limited area, but the area on screen is considerably smaller than the
screen, which would result in the artist having to rely on a tiny area on
his large tablet to engage in drawing, while most of the tablets surface
area lies bare unused. GIMP implements capturing modes to drawing area,
although the implementation is lacking and it cannot be switched
seamlessly. Photoshop implements capture to area which can be switched
seamlessly between mouse control and drawing utensil on surface control.

The analogy to pointer lock is fitting, however the conflation of
fullscreen+pointerlock is not appropriate and it is lacking the affine
transform aspect of a capture to area mode.
Received on Friday, 3 August 2012 17:09:45 GMT

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