device_solve.h

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#pragma once
 
// Device solve: XYZ -> per-emitter light (P7, #4041).
//
// For a three-emitter device the solve is exact and linear: the emitter
// matrix is inverted once when a profile is bound, and each pixel is one
// matrix multiply. A3/B11 forbid iterative solvers such as nnls3 on the
// per-pixel path; nothing here is iterative, and a structural test enforces
// that the implementation stays that way.
 
#include "fl/gfx/colorimetric_response.h"
#include "fl/stl/int.h"
#include "fl/stl/noexcept.h"
 
namespace fl {
 
// These three symbols are public for the same reason the P6 stage headers
// are: the pipeline is being landed stage by stage, and the `show()` wiring
// that will call them needs P7's gamut mapper first. They are not exposed
// through `fl/gfx/gfx.h` and are not part of the sketch-facing API.
//
// The existing colorimetric API cannot carry this. `solve_rgb_colorimetric`
// is float and may fall back to `nnls3`, which A3/B11 forbid per pixel --
// that is precisely what this replaces on the streaming path, and
// ci/tests/test_no_iterative_solver_per_pixel.py enforces the separation.

struct EmitterSolveMatrixQ16 {
    i32 m[3][3];
};

struct EmitterChromaticitiesQ16 {
    i32 xy_r[2];
    i32 xy_g[2];
    i32 xy_b[2];
    i32 lum_r;
    i32 lum_g;
    i32 lum_b;
};

bool buildRgbSolveMatrixFromQ16(const EmitterChromaticitiesQ16& profile,
                                EmitterSolveMatrixQ16* out) FL_NO_EXCEPT;

bool invert3x3Q16(const i32 (&in)[3][3], i32 (&out)[3][3]) FL_NO_EXCEPT;

bool q16FromFloatBits(float value, i32* out) FL_NO_EXCEPT;
 
namespace detail {
i64 roundedDivideQ16(i64 numerator, i64 denominator) FL_NO_EXCEPT;
bool xyzColumnQ16(const i32 (&xy)[2], i32 luminance, i64 (&column)[3]) FL_NO_EXCEPT;
i32 dotRowQ16(const i32 (&row)[3], const i32 (&v)[3]) FL_NO_EXCEPT;
}  // namespace detail

bool buildRgbSolveMatrixQ16(const colorimetric_response::EmitterProfile& profile,
                            EmitterSolveMatrixQ16* out) FL_NO_EXCEPT;

void solveRgbDrivesQ16(const EmitterSolveMatrixQ16& matrix,
                       const i32 (&xyz)[3], i32 (&drives)[3]) FL_NO_EXCEPT;
 
}  // namespace fl