vtk_with_qt_and_pyfits.py

"""
Example file in the the vtk.qt4 module, copied into sandbox
"""

"""
A simple VTK widget for PyQt v4, the Qt v4 bindings for Python.
See http://www.trolltech.com for Qt documentation, and
http://www.riverbankcomputing.co.uk for PyQt.

This class is based on the vtkGenericRenderWindowInteractor and is
therefore fairly powerful.  It should also play nicely with the
vtk3DWidget code.

Created by Prabhu Ramachandran, May 2002
Based on David Gobbi's QVTKRenderWidget.py

Changes by Gerard Vermeulen Feb. 2003
 Win32 support.

Changes by Gerard Vermeulen, May 2003
 Bug fixes and better integration with the Qt framework.

Changes by Phil Thompson, Nov. 2006
 Ported to PyQt v4.
 Added support for wheel events.

Changes by Phil Thompson, Oct. 2007
 Bug fixes.

Changes by Phil Thompson, Mar. 2008
 Added cursor support.
"""


from PyQt4 import QtCore, QtGui
import vtk
import pyfits
from numpy import *

class QVTKRenderWindowInteractor(QtGui.QWidget):

    """ A QVTKRenderWindowInteractor for Python and Qt.  Uses a
    vtkGenericRenderWindowInteractor to handle the interactions.  Use
    GetRenderWindow() to get the vtkRenderWindow.  Create with the
    keyword stereo=1 in order to generate a stereo-capable window.

    The user interface is summarized in vtkInteractorStyle.h:

    - Keypress j / Keypress t: toggle between joystick (position
    sensitive) and trackball (motion sensitive) styles. In joystick
    style, motion occurs continuously as long as a mouse button is
    pressed. In trackball style, motion occurs when the mouse button
    is pressed and the mouse pointer moves.

    - Keypress c / Keypress o: toggle between camera and object
    (actor) modes. In camera mode, mouse events affect the camera
    position and focal point. In object mode, mouse events affect
    the actor that is under the mouse pointer.

    - Button 1: rotate the camera around its focal point (if camera
    mode) or rotate the actor around its origin (if actor mode). The
    rotation is in the direction defined from the center of the
    renderer's viewport towards the mouse position. In joystick mode,
    the magnitude of the rotation is determined by the distance the
    mouse is from the center of the render window.

    - Button 2: pan the camera (if camera mode) or translate the actor
    (if object mode). In joystick mode, the direction of pan or
    translation is from the center of the viewport towards the mouse
    position. In trackball mode, the direction of motion is the
    direction the mouse moves. (Note: with 2-button mice, pan is
    defined as <Shift>-Button 1.)

    - Button 3: zoom the camera (if camera mode) or scale the actor
    (if object mode). Zoom in/increase scale if the mouse position is
    in the top half of the viewport; zoom out/decrease scale if the
    mouse position is in the bottom half. In joystick mode, the amount
    of zoom is controlled by the distance of the mouse pointer from
    the horizontal centerline of the window.

    - Keypress 3: toggle the render window into and out of stereo
    mode.  By default, red-blue stereo pairs are created. Some systems
    support Crystal Eyes LCD stereo glasses; you have to invoke
    SetStereoTypeToCrystalEyes() on the rendering window.  Note: to
    use stereo you also need to pass a stereo=1 keyword argument to
    the constructor.

    - Keypress e: exit the application.

    - Keypress f: fly to the picked point

    - Keypress p: perform a pick operation. The render window interactor
    has an internal instance of vtkCellPicker that it uses to pick. 

    - Keypress r: reset the camera view along the current view
    direction. Centers the actors and moves the camera so that all actors
    are visible.

    - Keypress s: modify the representation of all actors so that they
    are surfaces. 

    - Keypress u: invoke the user-defined function. Typically, this
    keypress will bring up an interactor that you can type commands in.

    - Keypress w: modify the representation of all actors so that they
    are wireframe.
    """

