go/src/image/jpeg/idct.go

const blockSize …

type block …

const w1 …

const w2 …

const w3 …

const w5 …

const w6 …

const w7 …

const w1pw7 …

const w1mw7 …

const w2pw6 …

const w2mw6 …

const w3pw5 …

const w3mw5 …

const r2 …

// idct performs a 2-D Inverse Discrete Cosine Transformation.
//
// The input coefficients should already have been multiplied by the
// appropriate quantization table. We use fixed-point computation, with the
// number of bits for the fractional component varying over the intermediate
// stages.
//
// For more on the actual algorithm, see Z. Wang, "Fast algorithms for the
// discrete W transform and for the discrete Fourier transform", IEEE Trans. on
// ASSP, Vol. ASSP- 32, pp. 803-816, Aug. 1984.
func idct(src *block) { … }