fade()

void MayaFlux::Kinesis::Discrete::fade ( std::span< double >  data, double  fade_in_ratio, double  fade_out_ratio  )

noexcept

Apply equal-power (cosine) fade-in then fade-out envelope in-place The cosine taper maintains constant perceived loudness at the crossover point (0 dB centre gain vs −6 dB for a linear taper).

Parameters

data	Target span
fade_in_ratio	Fraction of data length used for fade-in [0, 1]
fade_out_ratio	Fraction of data length used for fade-out [0, 1]

Definition at line 95 of file Transform.cpp.

{
    if (data.empty())
        return;
 
    const size_t n = data.size();
    const auto in_end = static_cast<size_t>(fade_in_ratio * static_cast<double>(n));
    const size_t out_start = n - static_cast<size_t>(fade_out_ratio * static_cast<double>(n));
 
    const double pi = std::numbers::pi;
 
    if (in_end > 0) {
        const auto in_len = static_cast<double>(in_end - 1);
        for (size_t i = 0; i < in_end; ++i) {
            const double t = (in_len > 0.0)
                ? static_cast<double>(i) / in_len
                : 1.0;
            data[i] *= std::sin(t * pi * 0.5);
        }
    }
 
    if (out_start < n) {
        const auto out_len = static_cast<double>(n - 1 - out_start);
        for (size_t i = out_start; i < n; ++i) {
            const double t = (out_len > 0.0)
                ? static_cast<double>(i - out_start) / out_len
                : 1.0;
            data[i] *= std::cos(t * pi * 0.5);
        }
    }
}