lurking signals in EventSensor
John M McIntosh
johnmci at mac.com
Thu Jul 3 00:33:39 UTC 2003
From time to time I've noticed in the browser windows in just the right
sequence of motions that
the cursor hangs up in the resizing area between panes. Not all the
time, just once in a blue moon.
Shaking the mouse grab it away and all is well. But why?
Now in my looking at millisecond clock usage I noticed that sometimes
we get 10 of thousands of
calls from the io process loop.
Why, well I suspect, mostly because I've not found it yet, is that
under the right sequence of events the mouse
over logic is hunting for cursor movement via say cursorPoint which
calls primMousePt which calls
inputSemaphore signal, and stacks LOTS of excess signals on the
Semaphore, at which point the
io processor loop consumes them. The issue here is LOTS, that this is
reflected in a glitchy pause as we
grind though them.
However I'll listen to other suggestions.
Right now I'm considering a subclass of EventSensor for image that have
VM that actually support
proper signalling of the semaphore from the VM, versus the existing
tampering that goes on in EventSensor.
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John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
Corporate Smalltalk Consulting Ltd. http://www.smalltalkconsulting.com
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