Basic Animations

In Algan you create animations by controlling Mob s, which are objects that will appear on screen. Algan provides a range of Mob s covering basic 2-D and 3-D shapes such as Circle, Rectangle Sphere, Cylinder, as well as Text Mob s for displaying text and Tex for LaTex. You can also import mobs from Manim using ManimMob.

Changing Animatable Attributes

All Mob s have the following animatable attributes: location, basis, color, glow, opacity. These attributes are special in that any modifications made to them will automatically be animated. Specifically, when a new value is assigned to an animatable attribute, that modification will take place over a 1 second period, during which the attribute is linearly interpolated from the old value to the new value.

location is a vector length 3 which specifies where in 3-D space a mob is located. By default, new Mobs are created at the ORIGIN (0, 0, 0).

Note

By default the camera is located at OUT*7 (0, 0, 7) and looks towards the ORIGIN.

basis is a vector of length 9 that specifies the orientation and scale of a Mob. It is not recommended to modify basis directly and instead use the helper methods like rotate() and scale().

color is a Color object which specifies the main color of the Mob.

Note

In Algan colors have red, green, blue components, as well as glow and opacity (and internally are stored as a vector of 5 components in that order). Colors with a non-zero glow component will ‘glow’, emitting light into nearby pixels. glow and opacity can optionally be set in the Color object, or as properties of the Mob itself.

Example: BasicChangingAttributes 

from algan import *

circle = Circle().spawn()

circle.location = circle.location + UP
circle.opacity = 0.5
circle.location = circle.location + DOWN + RIGHT
circle.glow = 0.5
circle.color = GREEN

render_to_file()

from algan import *

circle = Circle().spawn()

circle.location = circle.location + UP
circle.opacity = 0.5
circle.location = circle.location + DOWN + RIGHT
circle.glow = 0.5
circle.color = GREEN

render_to_file()

Important

Only non-inplace assignments are animated! That means that, for example, circle.location += UP * 0.5 will not be animated. You should NEVER assign animated attributes inplace!

Animated Functions

You will be able to get pretty far just modifying the animatable attributes, but there are some cases were linear interpolation just isn’t enough. For example, you may wish to move a Mob along a curved path. This animation cannot be expressed by linearly interpolating the Mob’s location. For such a case, you can create an animated_function().

Example: BasicAnimatedFunction 

from algan import *
import numpy as np

# Define a function mapping a scalar parameter t to a point on the circle.
def path_func(t):
    return (UP * np.sin(t) + RIGHT * np.cos(t))

# Create an animated_function which will move our mob along this path.
@animated_function(animated_args={'t': 0})
def move_along_path(mob, t):
    mob.location = path_func(t)

square = Square().spawn()
square.location = path_func(0) # Move to starting point.
move_along_path(square, 2*PI)

render_to_file()

from algan import *
import numpy as np

# Define a function mapping a scalar parameter t to a point on the circle.
def path_func(t):
    return (UP * np.sin(t) + RIGHT * np.cos(t))

# Create an animated_function which will move our mob along this path.
@animated_function(animated_args={'t': 0})
def move_along_path(mob, t):
    mob.location = path_func(t)

square = Square().spawn()
square.location = path_func(0) # Move to starting point.
move_along_path(square, 2*PI)

render_to_file()

The animated_function() decorator specifies that a function should be animated. This decorator accepts a parameter animated_args, which must be a dictionary mapping the names of animated arguments to their initial values when the animation begins. Like with attribute modification, the animation will take place over a 1 second period. The animation is created by linearly interpolating the animated_args from their initial values given in the dict, to the value the function is called with. In this example, we specify that parameter t has an initial value of 0, and we call the function with t=2*PI, so the animation will range from t=0 to t=2*PI.

Important

An animated_function() must accept at least one argument, and the first argument must be a Mob. Any arguments marked as animated_args must be floats.

Note

Inside of an animated_function(), the default animations created by modifying animatable attributes are disabled.

Mob Methods

Finally, the Mob class comes with a bunch of animated functions built in as methods, which should serve most of your common needs. Here are some examples:

Example: BasicMobMethods 

from algan import *

mob = RegularPolygon(5).spawn()
mob.move(RIGHT)
mob.rotate(360, OUT)
mob.rotate(360, UP)
mob.rotate_around_point(ORIGIN, 180, OUT)
mob = mob.become(Circle())

render_to_file()

from algan import *

mob = RegularPolygon(5).spawn()
mob.move(RIGHT)
mob.rotate(360, OUT)
mob.rotate(360, UP)
mob.rotate_around_point(ORIGIN, 180, OUT)
mob = mob.become(Circle())

render_to_file()

Here’s a brief explanation of the methods shown in the example:

  • Mob.move(): This method is used to translate (move) the Mob by a specified vector. For example, mob.move(RIGHT) moves the object to the right one unit.

  • Mob.rotate(): This method rotates the Mob by a given angle around a specified axis. For instance, mob.rotate(360, OUT) rotates the object 360 degrees around the outward-pointing Z-axis.

  • Mob.rotate_around_point(): This method rotates the Mob around a specific point in space. mob.rotate_around_point(ORIGIN, 180, OUT) rotates the object 180 degrees around the origin (0,0,0) along the Z-axis.

  • Mob.become(): This method smoothly transforms the current Mob into another Mob provided as an argument. For example, mob = mob.become(Circle()) transforms the existing mob into a circle.