terminal slides lol

slides.py

import abc
import collections.abc
import os
import shutil
import sys
import time
import typing


class RGBColor(typing.NamedTuple):
    red: int
    green: int
    blue: int

    def to_printable(self) -> str:
        return "\x1b[38;2;%d;%d;%dm{}\x1b[39m" % self


class RGBAColor(typing.NamedTuple):
    red: int
    green: int
    blue: int
    alpha: float = 1.0

    def remove_alpha(self) -> RGBColor:
        return RGBColor(*self[:-1])


def flatten_component(fgc: int, bgc: int, opacity: float) -> int:
    return int(((fgc - bgc) * opacity) + bgc)


def flatten_foreground(
    fg: RGBAColor,
    bg: RGBColor,
    strategy: collections.abc.Callable[[int, int, float], int] | None = None,
) -> RGBColor:
    _strategy = strategy or flatten_component

    return RGBColor(
        *(_strategy(c, bg[i], fg.alpha) for i, c in enumerate(fg.remove_alpha()))
    )


T_contra = typing.TypeVar("T_contra", contravariant=True)


class SupportsWrite(typing.Protocol[T_contra]):
    @abc.abstractmethod
    def write(self, __s: T_contra, /) -> typing.Any:
        pass


def set_bg(color: RGBColor, *, file: SupportsWrite[str] | None = None) -> None:
    _file = file or sys.stdout

    _file.write("\x1b[48;2;%d;%d;%dm" % color)


def reset_bg(*, file: SupportsWrite[str] | None = None) -> None:
    _file = file or sys.stdout

    _file.write("\x1b[49m")


def init_seq() -> None:
    sys.stdout.write("\x1b[?1049h")
    sys.stdout.write("\x1b[2J\x1b[H")
    sys.stdout.write("\x1b[?25l")


def end_seq() -> None:
    print("\x1b[?1049l\x1b[?25h")


def write_string(
    message: str,
    x: int,
    y: int,
    *,
    delay: float = 0.0,
    release: float = 0.0,
) -> None:
    time.sleep(delay)
    sys.stdout.write(f"\x1b[{x};{y}H")
    sys.stdout.write(message)
    sys.stdout.flush()
    time.sleep(release)


def write_strings(
    messages: collections.abc.Iterable[str],
    x: int,
    y: int,
    *,
    delay: float = 0.0,
    release: float = 0.0,
    postdelay: float = 0.0,
) -> None:
    for message in messages:
        write_string(message, x, y, delay=delay, release=release)

    time.sleep(postdelay)


def print_seq(
    message: str,
    message_length: int | None = None,
    /,
    fg: RGBColor = RGBColor(255, 255, 255),
    bg: RGBColor = RGBColor(0, 0, 0),
    framerate: int = 25,
    sustain: float = 1.0,
    release: float = 0.0,
) -> None:
    width, height = shutil.get_terminal_size()

    _message_length = len(message) if message_length is None else message_length

    top = (height - 1) // 2
    left = (width - _message_length) // 2

    fadein_frames = [
        flatten_foreground(RGBAColor(*fg, (a / framerate)), bg)
        for a in range(0, framerate)
    ]
    fadeout_frames = list(reversed(fadein_frames))

    fadein = list(map(lambda a: a.to_printable().format(message), fadein_frames))
    fadeout = list(map(lambda a: a.to_printable().format(message), fadeout_frames))

    set_bg(bg)

    for _ in range(height):
        print(" " * width)

    write_strings(fadein, top, left, release=1 / framerate, postdelay=sustain)
    write_strings(fadeout, top, left, release=1 / framerate, postdelay=release)


def main() -> int:
    FRAMERATE = 100

    fg = RGBColor(255, 255, 255)
    bg = RGBColor(0, 0, 0)

    mom_bg = RGBColor(48, 24, 0)
    son_bg = RGBColor(0, 24, 48)

    try:
        init_seq()

        print_seq(
            "© 2007 The Pokémon Company Inc.",
            fg=fg,
            bg=bg,
            framerate=FRAMERATE,
            release=0.5,
        )
        print_seq("Can you come out?", bg=mom_bg, framerate=FRAMERATE)
        print_seq("Mom, I am gay.", bg=son_bg, framerate=FRAMERATE)
        print_seq(
            "I know that, silly. Come out to the car.", bg=mom_bg, framerate=FRAMERATE
        )
        print_seq("Car, I am gay.", bg=son_bg, framerate=FRAMERATE)
    finally:
        end_seq()

    return os.EX_OK


if __name__ == "__main__":
    raise SystemExit(main())