indication

Attention animations: drawing the viewer’s eye to something.

These are the “look here” effects. Indicate() swells a Mob and flashes its color; Wiggle() shakes it; Blink() flickers it; FocusOn() dims everything else and closes a spotlight onto a point; the passing-flash family runs a highlight along an outline.

Each is an animated function returning a Mob, so it composes with the animation contexts like any other change – put several in a Sync to indicate things together, or a Lag to sweep across them.

there_and_back() and wiggle() are the rate functions behind them, and are useful on their own as easing arguments.

Functions

ApplyWave(mob, direction=tensor([0., 1., 0.]), amplitude=0.2, ripples=1, time_width=1.0, runtime=2.0, wave_func=<function smooth>)[source]

Ripple a wave across a Mob’s geometry, left to right.

The Mob’s own points are displaced, so it flexes like a flag rather than moving as a rigid body, and it returns to its original shape at the end.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime.

Parameters:

  • mob – The Mob to ripple.

  • direction – Direction points are displaced in, shape (*, 3). Defaults to UP. The wave always travels along x; this is which way the Mob bulges.

  • amplitude (float) – Peak displacement, in world units. Defaults to 0.2.

  • ripples (int) – How many oscillations pass through the Mob. Defaults to 1.

  • time_width (float) – Width of the wave as a fraction of the Mob. Defaults to 1.0.

  • runtime (float) – Runtime of the ripple, in seconds. Defaults to 2.0.

  • wave_func – Easing applied to the wave’s shape. Defaults to easings.smooth.

Returns:

The Mob that was passed in.

Return type:

Mob

Flash a Mob on and off.

Visibility is switched instantly rather than faded, so the Mob blinks crisply. Each cycle costs time_on + time_off seconds.

Animation

Recorded as an animation whose runtime comes from these parameters rather than the enclosing context. Opacity is driven through the Mob’s color, so parts with their own colors keep them.

Parameters:

  • mob – The Mob to blink.

  • time_on (float) – Seconds visible per cycle. Defaults to 0.5.

  • time_off (float) – Seconds hidden per cycle. Defaults to 0.5.

  • blinks (int) – How many on/off cycles to perform. Defaults to 1.

  • hide_at_end (bool) – Whether to leave the Mob hidden when the blinking stops. Defaults to False, which leaves it visible.

Returns:

The Mob that was passed in.

Return type:

Mob

Circumscribe(mob, shape=None, fade_in=False, fade_out=False, time_width=0.3, buff=0.2, color=Color([1., 1., 0., 0., 1.]), runtime=1.0, stroke_width=3)[source]

Trace an outline around a Mob to single it out.

A frame is drawn around the Mob and then removed, so the highlight is a gesture rather than a lasting box. fade_in and fade_out choose between four behaviours: neither traces a passing flash around the frame, both fades the whole frame in and out, and either one alone combines a fade with drawing or erasing the outline.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. The frame is created and despawned around it, so nothing is left in the scene.

Parameters:

  • mob – The Mob to circumscribe.

  • shape – Outline shape: Rectangle, Square or Circle (the classes themselves, not instances). Defaults to None, meaning a rectangle around the Mob’s bounding box.

  • fade_in (bool) – Whether the frame fades in. Defaults to False.

  • fade_out (bool) – Whether the frame fades out. Defaults to False.

  • time_width (float) – Length of the travelling segment when neither fade is used, as a fraction of the outline. Defaults to 0.3.

  • buff (float) – Gap between the Mob and the outline, in world units. Defaults to 0.2.

  • color – Color of the outline. Defaults to YELLOW.

  • runtime (float) – Runtime of the whole gesture, in seconds. Defaults to 1.0.

  • stroke_width (float) – Thickness of the outline. Defaults to 3.

Returns:

The Mob that was passed in.

Return type:

Mob

Raises:

ValueError – If shape is not Rectangle, Square, Circle or None.

Flash(point_or_mobject, line_length=0.2, num_lines=12, flash_radius=0.1, line_stroke_width=3, color=Color([1., 1., 0., 0., 1.]), time_width=1.0, runtime=1.0)[source]

Burst short lines outwards from a point, like a spark or a ping.

