import numpy as np
[docs]def fadein(clip, duration, initial_color=None):
"""
Makes the clip progressively appear from some color (black by default),
over ``duration`` seconds at the beginning of the clip. Can be used for
masks too, where the initial color must be a number between 0 and 1.
For cross-fading (progressive appearance or disappearance of a clip
over another clip, see ``composition.crossfade``
"""
if initial_color is None:
initial_color = 0 if clip.ismask else [0,0,0]
initial_color = np.array(initial_color)
def fl(gf, t):
if t>=duration:
return gf(t)
else:
fading = (1.0*t/duration)
return fading*gf(t) + (1-fading)*initial_color
return clip.fl(fl)