easing.js 2.6 KB

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  1. function linear(k) {
  2. return k;
  3. }
  4. function quadraticIn(k) {
  5. return k * k;
  6. }
  7. function quadraticOut(k) {
  8. return k * (2 - k);
  9. }
  10. function quadraticInOut(k) {
  11. if ((k *= 2) < 1) {
  12. return 0.5 * k * k;
  13. }
  14. return -0.5 * (--k * (k - 2) - 1);
  15. }
  16. function cubicIn(k) {
  17. return k * k * k;
  18. }
  19. function cubicOut(k) {
  20. return --k * k * k + 1;
  21. }
  22. function cubicInOut(k) {
  23. if ((k *= 2) < 1) {
  24. return 0.5 * k * k * k;
  25. }
  26. return 0.5 * ((k -= 2) * k * k + 2);
  27. }
  28. function elasticIn(k) {
  29. var s;
  30. var a = 0.1;
  31. var p = 0.4;
  32. if (k === 0) return 0;
  33. if (k === 1) return 1;
  34. if (!p) {
  35. p = 0.3;
  36. }
  37. if (!a || a < 1) {
  38. a = 1;
  39. s = p / 4;
  40. } else {
  41. s = p / (2 * Math.PI) * Math.asin(1 / a);
  42. }
  43. return -(a * Math.pow(2, 10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p));
  44. }
  45. function elasticOut(k) {
  46. var s;
  47. var a = 0.1;
  48. var p = 0.4;
  49. if (k === 0) return 0;
  50. if (k === 1) return 1;
  51. if (!p) {
  52. p = 0.3;
  53. }
  54. if (!a || a < 1) {
  55. a = 1;
  56. s = p / 4;
  57. } else {
  58. s = p / (2 * Math.PI) * Math.asin(1 / a);
  59. }
  60. return a * Math.pow(2, -10 * k) * Math.sin((k - s) * (2 * Math.PI) / p) + 1;
  61. }
  62. function elasticInOut(k) {
  63. var s;
  64. var a = 0.1;
  65. var p = 0.4;
  66. if (k === 0) return 0;
  67. if (k === 1) return 1;
  68. if (!p) {
  69. p = 0.3;
  70. }
  71. if (!a || a < 1) {
  72. a = 1;
  73. s = p / 4;
  74. } else {
  75. s = p / (2 * Math.PI) * Math.asin(1 / a);
  76. }
  77. if ((k *= 2) < 1) {
  78. return -0.5 * (a * Math.pow(2, 10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p));
  79. }
  80. return a * Math.pow(2, -10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p) * 0.5 + 1;
  81. }
  82. function backIn(k) {
  83. var s = 1.70158;
  84. return k * k * ((s + 1) * k - s);
  85. }
  86. function backOut(k) {
  87. var s = 1.70158;
  88. return (k = k - 1) * k * ((s + 1) * k + s) + 1;
  89. }
  90. function backInOut(k) {
  91. var s = 1.70158 * 1.525;
  92. if ((k *= 2) < 1) {
  93. return 0.5 * (k * k * ((s + 1) * k - s));
  94. }
  95. return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);
  96. }
  97. function bounceIn(k) {
  98. return 1 - bounceOut(1 - k);
  99. }
  100. function bounceOut(k) {
  101. if ((k /= 1) < 1 / 2.75) {
  102. return 7.5625 * k * k;
  103. } else if (k < 2 / 2.75) {
  104. return 7.5625 * (k -= 1.5 / 2.75) * k + 0.75;
  105. } else if (k < 2.5 / 2.75) {
  106. return 7.5625 * (k -= 2.25 / 2.75) * k + 0.9375;
  107. }
  108. return 7.5625 * (k -= 2.625 / 2.75) * k + 0.984375;
  109. }
  110. function bounceInOut(k) {
  111. if (k < 0.5) {
  112. return bounceIn(k * 2) * 0.5;
  113. }
  114. return bounceOut(k * 2 - 1) * 0.5 + 0.5;
  115. }
  116. export { linear, quadraticIn, quadraticOut, quadraticInOut, cubicIn, cubicOut, cubicInOut, elasticIn, elasticOut, elasticInOut, backIn, backOut, backInOut, bounceIn, bounceOut, bounceInOut };