keyframeを自動生成するスクリプト

generate_keyframes.py

#!/bin/env python

def ease_in_out_quad(x):
    if x < 0.5:
        return 2 * x * x
    else:
        return 1 - pow(-2 * x + 2, 2) / 2

n_step = 50
n_sway = 2
key_start = 50

x_start = -30
x_end = 20
x_diff = x_end - x_start

sway_step = n_step / n_sway
sway_init = (sway_step * abs(x_start / x_diff) / 2)

y_start = -70
y_end = 240
y_diff = y_end - y_start

for i in range(n_step):
    xi = 1 - abs((i + sway_init) % sway_step / sway_step * 2 - 1)
    x = x_diff * ease_in_out_quad(xi) + x_start;

    y = y_diff * ease_in_out_quad((i + 1) / n_step);

    if y > y_end:
        y = y - y_diff

    a = key_start + (i + 1) / n_step * (100 - key_start)

    print(f"{a}% {{ transform: translate({x:.2f}px, {y:.2f}px); }}")