[vtkusers] Issues with coordinate conversion, possible VTK bugs?

Wed May 24 12:14:18 EDT 2017

Den 24 maj 2017 5:27 em skrev "Bill Q" <bill.q.hdp at gmail.com>:
>
> Hi Dan,
> After set the layer, I got this error:
>
> VTK-7.1.0\Rendering\Core\vtkRendererCollection.cxx, line 61
vtkRendererCollection (000000001192E3A0): Invalid layer for renderer: not
rendered.
>
> And the text renderer didn't show up.

You'll need to call SetNumberOfLayers(2) on your render window first I
think.

Elvis

>
> Many thanks.
>
>
> Bill
>
> On Wed, May 24, 2017 at 11:06 PM, Dan Lipsa <dan.lipsa at kitware.com> wrote:
>>
>> Bill,
>> Try using SetLayer(1) for the renderer that has the text.
>>
>> Dan
>>
>>
>> On Wed, May 24, 2017 at 10:34 AM, Bill Q <bill.q.hdp at gmail.com> wrote:
>>>
>>> Hi Dan,
>>> Thanks a ton for the example. The example used 4 different viewports.
However, for my application, I need to set all renderers under the same
viewport. The problem is that if I add a second renderer into the render
window and using the default viewport, it will cover the first renderer and
nothing on the first renderer will show up. I am wondering if I did the
whole thing wrong.
>>>
>>> My purpose is to display some DICOM images, some texts, and scales on
the same screen. Also, I would like to make the scales zoom with the DICOM
images but the texts stay put. Most importantly, I would like to get the
world coordinates on the DICOM image when users click on the screen, so I
can mark the click properly.
>>>
>>> What should be done in order to get this working?
>>>
>>>
>>> Many thanks.
>>>
>>>
>>> Bill
>>>
>>> On Wed, May 24, 2017 at 12:02 AM, Dan Lipsa <dan.lipsa at kitware.com>
wrote:
>>>>
>>>> Not sure what is going on. Do the objects you are rendering have the
same world coordinates? Are both renderers added to the rendering window?
>>>> Here is an example with multiple renderer (they are over different
viewports but they could have the same viewport as well)
>>>>
http://www.vtk.org/Wiki/VTK/Examples/Cxx/Visualization/MultipleViewports
>>>>
>>>> On Tue, May 23, 2017 at 11:39 AM, Bill Q <bill.q.hdp at gmail.com> wrote:
>>>>>
>>>>> I just gave it a try. But when I added another renderer into the
window that I used for text actors, it overlaps and covered the first
renderer. So the first renderer won't show up. Is there a solution?
>>>>>
>>>>> Many thanks.
>>>>>
>>>>>
>>>>> Bill
>>>>>
>>>>> On Tue, May 23, 2017 at 10:16 PM, Dan Lipsa <dan.lipsa at kitware.com>
wrote:
>>>>>>
>>>>>> I think moving those text actors on a different renderer will solve
your problem.
>>>>>>
>>>>>> Dan
>>>>>>
>>>>>>
>>>>>> On Tue, May 23, 2017 at 9:40 AM, Bill Q <bill.q.hdp at gmail.com> wrote:
>>>>>>>
>>>>>>> Hi Dan,
>>>>>>> Thanks a lot for the reply. Yes, that's exactly the case. If I
remove the text actors, the world picker would return the correct
coordinates. So, what method should I use in order to get the correct
coordinates no matter how many actors I put in with the dicom image reader
actor?
>>>>>>>
>>>>>>> Many thanks.
>>>>>>>
>>>>>>>
>>>>>>> Bill
>>>>>>>
>>>>>>> On Mon, May 22, 2017 at 10:04 PM, Dan Lipsa <dan.lipsa at kitware.com>
wrote:
>>>>>>>>
>>>>>>>> Bill,
>>>>>>>> For display_to_world, the picker picks up only what is visible
(closes to the camera). You might have several objects (several values in
world coordinates) that end up over the same display coordinate. This might
explain why adding those text actors changes what you pick.
>>>>>>>>
>>>>>>>> Dan
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Sun, May 21, 2017 at 5:25 AM, Bill Q <bill.q.hdp at gmail.com>
wrote:
>>>>>>>>>
>>>>>>>>> Can anybody help? Many thanks.
>>>>>>>>>
>>>>>>>>> Many thanks.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Bill
>>>>>>>>>
>>>>>>>>> On Fri, May 19, 2017 at 11:20 PM, Bill Q <bill.q.hdp at gmail.com>
wrote:
>>>>>>>>>>
>>>>>>>>>> Hello Everyone,
>>>>>>>>>> I encountered a weird problem in coordinate conversion.
>>>>>>>>>>
>>>>>>>>>> In order to check the accuracy, I converted from display to
world, and from world back to display. Using the following ways:
>>>>>>>>>>
>>>>>>>>>> self.world_picker = vtk.vtkWorldPointPicker()
>>>>>>>>>>
>>>>>>>>>> def display_to_world(self, pt):
>>>>>>>>>>     self.world_picker.Pick(pt[0], pt[1], 0, self.ren)
>>>>>>>>>>     picker_pt = self.world_picker.GetPickPosition()
>>>>>>>>>>     picker_pt = (picker_pt[0], picker_pt[1], 0)
>>>>>>>>>>     return picker_pt
>>>>>>>>>>
>>>>>>>>>> def world_to_display(self, pt):
>>>>>>>>>>     if len(pt) == 3:
>>>>>>>>>>         pt = pt + (1.0,)
>>>>>>>>>>     elif len(pt) == 2:
>>>>>>>>>>         pt = pt + (0.0, 1.0)
>>>>>>>>>>     self.ren.SetWorldPoint(pt)
>>>>>>>>>>     self.ren.WorldToDisplay()
>>>>>>>>>>     pt = self.ren.GetDisplayPoint()
>>>>>>>>>>     pt = (pt[0], pt[1])
>>>>>>>>>>     return pt
>>>>>>>>>>
>>>>>>>>>> pt = [5, 5]
>>>>>>>>>>
>>>>>>>>>> world_pt = self. world_to_display(pt)
>>>>>>>>>>
>>>>>>>>>> display_pt = self. world_to_display(world_pt)
>>>>>>>>>>
>>>>>>>>>> In some cases, it's quite accurate, which means pt equals
display_pt. But, in some cases, the result is simply wrong. For example,
for (5, 5), after conversions back to display, the coordinate becomes
(20.89, 20.89).
>>>>>>>>>>
>>>>>>>>>> Any ideas?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Many thanks.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Bill
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
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>>>>>>>>>
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>>>>>>>>>
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>>>>>>>>>
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>>>>>>>>>
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>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
>
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