Re: gEDA-dev: Hiding location of grips from gschem

[Bert Timmerman <bert.timmerman@xxxxxxxxx>]

Hi all,

On Mon, 2008-07-14 at 13:40 +0200, Bernd Jendrissek wrote:
> On Mon, Jul 14, 2008 at 12:30 PM, Peter Clifton <pcjc2@xxxxxxxxx> wrote:
> > On Mon, 2008-07-14 at 11:47 +0200, Bernd Jendrissek wrote:
> >
> >> > The grip:
> >> > - knows how to draw itself
> >> ***
> >> > - calculates its own location from the object's geometry data
> >> ***
> >> > - updates its location when object geometry changes.
> >> > - updates object geometry when manipulated by view/controller
> >>

<deleted stuff used to be here>

> > Ok, so you're proposing putting part of the controller code in libgeda..
> > (teaching which points are special, and presumably providing code to
> > manipulate an object by dragging those points). No harm there, I'm just
> > not sure where it should live.
> 
> Note that libgeda would be free to expose far more "special" points
> than gschem really cared about.  One example is an arc's center -
> currently dragging the grip there changes the radius a bit abruptly,
> but it could equally well *move* the center.  libgeda could expose
> both GRIP_ARC_CENTER and GRIP_ARC_RADIUS, both at the same point, and
> leave it up to gschem to remember only one of them.
> 

FWIW, in my mechanical CAD universe I am used to the following
behaviour:

1) the complete arc (or circle) moves when the center grip
(GRIP_ARC_CENTER) is moved/dragged,

2) the radius is being modified (smaller/larger) when the radius grip
(GRIP_ARC_RADIUS) is moved/dragged.

There are probably some defacto conventions for the behaviour of grips
in CAD applications and related GUIs.

Just my EUR 0.02.

Kind regards,

Bert Timmerman.

<more deleted stuff used to be here>



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