NeoPixelBus/src/internal/RgbColor.cpp

/*-------------------------------------------------------------------------
RgbColor provides a color object that can be directly consumed by NeoPixelBus

Written by Michael C. Miller.

I invest time and resources providing this open source code,
please support me by dontating (see https://github.com/Makuna/NeoPixelBus)

-------------------------------------------------------------------------
This file is part of the Makuna/NeoPixelBus library.

NeoPixelBus is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.

NeoPixelBus is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with NeoPixel.  If not, see
<http://www.gnu.org/licenses/>.
-------------------------------------------------------------------------*/

#include "RgbColor.h"
#include "HslColor.h"
#include "HsbColor.h"
#include "HtmlColor.h"

static float _CalcColor(float p, float q, float t)
{
    if (t < 0.0f)
        t += 1.0f;
    if (t > 1.0f)
        t -= 1.0f;

    if (t < 1.0f / 6.0f)
        return p + (q - p) * 6.0f * t;

    if (t < 0.5f)
        return q;

    if (t < 2.0f / 3.0f)
        return p + ((q - p) * (2.0f / 3.0f - t) * 6.0f);

    return p;
}

RgbColor::RgbColor(const HtmlColor& color)
{
    uint32_t temp = color.Color;

    B = (temp & 0xff);
    temp = temp >> 8;
    G = (temp & 0xff);
    temp = temp >> 8;
    R = (temp & 0xff);
};

RgbColor::RgbColor(const HslColor& color)
{
    float r;
    float g;
    float b;

    float h = color.H;
    float s = color.S;
    float l = color.L;


    if (color.S == 0.0f || color.L == 0.0f)
    {
        r = g = b = l; // achromatic or black
    }
    else 
    {
        float q = l < 0.5f ? l * (1.0f + s) : l + s - (l * s);
        float p = 2.0f * l - q;
        r = _CalcColor(p, q, h + 1.0f / 3.0f);
        g = _CalcColor(p, q, h);
        b = _CalcColor(p, q, h - 1.0f / 3.0f);
    }

    R = (uint8_t)(r * 255.0f);
    G = (uint8_t)(g * 255.0f);
    B = (uint8_t)(b * 255.0f);
}

RgbColor::RgbColor(const HsbColor& color)
{
    float r;
    float g;
    float b;

    float h = color.H;
    float s = color.S;
    float v = color.B;

    if (color.S == 0.0f)
    {
        r = g = b = v; // achromatic or black
    }
    else
    {
        if (h < 0.0f)
        {
            h += 1.0f;
        }
        else if (h >= 1.0f)
        {
            h -= 1.0f;
        }
        h *= 6.0f;
        int i = (int)h;
        float f = h - i;
        float q = v * (1.0f - s * f);
        float p = v * (1.0f - s);
        float t = v * (1.0f - s * (1.0f - f));
        switch (i)
        {
        case 0:
            r = v;
            g = t;
            b = p;
            break;
        case 1:
            r = q;
            g = v;
            b = p;
            break;
        case 2:
            r = p;
            g = v;
            b = t;
            break;
        case 3:
            r = p;
            g = q;
            b = v;
            break;
        case 4:
            r = t;
            g = p;
            b = v;
            break;
        default:
            r = v;
            g = p;
            b = q;
            break;
        }
    }

    R = (uint8_t)(r * 255.0f);
    G = (uint8_t)(g * 255.0f);
    B = (uint8_t)(b * 255.0f);
}

uint8_t RgbColor::CalculateBrightness() const
{
    return (uint8_t)(((uint16_t)R + (uint16_t)G + (uint16_t)B) / 3);
}

RgbColor RgbColor::Dim(uint8_t ratio) const
{
    // specifically avoids float math
    return RgbColor(_elementDim(R, ratio), _elementDim(G, ratio), _elementDim(B, ratio));
}

RgbColor RgbColor::Brighten(uint8_t ratio) const
{
    // specifically avoids float math
    return RgbColor(_elementBrighten(R, ratio), _elementBrighten(G, ratio), _elementBrighten(B, ratio));
}

void RgbColor::Darken(uint8_t delta)
{
    if (R > delta)
    {
        R -= delta;
    }
    else
    {
        R = 0;
    }

    if (G > delta)
    {
        G -= delta;
    }
    else
    {
        G = 0;
    }

    if (B > delta)
    {
        B -= delta;
    }
    else
    {
        B = 0;
    }
}

void RgbColor::Lighten(uint8_t delta)
{
    if (R < 255 - delta)
    {
        R += delta;
    }
    else
    {
        R = 255;
    }

    if (G < 255 - delta)
    {
        G += delta;
    }
    else
    {
        G = 255;
    }

    if (B < 255 - delta)
    {
        B += delta;
    }
    else
    {
        B = 255;
    }
}

RgbColor RgbColor::LinearBlend(const RgbColor& left, const RgbColor& right, float progress)
{
    return RgbColor( left.R + ((right.R - left.R) * progress),
        left.G + ((right.G - left.G) * progress),
        left.B + ((right.B - left.B) * progress));
}

RgbColor RgbColor::BilinearBlend(const RgbColor& c00, 
    const RgbColor& c01, 
    const RgbColor& c10, 
    const RgbColor& c11, 
    float x, 
    float y)
{
    float v00 = (1.0f - x) * (1.0f - y);
    float v10 = x * (1.0f - y);
    float v01 = (1.0f - x) * y;
    float v11 = x * y;

    return RgbColor(
        c00.R * v00 + c10.R * v10 + c01.R * v01 + c11.R * v11,
        c00.G * v00 + c10.G * v10 + c01.G * v01 + c11.G * v11,
        c00.B * v00 + c10.B * v10 + c01.B * v01 + c11.B * v11);
}