Numbers¶

The film's code

import manimgx as m


class NumbersHero(m.Scene):
    def construct(self) -> None:
        number = m.DecimalNumber(0, num_decimal_places=2, font_size=96, color=m.YELLOW)
        variable = m.Variable(0, m.MathTex("x"), num_decimal_places=2).scale(1.5)
        tracker = variable.tracker
        m.VGroup(number, variable).arrange(m.DOWN, buff=1)

        def follow(mobject: m.DecimalNumber) -> None:
            mobject.set_value(tracker.get_value())

        number.add_updater(follow)
        self.add(number, variable)
        self.play(tracker.animate.set_value(3.14), run_time=2)
        self.wait()

A number is a text that knows its value. set_value shows another value in its place, with the same look, so a number can count while a scene plays: by an updater that sets it at every frame, or by ChangeDecimalToValue.

DecimalNumber ¶

A number, written with a fixed number of decimal places: white and filled unless styled.

Its parts are its characters, in order, each typeset by mob_class: the sign, the digits, the commas and the decimal point; then "…" and the unit, if any (and a background rectangle before them all, if asked for). The number shown is rounded (a negative one that rounds to zero loses its sign, in either component of a complex number), and a complex one is written a+bi. set_value shows another number, keeping the font size, the color and the edge edge_to_fix where they are: driven by a value tracker, or by ChangeDecimalToValue, the number counts on screen.

m.DecimalNumber(number=0, num_decimal_places=2, mob_class=MathTex, include_sign=False, group_with_commas=True, digit_buff_per_font_unit=0.001, show_ellipsis=False, unit=None, unit_buff_per_font_unit=0, include_background_rectangle=False, edge_to_fix=LEFT, font_size=DEFAULT_FONT_SIZE, **kwargs)

number: The number to show; a complex one too.
num_decimal_places: How many digits follow the decimal point.
mob_class: The class each character is typeset with.
include_sign: Whether a number that is not negative is written with a plus sign.
group_with_commas: Whether the digits before the decimal point are grouped in threes by commas.
digit_buff_per_font_unit: The gap between characters, per unit of font size (0.001: 0.048 scene units at 48).
show_ellipsis: Whether "…" follows the number.
unit: A unit after the number, in LaTeX math ("^\circ", r"\text{ m}"); one that starts with "^" is raised to the number's top.
unit_buff_per_font_unit: The gap before the unit, beyond the gap between characters, per unit of font size.
include_background_rectangle: Whether a background rectangle is behind the number.
edge_to_fix: The edge, as a direction, that stays where it is when a new value changes the number's width.
font_size: The characters' font size, as mob_class measures it.
color: The color of both fill and stroke (default white); None for the class's default.
fill_color: The fill's color; color if not given. Several colors make a gradient along sheen_direction.
fill_opacity: The fill's opacity, from 0 to 1 (default 0: no fill).
stroke_color: The stroke's color; color if not given. Several colors make a gradient.
stroke_opacity: The stroke's opacity, from 0 to 1 (default 1).
stroke_width: The stroke's width, in hundredths of a scene unit (default 4; 0: no stroke).
background_stroke_color: The color of an outline drawn behind the fill (default black).
background_stroke_opacity: The outline's opacity, from 0 to 1 (default 1).
background_stroke_width: The outline's width, in hundredths of a scene unit (default 0: none).
sheen_factor: How much the colors lighten toward sheen_direction, from -1 to 1 (default 0); a negative factor darkens.
sheen_direction: The direction the colors lighten toward (default UL).
joint_type: How the stroke is joined where its path turns: round, beveled or mitered, as a two-dimensional scene draws it (see LineJointType; default AUTO: mitered).
cap_style: How the stroke ends, at each end it shows (an open path's, a dash's): round, butt or square, as a two-dimensional scene draws it (see CapStyleType; default AUTO: butt).
shade_in_3d: Whether a three-dimensional scene's light shades the mobject.
material: How its surface reflects the scene's lights in a three-dimensional scene (see Material); None: Manim's shading (default).
name: A name for the mobject; its class's name if not given.
z_index: Its place in the drawing order: a higher index is drawn over a lower one (default 0).
target: The state MoveToTarget moves the mobject to.

It also takes the style keywords.

