# Detailed Resampling
# ===================

# This example uses `pyvista.DataObjectFilters.sample()`.
# `pyvista.DataObjectFilters.resample_to_image()` samples onto a new
# `ImageData` in a single call.
# `pyvista.DataSetFilters.interpolate()` is similar, and the two
# methods are compared in Compare Interpolation/Sampling Methods.
# Resample one mesh's point/cell arrays onto another mesh's nodes.
# This example will resample a volumetric mesh's scalar data onto the surface
# of a sphere contained in that volume.
import pyvista as pv
from pyvista import examples

# Simple Resample
# ---------------

# Query a grid's points onto a sphere
mesh = pv.Sphere(center=(4.5, 4.5, 4.5), radius=4.5)
data_to_probe = examples.load_uniform()

# Plot the two datasets
pl = pv.Plotter()
pl.add_mesh(mesh, color=True)
pl.add_mesh(data_to_probe, opacity=0.5)
pl.show()

# Run the algorithm and plot the result
result = mesh.sample(data_to_probe)

# Plot result
name = 'Spatial Point Data'
result.plot(scalars=name, clim=data_to_probe.get_data_range(name))

# `resample_to_image()` samples onto a new
# `ImageData` instead. Pass a `reference_volume` to give the
# output the geometry of an image which already exists.
mesh.resample_to_image(reference_volume=data_to_probe)

# Complex Resample
# ----------------

# Take a volume of data and create a grid of lower resolution to resample on
data_to_probe = examples.download_embryo()
mesh = pv.create_grid(data_to_probe, dimensions=(75, 75, 75))

result = mesh.sample(data_to_probe)

# `resample_to_image()` does both steps in one call.
data_to_probe.resample_to_image(dimensions=(75, 75, 75))

# To resample `ImageData` directly, use
# `resample()` instead.
data_to_probe.resample(dimensions=(75, 75, 75))

# Both meshes here are `ImageData`, and for that case
# `reslice()` is the closer fit than `sample`. It reads
# the image at the grid's points just as `sample` does, but returns only the resampled
# array, where `sample` also carries the grid's own arrays and the mask arrays probing
# adds, and it offers the border, interpolation, and anti-aliasing options an image
# needs. See Reslice Images.
data_to_probe.reslice(mesh, 'linear')

threshold = lambda m: m.threshold(75.0, scalars='SLCImage')
cpos = pv.CameraPosition(
    position=(468.9, -152.8, 152.1),
    focal_point=(121.7, 140.3, 112.3),
    viewup=(-0.1088, 0.006229, 0.994),
)
dargs = dict(clim=[0, 200], cmap='rainbow')

pl = pv.Plotter(shape=(1, 2))
pl.add_mesh(threshold(data_to_probe), **dargs)
pl.subplot(0, 1)
pl.add_mesh(threshold(result), **dargs)
pl.link_views()
pl.view_isometric()
pl.show(cpos=cpos)

# Resample a Processed Volume
# ---------------------------

# Clipping an image returns an `UnstructuredGrid`, which image filters do
# not accept. `resample_to_image()` puts the processed
# volume back on a regular grid.
# Start from a volumetric scan of a knee. Bone is the bright end of its intensity range,
# from 100 up.
knee = examples.download_knee_full()


knee.plot(volume=True, cmap='bone', clim=[100, 174])

# Clip the scan to the bone, and keep the three largest pieces: the tibia, the femur, and
# the patella. `connectivity()` numbers the regions from the
# largest down and stores the numbers as `'RegionId'`.
bone = knee.clip_scalar(scalars='SLCImage', value=100, invert=False)
bones = bone.connectivity('specified', [0, 1, 2])
bones.plot(scalars='RegionId', cmap='glasbey', categories=True)

# Resample the labeled bones onto the scan's own grid with `reference_volume`, so that
# a voxel of the output is a voxel of the scan. Sample the labels as categories to keep
# them whole, and blank the voxels which fall outside the bone.
labels = bones.resample_to_image(reference_volume=knee, categorical=True, mark_blank=True)

# The labels sit on the points of the image, so render them as voxel cells with
# `points_to_cells()`.
labels.points_to_cells().plot(scalars='RegionId', cmap='glasbey', categories=True)

# ----------------------------------------------------------------------
# Generated by sphinx-examples-as-code https://github.com/pyvista/sphinx-examples-as-code