Spin, step 2: Spinning
In step 1 the sheet turned once, back to rest. In this step it spins twice about the vertical axis and lands facing you again.
3D chapters used: Rotation, Animating in 3D.
Update the module
Replace myspin.py with this version:
"""MySpin, tutorial step 2: the sheet spins.
The text spins twice about the vertical axis and ends facing the viewer. Later steps build it up into the Spin
effect.
"""
from __future__ import annotations
from dataclasses import dataclass
from terminaltexteffects import easing
from terminaltexteffects.engine.base_config import BaseConfig
from terminaltexteffects.engine.base_effect import BaseEffect, BaseEffectIterator
from terminaltexteffects.engine.space3d import Body, Space3D
from terminaltexteffects.utils import argutils
def get_effect_resources() -> tuple[str, type[BaseEffect], type[BaseConfig]]:
"""Return the command name, effect class, and configuration class TTE registers."""
return "myspin", MySpin, MySpinConfig
@dataclass
class MySpinConfig(BaseConfig):
"""Configuration for the MySpin effect. It has no options yet."""
parser_spec = argutils.ParserSpec(
name="myspin",
help="The text tumbles in from the distance as a flat sheet, spins, and settles into place.",
description="myspin | The text tumbles in from the distance as a flat sheet, spins, and settles into place.",
epilog="Example: tte myspin",
)
class MySpinIterator(BaseEffectIterator[MySpinConfig]):
"""Produce the frames of the MySpin effect."""
def __init__(self, effect: MySpin) -> None:
"""Mount the text on a sheet and queue its spin."""
super().__init__(effect)
self.space = Space3D(self.terminal, perspective=0)
self.build()
def build(self) -> None:
"""Mount every visible character on the sheet and queue the spin."""
characters = [character for character in self.terminal.get_characters() if character.input_symbol != " "]
for character in characters:
self.terminal.set_character_visibility(character, is_visible=True)
self.active_characters.add(character)
self.sheet = self.space.body()
self.sheet.add_chars(characters, self.sheet.text_plane(characters))
self.sheet.spin("y", turns=2, frames=240, ease=easing.in_out_sine)
self.sheet.on_complete(self.finish)
def finish(self, sheet: Body) -> None:
"""Hand the characters back, on their input cells."""
sheet.release_all()
def __next__(self) -> str:
"""Move the sheet one frame, then the characters with it."""
if self.space.animating or self.active_characters:
self.space.step()
self.update()
return self.frame
raise StopIteration
class MySpin(BaseEffect[MySpinConfig]):
"""The text tumbles in from the distance as a flat sheet, spins, and settles into place."""
@property
def _config_cls(self) -> type[MySpinConfig]:
return MySpinConfig
@property
def _iterator_cls(self) -> type[MySpinIterator]:
return MySpinIterator
What changed
The set_rotation and turn_to_rest calls are replaced with one call:
spin turns the body about an axis by whole or partial turns, spread over frames. Two whole turns end where they
started, so the text lands at rest. in_out_sine starts slowly, speeds up and slows down again.
A spin turns about the world's axis, not the body's own. That doesn't matter yet, because the sheet isn't tilted. It will in step 5.
Run it
Halfway through each turn the sheet faces away, and you read the text mirrored. Step 4 deals with the back side.
Next step
Step 3 adds perspective, and starts the sheet far behind the canvas.