Re: [9fans] Raw Input Driver

[tlaronde@polynum.com]

On Fri, Mar 20, 2009 at 01:03:12PM +0000, roger peppe wrote:
>
> the problem with choosing a higher level of abstraction is that
> the input event generators can't in general be agnostic about
> what the mouse/keyboard/whatever are operating on,
> so you end up with a smart client or split application,
> which lack the same easy composability that you get
> from plan 9's remote devices.

For my own stuff, having to rewrite the 2 dimensions user interface, I
have created a library running on the terminal that keeps the
definitions of the graphical elements drawn with an identifier (3
members) giving to the processing unit (remote) a mean to unambiguously
identifies the antecedent for processing.

This has a lot of advantages. The UI is just a _representation_ of the
data (and in fact of the commands by means of labels/buttons).

All the user wandering on the UI, including selecting things, is done on
the terminal.

Since identifying an element (vectorial elements for KerGIS vectorial
stuff; or cell for a grid etc.) is indeed identifying the representation
of the element, there is no acrobatics trying to convert the
transformation leading to the window, the 1, 2 or 3 pixels between the
hot spot of the pointer and the element (in a GIS, converting the
distance between pixels to a ground distance and searching the element
in ground coordinates), but instead, using the representation for what
it is, so searching the representation near 1, 2 or whatever pixel
tolerance the representation is near (indeed reducing the search to what
is displayed, including ability to mask), and then only sending back the
identifier for the real element to processing.

This fundamental split between the representation, i.e. the UI, and the
processing is the fundamental flaw of the X11 approach which has put the
articulation (the network) on the wrong place: in X11, all the UI
handling, except dispatching window events, is done on the processing
unit (the client in X11 terminology).
--
Thierry Laronde (Alceste) <tlaronde +AT+ polynum +dot+ com>
                 http://www.kergis.com/
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