Add Motion with JavaFX Animation - JavaFX: Developing Rich Internet Applications - page 195

public override function curve(t: Number) : Number {
if( t == 0.0 or t == 1.0) {
return t;
}
if(type == IN) {
var xt = t - 1;
return -(amplitude*Math.pow(2,10*xt) *
Math.sin( (xt-s)*(2*Math.PI)/period ));
} else if(type == OUT) {
var xt = t;
return amplitude*Math.pow(2,-10*xt) *
Math.sin( (xt-s)*(2*Math.PI)/period )
+ 1.0;
} else { // type == BOTH
var dt = t * 2.0;
if(dt < 1.0) {
var xt = dt -1;
return -.5 * amplitude*Math.pow(2,10*(xt)) *
Math.sin( (xt-s)*(2*Math.PI)/
period );
} else {
var xt = dt-1;
return (0.5 * amplitude*
Math.pow(2,-10*(xt)) *
Math.sin(
(xt-s)*(2*Math.PI)/period )) + 1.0;
}
}
}
}
Elastic is similar to bounce or spring effects, but gives a snap out/in effect. There
are three flavors for Elastic: IN focuses the elastic movement at the start of the
animation, OUT focuses on the end of the animation, and BOTH focuses on both
ends of the animation.
The elastic graphs are shown in the following three figures. Figure 7.4 shows the
Elastic IN graph where the animated movement snaps into its final location.
Figure 7.5 shows the Elastic OUT graph where the movement jumps out of its
original position then smoothly moves to its final location.
Figure 7.6 shows the Elastic BOTH graph where the movement jumps out of its
original position and then snaps into its final position.