4 Oct
2005
4 Oct
'05
4:10 p.m.
On Tuesday 04 October 2005 11:04 am,
linux-audio-dev-request(a)music.columbia.edu wrote:
From: Alfons Adriaensen
<fons.adriaensen(a)alcatel.be>
Interesting. I'll have to go through some mental exercise to convince
myself that this will never cause infinite cycles.
The controllers should not send a change back to the M when they are told by
the M what their value is.
You'll also want some logic in the M that says "if I receive a change that
tells me to go to my current value, then don't send updates to anyone".
-Ben Loftis
4 Oct
4 Oct
8:03 p.m.
On Tue, Oct 04, 2005 at 01:41:42PM -0500, Ben Loftis wrote:
The whole point about Paul's scheme is that he *is* doing exactly that.
And while does seem odd, I will not dismiss the idea without giving it
a full-length meditation :-)
Interesting.
I'll have to go through some mental exercise to convince
myself that this will never cause infinite cycles.
The controllers should not send a change back to the M when they are told by
the M what their value is. You'll also want some logic in the M that says
"if I receive a change that
tells me to go to my current value, then don't send updates to anyone".
This should be a rare occurence, so I wonder if it's worth the extra code.
What could be important when the client is a GUI is to limit the number of
updates. Dragging a slider could result in *a lot of* X move events, and it's
probably unwise to try and update the model and all clients for each one.
--
FA
8:50 p.m.
The
controllers should not send a change back to the M when they are told by
the M what their value is.
The whole point about Paul's scheme is that he *is* doing exactly that.
And while does seem odd, I will not dismiss the idea without giving it
a full-length meditation :-)
You'll also want some logic in the M that
says "if I receive a change that
tells me to go to my current value, then don't send updates to anyone".
This should be a rare occurence, so I wonder if it's worth the extra code.
9:35 p.m.
On Tue, Oct 04, 2005 at 06:52:27PM -0400, Paul Davis wrote:
that was precisely what my code did, though :)
You'll also want some logic in the M that says
"if I receive a change that
tells me to go to my current value, then don't send updates to anyone".
This should be a rare occurence, so I wonder if it's worth the extra code. From your code
void change_my_view_state_value (float newval)
{
if (my_view_state->value != newval) {
my_view_state->value = newval;
send_change_to_model (my_view_state->value);
}
}
you are doing this in V, while the suggestion I commented on was to do this
in M.
--
FA
5 Oct
5 Oct
10:39 a.m.
On Tue, Oct 04, 2005 at 01:41:42PM -0500, Ben Loftis wrote:
> The controllers should not send a change back to
the M when they are told
> by the M what their value is.
On Tuesday 04 October 2005 18:08, fons adriaensen wrote:
The whole point about Paul's scheme is that he
*is* doing exactly that.
And while does seem odd, I will not dismiss the idea without giving it
a full-length meditation :-)
Some of this may depend upon what your toolkit expects. For example, in Qt,
the QSlider widget has *two* signals that are emitted when a slider position
changes. One ('valueChanged(int)') is emitted whenever the position changes,
for whatever reason, while the other ('sliderMoved(int)') is emitted only
when the change was due to the *user* moving the control --i.e. not when
updated by the program itself. Choosing the correct one to use in a given
context is important in order to avoid the kind of problems Fons has
mentioned.
Cheers!
|-------------------------------------------------------------------------|
| Frederick F. Gleason, Jr. | Director of Broadcast Software Development |
| | Salem Radio Labs |
|-------------------------------------------------------------------------|
| Every morning in Africa, a gazelle wakes up. It knows it must run |
| faster than the fastest lion or it will be killed. Every morning a |
| lion wakes up. It knows it must outrun the slowest gazelle or it will |
| starve to death. It doesn't matter whether you are a lion or a |
| gazelle: when the sun comes up, you'd better be running! |
| -- Anonymous |
|-------------------------------------------------------------------------|
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4 comments
4 participants
participants (4)
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Ben Loftis -
fons adriaensen -
Fred Gleason -
Paul Davis