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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The methods in the widget are intentional. Maybe I just don’t
get the widget rep separation code but the way I viewed it was that the
representation is just a representation (think of a view in the data/view or
model/view design pattern) Basically my take is that once you set the
properties of the representation (size, color, whatever) then you are done with
it and the program interacts with the widget. The model that I have seen in some
other places is that both the widget and the representation contain data and
the program continues to query and set both. I think there are some downsides
to that but it gets long winded. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>FWIW values such as Tilt do not necessarily have anything to do
with the appearance of the representation. For example with a centered slider
the slider may be centered when the value is 1.0 or 2.0. It is always centered
when at rest regardless of value. So the value is not clearly a property of the
representation but to me more clearly a property of the widget which handles
how the interactions of the representation modify the properties (such as tilt)
that the widget provides.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Ken <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Ken Martin PhD<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Kitware Inc.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>28 Corporate Drive<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Clifton Park NY 12065<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>ken.martin@kitware.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>518 371 3971 (w/f)<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> vtk-developers-bounces@vtk.org
[mailto:vtk-developers-bounces@vtk.org] <b>On Behalf Of </b>Will Schroeder<br>
<b>Sent:</b> Friday, June 20, 2008 9:25 AM<br>
<b>To:</b> David Cole<br>
<b>Cc:</b> VTK Developers; Prabhu Ramachandran<br>
<b>Subject:</b> Re: [vtk-developers] Crash with vtkCompassWidget<o:p></o:p></span></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:
12.0pt;margin-left:.5in'>This is the first time I've looked at the
implementation of this class, so I may be missing something.<br>
<br>
Generally methods that retrieve "geometric" or representational
information (heading, tilt, distance) belong in the representation. Event stuff
belongs in the widget. However, the boundary between the widget and
representation can be confusing, hence the boundary is blurry. At a minimum the
code should be written so that a default representation is created if not
present, and we can consider these "convenience" methods and leave
them in the widget. A more drastic measure would be to remove the methods and
make people go to the representation for the information.<br>
<br>
W<o:p></o:p></p>
<div>
<p class=MsoNormal style='margin-left:.5in'>2008/6/20 David Cole <<a
href="mailto:david.cole@kitware.com">david.cole@kitware.com</a>>:<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.5in'>A widget requires an attached
widget representation to work properly for all of its methods...<br>
<br>
Is this a bug? Or an intended "it's not gonna work unless there's a
representation connected to it..."?<br>
<br>
Any Widgets folks want to chime in on whether this should be expected to work?<br>
<br>
<br>
Thx,<br>
<span style='color:#888888'>David</span><o:p></o:p></p>
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<p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:
12.0pt;margin-left:.5in'><br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal style='margin-left:.5in'>On Thu, Jun 19, 2008 at 4:39 PM,
Prabhu Ramachandran <<a href="mailto:prabhu@aero.iitb.ac.in" target="_blank">prabhu@aero.iitb.ac.in</a>>
wrote:<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.5in'>Hi,<br>
<br>
There is a bug with vtkCompassWidget. It is trivial to reproduce.
Here is a Python example:<br>
<br>
import vtk<br>
w = vtk.vtkCompassWidget()<br>
print w.GetDistance()<br>
<br>
I get a bus error on my mac and others seem to get segmentation violations.<br>
<br>
Thanks.<br>
<br>
cheers,<br>
<span style='color:#888888'>-- <br>
Prabhu Ramachandran <a
href="http://www.aero.iitb.ac.in/%7Eprabhu" target="_blank">http://www.aero.iitb.ac.in/~prabhu</a><br>
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<p class=MsoNormal style='margin-left:.5in'><br>
<br clear=all>
<br>
-- <br>
William J. Schroeder, PhD<br>
Kitware, Inc.<br>
28 Corporate Drive<br>
Clifton Park, NY 12065<br>
<a href="mailto:will.schroeder@kitware.com">will.schroeder@kitware.com</a><br>
<a href="http://www.kitware.com">http://www.kitware.com</a><br>
518-371-3971 (phone and fax) <o:p></o:p></p>
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