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MouseStack not working?
Posted: Thu Sep 24, 2015 3:01 am
by dunbarx
I have two handlers in a button, and there are a few stack windows hanging around:
Code: Select all
on mouseUp
doThis
end mouseUp
on doThis
if the optionkey is down then exit to top
put the mousestack && the mouseLoc
send "doThis" to me in 5
end doThis
Works fine, and all other mouseFunctions (mouseChunk, mouseWhatever) do as well. But for this:
Code: Select all
on mouseUp
repeat until the optionKey is down
put the mouseStack && the mouseLoc
end repeat
end mouseUp
The mouseLoc tracks just fine, but the no other mouseFunction does. Doesn't seem too hard to figure out, but I can't. Is it because there is no "repeat with messages"?
Craig Newman
Re: MouseStack not working?
Posted: Thu Sep 24, 2015 3:14 am
by shaosean
If you want other events/messages to fire during a repeat loop, use the "with messages" form..
Re: MouseStack not working?
Posted: Thu Sep 24, 2015 3:50 am
by dunbarx
Hi.
If you want other events/messages to fire during a repeat loop, use the "with messages" form..
I was sort of joking when I wrote
...is iit because there is no "repeat with messages"?
Such a construction will not throw an error, but it also has no effect on the control structure. It is not indicated in the dictionary, and no pendingMessages are queued.
My point was: why does the mouseLoc fire, but no other mouseFunction?
I am starting to use those emoticons like Klaus.
Craig
Re: MouseStack not working?
Posted: Thu Sep 24, 2015 5:52 pm
by SparkOut
Try
Code: Select all
on mouseUp
repeat until the optionKey is down
put the mouseStack && the mouseLoc
wait 5 with messages
end repeat
end mouseUp
This gives you a "with messages" effect inside the repeat loop, and the same interval as the send in time method. Works as you describe without the wait 5 "with messages" but tracks the mouseStack like the send in time version with the wait with messages line included.
The answer to the question why does the mouseLoc track but not the other mouseMessages, when in the repeat loop without the wait with messages... I have no idea. But I know that unblocking a repeat loop with the with messages form of wait, to give the engine a bit of housekeeping time is one trick I use very frequently.
Re: MouseStack not working?
Posted: Fri Sep 25, 2015 6:42 pm
by dunbarx
Sparkout.
A very clever idea. Add a line of code to force what I thought was a non-blocking process to work the way I thought it ought to all by itself. I like it.
But I am going to submit to QCC as a bug. If for nothing else than to be told it is not a big deal, or I am misunderstanding something.
Craig
Re: MouseStack not working?
Posted: Sat Sep 26, 2015 9:09 am
by SparkOut
Mmm. I don't know about clever, I have had this idea beaten into my brain ever since I started with LiveCode (Rev 2.7).
Of course a repeat loop is still blocking even if the engine is allowed to handle messages, send in time is more suitable if you want to have modules running independently.
There is a thread somewhere that suggests this approach is a workaround to an issue affecting Mac OS X but was resolved in an earlier version. That surprised me, as it has always been the same in every version I have used on windows.
Edit:
http://forums.livecode.com/viewtopic.ph ... es#p109006
I'm not sure the Mac bug fix referred to is addressing quite the same thing. Bug 13142 referred to later is more like it.
Re: MouseStack not working?
Posted: Sat Sep 26, 2015 6:58 pm
by dunbarx
Hi.
I really misSpoke. I know repeat loops are "blocking", because they run in-line. As opposed to "wait" (without messages), which puts the whole world to sleep.
But the properties I mentioned are requested in an explicit line of code, in line, and only the mouseLoc comes back. The line is not fully resolved and executed. That is why I consider it a bug.
Craig
Re: MouseStack not working?
Posted: Sun Sep 27, 2015 1:18 am
by SparkOut
No, I agree, no misspeaking involved. (Of course [and you know that]... etc etc rhetorical blah)
Re: MouseStack not working?
Posted: Mon Sep 28, 2015 10:51 pm
by dunbarx
Mark W. replied:
Hi Craig,
Thanks for the report.
The only mouse function which is asynchronous is 'the mouseLoc' this returns
the position of the mouse at the time it is evaluated. The rest of the mouse
related functions all tie their result to the last dispatched mouse event - so
in the above case they will correspond to the position of the mouseUp.
I wouldn't say this is a bug as if it did not work like this then you would not
be able to capture mouse information reliably corresponding to the position of
the mouse event.
On the other hand, it does highlight a missing feature - the ability to get the
mouse position which is related to the current mouse event. Indeed, one could
argue that you should be able to do 'the mouse*' (related to position of mouse
event); and 'the current mouse*' (using the current asynchronous position).
I'm marking this as an anomaly for now. If you want to process mouse updates in
a tight loop then you need to use 'wait with messages' (but be careful about
re-entrancy) so the engine continues to dispatch mouse events whilst you are in
your loop (you can always stop message delivery with lock messages).
I replied back that I had included the wait just in order to make things work.
It is expected behavior, though, as the mouse functions are designed to return information about the target event, down to the "mouseChar" level, and no further, and not the current state of affairs. Well and good, though I would have preferred to have it default to the other way around, which seems far, far more intuitive to me. Anyway, it is something new learned, and we go forward...
Craig
Re: MouseStack not working?
Posted: Mon Sep 28, 2015 11:22 pm
by SparkOut
Mmmm. Nice to get Mark's take on it, and it does make a bit of sense. But it isn't limited to mouse events. It's bad form to waste cycles updating a field within a repeat loop, but
Code: Select all
repeat with tLoop = 1 to 10000
add 1 to field "fldTotal"
end repeat
will stop visibly adding numbers in the field and give a "(not responding)" caption in the title bar of the window, and in task manager on Windows. You have to let the engine and OS have an opportunity to pick up some cycles, which is introduced by the wait with messages. This is because the repeat loop is blocking - except how come it can still give cycles to the mouseLoc updates?
Re: MouseStack not working?
Posted: Tue Sep 29, 2015 2:28 am
by dunbarx
As I understand it, synchronicity is an engine attribute, hard coded.
So I made two buttons. In btn 1:
Code: Select all
on mouseUp
repeat until the optionKey is down
put the mouseLoc && the backColor of btn 2
wait 10
end repeat
end mouseUp
And in btn 2:
Code: Select all
on mouseUp
setBackColor
end mouseUp
on setBackColor
if the optionKey is down then exit to top
set the backColor of btn 2 to any item of "red,green,blue,yellow,orange"
send setBackColor to me in 10
end setBackColor
If I click on btn 2, to start the color changes, and then click on btn 1 to see what comes back, the mouseLoc tracks, but the backColor is locked to the backColor current when the click took place. Same for the "top", which is a property, unrelated to mouse functions. And now is it so for every property and function? I am not going to try them all
On the other hand, if in button 1:
Code: Select all
on mouseUp
repeat until the optionKey is down
put the mouseLoc && the backColor of btn 2
set the backColor of btn 2 to any item of "red,green,blue,yellow,orange"
wait 10
end repeat
end mouseUp
This returns both. The backColor is set, and then the property is returned. Why should the backColor be "read" if in the same handler, but not if set in a different handler?
Craig