# dleslie/tween-egg

Fetching contributors…
Cannot retrieve contributors at this time
213 lines (202 sloc) 6.13 KB
 (define (linear-ease direction percent) (assert (and (<= 0 percent) (>= 1 percent))) percent) (define (quadratic-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (expt percent 2)) ((eq? direction 'out) (* percent (- 2 percent))) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* 0.5 (expt percent 2)) (let ((p (- p 1))) (* -0.5 (- (* p (- p 2)) 1))))))))) (define (cubic-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (expt percent 3)) ((eq? direction 'out) (let ((p (- percent 1))) (+ 1 (* (expt p 3))))) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* 0.5 (expt p 3)) (let ((p (- p 2))) (* 0.5 (+ 2 (expt p 3)))))))))) (define (quartic-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (expt percent 4)) ((eq? direction 'out) (let ((p (- percent 1))) (- 1 (expt p 4)))) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* 0.5 (expt p 4)) (let ((p (- p 2))) (* -0.5 (- (expt p 4) 2))))))))) (define (quintic-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (expt percent 5)) ((eq? direction 'out) (let ((p (- percent 1))) (+ 1 (expt p 5)))) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* 0.5 (expt p 5)) (let ((p (- p 2))) (* 0.5 (+ (expt p 5) 2))))))))) (define (sinusoidal-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (define pi 3.14159265358979) (linear-ease direction (cond ((eq? direction 'in) (- 1 (cos (* percent pi 0.5)))) ((eq? direction 'out) (sin (* percent pi 0.5))) ((eq? direction 'inout) (* 0.5 (- 1 (cos (* pi percent)))))))) (define (exponential-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (if (= percent 0) 0 (expt 1024 (- percent 1)))) ((eq? direction 'out) (if (= percent 1) 1 (- 1 (expt 2 (* -10 percent))))) ((eq? direction 'inout) (cond ((= percent 0) 0) ((= percent 1) 1) ((< (* percent 2) 1) (* 0.5 (expt 1024 (- (* percent 2) 1)))) (else (* 0.5 (- 2 (expt 2 (* -10 (- (* percent 2) 1))))))))))) (define (circular-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (linear-ease direction (cond ((eq? direction 'in) (- 1 (sqrt (- 1 (expt percent 2))))) ((eq? direction 'out) (sqrt (- 1 (expt (- percent 1) 2)))) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* -0.5 (- (sqrt (- 1 (expt p 2))) 1)) (* 0.5 (+ (sqrt (- 1 (expt (- p 2) 2))) 1)))))))) (define (elastic-ease direction percent #!optional (a 1.0) (p 0.4)) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (define pi 3.14159265358979) (define invpi (/ 1 pi)) (define invp (/ 1 p)) (define k (let ((s (if (< a 1) (/ p 4) (* p (asin (/ 1 a)) 0.5 invpi))) (a (if (< a 1) 1 a))) (cond ((= percent 0) 0) ((= percent 1) 1) ((eq? direction 'in) (let ((percent (- percent 1))) (- (* a (expt 2 (* 10 percent)) (sin (* (- percent s) 2 pi invp)))))) ((eq? direction 'out) (+ (* a (expt 2 (* -10 percent)) (sin (* (- percent s) 2 pi invp))) 1)) ((eq? direction 'inout) (let ((p (* percent 2))) (if (< p 1) (* -0.5 a (expt 2 (* 10 (- p 1))) (sin (* (- p 1 s) 2 pi invp))) (+ 1 (* a 0.5 (expt 2 (* -10 (- p 1))) (sin (* (- p 1 s) 2 pi invpi)))))))))) (linear-ease direction (cond ((< k 0) 0) ((> k 1) 1) (else k)))) (define (back-ease direction percent #!optional (s 1.70158)) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (define k (cond ((eq? direction 'in) (* (expt percent 2) (- (* percent (+ s 1)) s))) ((eq? direction 'out) (let ((p (- percent 1))) (+ 1 (* (expt p 2) (+ s (* p (+ s 1))))))) ((eq? direction 'inout) (let ((s (* s 1.525)) (p (* percent 2))) (if (< p 1) (* 0.5 (* (expt p 2) (- (* p (+ s 1)) s))) (let ((p (- p 2))) (* 0.5 (+ 2 (* (expt p 2) (+ s (* p (+ s 1)))))))))))) (linear-ease direction (cond ((< k 0) 0) ((> k 1) 1) (else k)))) (define (bounce-ease direction percent) (assert (or (eq? direction 'in) (eq? direction 'out) (eq? direction 'inout))) (define (out p) (cond ((< p (/ 1 2.75)) (* 7.5625 (expt p 2))) ((< p (/ 2 2.75)) (let ((p (- p (/ 1.5 2.75)))) (+ 0.75 (* 7.5625 (expt p 2))))) ((< p (/ 2.5 2.75)) (let ((p (- p (/ 2.25 2.75)))) (+ 0.9375 (* 7.5625 (expt p 2))))) (else (let ((p (- p (/ 2.625 2.75)))) (+ 0.984375 (* 7.5625 (expt p 2))))))) (define (in p) (- 1 (out (- 1 p)))) (linear-ease direction (cond ((eq? direction 'in) (in percent)) ((eq? direction 'out) (out percent)) ((eq? direction 'inout) (if (< percent 0.5) (* 0.5 (in (* percent 2))) (+ 0.5 (* 0.5 (out (- (* percent 2) 1)))))))))