[vtk-developers] A weird 6.x specific bug with ModifiedEvents

[Bill Lorensen]

I do not think that GetColor should change the value of Color. If we
need the composite color, we could have a method GetCompositeColor().
No SetCompositeColor.

Bill


On Mon, Apr 14, 2014 at 12:24 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> Really bad stuff. ComputeCompositeColor "sets" this->Color directly.
> ComputeCompositeColor was added about a year ago...
>
>
>
> On Mon, Apr 14, 2014 at 12:18 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>> This is indeed weird.
>>
>> GetColor does not return the value set by SetColor. It calls
>> ComputeCompositeColor.
>>
>> Also, SetColor calls SetAmbientColor, SetDiffuseColor and
>> SetSpecularColor. Each should cause a Modified event. In fact if you
>> remove the o.GetColor() call in the Modified callback, you will see
>> three modified events and each call will change one more of the color
>> s (ambeint, diffuse, specular).
>>
>>
>> Very strange.
>>
>> Bill
>>
>>
>> On Mon, Apr 14, 2014 at 11:35 AM, Prabhu Ramachandran
>> <prabhu at aero.iitb.ac.in> wrote:
>>> Hi everyone,
>>>
>>> I just discovered a weird bug with VTK 6.1 and 6.0 that doesn't happen with
>>> VTK 5.x.  Here is a tiny Python script:
>>>
>>> ##################################################
>>> import vtk
>>> def f(o, e):
>>>     print e, o.GetAmbientColor(), o.GetColor(),
>>>     print o.GetDiffuseColor(), o.GetSpecularColor()
>>>
>>> p = vtk.vtkProperty()
>>> p.AddObserver('ModifiedEvent', f)
>>> p.SetColor(0,0,0)
>>> print p.GetColor()
>>> ##################################################
>>>
>>> If you comment out the AddObserver line, everything works correctly but with
>>> it, you can never set the color of the property!  This doesn't seem to be
>>> specific to Python and happens with a small C++ example as well.
>>>
>>> Thoughts?
>>>
>>> cheers,
>>> Prabhu
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>>
>>
>>
>> --
>> Unpaid intern in BillsBasement at noware dot com
>
>
>
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> Unpaid intern in BillsBasement at noware dot com



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Unpaid intern in BillsBasement at noware dot com