animation_reverse interface

This page explains the animation_reverse method interface.

What interface is this?

The animation_reverse interface reverses the running animations.

This interface exists in the instances that have the animation interfaces (such as the animation_x, animation_move).

Basic usage

The following example sets the x-coordinate animation and starts the 1-second interval timer to reverse animation with the animation_reverse interface.

from typing_extensions import TypedDict

import apysc as ap


class _RectOptions(TypedDict):
    rectangle: ap.Rectangle


def on_timer_1(e: ap.TimerEvent, options: _RectOptions) -> None:
    """
    The event handler that timer calls after the 3 seconds.

    Parameters
    ----------
    e : ap.TimerEvent
        Event instance.
    options : dict
        Optional arguments dictionary.
    """
    ap.Timer(on_timer_2, delay=1000, options=options).start()


def on_timer_2(e: ap.TimerEvent, options: _RectOptions) -> None:
    """
    The event handler that timer calls every second.

    Parameters
    ----------
    e : ap.TimerEvent
        Event instance.
    options : dict
        Optional arguments dictionary.
    """
    rectangle: ap.Rectangle = options["rectangle"]
    rectangle.animation_reverse()


ap.Stage(
    stage_width=500,
    stage_height=150,
    background_color=ap.Color("#333"),
    stage_elem_id="stage",
)
sprite: ap.Sprite = ap.Sprite()
sprite.graphics.begin_fill(color=ap.Color("#0af"))

rectangle: ap.Rectangle = sprite.graphics.draw_rect(x=50, y=50, width=50, height=50)
rectangle.animation_x(x=400, duration=5000).start()
options: _RectOptions = {"rectangle": rectangle}
ap.Timer(on_timer_1, delay=3000, repeat_count=1, options=options).start()

ap.save_overall_html(dest_dir_path="animation_reverse_basic_usage/")

Interface Notes

This interface can only use during animation. If you use this at the end of the animation, nothing happens, as follows:

from typing_extensions import TypedDict

import apysc as ap


class _RectOptions(TypedDict):
    rectangle: ap.Rectangle


def on_timer(e: ap.TimerEvent, options: _RectOptions) -> None:
    """
    The handler that the timer calls.

    Parameters
    ----------
    e : ap.TimerEvent
        Event instance.
    options : dict
        Optional arguments dictionary.
    """
    rectangle: ap.Rectangle = options["rectangle"]

    # Nothing happens since the animation has already been completed.
    rectangle.animation_reverse()


ap.Stage(
    stage_width=500,
    stage_height=150,
    background_color=ap.Color("#333"),
    stage_elem_id="stage",
)
sprite: ap.Sprite = ap.Sprite()
sprite.graphics.begin_fill(color=ap.Color("#0af"))

rectangle: ap.Rectangle = sprite.graphics.draw_rect(x=50, y=50, width=50, height=50)
rectangle.animation_x(x=400, duration=1000).start()

options: _RectOptions = {"rectangle": rectangle}
ap.Timer(on_timer, delay=1500, repeat_count=1, options=options).start()

ap.save_overall_html(dest_dir_path="animation_reverse_notes/")

animation_reverse API

Note: the document build script generates and updates this API document section automatically. Maybe this section is duplicated compared with previous sections.

[Interface signature] animation_reverse(self) -> None

[Interface summary]

Reverse all running animations.

[Notes]

Suppose you call this interface multiple times and animations reach the beginning or end of the animation. In that case, this interface ignores the reverse instruction. This behavior means that the same interval’s timer tick reverse setting does not work correctly (since the same interval setting reaches the animation start).

[Examples]

>>> from typing_extensions import TypedDict
>>> import apysc as ap
>>> class RectOptions(TypedDict):
...     rectangle: ap.Rectangle
...
>>> def on_timer(e: ap.TimerEvent, options: RectOptions) -> None:
...     rectangle: ap.Rectangle = options["rectangle"]
...     rectangle.animation_reverse()
>>> stage: ap.Stage = ap.Stage()
>>> sprite: ap.Sprite = ap.Sprite()
>>> sprite.graphics.begin_fill(color=ap.Color("#0af"))
>>> rectangle: ap.Rectangle = sprite.graphics.draw_rect(
...     x=50, y=50, width=50, height=50
... )
>>> _ = rectangle.animation_x(
...     x=100,
...     duration=1500,
...     easing=ap.Easing.EASE_OUT_QUINT,
... ).start()
>>> options: RectOptions = {"rectangle": rectangle}
>>> ap.Timer(on_timer, delay=750, options=options).start()