Lines are arranged radially in the screen plane and each one flashes outwards, marking a moment at a location.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. The lines are created instantly beforehand and removed by their own flashes.

Parameters:

  • point_or_mobject – A Mob to flash around – its center is used – or a point of shape (*, 3).

  • line_length (float) – Length of each line, in world units. Defaults to 0.2.

  • num_lines (int) – How many lines to arrange around the point. Defaults to 12.

  • flash_radius (float) – Distance from the point at which the lines begin, in world units. Defaults to 0.1.

  • line_stroke_width (float) – Thickness of each line. Defaults to 3.

  • color – Color of the lines. Defaults to YELLOW.

  • time_width (float) – Fraction of each line visible at a time. Defaults to 1.0, i.e. the whole line.

  • runtime (float) – Runtime of the burst, in seconds. Defaults to 1.0.

Returns:

Whatever was passed in.

Return type:

Mob or torch.Tensor

FocusOn(focus_point, opacity=0.2, color=Color([0.5333, 0.5333, 0.5333, 0.0000, 1.0000]), runtime=2.0)[source]

Contract a large translucent disc onto a point, like a closing spotlight.

Draws the eye to one spot by shrinking a tinted circle down to nothing there. The circle is created and removed for you.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. The spotlight is spawned and despawned instantly around it, so it costs no extra video time.

Parameters:

  • focus_point – A Mob to focus on – its center is used – or a point of shape (*, 3).

  • opacity (float) – Peak opacity of the disc as it closes in, 0 to 1. Defaults to 0.2.

  • color – Color of the disc. Defaults to GRAY.

  • runtime (float) – Runtime of the contraction, in seconds. Defaults to 2.0.

Returns:

The spotlight Mob, already despawned.

Return type:

Circle

Indicate(mob, scale_factor=1.2, color=Color([1., 1., 0., 0., 1.]), runtime=1.0)[source]

Draw attention to a Mob by briefly growing and recoloring it.

The Mob swells and flashes color, then returns to exactly how it was – the standard “look here” gesture.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. The scale pulse is relative to each part’s own size, so a composite Mob whose parts were scaled separately keeps its proportions.

Parameters:

  • mob – The Mob to indicate.

  • scale_factor (float) – How large the Mob grows at the peak, as a multiple of its current size. Defaults to 1.2.

  • color – Color to flash. Defaults to YELLOW.

  • runtime (float) – Runtime of the whole gesture, in seconds. Defaults to 1.0.

Returns:

The Mob that was passed in.

Return type:

Mob

ShowPassingFlash(mob, time_width=0.1, runtime=1.0)[source]

Run a bright segment along a curve, like a spark following a wire.

A short piece of the curve is visible at a time and travels from one end to the other, leaving nothing behind. Works on any Mob built from curves; for a composite, every curve in it flashes at once.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. A transient stroke-only clone is spawned and despawned around the flash, so the Mob does not need to be spawned beforehand. A visible source Mob is hidden during the traversal and restored exactly afterwards.

Parameters:

  • mob – The curve, or a Mob containing curves, to flash along.

  • time_width (float) – Length of the travelling segment as a fraction of the curve. Defaults to 0.1; smaller values look like a sharper spark.

  • runtime (float) – Runtime of the traversal, in seconds. Defaults to 1.0.

Returns:

The Mob that was passed in.

Return type:

Mob

ShowPassingFlashWithThinningStrokeWidth(vmobject, n_segments=10, time_width=0.1, runtime=1.0)[source]

Run a tapering flash along a curve, like a comet with a tail.

Several passing flashes are layered, each thinner and longer than the last, so the travelling spark trails off behind itself instead of ending abruptly.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. The layers are clones created instantly beforehand; the original Mob is untouched.

Parameters:

  • vmobject – The curve to flash along. Its stroke_width sets the thickest layer.

  • n_segments (int) – How many layers to draw. Defaults to 10; more is smoother and slower.

  • time_width (float) – Length of the leading segment as a fraction of the curve. Defaults to 0.1.

  • runtime (float) – Runtime of the traversal, in seconds. Defaults to 1.0.

Returns:

The Mob that was passed in.

