減衰振動(1次元)

UIView+GRBLSpringAdditions.m

@implementation UIView (GRBLSpringAdditions)
+ (void)dampedOscillationAlongXAxis:(UIView *)view
                                toX:(CGFloat)toX
                                  k:(CGFloat)k
                              omega:(CGFloat)omega
                    minimumDuration:(CGFloat)minimumDuration
                    completionBlock:(void (^)(BOOL))completionBlock {
    
    /*******************
     4回の振動で減衰終了するの前提
     
     減衰カーブ
     y = Ae^(-kt)sin(wt)
     
     2*T = duration
     
     w * 0.25 * duration = 2*PI/2
     w * 0.50 * duration = 4*PI/2
     w * 0.75 * duration = 6*PI/2
     w * 1.00 * duration = 8*PI/2
     ********************/
    
    CGFloat fromX = view.frame.origin.x;
    CGFloat amplitude = fabs(toX - fromX);
    CGFloat duration = minimumDuration * log10(amplitude + 1.0);   // 1/2kx^2 = 1/2mv^2
    NSLog(@"duration:%f", duration);
    
    CGRect lastRect = view.frame;
    lastRect.origin.x = toX;
    
    CGRect toRect1 = lastRect;
    CGRect toRect2 = lastRect;
    CGRect toRect3 = lastRect;
    
    if (fromX - toX > 0) {
        // Right -> Left
        toRect1.origin.x -= amplitude * exp(-k* 2.0*M_PI/(2*omega));
        toRect2.origin.x += amplitude * exp(-k* 4.0*M_PI/(2*omega));
        toRect3.origin.x -= amplitude * exp(-k* 6.0*M_PI/(2*omega));
    }else {
        // Left -> Right
        toRect1.origin.x += amplitude * exp(-k* 2.0*M_PI/(2*omega));
        toRect2.origin.x -= amplitude * exp(-k* 4.0*M_PI/(2*omega));
        toRect3.origin.x += amplitude * exp(-k* 6.0*M_PI/(2*omega));
    }
    
    [UIView animateWithDuration:0.25*duration
                          delay:0.0
                        options:UIViewAnimationOptionCurveEaseInOut
                     animations:^{view.frame = toRect1;}
                     completion:^(BOOL finished){
                         
                         [UIView animateWithDuration:0.25*duration
                                               delay:0.0
                                             options:UIViewAnimationOptionCurveEaseInOut
                                          animations:^{view.frame = toRect2;}
                                          completion:^(BOOL finished){
                                              
                                              [UIView animateWithDuration:0.25*duration
                                                                    delay:0.0
                                                                  options:UIViewAnimationOptionCurveEaseInOut
                                                               animations:^{view.frame = toRect3;}
                                                               completion:^(BOOL finished){
                                                                   
                                                                   [UIView animateWithDuration:0.25*duration
                                                                                         delay:0.0
                                                                                       options:UIViewAnimationOptionCurveEaseInOut
                                                                                    animations:^{view.frame = lastRect;}
                                                                                    completion:^(BOOL finished){
                                                                                        
                                                                                        // 終了block実行
                                                                                        completionBlock(YES);
                                                                                    }
                                                                    ];
                                                               }
                                               ];
                                          }
                          ];
                     }
     ];
}
@end