34 lines
1.4 KiB
C#
34 lines
1.4 KiB
C#
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namespace PCL.Core.Utils;
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internal static class EaseUtils
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{
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// 预计算常量
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private const double BounceN1 = 7.5625;
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private const double BounceInvD1 = 0.3636363636363636; // 1 / 2.75
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private const double BounceThreshold2 = 0.7272727272727273; // 2 / 2.75
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private const double BounceThreshold3 = 0.9090909090909091; // 2.5 / 2.75
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private const double BounceOffset1 = 0.5454545454545454; // 1.5 / 2.75
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private const double BounceOffset2 = 0.8181818181818182; // 2.25 / 2.75
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private const double BounceOffset3 = 0.9545454545454546; // 2.625 / 2.75
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internal const double ElasticLn2Times10 = 6.931471805599453; // Math.Log(2d) * 10d
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internal const double ElasticPiTimes6Point5 = 20.420352248333657; // Math.PI * 6.5d
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internal static double Bounce(double progress)
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{
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switch (progress)
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{
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case < BounceInvD1:
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return BounceN1 * progress * progress;
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case < BounceThreshold2:
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progress -= BounceOffset1;
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return BounceN1 * progress * progress + 0.75;
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case < BounceThreshold3:
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progress -= BounceOffset2;
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return BounceN1 * progress * progress + 0.9375;
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default:
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progress -= BounceOffset3;
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return BounceN1 * progress * progress + 0.984375;
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}
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}
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}
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