#!/usr/bin/env python

import vtk


def main():
    colors = vtk.vtkNamedColors()
    # Set the background color. Match those in VTKTextbook.pdf.
    bkg = map(lambda x: x / 256.0, [25, 51, 102])
    colors.SetColor("BkgColor", *bkg)

    # create a rendering window and renderer
    ren = vtk.vtkRenderer()
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(ren)

    # create a renderwindowinteractor
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)

    # create source
    source = vtk.vtkSphereSource()
    source.SetCenter(0, 0, 0)
    source.SetRadius(5.0)

    # mapper
    mapper = vtk.vtkPolyDataMapper()
    mapper.SetInputConnection(source.GetOutputPort())

    # actor
    actor = vtk.vtkActor()
    actor.SetMapper(mapper)

    # color the actor
    actor.GetProperty().SetColor(colors.GetColor3d("Yellow"))

    # assign actor to the renderer
    ren.AddActor(actor)
    ren.SetBackground(colors.GetColor3d("BkgColor"))

    renWin.Render()
    ext = ['', '.png', '.jpg', '.ps', '.tiff', '.bmp', '.pnm']
    filenames = list(map(lambda x: 'ImageWriter' + x, ext))
    filenames[0] = filenames[0] + '1'
    for f in filenames:
        WriteImage(f, renWin, rgba=False)

    iren.Initialize()
    iren.Start()


def WriteImage(fileName, renWin, rgba=True):
    """
    Write the render window view to an image file.

    Image types supported are:
     BMP, JPEG, PNM, PNG, PostScript, TIFF.
    The default parameters are used for all writers, change as needed.

    :param fileName: The file name, if no extension then PNG is assumed.
    :param renWin: The render window.
    :param rgba: Used to set the buffer type.
    :return:
    """

    import os

    if fileName:
        # Select the writer to use.
        path, ext = os.path.splitext(fileName)
        ext = ext.lower()
        if not ext:
            ext = '.png'
            fileName = fileName + ext
        if ext == '.bmp':
            writer = vtk.vtkBMPWriter()
        elif ext == '.jpg':
            writer = vtk.vtkJPEGWriter()
        elif ext == '.pnm':
            writer = vtk.vtkPNMWriter()
        elif ext == '.ps':
            if rgba:
                rgba = False
            writer = vtk.vtkPostScriptWriter()
        elif ext == '.tiff':
            writer = vtk.vtkTIFFWriter()
        else:
            writer = vtk.vtkPNGWriter()

        windowto_image_filter = vtk.vtkWindowToImageFilter()
        windowto_image_filter.SetInput(renWin)
        windowto_image_filter.SetScale(1)  # image quality
        if rgba:
            windowto_image_filter.SetInputBufferTypeToRGBA()
        else:
            windowto_image_filter.SetInputBufferTypeToRGB()
            # Read from the front buffer.
            windowto_image_filter.ReadFrontBufferOff()
            windowto_image_filter.Update()

        writer.SetFileName(fileName)
        writer.SetInputConnection(windowto_image_filter.GetOutputPort())
        writer.Write()
    else:
        raise RuntimeError('Need a filename.')


if __name__ == '__main__':
    main()
