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# $Id: arrowPlot.py,v 1.2 2005/06/20 05:20:26 paultcochrane Exp $ |
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""" |
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Example of plotting a vector field |
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""" |
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|
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# set up some data to plot |
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from Numeric import * |
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|
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# the positions of the vectors |
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x = arange(20, typecode=Float) |
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y = arange(20, typecode=Float) |
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|
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# the vector displacements |
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# (I may need to rethink how this works in the interface) |
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dx = arange(20, typecode=Float) |
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dy = arange(20, typecode=Float) |
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|
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# set the positions randomly, and set the displacements to be the square of |
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# the positions |
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import random |
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random.seed() |
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for i in range(len(x)): |
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x[i] = random.random() |
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y[i] = random.random() |
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dx[i] = x[i]*x[i] |
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dy[i] = y[i]*y[i] |
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|
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import vtk |
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|
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if len(x) != len(y) != len(dx) != len(dy): |
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raise ValueError, "x, y, dx and dy vectors must be of equal length" |
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|
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numPoints = len(x) |
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|
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# construct the points data |
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points = vtk.vtkPoints() |
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points.SetNumberOfPoints(numPoints) |
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for i in range(numPoints): |
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points.InsertPoint(i, x[i], y[i], 0.0) |
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|
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# make the vectors |
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vectors = vtk.vtkFloatArray() |
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vectors.SetNumberOfComponents(3) |
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vectors.SetNumberOfTuples(numPoints) |
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vectors.SetName("vectors") |
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for i in range(numPoints): |
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vectors.InsertTuple3(i, dx[i], dy[i], 0.0) |
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|
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# construct the grid |
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grid = vtk.vtkUnstructuredGrid() |
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grid.SetPoints(points) |
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grid.GetPointData().AddArray(vectors) |
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grid.GetPointData().SetActiveVectors("vectors") |
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|
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# make the arrow source |
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arrow = vtk.vtkArrowSource() |
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|
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# make the glyph |
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glyph = vtk.vtkGlyph2D() |
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glyph.ScalingOn() |
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glyph.SetScaleModeToScaleByVector() |
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glyph.SetColorModeToColorByVector() |
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glyph.SetScaleFactor(0.5) |
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glyph.SetSource(arrow.GetOutput()) |
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glyph.SetInput(grid) |
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glyph.ClampingOff() |
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|
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# set up a stripper for faster rendering |
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stripper = vtk.vtkStripper() |
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stripper.SetInput(glyph.GetOutput()) |
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|
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# get the maximum norm of the data |
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maxNorm = grid.GetPointData().GetVectors().GetMaxNorm() |
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|
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# now set up the mapper |
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mapper = vtk.vtkPolyDataMapper() |
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mapper.SetInput(stripper.GetOutput()) |
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mapper.SetScalarRange(0, maxNorm) |
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|
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# set up the actor |
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actor = vtk.vtkActor() |
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actor.SetMapper(mapper) |
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|
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# set up the renderer stuff |
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ren = vtk.vtkRenderer() |
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renWin = vtk.vtkRenderWindow() |
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renWin.SetSize(640,480) |
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renWin.AddRenderer(ren) |
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ren.SetBackground(1,1,1) |
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|
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ren.AddActor(actor) |
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|
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# set up some text properties |
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font_size = 14 |
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textProp = vtk.vtkTextProperty() |
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textProp.SetFontSize(font_size) |
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textProp.SetFontFamilyToArial() |
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textProp.BoldOff() |
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textProp.ItalicOff() |
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textProp.ShadowOff() |
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textProp.SetColor(0,0,0) |
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|
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# add a title |
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titleMapper = vtk.vtkTextMapper() |
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title = 'Example 2D arrow/quiver/vector field plot' |
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titleMapper.SetInput(title) |
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|
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titleProp = titleMapper.GetTextProperty() |
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titleProp.ShallowCopy(textProp) |
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titleProp.SetJustificationToCentered() |
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titleProp.SetVerticalJustificationToTop() |
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titleProp.SetFontSize(18) |
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|
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# set up the text actor |
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titleActor = vtk.vtkTextActor() |
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titleActor.SetMapper(titleMapper) |
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titleActor.GetPositionCoordinate().SetCoordinateSystemToNormalizedDisplay() |
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titleActor.GetPositionCoordinate().SetValue(0.5, 0.95) |
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|
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ren.AddActor(titleActor) |
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|
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# set up some axes |
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axes = vtk.vtkCubeAxesActor2D() |
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#axes.SetInput(grid) |
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axes.SetCamera(ren.GetActiveCamera()) |
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axes.SetFlyModeToOuterEdges() |
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axes.SetBounds(min(x), max(x)+maxNorm, min(y), max(y)+maxNorm, 0, 0) |
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axes.SetXLabel("x") |
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axes.SetYLabel("y") |
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axes.SetZLabel("") |
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axes.YAxisVisibilityOff() # but this is the z axis!! |
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|
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axesProp = axes.GetProperty() |
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axesProp.SetColor(0,0,0) |
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|
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axesTitleProp = axes.GetAxisTitleTextProperty() |
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axesTitleProp.ShallowCopy(textProp) |
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|
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axesLabelProp = axes.GetAxisLabelTextProperty() |
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axesLabelProp.ShallowCopy(textProp) |
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axesLabelProp.SetFontSize(8) |
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|
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ren.AddActor(axes) |
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|
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ren.ResetCamera() |
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|
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# set up the interactive renderer and render the scene |
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iren = vtk.vtkRenderWindowInteractor() |
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iren.SetRenderWindow(renWin) |
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iren.Initialize() |
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renWin.Render() |
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iren.Start() |
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|
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# convert the render window to an image |
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win2img = vtk.vtkWindowToImageFilter() |
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win2img.SetInput(renWin) |
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# save the image to file |
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outWriter = vtk.vtkPNGWriter() |
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outWriter.SetInput(win2img.GetOutput()) |
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outWriter.SetFileName("arrowPlot.png") |
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outWriter.Write() |
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|
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# vim: expandtab shiftwidth=4: |
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