    # Map between VTK and Qt cursors.
    _CURSOR_MAP = {
        0:  QtCore.Qt.ArrowCursor,          # VTK_CURSOR_DEFAULT
        1:  QtCore.Qt.ArrowCursor,          # VTK_CURSOR_ARROW
        2:  QtCore.Qt.SizeBDiagCursor,      # VTK_CURSOR_SIZENE
        3:  QtCore.Qt.SizeFDiagCursor,      # VTK_CURSOR_SIZENWSE
        4:  QtCore.Qt.SizeBDiagCursor,      # VTK_CURSOR_SIZESW
        5:  QtCore.Qt.SizeFDiagCursor,      # VTK_CURSOR_SIZESE
        6:  QtCore.Qt.SizeVerCursor,        # VTK_CURSOR_SIZENS
        7:  QtCore.Qt.SizeHorCursor,        # VTK_CURSOR_SIZEWE
        8:  QtCore.Qt.SizeAllCursor,        # VTK_CURSOR_SIZEALL
        9:  QtCore.Qt.PointingHandCursor,   # VTK_CURSOR_HAND
        10: QtCore.Qt.CrossCursor,          # VTK_CURSOR_CROSSHAIR
    }

    def __init__(self, parent=None, wflags=QtCore.Qt.WindowFlags(), **kw):
        # the current button
        self._ActiveButton = QtCore.Qt.NoButton

        # private attributes
        self.__oldFocus = None
        self.__saveX = 0
        self.__saveY = 0
        self.__saveModifiers = QtCore.Qt.NoModifier
        self.__saveButtons = QtCore.Qt.NoButton

        # do special handling of some keywords:
        # stereo, rw

        stereo = 0

        if kw.has_key('stereo'):
            if kw['stereo']:
                stereo = 1

        rw = None

        if kw.has_key('rw'):
            rw = kw['rw']

        # create qt-level widget
        QtGui.QWidget.__init__(self, parent, wflags|QtCore.Qt.MSWindowsOwnDC)

        if rw: # user-supplied render window
            self._RenderWindow = rw
        else:
            self._RenderWindow = vtk.vtkRenderWindow()

        self._RenderWindow.SetWindowInfo(str(int(self.winId())))

        if stereo: # stereo mode
            self._RenderWindow.StereoCapableWindowOn()
            self._RenderWindow.SetStereoTypeToCrystalEyes()

        self._Iren = vtk.vtkGenericRenderWindowInteractor()
        self._Iren.SetRenderWindow(self._RenderWindow)

        # do all the necessary qt setup
        self.setAttribute(QtCore.Qt.WA_OpaquePaintEvent)
        self.setAttribute(QtCore.Qt.WA_PaintOnScreen)
        self.setMouseTracking(True) # get all mouse events
        self.setFocusPolicy(QtCore.Qt.WheelFocus)
        self.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding))

        self._Timer = QtCore.QTimer(self)
        self.connect(self._Timer, QtCore.SIGNAL('timeout()'), self.TimerEvent)

        self._Iren.AddObserver('CreateTimerEvent', self.CreateTimer)
        self._Iren.AddObserver('DestroyTimerEvent', self.DestroyTimer)
        self._Iren.GetRenderWindow().AddObserver('CursorChangedEvent',
                                                 self.CursorChangedEvent)

    def __getattr__(self, attr):
        """Makes the object behave like a vtkGenericRenderWindowInteractor"""
        if attr == '__vtk__':
            return lambda t=self._Iren: t
        elif hasattr(self._Iren, attr):
            return getattr(self._Iren, attr)
        else:
            raise AttributeError, self.__class__.__name__ + \
                  " has no attribute named " + attr

    def CreateTimer(self, obj, evt):
        self._Timer.start(10)

    def DestroyTimer(self, obj, evt):
        self._Timer.stop()
        return 1

    def TimerEvent(self):
        self._Iren.TimerEvent()

    def CursorChangedEvent(self, obj, evt):
        """Called when the CursorChangedEvent fires on the render window."""
        # This indirection is needed since when the event fires, the current
        # cursor is not yet set so we defer this by which time the current
        # cursor should have been set.
        QtCore.QTimer.singleShot(0, self.ShowCursor)

    def HideCursor(self):
        """Hides the cursor."""
        self.setCursor(QtCore.Qt.BlankCursor)

    def ShowCursor(self):
        """Shows the cursor."""
        vtk_cursor = self._Iren.GetRenderWindow().GetCurrentCursor()
        qt_cursor = self._CURSOR_MAP.get(vtk_cursor, QtCore.Qt.ArrowCursor)
        self.setCursor(cursor)

    def sizeHint(self):
        return QtCore.QSize(400, 400)

    def paintEngine(self):
        return None

    def paintEvent(self, ev):
        self._RenderWindow.Render()

    def resizeEvent(self, ev):
        w = self.width()
        h = self.height()

        self._RenderWindow.SetSize(w, h)
        self._Iren.SetSize(w, h)

