skia/public/mojom/skcolorspace.mojom

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module skia.mojom;

// A 3x3 matrix to convert between primaries in linear space.
struct SkcmsMatrix3x3 {
  array<float,9> vals;
};

// A transfer function mapping encoded values to linear values. This can be the
// standard 7-parameter piecewise function:
//
//   F(x) = { c*x + f                           : 0 <= |x| < d
//          { sign(x) * ((a*abs(x) + b)^g + e)  : d <= |x|
//
// A negative value for g can indicate some special transfer functions (HLG, and
// PQ), or can indicate that the function is invalid (and will always evaluate
// to zero).
struct SkcmsTransferFunction {
  float g;
  float a;
  float b;
  float c;
  float d;
  float e;
  float f;
};

// A color space specified by the transformation to linear space and then to
// XYZD50 primaries. Either none or both of `to_linear` and `to_xyzd50` are
// nullopt.
struct SkColorSpace {
  // The transformation from encoded space to linear space.
  SkcmsTransferFunction? to_linear;

  // The transformation from linear space to XYZD50 primaries.
  SkcmsMatrix3x3? to_xyzd50;
};