RT-20302: Consider changing picking behavior of dashed strokes

Dr. Michael Paus mp at jugs.org
Wed May 9 09:54:43 PDT 2012

It is in general always a good idea to keep things consistent but one 
also has to keep in mind
performance and the potential use-cases. So, how do you expect the 
picking performance to be
affected by this change? Concerning use-cases. What is the expectation 
of a user? I have to admit
that I would probably be surprised if I could not pick/select say a 
circle at some point of its
obvious border only because the border happens to be dashed instead of 
being solid.

Finally it all depends on how you want picking to behave in general. Is 
it a geometrical
operation of a graphical operation. It's a pity that JavaFX does not 
offer us any choice
here, because for some use-cases a geometrical interpretation, which is 
independent of
the graphical appearance of a shape, is much better suited as I have 
outlined here:


Am 09.05.2012 17:44, schrieb Lubomir Nerad:
> Hi,
> I would like to change mouse picking behavior of objects with dashed 
> stroke as described in http://javafx-jira.kenai.com/browse/RT-20302. 
> Currently an object is picked even when the mouse click happens in the 
> non-filled parts (inside spaces) of the dashed stroke (stroke dash 
> array and dash offset have no impact on picking). With RT-19994, this 
> can create an unexpected situation, when a Shape is picked inside 
> stroke spaces, but if it is used in a CAG operation (for example 
> Shape.intersect(shape1, shape1)) the resulting Shape won't include the 
> spaces and so won't be picked inside of them. To get consistent 
> behavior I propose not to pick the spaces inside object stokes.
> Do you agree?
> Thanks,
> Lubo

Dr. Michael Paus, Chairman of the Java User Group Stuttgart e.V. (JUGS).
For more information visit www.jugs.de.

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