Function initializeTestVals

src/OpenColorIO/ConfigUtils.cpp:1239–1358

Define a set of test values to use for a config and store them in the fingerprints struct. An attempt is made to convert them to the reference spaces of the config being used. There are separate values for scene-referred and display-referred color spaces.

// There are separate values for scene-referred and display-referred color spaces.
//
void initializeTestVals(ColorSpaceFingerprints & fingerprints, const ConstConfigRcPtr & config)
{
    // Define a set of test values that are slightly inside the Rec.709 gamut
    // for the most common scene-referred and display-referred reference spaces.

    // TODO: Including negative values would exclude some matches that are probably
    // desirable, it's an open question how strict the matching should be.

    std::vector<float> ACESvals = { 
        0.408933127871f, 0.106169822808f, 0.027842572707f, 0.f, // lin_rec709 {0.9, 0.03, 0.01}
        0.374615373650f, 0.739417755017f, 0.118862613721f, 0.f, // lin_rec709 {0.06, 0.9, 0.02}
        0.171696591718f, 0.104272268468f, 0.786227391453f, 0.f, // lin_rec709 {0.01, 0.02, 0.9}
        0.f            , 0.f            , 0.f            , 0.5f,
        0.037018876439f, 0.030827687576f, 0.021641700645f, 0.f, // lin_rec709 {0.05, 0.03, 0.02}
        1.f            , 1.f            , 1.f            , 1.f };

    std::vector<float> XYZvals = { 
        // Adjusted to keep it inside both Rec.601 and Rec.601 PAL.
        0.383684057405f, 0.213552088801f, 0.030478901760f, 0.f, // lin_rec709 {0.9, 0.03, 0.01}
        0.350178969169f, 0.657853997550f, 0.127445793983f, 0.f, // lin_rec709 {0.06, 0.9, 0.02}
        0.173708304342f, 0.081402847459f, 0.858056140808f, 0.f, // lin_rec709 {0.01, 0.02, 0.9}
        0.f            , 0.f            , 0.f            , 0.5f,
        0.034956685913f, 0.033530856964f, 0.023553027375f, 0.f, // lin_rec709 {0.05, 0.03, 0.02}
        0.950455927052f, 1.f            , 1.089057750760f, 1.f };

    // Try to convert to the actual reference spaces of the config.

    fingerprints.sceneRefTestVals = ACESvals;
    fingerprints.displayRefTestVals = XYZvals;

    ConstProcessorRcPtr p;
    try
    {
        // First check if the config recognizes one of the common names.
        ConstColorSpaceRcPtr cs;
        cs = config->getColorSpace("aces_interchange");
        if (!cs)
        {
            cs = config->getColorSpace("ACES2065-1");
            if (!cs)
            {
                cs = config->getColorSpace("lin_ap0_scene");
                if (!cs)
                {
                    // Otherwise, see if it's present using a different name.
                    ConstConfigRcPtr builtinConfig = Config::CreateFromBuiltinConfig("ocio://cg-config-latest");
                    // This throws if it cannot find the requested space.
                    const char * cs_name = 
                        Config::IdentifyBuiltinColorSpace(config, builtinConfig, "aces_interchange");
                    cs = config->getColorSpace(cs_name);
                }
            }
        }

        ConstTransformRcPtr toRef = getTransformForDir(cs, COLORSPACE_DIR_TO_REFERENCE);
        p = config->getProcessor(toRef);

        const size_t n = ACESvals.size();