Basic Animations

In Algan you build animations by creating Mob s and then changing them. By default, changes you make to a mob are animated over a one second period. More complex animation behaviour will be covered in the later Combining Animations tutorial.

Changing Animatable Attributes

Every Mob has these animatable attributes:

Attribute

Shape

Meaning

location

3 floats

Where the Mob sits in 3-D space. New Mobs start at ORIGIN.

basis

9 floats

Orientation and scale, as three basis vectors. Change it with rotate() / scale(), not by hand.

color

Color

The Mob’s main color.

glow

float

How strongly the mob glows. 0 is off.

opacity

float

How see-through the mob is. 1 is opaque, 0 is invisible.

These attributes are special: assigning to one performs a 1-second animation that interpolates from the old value to the new value.

Example: BasicChangingAttributes 

from algan import *

circle = Circle().spawn()

circle.location = circle.location + UP * 2
circle.color = GREEN
circle.location = circle.location + DOWN + RIGHT * 2
circle.glow = 0.5
circle.opacity = 0.0
Scene.wait()

Scene.save_video()

Important

Reading an animatable attribute gives you a copy. circle.location hands back a copy of the value on the timeline, so editing that copy in place (e.g. circle.location[0] = 1 ) changes nothing and records nothing. The write goes into the copy and is thrown away silently.

Assignment is what Algan records, so both circle.location = circle.location + UP and circle.location += UP work.

A note on colors

An Algan Color carries five components: red, green, blue, glow and opacity, in that order. So glow and opacity can be set either on the Mob or baked into the color you assign:

Example: BasicColorComponents 

from algan import *

circle = Circle().spawn()

circle.color = BLUE                     # leaves glow and opacity alone
circle.opacity = 0.5                    # ... or set them separately

circle.color = GREEN.set_glow(0.5)   # ... or together, in one animation
Scene.wait()

Scene.save_video()

Algan ships the full Manim color palette: RED, BLUE_E, TEAL_A, GOLD and so on, plus WHITE, BLACK and TRANSPARENT.

Note

The two spellings compose, but they do not read each other back. A glow or an opacity baked into a color lands in that color’s own channel, so circle.glow still reports 0.0 after circle.color = GREEN.set_glow(0.5) – read circle.color[..., 3] for the glow the color carries, and [..., 4] for its opacity. What is rendered is correct either way, and setting one does not undo the other: assigning circle.opacity after a color with its own opacity leaves the color’s channel where it was.

See also

Mob Methods

Mob s also have a bunch of common operations built in to them as methods. Most of the time, these are what you will use.

Example: BasicMobMethods 

from algan import *

pentagon = RegularPolygon(5).spawn()
pentagon.move(RIGHT * 2)
pentagon.rotate(360, OUT)
pentagon.rotate(360, UP)
pentagon.rotate(360, OUT, about=ORIGIN)
pentagon.scale(2)
pentagon = pentagon.become(Circle(add_to_scene=False))
pentagon.wait(2)

Scene.save_video()

The methods used above:

  • move() translates the Mob by a vector: pentagon.move(RIGHT) slides it one unit right. To move to an absolute point instead, use move_to().

  • rotate() turns the Mob about an axis through its own centre. Passing about turns it about that point instead, which sweeps the Mob around in an arc: pentagon.rotate(180, OUT, about=ORIGIN) swings it half way around the origin.

  • become() morphs the Mob into a different Mob. It returns the resulting Mob, so assign it back: pentagon = pentagon.become(Circle(add_to_scene=False)). Build the target with add_to_scene=False: it is only there to say what shape to become, and is never itself drawn on screen. Without that flag Algan registers it as a Mob you meant to show, and warns that you never spawned it.

  • scale() grows or shrinks the Mob: pentagon.scale(2) doubles its size.

  • wait() holds the Mob still: pentagon.wait(2) leaves two seconds of nothing happening. Scene.wait(2) also does the same thing.

The Mob reference lists every method.

See also