distinguishing double click and single click and drag

I'd like to have an input model which does one action on a double click,
and a different action after a single-click -> drag -> release. I need to record
the starting point of the drag, which I think would be a :press, but whatever
I specify to happen on the :press gets invoked when I try to double click.
I hope it doesn't make a difference, but I'm on LWM 4.4.6. How does one
distinguish between a single and double click? I know about :press and
:second-press, but with
(:button-1 :press) foo
(:button-1 :second-press) bar
If I double click (or try to) foo gets called. Thoughts?
-- 
=====================
Joshua Taylor
tayloj@rpi.edu

"A lot of good things went down one time,
     back in the goodle days."
               John Hartford

Re: distinguishing double click and single click and drag

On Fri, 29 Dec 2006 11:41:44 -0500, "Taylor, Joshua" <tayloj@rpi.edu> wrote:

> I'd like to have an input model which does one action on a double
> click, and a different action after a single-click -> drag ->
> release. I need to record the starting point of the drag, which I
> think would be a :press, but whatever I specify to happen on the
> :press gets invoked when I try to double click.  I hope it doesn't
> make a difference, but I'm on LWM 4.4.6. How does one distinguish
> between a single and double click? I know about :press and
> :second-press, but with
> (:button-1 :press) foo
> (:button-1 :second-press) bar
> If I double click (or try to) foo gets called. Thoughts?

Try to play with

  (:button-1 :press)        foo
  (:button-1 :second-press) bar
  (:button-1 :release)      baz

Put the actual "action" into BAZ and in FOO and BAR only "record"
whether the button has been pressed once or twice before it was
released.  That worked for me with LWW 4.4.6.

HTH,
Edi.

Re: distinguishing double click and single click and drag

On Friday 29 December 2006 11:41 am, Taylor, Joshua wrote:
> I'd like to have an input model which does one action on a double click,
> and a different action after a single-click -> drag -> release. I need to
> record the starting point of the drag, which I think would be a :press, but
> whatever I specify to happen on the :press gets invoked when I try to
> double click. I hope it doesn't make a difference, but I'm on LWM 4.4.6.
> How does one distinguish between a single and double click? I know about
> :press and
>
> :second-press, but with
>
> (:button-1 :press) foo
> (:button-1 :second-press) bar
> If I double click (or try to) foo gets called. Thoughts?

My recollection might be rusty, but I think that :second-press comes 
after :press.  So, when a double-click happens, you see :press 
then :second-press then :release.  When a click-drag happens, you see :press 
followed by one or more :motions followed by :release.

The best way to think about this problem is to use a state machine, which I 
will sketch using an impromptu textual language:

state-machine MOUSE-TRACKER:

  state IDLE:
    on :press execute 'save-mouse-coordinates and goto-state PRESSED
    otherwise ignore
  end state

  state PRESSED:
    on :release execute 'clicked and goto-state IDLE
    on :second-press execute 'double-click and goto-state IDLE
    on :motion execute 'relative-motion and goto-state DRAGGING
    otherwise ignore
  end state

  state DRAGGING:
    on :release execute 'finalize-drag and goto-state IDLE
    on :motion execute 'relative-motion and goto-state DRAGGING
    otherwise ignore
  end state

end state-machine

A much better way to do this is to draw the state machine on paper - use one 
circle / oval for each state, and transitions (goto-state) are drawn as 
arrows from one state bubble to another.  You won't regret going to the 
trouble of drawing out the state diagram when you try to incorporate all of 
the other mouse actions and buttons into your mouse-handling code.

pt

Re: distinguishing double click and single click and drag

Ah yes, I do seem to recall this sort of approach some time ago.
I haven't had a chance to play with it yet, but I think this will do
the trick; thank you!

My next question may be (and I'll ask it explicitly if it comes up)
is whether there's a nice way to encode these in terms of the
capi:define-command? It seems that the commands provide a
nice abstraction for some of things, e.g., if I decide to use
ctrl-shift-x-button-1-second-press instead of something else
to make a selection later, I can just change the capi:define-command
and leave :make-selection in the input model. It seems awkward
if conceptually distinct gestures, e.g., double-click, single-click,
etc., could be thrown into the mix, but maybe that's not feasible.
We'll see if I get there. ^_^

Thanks!

On 12/29/06, Paul Tarvydas <tarvydas@visualframeworksinc.com> wrote:
> On Friday 29 December 2006 11:41 am, Taylor, Joshua wrote:
> > I'd like to have an input model which does one action on a double click,
> > and a different action after a single-click -> drag -> release. I need to
> > record the starting point of the drag, which I think would be a :press, but
> > whatever I specify to happen on the :press gets invoked when I try to
> > double click. I hope it doesn't make a difference, but I'm on LWM 4.4.6.
> > How does one distinguish between a single and double click? I know about
> > :press and
> >
> > :second-press, but with
> >
> > (:button-1 :press) foo
> > (:button-1 :second-press) bar
> > If I double click (or try to) foo gets called. Thoughts?
>
> My recollection might be rusty, but I think that :second-press comes
> after :press.  So, when a double-click happens, you see :press
> then :second-press then :release.  When a click-drag happens, you see :press
> followed by one or more :motions followed by :release.
>
> The best way to think about this problem is to use a state machine, which I
> will sketch using an impromptu textual language:
>
> state-machine MOUSE-TRACKER:
>
>   state IDLE:
>     on :press execute 'save-mouse-coordinates and goto-state PRESSED
>     otherwise ignore
>   end state
>
>   state PRESSED:
>     on :release execute 'clicked and goto-state IDLE
>     on :second-press execute 'double-click and goto-state IDLE
>     on :motion execute 'relative-motion and goto-state DRAGGING
>     otherwise ignore
>   end state
>
>   state DRAGGING:
>     on :release execute 'finalize-drag and goto-state IDLE
>     on :motion execute 'relative-motion and goto-state DRAGGING
>     otherwise ignore
>   end state
>
> end state-machine
>
> A much better way to do this is to draw the state machine on paper - use one
> circle / oval for each state, and transitions (goto-state) are drawn as
> arrows from one state bubble to another.  You won't regret going to the
> trouble of drawing out the state diagram when you try to incorporate all of
> the other mouse actions and buttons into your mouse-handling code.
>
> pt
>
>


-- 
=====================
Joshua Taylor
tayloj@rpi.edu

"A lot of good things went down one time,
     back in the goodle days."
               John Hartford