Source

src/manimgx/mobjects/numbers.py

@prototype
def __init__(
    self,
    number: float = 0,
    num_decimal_places: int = 2,
    mob_class: type[ManimTextLabel] = MathTex,
    include_sign: bool = False,
    group_with_commas: bool = True,
    digit_buff_per_font_unit: float = 0.001,
    show_ellipsis: bool = False,
    unit: str | None = None,
    unit_buff_per_font_unit: float = 0,
    include_background_rectangle: bool = False,
    edge_to_fix: Vector3DLike = LEFT,
    font_size: float = DEFAULT_FONT_SIZE,
    **kwargs: Unpack[Style],
):
    if font_size <= 0:
        raise ValueError("font_size must be greater than 0.")
    super().__init__(**kwargs)
    self.number = number
    self.num_decimal_places = num_decimal_places
    self.include_sign = include_sign
    self.mob_class = mob_class
    self.group_with_commas = group_with_commas
    self.digit_buff_per_font_unit = digit_buff_per_font_unit
    self.show_ellipsis = show_ellipsis
    self.unit = unit
    self.unit_buff_per_font_unit = unit_buff_per_font_unit
    self.include_background_rectangle = include_background_rectangle
    self.edge_to_fix = edge_to_fix
    self._font_size = font_size
    self._set_submobjects_from_number(number)
    self.init_colors()

font_size ¶

The number's font size: the one it was made with, times how much it has been scaled since. Set it, to a positive size, to scale the number to it.

number.font_size

Source

src/manimgx/mobjects/numbers.py

def font_size(self) -> float:
    """The number's font size: the one it was made with, times how much it has been
    scaled since. Set it, to a positive size, to scale the number to it."""
    return_value: float = self.height / self.initial_height * self._font_size
    return return_value

get_value ¶

The number shown, as it was given: not rounded.

number.get_value()

Source

src/manimgx/mobjects/numbers.py

def get_value(self) -> float:
    """The number shown, as it was given: not rounded."""
    return self.number

increment_value ¶

Show the number plus delta_t.

number.increment_value(delta_t=1)

delta_t: What to add.

Source

src/manimgx/mobjects/numbers.py

def increment_value(self, delta_t: float = 1) -> Self:
    """Show the number plus `delta_t`.

    Args:
        delta_t: What to add.
    """
    return self.set_value(self.get_value() + delta_t)

set_value ¶

Code

import manimgx as m


class DecimalNumberSetValueExample(m.Scene):
    def construct(self) -> None:
        tracker = m.ValueTracker(0)
        number = m.DecimalNumber(0, font_size=144).shift(2 * m.LEFT)
        number.add_updater(lambda n: n.set_value(tracker.get_value()))
        self.add(number)
        self.play(tracker.animate.set_value(100), run_time=3)

Show another number, keeping the look: the font size, the edge edge_to_fix where it is, and the color — every character takes the number's own, so a color given to single characters is not kept.

number.set_value(number)

number: The number to show.

Source

src/manimgx/mobjects/numbers.py

def set_value(self, number: float) -> Self:
    """Show another number, keeping the look: the font size, the edge `edge_to_fix`
    where it is, and the color — every character takes the number's own, so a color
    given to single characters is not kept.

    Args:
        number: The number to show.

    Examples:
        ```python
        import manimgx as m


        class DecimalNumberSetValueExample(m.Scene):
            def construct(self) -> None:
                tracker = m.ValueTracker(0)
                number = m.DecimalNumber(0, font_size=144).shift(2 * m.LEFT)
                number.add_updater(lambda n: n.set_value(tracker.get_value()))
                self.add(number)
                self.play(tracker.animate.set_value(100), run_time=3)
        ```
    """
    # every glyph takes the number's own color, as CE's `init_colors` repaints them.
    # A number still as it was left showing the same string is left alone: its
    # members' geometry and paint are values, so "as it was left" is the same objects
    shown = self._get_num_string(number)
    key = self._row_key(shown)
    last = self._shown
    if last is not None and last[0] == key:
        family = self.get_family()
        if len(family) == len(last[1]) and all(
            m is was and m._geometry is g and m.paint is p
            for m, (was, g, p) in zip(family, last[1], strict=True)
        ):
            self.number = number
            return self
    old_font_size = self.font_size
    move_to_point = self.get_critical_point(self.edge_to_fix)
    key = self._set_submobjects_from_number(number)
    self.font_size = old_font_size
    self.move_to(move_to_point, self.edge_to_fix)
    self.init_colors()
    self._shown = (
        key,
        tuple((m, m._geometry, m.paint) for m in self.get_family()),
    )
    return self

Integer ¶

Code

import manimgx as m


class IntegerExample(m.Scene):
    def construct(self) -> None:
        count = m.Integer(0, font_size=144).shift(1.5 * m.LEFT)
        self.add(count)
        self.play(m.ChangeDecimalToValue(count, 1000), run_time=3)

An integer: a DecimalNumber with no decimal places, white and filled unless styled.