    def _GetCtrlShift(self, ev):
        ctrl = shift = False

        if hasattr(ev, 'modifiers'):
            if ev.modifiers() & QtCore.Qt.ShiftModifier:
                shift = True
            if ev.modifiers() & QtCore.Qt.ControlModifier:
                ctrl = True
        else:
            if self.__saveModifiers & QtCore.Qt.ShiftModifier:
                shift = True
            if self.__saveModifiers & QtCore.Qt.ControlModifier:
                ctrl = True

        return ctrl, shift

    def enterEvent(self, ev):
        if not self.hasFocus():
            self.__oldFocus = self.focusWidget()
            self.setFocus()

        ctrl, shift = self._GetCtrlShift(ev)
        self._Iren.SetEventInformationFlipY(self.__saveX, self.__saveY,
                                            ctrl, shift, chr(0), 0, None)
        self._Iren.EnterEvent()

    def leaveEvent(self, ev):
        if self.__saveButtons == QtCore.Qt.NoButton and self.__oldFocus:
            self.__oldFocus.setFocus()
            self.__oldFocus = None

        ctrl, shift = self._GetCtrlShift(ev)
        self._Iren.SetEventInformationFlipY(self.__saveX, self.__saveY,
                                            ctrl, shift, chr(0), 0, None)
        self._Iren.LeaveEvent()

    def mousePressEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        repeat = 0
        if ev.type() == QtCore.QEvent.MouseButtonDblClick:
            repeat = 1
        self._Iren.SetEventInformationFlipY(ev.x(), ev.y(),
                                            ctrl, shift, chr(0), repeat, None)

        self._ActiveButton = ev.button()

        if self._ActiveButton == QtCore.Qt.LeftButton:
            self._Iren.LeftButtonPressEvent()
        elif self._ActiveButton == QtCore.Qt.RightButton:
            self._Iren.RightButtonPressEvent()
        elif self._ActiveButton == QtCore.Qt.MidButton:
            self._Iren.MiddleButtonPressEvent()

    def mouseReleaseEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        self._Iren.SetEventInformationFlipY(ev.x(), ev.y(),
                                            ctrl, shift, chr(0), 0, None)

        if self._ActiveButton == QtCore.Qt.LeftButton:
            self._Iren.LeftButtonReleaseEvent()
        elif self._ActiveButton == QtCore.Qt.RightButton:
            self._Iren.RightButtonReleaseEvent()
        elif self._ActiveButton == QtCore.Qt.MidButton:
            self._Iren.MiddleButtonReleaseEvent()

    def mouseMoveEvent(self, ev):
        self.__saveModifiers = ev.modifiers()
        self.__saveButtons = ev.buttons()
        self.__saveX = ev.x()
        self.__saveY = ev.y()

        ctrl, shift = self._GetCtrlShift(ev)
        self._Iren.SetEventInformationFlipY(ev.x(), ev.y(),
                                            ctrl, shift, chr(0), 0, None)
        self._Iren.MouseMoveEvent()

    def keyPressEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        if ev.key() < 256:
            key = str(ev.text())
        else:
            key = chr(0)

        self._Iren.SetEventInformationFlipY(self.__saveX, self.__saveY,
                                            ctrl, shift, key, 0, None)
        self._Iren.KeyPressEvent()
        self._Iren.CharEvent()

    def keyReleaseEvent(self, ev):
        ctrl, shift = self._GetCtrlShift(ev)
        if ev.key() < 256:
            key = chr(ev.key())
        else:
            key = chr(0)

        self._Iren.SetEventInformationFlipY(self.__saveX, self.__saveY,
                                            ctrl, shift, key, 0, None)
        self._Iren.KeyReleaseEvent()

    def wheelEvent(self, ev):
        if ev.delta() >= 0:
            self._Iren.MouseWheelForwardEvent()
        else:
            self._Iren.MouseWheelBackwardEvent()

    def GetRenderWindow(self):
        return self._RenderWindow

    def Render(self):
        self.update()


def QVTKRenderWidgetPyFITSExample():    
    """A simple example that uses the QVTKRenderWindowInteractor class."""

