缓动函数 (Easie)

一个用 Swift 编写的跨平台缓动函数集合，不依赖于 SwiftUI 或 CoreGraphics。

简单示例

// An ease-out curve
let unitCurve = EaseOutInEaseOut()
let unitY = unitCurve.value(at: 0.88)

缓动类型

类型	`EaseIn (缓入)`	`EaseOut (缓出)`	`EaseInEaseOut (缓入缓出)`
`sine (正弦)`
`cubic (三次)`
`quint (五次)`
`circ (圆形)`
`quad (二次)`
`quart (四次)`
`expo (指数)`
`bounce (弹跳)`
`back (回弹)`
`elastic (弹性)`

示例

// An ease-out curve
let unitCurve = EaseOut(.cubic)
let unitY = unitCurve.value(at: 0.25)

// An ease-in-ease-out elastic curve
let unitY = easeInEaseOutElastic(at: 0.68)

三次类型

一个三次贝塞尔曲线，第一个点 P0 为 (0.0, 0.0)，最后一个点 P3 为 (1.0, 1.0)。

三次贝塞尔曲线由四个点定义：P0、P1、P2 和 P3。点 P0 和 P3 代表曲线的开始和结束。

P1 或 P2 坐标超出 [0, 1] 范围的三次贝塞尔曲线可能导致值超过最终状态，然后返回。

let unitCurve = CubicBezierCurve(x1: 0.1, y1: 0.6, x2: 0.7, y2: 0.2)
let unitY = unitCurve.value(at: 0.25)

线性类型

线性曲线定义了沿 t 轴等间距的 Y 值。

线性曲线必须始终以 0.0 开始，以 1.0 结束。

示例

let linear = Linear(values: [0.0, 0.25, 0.25, 1.0])
let unitY = linear.value(at: 0.25)

// An linear curve
let linear = Linear(values: [0.0, 0.1, 0.5, 0.9, 1.0])
let unitY = linear.value(at: 0.68)

跳转 (阶跃) 类型

跳转曲线定义阶跃函数，该函数将输出值域划分为等距阶跃

类型	图像	描述
`jumpStart (起始跳转)`		在 t=0.0 点跳转到第一个阶跃，最终阶跃位于 t=1.0。
`jumpEnd (结束跳转)`		在第一个阶跃的末尾跳转到第一个阶跃。
`jumpNone (无跳转)`		在第一个阶跃的末尾跳转到第一个阶跃，最终阶跃位于 1.0。
`jumpBoth (双端跳转)`		在 t=0 时跳转到第一个阶跃，最终阶跃位于 1.0。

示例

let jump = Jump(.jumpEnd, steps: 4)
let unitY = jump.value(at: 0.25)

let jump = Jump(.jumpBoth, steps: 3)
let unitY = jump.value(at: 0.68)

参考资料

许可证

MIT License

Copyright (c) 2024 Darren Ford

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Robert Penner MIT 许可证

缓动使用条款 (archive.org)

MIT License

Copyright © 2001 Robert Penner

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all 
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.