Vfrdtyky

I am writing an application to render a point cloud in VTK, using a wxPython GUI. I've based the code on the excellent examples by Sukhbinder Singh here and here. I'd like now to implement a right-mouse-click option in my data panel, which allows the user to do various tasks (like reset the camera position) through a context menu. I've tried a couple of different scenarios but the behavior is slightly wrong in each one:

A) The event "RightButtonPressEvent" allows me to select the right item out of my context menu and performs the bound function, but then won't respond to the left mouse button anymore, and

B) the event "RightButtonReleaseEvent" gets to performing the bound function as well, but then any subsequent movement of the mouse acts as though I still have the right button depressed. In my current VTK render window interactor style, this means zooming in/out - until I click the left mouse button.

I've tried (B) with a subsequent PostEvent call to simulate a left-mouse-click, to no avail. Adding the event directly to the interactor rather than to its style has the same effect. Can anyone tell me what I'm missing?

Using Python 3.4/3.6 on Win7, wx 4.0.3, vtk 8.1.1.

My long-ish "minimal" example below:

import wx

import vtk

from vtk.wx.wxVTKRenderWindowInteractor import wxVTKRenderWindowInteractor

import numpy as np



class VtkPointCloud:



    def __init__(self, zMin=-10.0, zMax=10.0):

        self.maxNumPoints = 1e6

        self.vtkPolyData = vtk.vtkPolyData()

        self.clearPoints()

        mapper = vtk.vtkPolyDataMapper()

        mapper.SetInputData(self.vtkPolyData)

        mapper.SetColorModeToDefault()

        mapper.SetScalarRange(zMin, zMax)

        mapper.SetScalarVisibility(1)

        self.vtkActor = vtk.vtkActor()

        self.vtkActor.SetMapper(mapper)



    def addPoint(self, point):

        if self.vtkPoints.GetNumberOfPoints() < self.maxNumPoints:

            pointId = self.vtkPoints.InsertNextPoint(point[:])

            self.vtkDepth.InsertNextValue(point[2])

            self.vtkCells.InsertNextCell(1)

            self.vtkCells.InsertCellPoint(pointId)

        self.vtkCells.Modified()

        self.vtkPoints.Modified()

        self.vtkDepth.Modified()



    def clearPoints(self):

        self.vtkPoints = vtk.vtkPoints()

        self.vtkCells = vtk.vtkCellArray()

        self.vtkDepth = vtk.vtkDoubleArray()

        self.vtkDepth.SetName('DepthArray')

        self.vtkPolyData.SetPoints(self.vtkPoints)

        self.vtkPolyData.SetVerts(self.vtkCells)

        self.vtkPolyData.GetPointData().SetScalars(self.vtkDepth)

        self.vtkPolyData.GetPointData().SetActiveScalars('DepthArray')





class p1(wx.Panel):

    # ---------------------------------------------------------------------------------------------

    def __init__(self,parent):

        wx.Panel.__init__(self, parent)



        self.widget = wxVTKRenderWindowInteractor(self, -1)

        self.widget.SetInteractorStyle(vtk.vtkInteractorStyleTrackballCamera())

        self.widget.Enable(1)

        self.widget.AddObserver("ExitEvent", lambda o,e,f=self: f.Close())

        i_style = self.widget.GetInteractorStyle()

        #i_style.AddObserver("RightButtonPressEvent", self._context_menu) # Freezes panel!

        i_style.AddObserver("RightButtonReleaseEvent", self._context_menu)

        self.sizer = wx.BoxSizer(wx.VERTICAL)

        self.sizer.Add(self.widget, 1, wx.EXPAND)

        self.SetSizer(self.sizer)

        self.Layout()

        self.is_plotted = False



    # ---------------------------------------------------------------------------------------------

    def renderthis(self):

        # open a window and create a renderer

        pointCloud = VtkPointCloud()

        data = 20*(np.random.rand(3,1000)-0.5)

        for i in range(data.shape[1]):

            pointCloud.addPoint(data[:,i])



        camera = vtk.vtkCamera()

        midpoint_x = 0

        midpoint_y = 0

        camera.SetPosition(midpoint_x, midpoint_y, -np.nanmax(data[2,:])); # eye position

        camera.SetFocalPoint(midpoint_x, midpoint_y, np.nanmax(data[2,:])) # perspective vanishing point



        # Save the default view

        self._default_cam_pos = camera.GetPosition()

        self._default_cam_focal = camera.GetFocalPoint()

        self._default_view_up = camera.GetViewUp()



        # Renderer

        self._renderer = vtk.vtkRenderer()

        self._renderer.AddActor(pointCloud.vtkActor)

        self._renderer.SetBackground(0.0, 0.0, 0.0)

        self._renderer.SetActiveCamera(camera)



        # Render Window

        self.widget.GetRenderWindow().AddRenderer(self._renderer)





 # ---------------------------------------------------------------------------------------------

    def _context_menu(self, caller, event):

        reset_cam_ID = wx.NewId()

        self.Bind(wx.EVT_MENU, self._on_reset_cam, id=reset_cam_ID)

        menu = wx.Menu()

        menu.Append(reset_cam_ID, "Reset camera")

        self.PopupMenu(menu)

        menu.Destroy()





    # ---------------------------------------------------------------------------------------------

    def _on_reset_cam(self, event):

        cam = self._renderer.GetActiveCamera()

        cam.SetPosition(self._default_cam_pos)

        cam.SetFocalPoint(self._default_cam_focal)

        cam.SetViewUp(self._default_view_up)

        self.Refresh()





class TestFrame(wx.Frame):



    # ---------------------------------------------------------------------------------------------

    def __init__(self, parent, title):

        wx.Frame.__init__(self, parent, title=title, size=(650,600), 

                          style=(wx.MINIMIZE_BOX | 

                          wx.SYSTEM_MENU | 

                          wx.CAPTION | 

                          wx.CLOSE_BOX | 

                          wx.CLIP_CHILDREN))

        self.sp = wx.SplitterWindow(self)

        self.p1 = p1(self.sp)

        self.p2 = wx.Panel(self.sp, style=wx.SUNKEN_BORDER)



        self.sp.SplitHorizontally(self.p1, self.p2, 470)



        self.statusbar = self.CreateStatusBar()

        self.statusbar.SetStatusText("Click on the Plot Button")



        self.plotbut = wx.Button(self.p2, -1, "Plot", size=(40,20), pos=(10,10))

        self.plotbut.Bind(wx.EVT_BUTTON,self.plot)



    # ---------------------------------------------------------------------------------------------

    def plot(self,event):

        if not self.p1.is_plotted:

            self.p1.renderthis()

            self.statusbar.SetStatusText("Use your mouse to interact with the model")





app = wx.App(redirect=False)

frame = TestFrame(None, "Pointcloud")

frame.Show()

app.MainLoop()