# Sphere Widget
# =============

# The sphere widget can be enabled and disabled by the
# `pyvista.Plotter.add_sphere_widget()` and
# `pyvista.Plotter.clear_sphere_widgets()` methods respectively.
# This is a very versatile widget as it can control vertex location that can
# be used to control or update the location of just about anything.
# We don't have any convenient helper methods that utilize this widget out of
# the box, but we have added a lot of ways to use this widget so that you can
# easily add several widgets to a scene.
# Let's look at a few use cases that all update a surface mesh.

# Example A
# ---------

# Use a single sphere widget
import numpy as np
import pyvista as pv

# Create a triangle surface
surf = pv.PolyData()
surf.points = np.array(
    [
        [-10, -10, -10],
        [10, 10, -10],
        [-10, 10, 0],
    ],
)
surf.faces = np.array([3, 0, 1, 2])

pl = pv.Plotter()


def callback(point):
    surf.points[0] = point


pl.add_sphere_widget(callback)
pl.add_mesh(surf, color=True)

pl.show_grid()
pl.show()

# And here is a screen capture of a user interacting with this

# Example B
# ---------

# Use several sphere widgets at once
import numpy as np
import pyvista as pv

# Create a triangle surface
surf = pv.PolyData()
surf.points = np.array(
    [
        [-10, -10, -10],
        [10, 10, -10],
        [-10, 10, 0],
    ],
)
surf.faces = np.array([3, 0, 1, 2])


pl = pv.Plotter()


def callback(point, i):
    surf.points[i] = point


pl.add_sphere_widget(callback, center=surf.points)
pl.add_mesh(surf, color=True)

pl.show_grid()
pl.show()

# And here is a screen capture of a user interacting with this

# Example C
# ---------

# This one is the coolest - use four sphere widgets to update perturbations on
# a surface and interpolate between them with some boundary conditions
import numpy as np
import pyvista as pv
from scipy.interpolate import griddata


def get_colors(n):
    """Get n colors."""
    import itertools

    import matplotlib as mpl

    cycler = mpl.rcParams['axes.prop_cycle']
    colors = itertools.cycle(cycler)
    return [next(colors)['color'] for i in range(n)]


# Create a grid to interpolate to
xmin, xmax, ymin, ymax = 0, 100, 0, 100
x = np.linspace(xmin, xmax, num=25)
y = np.linspace(ymin, ymax, num=25)
xx, yy, zz = np.meshgrid(x, y, [0])

# Make sure boundary conditions exist
boundaries = np.array(
    [[xmin, ymin, 0], [xmin, ymax, 0], [xmax, ymin, 0], [xmax, ymax, 0]]
)

# Create the PyVista mesh to hold this grid
surf = pv.StructuredGrid(xx, yy, zz)

# Create some initial perturbations
# - this array will be updated inplace
points = np.array([[33, 25, 45], [70, 80, 13], [51, 57, 10], [25, 69, 20]])


# Create an interpolation function to update that surface mesh
def update_surface(point, i):
    points[i] = point
    tp = np.vstack((points, boundaries))
    zz = griddata(tp[:, 0:2], tp[:, 2], (xx[:, :, 0], yy[:, :, 0]), method='cubic')
    surf.points[:, -1] = zz.ravel(order='F')


# Get a list of unique colors for each widget
colors = get_colors(len(points))

# Begin the plotting routine
pl = pv.Plotter()

# Add the surface to the scene
pl.add_mesh(surf, color=True)

# Add the widgets which will update the surface
pl.add_sphere_widget(update_surface, center=points, color=colors, radius=3)
# Add axes grid
pl.show_grid()

# Show it
pl.show()

# And here is a screen capture of a user interacting with this
# %%
# .. tags:: widgets

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