color_functions.c

unsigned int value_to_hue_inverted(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 5.0 / maxv;
    int x = (int)f;
    if (x > 4) { x = 4; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff0000ff + ((int)(255*f)<<8);
        case 1:
            return 0xff00ff00 + 255*(1-f);
        case 2:
            return 0xff00ff00 + ((int)(255*f)<<16);
        case 3:
            return 0xffff0000 + ((int)(255*(1-f))<<8);
        case 4:
            return 0xffff0000 + 255*f;
    }

    return 0xffff0000;
}

unsigned int value_to_hue(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 5.0 / maxv;
    int x = (int)f;
    if (x > 4) { x = 4; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xffff0000 + 255*(1-f);
        case 1:
            return 0xffff0000 + ((int)(255*f)<<8);
        case 2:
            return 0xff00ff00 + ((int)(255*(1-f))<<16);
        case 3:
            return 0xff00ff00 + 255*f;
        case 4:
            return 0xff0000ff + ((int)(255*(1-f))<<8);
    }

    return 0xffff0000;
}

unsigned int value_to_bryw(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v*v * 4.0 / (maxv*maxv);
    int x = (int)f;
    if (x > 3) { x = 3; f = 1.0; } else f = f - x;

    switch  (x) {
        case 0:
            return 0xff000000 + 255*f;
        case 1:
            return 0xff000000 + ((int)(255*f)<<16) + 255*(1-f);
        case 2:
            return 0xffff0000 + ((int)(255*f)<<8);
        case 3:
            return 0xffffff00 + 255*f;
    }

    return 0xffff0000;
}

unsigned int value_to_bryw2(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 4.0 / maxv;
    int x = (int)f;
    if (x > 3) { x = 3; f = 1.0; } else f = f - x;

    switch  (x) {
        case 0:
            return 0xff000000 + 255*f;
        case 1:
            return 0xff000000 + ((int)(255*f)<<16) + 255*(1-f);
        case 2:
            return 0xffff0000 + ((int)(255*f)<<8);
        case 3:
            return 0xffffff00 + 255*f;
    }

    return 0xffff0000;
}

unsigned int value_to_bcy(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 3.0 / maxv;
    int x = (int)f;
    if (x > 2) { x = 2; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff000000 + 255*f;
        case 1:
            return 0xff0000ff + ((int)(255*f)<<8);
        case 2:
            return 0xff00ffff + ((int)(255*f)<<16);
    }

    return 0xffff0000;
}

unsigned int value_to_orange_range(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 3.0 / maxv;
    int x = (int)f;
    if (x > 2) { x = 2; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff000000 + ((int)(255*f)<<16) + ((int)(51*f)<<8);
        case 1:
            return 0xffff0000 + ((int)(51+204*f)<<8);
        case 2:
            return 0xffffff00 + 255*f;
    }

    return 0xffff0000;
}

unsigned int value_to_green_range(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 2.0 / maxv;
    int x = (int)f;
    if (x > 1) { x = 1; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff000000 + ((int)(162*f)<<8) + 89*f;
        case 1:
            return 0xff000000 + ((int)(255*f)<<16) + ((int)(162+93*f)<<8) + (89+166*f);
    }

    return 0xffff0000;
}

unsigned int value_to_purple_range(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 2.0 / maxv;
    int x = (int)f;
    if (x > 1) { x = 1; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff000000 + ((int)(230*f)<<16) + 172*f;
        case 1:
            return 0xff000000 + ((int)(230+25*f)<<16) + ((int)(255*f)<<8) + (172+83*f);
    }

    return 0xffff0000;
}

unsigned int value_to_ideal_blue_range(double v, double maxv) {

    if (v < 0) return 0xff000000;

    double f = v * 2.0 / maxv;
    int x = (int)f;
    if (x > 1) { x = 1; f = 1.0; } else f = f - x;

    switch (x) {
        case 0:
            return 0xff000000 + ((int)(144*f)<<8) + 255*f;
        case 1:
            return 0xff0000ff + ((int)(255*f)<<16) + ((int)(144+111*f)<<8);
    }

    return 0xffff0000;
}


unsigned int (*COLOR_FUNCTIONS[])(double, double) = {
    value_to_hue_inverted,
    value_to_hue,

    value_to_bryw,
    value_to_bryw2,

    value_to_bcy,

    value_to_green_range,
    value_to_purple_range,
    value_to_orange_range,
    value_to_ideal_blue_range,
};

const int COLOR_FUNCTIONS_COUNT = 9;
int CURRENT_CF = 8;     // value_to_ideal_blue_range