Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 54534742 authored by Romain Guy's avatar Romain Guy
Browse files

Add color space connection 

This will be used to generate a 3D LUT to convert wide gamut bitmaps
to the render target's color space at draw time.

Bug: 32984164
Test: colorspace_test
Change-Id: I1ea8d2b3129dfc8b994c8abc926b24e7e097558c
parent 11ecb634

include/ui/ColorSpace.h

+25 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <array>

#include <cmath>

#include <functional>

#include <memory>

#include <string>



#include <ui/mat3.h>
@@ -165,6 +166,30 @@ public: 
    static const ColorSpace ACES();

    static const ColorSpace ACEScg();



    class Connector {

    public:

        Connector(const ColorSpace& src, const ColorSpace& dst) noexcept;



        constexpr const ColorSpace& getSource() const noexcept { return mSource; }

        constexpr const ColorSpace& getDestination() const noexcept { return mDestination; }



        constexpr const mat3& getTransform() const noexcept { return mTransform; }



        constexpr float3 transform(const float3& v) const noexcept {

            float3 linear = mSource.toLinear(apply(v, mSource.getClamper()));

            return apply(mDestination.fromLinear(mTransform * linear), mDestination.getClamper());

        }



    private:

        const ColorSpace& mSource;

        const ColorSpace& mDestination;

        mat3 mTransform;

    };



    static const Connector connect(const ColorSpace& src, const ColorSpace& dst) {

        return Connector(src, dst);

    }



private:

    static constexpr mat3 computeXYZMatrix(

            const std::array<float2, 3>& primaries, const float2& whitePoint);

libs/ui/ColorSpace.cpp

+50 −5
Original line number Diff line number Diff line
@@ -96,6 +96,47 @@ constexpr mat3 ColorSpace::computeXYZMatrix( 
    };

}



static const float2 ILLUMINANT_D50_XY = {0.34567f, 0.35850f};

static const float3 ILLUMINANT_D50_XYZ = {0.964212f, 1.0f, 0.825188f};

static const mat3 VON_KRIES = mat3{

    float3{ 0.8951f, -0.7502f,  0.0389f},

    float3{ 0.2664f,  1.7135f, -0.0685f},

    float3{-0.1614f,  0.0367f,  1.0296f}

};



static mat3 adaptation(const mat3& matrix, const float3& srcWhitePoint, const float3& dstWhitePoint) {

    float3 srcLMS = matrix * srcWhitePoint;

    float3 dstLMS = matrix * dstWhitePoint;

    return inverse(matrix) * mat3{dstLMS / srcLMS} * matrix;

}



ColorSpace::Connector::Connector(

        const ColorSpace& src,

        const ColorSpace& dst) noexcept

        : mSource(src)

        , mDestination(dst) {



    if (all(lessThan(abs(src.getWhitePoint() - dst.getWhitePoint()), float2{1e-3f}))) {

        mTransform = dst.getXYZtoRGB() * src.getRGBtoXYZ();

    } else {

        mat3 rgbToXYZ(src.getRGBtoXYZ());

        mat3 xyzToRGB(dst.getXYZtoRGB());



        float3 srcXYZ = XYZ(float3{src.getWhitePoint(), 1});

        float3 dstXYZ = XYZ(float3{dst.getWhitePoint(), 1});



        if (any(greaterThan(abs(src.getWhitePoint() - ILLUMINANT_D50_XY), float2{1e-3f}))) {

            rgbToXYZ = adaptation(VON_KRIES, srcXYZ, ILLUMINANT_D50_XYZ) * src.getRGBtoXYZ();

        }



        if (any(greaterThan(abs(dst.getWhitePoint() - ILLUMINANT_D50_XY), float2{1e-3f}))) {

            xyzToRGB = inverse(adaptation(VON_KRIES, dstXYZ, ILLUMINANT_D50_XYZ) * dst.getRGBtoXYZ());

        }



        mTransform = xyzToRGB * rgbToXYZ;

    }

}



static constexpr float rcpResponse(float x, float g,float a, float b, float c, float d) {

    return x >= d * c ? (std::pow(x, 1.0f / g) - b) / a : x / c;

}
@@ -112,6 +153,10 @@ static float absResponse(float x, float g, float a, float b, float c, float d) { 
    return std::copysign(response(std::abs(x), g, a, b, c, d), x);

}



static float safePow(float x, float e) {

    return powf(x < 0.0f ? 0.0f : x, e);

}



const ColorSpace ColorSpace::sRGB() {

    return {

        "sRGB IEC61966-2.1",
@@ -187,8 +232,8 @@ const ColorSpace ColorSpace::AdobeRGB() { 
        "Adobe RGB (1998)",

        {{float2{0.64f, 0.33f}, {0.21f, 0.71f}, {0.15f, 0.06f}}},

        {0.3127f, 0.3290f},

        std::bind(powf, _1, 1.0f / 2.2f),

        std::bind(powf, _1, 2.2f)

        std::bind(safePow, _1, 1.0f / 2.2f),

        std::bind(safePow, _1, 2.2f)

    };

}
@@ -196,7 +241,7 @@ const ColorSpace ColorSpace::ProPhotoRGB() { 
    return {

        "ROMM RGB ISO 22028-2:2013",

        {{float2{0.7347f, 0.2653f}, {0.1596f, 0.8404f}, {0.0366f, 0.0001f}}},

        {0.3457f, 0.3585f},

        {0.34567f, 0.35850f},

        std::bind(rcpResponse, _1, 1.8f, 1.0f, 0.0f, 1 / 16.0f, 0.031248f),

        std::bind(response,    _1, 1.8f, 1.0f, 0.0f, 1 / 16.0f, 0.031248f)

    };
@@ -217,8 +262,8 @@ const ColorSpace ColorSpace::DCIP3() { 
        "SMPTE RP 431-2-2007 DCI (P3)",

        {{float2{0.680f, 0.320f}, {0.265f, 0.690f}, {0.150f, 0.060f}}},

        {0.314f, 0.351f},

        std::bind(powf, _1, 1.0f / 2.6f),

        std::bind(powf, _1, 2.6f)

        std::bind(safePow, _1, 1.0f / 2.6f),

        std::bind(safePow, _1, 2.6f)

    };

}

libs/ui/tests/colorspace_test.cpp

+12 −0
Original line number Diff line number Diff line
@@ -150,4 +150,16 @@ TEST_F(ColorSpaceTest, Clamping) { 
    EXPECT_TRUE(extendedSRGB.g > 1.0f);

}



TEST_F(ColorSpaceTest, Connect) {

    // No chromatic adaptation

    auto r = ColorSpace::connect(ColorSpace::sRGB(), ColorSpace::AdobeRGB())

            .transform({1.0f, 0.5f, 0.0f});

    EXPECT_TRUE(all(lessThan(abs(r - float3{0.8912f, 0.4962f, 0.1164f}), float3{1e-4f})));



    // Test with chromatic adaptation

    r = ColorSpace::connect(ColorSpace::sRGB(), ColorSpace::ProPhotoRGB())

            .transform({1.0f, 0.0f, 0.0f});

    EXPECT_TRUE(all(lessThan(abs(r - float3{0.70226f, 0.2757f, 0.1036f}), float3{1e-4f})));

}



}; // namespace android