A number with a fractional part is shown rounded, and get_value rounds it too.

m.Integer(number=0, num_decimal_places=0, **kwargs)

number: The number to show.
num_decimal_places: How many digits follow the decimal point: none unless given.

It also takes the DecimalNumber keywords.

Source

src/manimgx/mobjects/numbers.py

def __init__(
    self,
    number: float = 0,
    num_decimal_places: int = 0,
    **kwargs: Unpack[NumberStyle],
) -> None:
    super().__init__(number=number, num_decimal_places=num_decimal_places, **kwargs)

get_value ¶

The number shown: the number given, rounded to an integer.

integer.get_value()

Source

src/manimgx/mobjects/numbers.py

def get_value(self) -> int:
    """The number shown: the number given, rounded to an integer."""
    return int(np.round(super().get_value()))

Variable ¶

Code

import manimgx as m


class VariableExample(m.Scene):
    def construct(self) -> None:
        x = m.Variable(2.0, "x", num_decimal_places=3)
        y = m.Variable(4.0, "x^2", num_decimal_places=3)
        self.add(m.VGroup(x, y).arrange(m.DOWN, buff=0.5).scale(2))
        t = x.tracker
        y.add_updater(lambda v: v.tracker.set_value(t.get_value() ** 2))
        self.play(t.animate.set_value(5), run_time=3, rate_func=m.linear)

A named value: a label, "=", and a number that shows a value tracker's value.

Its parts are its label, followed by "=", and its value, a DecimalNumber or an Integer that shows its tracker's value at every frame: animate the tracker, and the number counts.

m.Variable(var, label, var_type=DecimalNumber, num_decimal_places=2, **kwargs)

var: The value it starts with.
label: The label: a string, typeset as math (MathTex), or a text or math mobject.
var_type: The number's class: DecimalNumber or a subclass, such as Integer.
num_decimal_places: How many digits follow the decimal point. Integer classes use their own precision defaults instead.
color: The color of both fill and stroke (default white); None for the class's default.
fill_color: The fill's color; color if not given. Several colors make a gradient along sheen_direction.
fill_opacity: The fill's opacity, from 0 to 1 (default 0: no fill).
stroke_color: The stroke's color; color if not given. Several colors make a gradient.
stroke_opacity: The stroke's opacity, from 0 to 1 (default 1).
stroke_width: The stroke's width, in hundredths of a scene unit (default 4; 0: no stroke).
background_stroke_color: The color of an outline drawn behind the fill (default black).
background_stroke_opacity: The outline's opacity, from 0 to 1 (default 1).
background_stroke_width: The outline's width, in hundredths of a scene unit (default 0: none).
sheen_factor: How much the colors lighten toward sheen_direction, from -1 to 1 (default 0); a negative factor darkens.
sheen_direction: The direction the colors lighten toward (default UL).
joint_type: How the stroke is joined where its path turns: round, beveled or mitered, as a two-dimensional scene draws it (see LineJointType; default AUTO: mitered).
cap_style: How the stroke ends, at each end it shows (an open path's, a dash's): round, butt or square, as a two-dimensional scene draws it (see CapStyleType; default AUTO: butt).
shade_in_3d: Whether a three-dimensional scene's light shades the mobject.
material: How its surface reflects the scene's lights in a three-dimensional scene (see Material); None: Manim's shading (default).
name: A name for the mobject; its class's name if not given.
z_index: Its place in the drawing order: a higher index is drawn over a lower one (default 0).
target: The state MoveToTarget moves the mobject to.

It also takes the style keywords.

