Source code for paraview.python_view

# SPDX-FileCopyrightText: Copyright (c) Kitware Inc.
# SPDX-License-Identifier: BSD-3-Clause

r"""python_view is a module providing access to a PythonView. It is
possible to use the PythonView API directly, but this module provides
convenience classes in Python.
import paraview
from vtkmodules.vtkCommonDataModel import vtkImageData

[docs]def numpy_to_image(numpy_array): """Convert a numpy 2D or 3D array to a vtkImageData object. numpy_array 2D or 3D numpy array containing image data return vtkImageData with the numpy_array content """ try: import numpy except: paraview.print_error("Error: Cannot import numpy") shape = numpy_array.shape if len(shape) < 2: raise Exception('numpy array must have dimensionality of at least 2') h, w = shape[0], shape[1] c = 1 if len(shape) == 3: c = shape[2] # Reshape 2D image to 1D array suitable for conversion to a # vtkArray with numpy_support.numpy_to_vtk() linear_array = numpy.reshape(numpy_array, (w * h, c)) try: from vtkmodules.util import numpy_support except: paraview.print_error("Error: Cannot import vtkmodules.util.numpy_support") vtk_array = numpy_support.numpy_to_vtk(linear_array) image = vtkImageData() image.SetDimensions(w, h, 1) image.AllocateScalars(vtk_array.GetDataType(), 4) image.GetPointData().GetScalars().DeepCopy(vtk_array) return image
[docs]def figure_to_data(figure): """Convert a Matplotlib figure to a numpy 2D array with RGBA uint8 channels and return it. figure A matplotlib figure. return A numpy 2D array of RGBA values. """ # Draw the renderer try: import matplotlib except: paraview.print_error("Error: Cannot import matplotlib") figure.canvas.draw() # Get the RGBA buffer from the figure w, h = figure.canvas.get_width_height() try: import numpy except: paraview.print_error("Error: Cannot import numpy") buf = numpy.fromstring(figure.canvas.tostring_argb(), dtype=numpy.uint8) buf.shape = (h, w, 4) # canvas.tostring_argb gives pixmap in ARGB mode. Roll the alpha channel to have it in RGBA mode buf = numpy.roll(buf, 3, axis=2) return buf
[docs]def figure_to_image(figure): """Convert a Matplotlib figure to a vtkImageData with RGBA unsigned char channels. figure A matplotlib figure. return A vtkImageData with the Matplotlib figure content. """ buf = figure_to_data(figure) # Flip rows to be suitable for vtkImageData. buf = buf[::-1, :, :].copy() return numpy_to_image(buf)
[docs]def matplotlib_figure(width, height): """Create a Matplotlib figure with specified width and height for rendering. w Width of desired plot. h Height of desired plot. return A Matplotlib figure. """ try: from matplotlib.backends.backend_agg import FigureCanvasAgg except: paraview.print_error("Error: Cannot import matplotlib.backends.backend_agg.FigureCanvasAgg") try: from matplotlib.figure import Figure except: paraview.print_error("Error: Cannot import matplotlib.figure.Figure") figure = Figure() figureCanvas = FigureCanvasAgg(figure) figure.set_dpi(72) figure.set_size_inches(float(width) / 72.0, float(height) / 72.0) return figure
[docs]def call_render(render_function, view, width, height): """Utility function to call the user-defined render function. This is called by the C++ side of the vtkPythonView class. view vtkPythonView object width Width of view height Height of view """ if render_function == None: return # Check how many parameters it takes. num_args = render_function.__code__.co_argcount image = None if (num_args == 3): # Current-style render() function image = render_function(view, width, height) elif (num_args == 2): # Old-style render() function introduced in ParaView 4.1 figure = matplotlib_figure(width, height) render_function(view, figure) image = figure_to_image(figure) view.SetImageData(image)