    # We begin by creating the data we want to render.
    # For this tutorial, we create a 3D-image containing three overlaping cubes.
    # This data can of course easily be replaced by data from a medical CT-scan or anything else three dimensional.
    # The only limit is that the data must be reduced to unsigned 8 bit or 16 bit integers.
    data_matrix = pyfits.getdata('L1448_13CO.fits.gz')
    data_matrix = data_matrix[145:245,:,:]
    data_matrix[data_matrix < 0.7] = 0.
    data_matrix = (data_matrix * 100).astype(uint8)
    nz, ny, nx = data_matrix.shape
 
    # For VTK to be able to use the data, it must be stored as a VTK-image. This can be done by the vtkImageImport-class which
    # imports raw data and stores it.
    dataImporter = vtk.vtkImageImport()
    # The preaviusly created array is converted to a string of chars and imported.
    data_string = data_matrix.tostring()
    dataImporter.CopyImportVoidPointer(data_string, len(data_string))
    # The type of the newly imported data is set to unsigned char (uint8)
    dataImporter.SetDataScalarTypeToUnsignedChar()
    # Because the data that is imported only contains an intensity value (it isnt RGB-coded or someting similar), the importer
    # must be told this is the case.
    dataImporter.SetNumberOfScalarComponents(1)
    # The following two functions describe how the data is stored and the dimensions of the array it is stored in. For this
    # simple case, all axes are of length 75 and begins with the first element. For other data, this is probably not the case.
    # I have to admit however, that I honestly dont know the difference between SetDataExtent() and SetWholeExtent() although
    # VTK complains if not both are used.
    dataImporter.SetDataExtent(0, nx-1, 0, ny-1, 0, nz-1)
    dataImporter.SetWholeExtent(0, nx-1, 0, ny-1, 0, nz-1)
 
    # The following class is used to store transparencyv-values for later retrival. In our case, we want the value 0 to be
    # completly opaque whereas the three different cubes are given different transperancy-values to show how it works.
    alphaChannelFunc = vtk.vtkPiecewiseFunction()
    alphaChannelFunc.AddPoint(0, 0.0)
    alphaChannelFunc.AddPoint(50, 0.05)
    alphaChannelFunc.AddPoint(100, 0.1)
    alphaChannelFunc.AddPoint(150, 0.2)
 
    # This class stores color data and can create color tables from a few color points. For this demo, we want the three cubes
    # to be of the colors red green and blue.

    colorFunc = vtk.vtkColorTransferFunction()
    colorFunc.AddRGBPoint(0.0, 0.0, 0.0, 0.0)
    colorFunc.AddRGBPoint(64.0, 1.0, 0.0, 0.0)
    colorFunc.AddRGBPoint(128.0, 0.0, 0.0, 1.0)
    colorFunc.AddRGBPoint(192.0, 0.0, 1.0, 0.0)
    colorFunc.AddRGBPoint(255.0, 0.0, 0.2, 0.0)

    # colorFunc = vtk.vtkColorTransferFunction()
    # colorFunc.AddRGBPoint(1, 0.0, 0.0, 0.0)
    # colorFunc.AddRGBPoint(50, 1.0, 0.0, 0.0)
    # colorFunc.AddRGBPoint(100, 0.0, 1.0, 0.0)
    # colorFunc.AddRGBPoint(150, 0.0, 0.0, 1.0)
 
    # The preavius two classes stored properties. Because we want to apply these properties to the volume we want to render,
    # we have to store them in a class that stores volume prpoperties.
    volumeProperty = vtk.vtkVolumeProperty()
    volumeProperty.SetColor(colorFunc)
    volumeProperty.SetScalarOpacity(alphaChannelFunc)
 
    # This class describes how the volume is rendered (through ray tracing).
    compositeFunction = vtk.vtkVolumeRayCastCompositeFunction()
    # We can finally create our volume. We also have to specify the data for it, as well as how the data will be rendered.
    volumeMapper = vtk.vtkVolumeRayCastMapper()
    volumeMapper.SetVolumeRayCastFunction(compositeFunction)
    volumeMapper.SetInputConnection(dataImporter.GetOutputPort())
 
    # The class vtkVolume is used to pair the preaviusly declared volume as well as the properties to be used when rendering that volume.
    volume = vtk.vtkVolume()
    volume.SetMapper(volumeMapper)
    volume.SetProperty(volumeProperty)

    # every QT app needs an app
    app = QtGui.QApplication(['QVTKRenderWindowInteractor'])

    # create the widget
    widget = QVTKRenderWindowInteractor()
    widget.Initialize()
    widget.Start()
    # if you dont want the 'q' key to exit comment this.
    widget.AddObserver("ExitEvent", lambda o, e, a=app: a.quit())

    ren = vtk.vtkRenderer()
    widget.GetRenderWindow().AddRenderer(ren)

    ren.AddVolume(volume)
    ren.SetBackground(0,0,0)

    # show the widget
    widget.show()

    # start event processing
    app.exec_()

if __name__ == "__main__":
    QVTKRenderWidgetPyFITSExample()