Return type:

Mob

Wiggle(mob, scale_value=1.1, rotation_angle=0.06283185307179587, n_wiggles=6, scale_about_point=None, rotate_about_point=None, runtime=2.0)[source]

Shake a Mob back and forth, as if jostled.

The Mob rocks a few degrees either way while swelling slightly, then settles exactly where it started. Reads as “this thing is trying to get your attention” without moving it anywhere.

Animation

Recorded as an animation of runtime seconds, regardless of the enclosing context’s runtime. Position and orientation are rebuilt each frame from the pre-wiggle state, so nothing accumulates.

Parameters:

  • mob – The Mob to wiggle.

  • scale_value (float) – Peak size during the wiggle, as a multiple of the current size. Defaults to 1.1.

  • rotation_angle (float) – Peak rocking angle, in radians – unusually for Algan, since this mirrors Manim’s signature. Defaults to 0.02 * pi (about 3.6 degrees).

  • n_wiggles (int) – How many times the Mob rocks. Defaults to 6.

  • scale_about_point – Point to scale around, shape (*, 3). Defaults to None, meaning scale in place.

  • rotate_about_point – Point to rock around, shape (*, 3). Defaults to None, meaning rock in place.

  • runtime (float) – Runtime of the whole wiggle, in seconds. Defaults to 2.0.

Returns:

The Mob that was passed in.

Return type:

Mob

draw_step(mob, t, full_control_points)[source]

Internal: show one instant of a curve being drawn in.

Reveals the curve from its start up to progress t.

Parameters:

  • mob – The bezier circuit being drawn.

  • t – Animation progress, 0 to 1, supplied per frame.

  • full_control_points – The circuit’s complete control points, captured before the animation.

passing_flash_step(mob, t, time_width, full_control_points)[source]

Internal: show one instant of a ShowPassingFlash().

Reveals a moving window of the curve, sliding from start to end.

Parameters:

  • mob – The bezier circuit being flashed.

  • t – Animation progress, 0 to 1, supplied per frame.

  • time_width – Width of the visible window as a fraction of the curve.

  • full_control_points – The circuit’s complete control points, captured before the flash.

there_and_back(t, inflection=10.0)[source]

Rate function that eases out to 1 and back to 0.

Progress rises over the first half and returns over the second, which turns any animation into a there-and-back gesture.

Parameters:

  • t – Animation progress, 0 to 1.

  • inflection (float) – Steepness of the easing at the midpoint; larger is snappier. Defaults to 10.0.

Returns:

Adjusted progress, 0 at both ends and 1 in the middle.

Return type:

torch.Tensor

undraw_step(mob, t, full_control_points)[source]

Internal: show one instant of a curve being erased.

The reverse of draw_step(): the curve retreats towards its start.

Parameters:

  • mob – The bezier circuit being erased.

  • t – Animation progress, 0 to 1, supplied per frame.

  • full_control_points – The circuit’s complete control points, captured before the animation.

wiggle(t, wiggles=2)[source]

Rate function that oscillates, with the swing fading in and out.

A sine wave scaled by there_and_back(), so the oscillation grows towards the middle and settles by the end rather than stopping mid-swing.

Parameters:

  • t – Animation progress, 0 to 1.

  • wiggles (int) – How many half-oscillations to perform. Defaults to 2.

Returns:

Signed oscillation, starting and ending at 0.

Return type:

torch.Tensor

wiggle_step(mob, t, basis_0, location_0, scale_value, rotation_angle, n_wiggles, scale_about_point, rotate_about_point)[source]

Internal: place a Mob at one instant of a Wiggle().

Rebuilds the Mob’s basis and location from the values it had before the wiggle started, so the effect leaves no drift. Use Wiggle().

Parameters:

  • mob – The Mob being wiggled.

  • t – Animation progress, 0 to 1, supplied per frame.

  • basis_0 – The Mob’s basis before the wiggle began.

  • location_0 – The Mob’s location before the wiggle began.

  • scale_value – Peak scale, as a multiple of the original size.

  • rotation_angle – Peak rotation, in radians (converted internally to degrees).

  • n_wiggles – Number of half-oscillations.

  • scale_about_point – Point to scale around, or None to scale in place.

  • rotate_about_point – Point to rotate around, or None to rotate in place.