"""
.. _using_filters_example:

Using Common Filters
~~~~~~~~~~~~~~~~~~~~

Using common filters like thresholding and clipping.
"""

# sphinx_gallery_thumbnail_number = 2
import pyvista as pv
from pyvista import examples

# %%
# PyVista wrapped data objects have a suite of common filters ready for immediate
# use directly on the object. These filters include the following
# (see :ref:`filters` for a complete list):
#
# * ``slice``: creates a single slice through the input dataset on a user defined plane
# * ``slice_orthogonal``: creates a ``MultiBlock`` dataset of three orthogonal slices
# * ``slice_along_axis``: creates a ``MultiBlock`` dataset of many slices along a
#   specified axis
# * ``threshold``: Thresholds a dataset by a single value or range of values
# * ``threshold_percent``: Threshold by percentages of the scalar range
# * ``clip``: Clips the dataset by a user defined plane
# * ``outline_corners``: Outlines the corners of the data extent
# * ``extract_surface``: Extract surface geometry
#
# To use these filters, call the method of your choice directly on your data
# object:

dataset = examples.load_uniform()
dataset.set_active_scalars('Spatial Point Data')

# Apply a threshold over a data range
threshed = dataset.threshold([100, 500])

outline = dataset.outline()

# %%
# And now there is a thresholded version of the input dataset in the new
# ``threshed`` object. To learn more about what keyword arguments are available to
# alter how filters are executed, print the docstring for any filter attached to
# PyVista objects with either ``help(dataset.threshold)`` or using ``shift+tab``
# in an IPython environment.
#
# We can now plot this filtered dataset along side an outline of the original
# dataset

pl = pv.Plotter()
pl.add_mesh(outline, color='k')
pl.add_mesh(threshed)
pl.camera_position = [-2, 5, 3]
pl.show()


# %%
# What about other filters? Let's collect a few filter results and compare them:

contours = dataset.contour()
slices = dataset.slice_orthogonal()
glyphs = dataset.glyph(factor=1e-3, geom=pv.Sphere(), orient=False)

pl = pv.Plotter(shape=(2, 2))
# Show the threshold
pl.add_mesh(outline, color='k')
pl.add_mesh(threshed, show_scalar_bar=False)
pl.camera_position = [-2, 5, 3]
# Show the contour
pl.subplot(0, 1)
pl.add_mesh(outline, color='k')
pl.add_mesh(contours, show_scalar_bar=False)
pl.camera_position = [-2, 5, 3]
# Show the slices
pl.subplot(1, 0)
pl.add_mesh(outline, color='k')
pl.add_mesh(slices, show_scalar_bar=False)
pl.camera_position = [-2, 5, 3]
# Show the glyphs
pl.subplot(1, 1)
pl.add_mesh(outline, color='k')
pl.add_mesh(glyphs, show_scalar_bar=False)
pl.camera_position = [-2, 5, 3]

pl.link_views()
pl.show()

# %%
# Filter Pipeline
# +++++++++++++++
#
# In VTK, filters are often used in a pipeline where each algorithm passes its
# output to the next filtering algorithm. In PyVista, we can mimic the
# filtering pipeline through a chain; attaching each filter to the last filter.
# In the following example, several filters are chained together:
#
# 1. First, use :func:`~pyvista.DataSetFilters.remove_nan_cells` to drop any
#    cells whose scalar values are ``NaN``.
# 2. Use an ``elevation`` filter to generate scalar values corresponding to height.
# 3. Use the ``clip`` filter to cut the dataset in half.
# 4. Create three slices along each axial plane using the ``slice_orthogonal`` filter.

# Apply a filtering chain
result = dataset.remove_nan_cells().elevation().clip(normal='z').slice_orthogonal()

# %%
# And to view this filtered data, simply call the ``plot`` method
# (``result.plot()``) or create a rendering scene:

pl = pv.Plotter()
pl.add_mesh(outline, color='k')
pl.add_mesh(result, scalars='Elevation')
pl.view_isometric()
pl.show()
# %%
# .. tags:: filter
