# Animation¶

All (or most of) the changes in scatter and quiver plots are (linearly) interpolated. On top top that, scatter plots and quiver plots can take a sequence of arrays (the first dimension), where only one array is visualized. Together this can make smooth animations with coarse timesteps. Lets see an example.

```
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```
import ipyvolume.pylab as p3
import numpy as np
```

## Basic animation¶

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```
# only x is a sequence of arrays
x = np.array([[-1, -0.8], [1, -0.1], [0., 0.5]])
y = np.array([0.0, 0.0])
z = np.array([0.0, 0.0])
p3.figure()
s = p3.scatter(x, y, z)
p3.xyzlim(-1, 1)
p3.animation_control(s) # shows controls for animation controls
p3.show()
```

You can control which array to visualize, using the
`scatter.sequence_index`

property. Actually, the
`pylab.animate_glyphs`

is connecting the `Slider`

and `Play`

button to that property, but you can also set it from Python.

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```
s.sequence_index = 1
```

## Animating color and size¶

We now demonstrate that you can also animate color and size

```
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```
# create 2d grids: x, y, and r
u = np.linspace(-10, 10, 25)
x, y = np.meshgrid(u, u)
r = np.sqrt(x**2+y**2)
print("x,y and z are of shape", x.shape)
# and turn them into 1d
x = x.flatten()
y = y.flatten()
r = r.flatten()
print("and flattened of shape", x.shape)
```

```
x,y and z are of shape (25, 25)
and flattened of shape (625,)
```

Now we only animate the z component

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```

```
# create a sequence of 15 time elements
time = np.linspace(0, np.pi*2, 15)
z = np.array([(np.cos(r + t) * np.exp(-r/5)) for t in time])
print("z is of shape", z.shape)
```

```
z is of shape (15, 625)
```

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```
# draw the scatter plot, and add controls with animate_glyphs
p3.figure()
s = p3.scatter(x, z, y, marker="sphere")
p3.animation_control(s, interval=200)
p3.ylim(-3,3)
p3.show()
```

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```
# Now also include, color, which containts rgb values
color = np.array([[np.cos(r + t), 1-np.abs(z[i]), 0.1+z[i]*0] for i, t in enumerate(time)])
size = (z+1)
print("color is of shape", color.shape)
```

```
color is of shape (15, 3, 625)
```

color is of the wrong shape, the last dimension should contain the rgb value, i.e. the shape of should be (15, 2500, 3)

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```
color = np.transpose(color, (0, 2, 1)) # flip the last axes
```

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```
p3.figure()
s = p3.scatter(x, z, y, color=color, size=size, marker="sphere")
p3.animation_control(s, interval=200)
p3.ylim(-3,3)
p3.show()
```

## Creating movie files¶

We now make a movie, with a 2 second duration, where we rotate the camera, and change the size of the scatter points.

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```

```
def set_view(figure, framenr, fraction):
p3.view(fraction*360, (fraction - 0.5) * 180)
s.size = size * (1+0.5*np.sin(fraction * 6 * np.pi))
p3.movie('wave.gif', set_view, fps=20, frames=40)
```

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```
# include the gif with base64 encoding
import IPython.display
import base64
with open('wave.gif', 'rb') as gif:
url = b"data:image/gif;base64," +base64.b64encode(gif.read())
IPython.display.Image(url=url.decode('ascii'))
```

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```