Re: Accuracy of motion events

[ax487 <ax487 gmx de>]

On 30.08.2014 04:55, Stefan Salewski wrote:
> On Sat, 2014-08-30 at 03:46 +0200, Stefan Salewski wrote:
> > Just for fun I have tested with GTK 3.12 for Nimrod, but I can not see
> > an effect of event compression... (It was necessary to put
> > set_event_compression() after window.show_all(), seem that Ruby
> > bindings
> > ensure that a Gdk window is always available, while plain Nimrod
> > bindings needs realize before.)  I may try plain C tomorrow, or in
> > winter.
>
> OK, I should not complain to loud -- indeed I moved the mouse pointer
> fast...
>
> I have just added a time output to the Nimrod program:
>
> echo round(event.x), " ", round(event.y), ":", event.time 
>
> stefan AMD64X2 ~/fups $ ./test 
> 3 461:32626589
> 54 459:32626605
> 99 459:32626617
> 144 459:32626628
> 183 466:32626640
> 232 468:32626652
> 281 468:32626664
> 344 468:32626676
> 393 468:32626689
>
> So we get an event every 12 ms -- more makes no sense for a 60 Hz TFT
> display.
>
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Ok, as far as I am concerned disabling the event compression solves the
problem. In my case I have optimized the drawing routines such that the
time needed to process a motion event (i.e. to draw a new segment onto
the canvas) is << 1ms. Since my code is able to keep up with the rate at
which uncompressed events are generated disabling the compression makes
sense in my case.

Thank you for the suggestion, I appreciate the help :)

ax487