Source

src/manimgx/mobjects/numbers.py

def __init__(
    self,
    var: float,
    label: str | MathTex | Text | SingleStringMathTex,
    var_type: type[DecimalNumber] = DecimalNumber,
    num_decimal_places: int = 2,
    **kwargs: Unpack[Style],
):
    self.label = MathTex(label) if isinstance(label, str) else label
    """The label, followed by "=", one of its submobjects."""
    equals = MathTex("=").next_to(self.label, RIGHT)
    self.label.add(equals)
    self.tracker = ValueTracker(var)
    """The value tracker the number shows: set or animate it to change the
    number."""
    self.value = (
        var_type(self.tracker.get_value())
        if issubclass(var_type, Integer)
        else var_type(
            self.tracker.get_value(), num_decimal_places=num_decimal_places
        )
    )
    """The number, which shows the tracker's value at every frame."""
    self.value.add_updater(self._update_value).next_to(self.label, RIGHT)
    super().__init__(**kwargs)
    self.add(self.label, self.value)

label ¶

The label, followed by "=", one of its submobjects.

tracker ¶

The value tracker the number shows: set or animate it to change the number.

value ¶

The number, which shows the tracker's value at every frame.

Count to a value¶

ChangeDecimalToValue ¶

Code

import manimgx as m


class ChangeDecimalToValueExample(m.Scene):
    def construct(self) -> None:
        number = m.DecimalNumber(0, font_size=144)
        self.add(number)
        self.play(m.ChangeDecimalToValue(number, 3.14, run_time=2))

Count a number to a value.

It goes from the value it has when the animation is made to target_number, eased by the rate function.

m.ChangeDecimalToValue(decimal_mob, target_number, **kwargs)

decimal_mob: The number to change.
target_number: The value it ends at.
run_time: How long the animation plays, in seconds (default 1).
lag_ratio: How the parts of the mobject are staggered: each begins this fraction of its run after the one before it begins (default 0: all together; 1: one after another).
rate_func: How the animation's progress runs with time: a function from [0, 1] to [0, 1] (default smooth; see rate functions).
reverse_rate_function: Whether to run the animation backward (default False).
name: A name for the animation.
remover: Whether the mobject leaves the scene when the animation finishes (default False).
suspend_mobject_updating: Whether the mobject's updaters run beneath the animation (default True): they keep acting on the mobject, and each frame shows the animation applied to the result. If False, they act on the animated mobject itself.
introducer: Whether the mobject joins the scene when the animation begins (default False); otherwise the play brings it in when the play begins, if the scene lacks it.
use_override: Whether a mobject whose class plays another animation in place of this one does so (default True).

It also takes the animation keywords.

Source

src/manimgx/animation/motion.py

def __init__(
    self,
    decimal_mob: DecimalNumber,
    target_number: float,
    **kwargs: Unpack[AnimationOptions],
) -> None:
    start = decimal_mob.number
    super().__init__(
        decimal_mob, lambda a: interpolate(start, target_number, a), **kwargs
    )

ChangingDecimal ¶

Code

import manimgx as m


class ChangingDecimalExample(m.Scene):
    def construct(self) -> None:
        number = m.DecimalNumber(0, font_size=144)
        self.add(number)
        self.play(m.ChangingDecimal(number, lambda a: 100 * a, run_time=3))

Change the value a number shows with the animation's progress.

At every frame, the number shows number_update_func of the progress, from 0 to 1, eased by the rate function.

m.ChangingDecimal(decimal_mob, number_update_func, **kwargs)

decimal_mob: The number to change.
number_update_func: A function from the progress to the value to show.
run_time: How long the animation plays, in seconds (default 1).
lag_ratio: How the parts of the mobject are staggered: each begins this fraction of its run after the one before it begins (default 0: all together; 1: one after another).
rate_func: How the animation's progress runs with time: a function from [0, 1] to [0, 1] (default smooth; see rate functions).
reverse_rate_function: Whether to run the animation backward (default False).
name: A name for the animation.
remover: Whether the mobject leaves the scene when the animation finishes (default False).
suspend_mobject_updating: Whether the mobject's updaters run beneath the animation (default True): they keep acting on the mobject, and each frame shows the animation applied to the result. If False, they act on the animated mobject itself.
introducer: Whether the mobject joins the scene when the animation begins (default False); otherwise the play brings it in when the play begins, if the scene lacks it.
use_override: Whether a mobject whose class plays another animation in place of this one does so (default True).

It also takes the animation keywords.

Source

src/manimgx/animation/motion.py

def __init__(
    self,
    decimal_mob: DecimalNumber,
    number_update_func: Callable[[float], float],
    **kwargs: Unpack[AnimationOptions],
) -> None:
    self.number_update_func = number_update_func
    super().__init__(decimal_mob, **kwargs)