BackgroundImage
VTKExamples/Python//BackgroundImage
Description¶
This example displays an image as the "background" of a scene, and renders a superquadric in front of it.
The example accepts a jpeg file on the command line to use as a background image. If there is no file, it generates a simple background.
Code¶
BackgroundImage.py
#!/usr/bin/env python """ based on: - http://www.vtk.org/Wiki/VTK/Examples/Cxx/Images/BackgroundImage tested with: - VTK 6.3, Python 2.7 - VTK 7.0, Python 3.5 >>> python background_image.py image_filename.jpg """ from __future__ import print_function import sys from vtk import ( vtkJPEGReader, vtkImageCanvasSource2D, vtkImageActor, vtkPolyDataMapper, vtkRenderer, vtkRenderWindow, vtkRenderWindowInteractor, vtkSuperquadricSource, vtkActor, VTK_MAJOR_VERSION ) def main(argv): # Verify input arguments if len(argv) > 1: # Read the image jpeg_reader = vtkJPEGReader() if not jpeg_reader.CanReadFile(argv[1]): print("Error reading file %s" % argv[1]) return jpeg_reader.SetFileName(argv[1]) jpeg_reader.Update() image_data = jpeg_reader.GetOutput() else: canvas_source = vtkImageCanvasSource2D() canvas_source.SetExtent(0, 100, 0, 100, 0, 0) canvas_source.SetScalarTypeToUnsignedChar() canvas_source.SetNumberOfScalarComponents(3) canvas_source.SetDrawColor(127, 127, 100) canvas_source.FillBox(0, 100, 0, 100) canvas_source.SetDrawColor(100, 255, 255) canvas_source.FillTriangle(10, 10, 25, 10, 25, 25) canvas_source.SetDrawColor(255, 100, 255) canvas_source.FillTube(75, 75, 0, 75, 5.0) canvas_source.Update() image_data = canvas_source.GetOutput() # Create an image actor to display the image image_actor = vtkImageActor() if VTK_MAJOR_VERSION <= 5: image_actor.SetInput(image_data) else: image_actor.SetInputData(image_data) # Create a renderer to display the image in the background background_renderer = vtkRenderer() # Create a superquadric superquadric_source = vtkSuperquadricSource() superquadric_source.SetPhiRoundness(1.1) superquadric_source.SetThetaRoundness(.2) # Create a mapper and actor superquadric_mapper = vtkPolyDataMapper() superquadric_mapper.SetInputConnection(superquadric_source.GetOutputPort()) superquadric_actor = vtkActor() superquadric_actor.SetMapper(superquadric_mapper) scene_renderer = vtkRenderer() render_window = vtkRenderWindow() # Set up the render window and renderers such that there is # a background layer and a foreground layer background_renderer.SetLayer(0) background_renderer.InteractiveOff() scene_renderer.SetLayer(1) render_window.SetNumberOfLayers(2) render_window.AddRenderer(background_renderer) render_window.AddRenderer(scene_renderer) render_window_interactor = vtkRenderWindowInteractor() render_window_interactor.SetRenderWindow(render_window) # Add actors to the renderers scene_renderer.AddActor(superquadric_actor) background_renderer.AddActor(image_actor) # Render once to figure out where the background camera will be render_window.Render() # Set up the background camera to fill the renderer with the image origin = image_data.GetOrigin() spacing = image_data.GetSpacing() extent = image_data.GetExtent() camera = background_renderer.GetActiveCamera() camera.ParallelProjectionOn() xc = origin[0] + 0.5*(extent[0] + extent[1]) * spacing[0] yc = origin[1] + 0.5*(extent[2] + extent[3]) * spacing[1] # xd = (extent[1] - extent[0] + 1) * spacing[0] yd = (extent[3] - extent[2] + 1) * spacing[1] d = camera.GetDistance() camera.SetParallelScale(0.5 * yd) camera.SetFocalPoint(xc, yc, 0.0) camera.SetPosition(xc, yc, d) # Render again to set the correct view render_window.Render() # Interact with the window render_window_interactor.Start() if __name__ == '__main__': main(sys.argv)