rgb utilities

rgb

// This is a subfunction of HSLtoRGB
inline void HSLtoRGB_Subfunction(unsigned int& c, const float& temp1, const float& temp2, const float& temp3)
{
    if((temp3 * 6) < 1)
        c = (unsigned int)((temp2 + (temp1 - temp2) * 6 * temp3) * 100);
    else if((temp3 * 2) < 1)
        c = (unsigned int)(temp1 * 100);
    else if((temp3 * 3) < 2)
        c = (unsigned int)((temp2 + (temp1 - temp2) * (.66666 - temp3) * 6) * 100);
    else
        c = (unsigned int)(temp2 * 100);
    return;
}

// This function extracts the hue, saturation, and luminance from "color"
// and places these values in h, s, and l respectively.
inline void RGBtoHSL(unsigned int color, unsigned int& h, unsigned int& s, unsigned int& l)
{
    unsigned int r = (unsigned int)GetRValue(color);
    unsigned int g = (unsigned int)GetGValue(color);
    unsigned int b = (unsigned int)GetBValue(color);

    float r_percent = ((float)r) / 255;
    float g_percent = ((float)g) / 255;
    float b_percent = ((float)b) / 255;

    float max_color = 0;
    if((r_percent >= g_percent) && (r_percent >= b_percent))
    {
        max_color = r_percent;
    }
    if((g_percent >= r_percent) && (g_percent >= b_percent))
        max_color = g_percent;
    if((b_percent >= r_percent) && (b_percent >= g_percent))
        max_color = b_percent;

    float min_color = 0;
    if((r_percent <= g_percent) && (r_percent <= b_percent))
        min_color = r_percent;
    if((g_percent <= r_percent) && (g_percent <= b_percent))
        min_color = g_percent;
    if((b_percent <= r_percent) && (b_percent <= g_percent))
        min_color = b_percent;

    float L = 0;
    float S = 0;
    float H = 0;

    L = (max_color + min_color) / 2;

    if(max_color == min_color)
    {
        S = 0;
        H = 0;
    }
    else
    {
        if(L < .50)
        {
            S = (max_color - min_color) / (max_color + min_color);
        }
        else
        {
            S = (max_color - min_color) / (2 - max_color - min_color);
        }
        if(max_color == r_percent)
        {
            H = (g_percent - b_percent) / (max_color - min_color);
        }
        if(max_color == g_percent)
        {
            H = 2 + (b_percent - r_percent) / (max_color - min_color);
        }
        if(max_color == b_percent)
        {
            H = 4 + (r_percent - g_percent) / (max_color - min_color);
        }
    }
    s = (unsigned int)(S * 100);
    l = (unsigned int)(L * 100);
    H = H * 60;
    if(H < 0)
        H += 360;
    h = (unsigned int)H;
}

// This function converts the "color" object to the equivalent RGB values of
// the hue, saturation, and luminance passed as h, s, and l respectively
inline unsigned int HSLtoRGB(const unsigned int& h, const unsigned int& s, const unsigned int& l)
{
    unsigned int r = 0;
    unsigned int g = 0;
    unsigned int b = 0;

    float L = ((float)l) / 100;
    float S = ((float)s) / 100;
    float H = ((float)h) / 360;

    if(s == 0)
    {
        r = l;
        g = l;
        b = l;
    }
    else
    {
        float temp1 = 0;
        if(L < .50)
        {
            temp1 = L * (1 + S);
        }
        else
        {
            temp1 = L + S - (L * S);
        }

        float temp2 = 2 * L - temp1;

        float temp3 = 0;
        for(int i = 0 ; i < 3 ; i++)
        {
            switch(i)
            {
            case 0: // red
            {
                temp3 = H + .33333f;
                if(temp3 > 1)
                    temp3 -= 1;
                HSLtoRGB_Subfunction(r, temp1, temp2, temp3);
                break;
            }
            case 1: // green
            {
                temp3 = H;
                HSLtoRGB_Subfunction(g, temp1, temp2, temp3);
                break;
            }
            case 2: // blue
            {
                temp3 = H - .33333f;
                if(temp3 < 0)
                    temp3 += 1;
                HSLtoRGB_Subfunction(b, temp1, temp2, temp3);
                break;
            }
            default:
            {

            }
            }
        }
    }
    r = (unsigned int)((((float)r) / 100) * 255);
    g = (unsigned int)((((float)g) / 100) * 255);
    b = (unsigned int)((((float)b) / 100) * 255);
    return RGB(r, g, b);
}

inline unsigned int hsl_to_rgb(unsigned int h, unsigned int s, unsigned int l)
{
    return HSLtoRGB(h, s, l);
}

inline unsigned int lighten(unsigned int color, unsigned int amount)
{
    unsigned int h, s, l;

    RGBtoHSL(color, h, s, l);
    l += amount;
    if(l > 100)
    {
        l = 100;
    }
    return HSLtoRGB(h, s, l);
}

inline unsigned int darken(unsigned int color, unsigned int amount)
{
    unsigned int h, s, l;

    RGBtoHSL(color, h, s, l);
    if(amount >= l)
    {
        l = 0;
    }
    else
    {
        l -= amount;
    }
    return HSLtoRGB(h, s, l);
}

inline unsigned int* get_lighter_colors(const unsigned int* const clr, int size, int val)
{
    unsigned int* out = (unsigned int*) malloc(sizeof(unsigned int) * size);
    for(int n = 0; n < size; ++n)
        out[n] = lighten(clr[n], val);
    return out;
}

inline unsigned int* get_darker_colors(const unsigned int* const clr, int size, int val)
{
    unsigned int* out = (unsigned int*) malloc(sizeof(unsigned int) * size);
    for(int n = 0; n < size; ++n)
        out[n] = darken(clr[n], val);
    return out;
}

inline unsigned int* make_palatte(int gian, int hue, int sat, int lum)
{
    unsigned int* out = (unsigned int*) calloc(sizeof(int), gian);

    for(int n = 0; n < gian; ++n)
        out[n] = hsl_to_rgb(hue + n, sat, lum);
    return out;
}