第5月第18天 视频编辑 水印

//*********** For A Special Time
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
    [animation setDuration:0];
    [animation setFromValue:[NSNumber numberWithFloat:1.0]];
    [animation setToValue:[NSNumber numberWithFloat:0.0]];
    [animation setBeginTime:5];
    [animation setRemovedOnCompletion:NO];
    [animation setFillMode:kCAFillModeForwards];
    [overlayLayer addAnimation:animation forKey:@"animateOpacity"];