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#!/usr/bin/env python
# This example shows how to load a 3D image into VTK and then reformat
# that image into a different orientation for viewing. It uses
# vtkImageReslice for reformatting the image, and uses vtkImageActor
# and vtkInteractorStyleImage to display the image. This InteractorStyle
# forces the camera to stay perpendicular to the XY plane.
import vtk
from vtk.util.misc import vtkGetDataRoot
VTK_DATA_ROOT = vtkGetDataRoot()
# Start by loading some data.
reader = vtk.vtkImageReader2()
reader.SetFilePrefix(VTK_DATA_ROOT + "/Data/headsq/quarter")
reader.SetDataExtent(0, 63, 0, 63, 1, 93)
reader.SetDataSpacing(3.2, 3.2, 1.5)
reader.SetDataOrigin(0.0, 0.0, 0.0)
reader.SetDataScalarTypeToUnsignedShort()
reader.UpdateWholeExtent()
# Calculate the center of the volume
reader.Update()
(xMin, xMax, yMin, yMax, zMin, zMax) = reader.GetExecutive().GetWholeExtent(reader.GetOutputInformation(0))
(xSpacing, ySpacing, zSpacing) = reader.GetOutput().GetSpacing()
(x0, y0, z0) = reader.GetOutput().GetOrigin()
center = [x0 + xSpacing * 0.5 * (xMin + xMax),
y0 + ySpacing * 0.5 * (yMin + yMax),
z0 + zSpacing * 0.5 * (zMin + zMax)]
# Matrices for axial, coronal, sagittal, oblique view orientations
axial = vtk.vtkMatrix4x4()
axial.DeepCopy((1, 0, 0, center[0],
0, 1, 0, center[1],
0, 0, 1, center[2],
0, 0, 0, 1))
coronal = vtk.vtkMatrix4x4()
coronal.DeepCopy((1, 0, 0, center[0],
0, 0, 1, center[1],
0,-1, 0, center[2],
0, 0, 0, 1))
sagittal = vtk.vtkMatrix4x4()
sagittal.DeepCopy((0, 0,-1, center[0],
1, 0, 0, center[1],
0,-1, 0, center[2],
0, 0, 0, 1))
oblique = vtk.vtkMatrix4x4()
oblique.DeepCopy((1, 0, 0, center[0],
0, 0.866025, -0.5, center[1],
0, 0.5, 0.866025, center[2],
0, 0, 0, 1))
# Extract a slice in the desired orientation
reslice = vtk.vtkImageReslice()
reslice.SetInputConnection(reader.GetOutputPort())
reslice.SetOutputDimensionality(2)
reslice.SetResliceAxes(sagittal)
reslice.SetInterpolationModeToLinear()
# Create a greyscale lookup table
table = vtk.vtkLookupTable()
table.SetRange(0, 2000) # image intensity range
table.SetValueRange(0.0, 1.0) # from black to white
table.SetSaturationRange(0.0, 0.0) # no color saturation
table.SetRampToLinear()
table.Build()
# Map the image through the lookup table
color = vtk.vtkImageMapToColors()
color.SetLookupTable(table)
color.SetInputConnection(reslice.GetOutputPort())
# Display the image
actor = vtk.vtkImageActor()
actor.GetMapper().SetInputConnection(color.GetOutputPort())
renderer = vtk.vtkRenderer()
renderer.AddActor(actor)
window = vtk.vtkRenderWindow()
window.AddRenderer(renderer)
# Set up the interaction
interactorStyle = vtk.vtkInteractorStyleImage()
interactor = vtk.vtkRenderWindowInteractor()
interactor.SetInteractorStyle(interactorStyle)
window.SetInteractor(interactor)
window.Render()
# Create callbacks for slicing the image
actions = {}
actions["Slicing"] = 0
def ButtonCallback(obj, event):
if event == "LeftButtonPressEvent":
actions["Slicing"] = 1
else:
actions["Slicing"] = 0
def MouseMoveCallback(obj, event):
(lastX, lastY) = interactor.GetLastEventPosition()
(mouseX, mouseY) = interactor.GetEventPosition()
if actions["Slicing"] == 1:
deltaY = mouseY - lastY
reslice.Update()
sliceSpacing = reslice.GetOutput().GetSpacing()[2]
matrix = reslice.GetResliceAxes()
# move the center point that we are slicing through
center = matrix.MultiplyPoint((0, 0, sliceSpacing*deltaY, 1))
matrix.SetElement(0, 3, center[0])
matrix.SetElement(1, 3, center[1])
matrix.SetElement(2, 3, center[2])
window.Render()
else:
interactorStyle.OnMouseMove()
interactorStyle.AddObserver("MouseMoveEvent", MouseMoveCallback)
interactorStyle.AddObserver("LeftButtonPressEvent", ButtonCallback)
interactorStyle.AddObserver("LeftButtonReleaseEvent", ButtonCallback)
# Start interaction
interactor.Start()
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