JUCE/modules/juce_graphics/colour/juce_PixelFormats.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
#if JUCE_MSVC
 #pragma pack (push, 1)
#endif

class PixelRGB;
class PixelAlpha;

inline uint32 maskPixelComponents (uint32 x) noexcept
{
    return (x >> 8) & 0x00ff00ff;
}

inline uint32 clampPixelComponents (uint32 x) noexcept
{
    return (x | (0x01000100 - maskPixelComponents (x))) & 0x00ff00ff;
}

//==============================================================================
/**
    Represents a 32-bit INTERNAL pixel with premultiplied alpha, and can perform compositing
    operations with it.

    This is used internally by the imaging classes.

    @see PixelRGB

    @tags{Graphics}
*/
class JUCE_API  PixelARGB
{
public:
    /** Creates a pixel without defining its colour. */
    PixelARGB() noexcept = default;

    PixelARGB (uint8 a, uint8 r, uint8 g, uint8 b) noexcept
    {
        components.b = b;
        components.g = g;
        components.r = r;
        components.a = a;
    }

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format. */
    forcedinline uint32 getNativeARGB() const noexcept   { return internal; }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((components.a << 24) | (components.r << 16) | (components.g << 8) | (components.b << 0));
       #else
        return getNativeARGB();
       #endif
    }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept
    {
       #if JUCE_BIG_ENDIAN
        return getInARGBMaskOrder();
       #else
        return (uint32) ((components.b << 24) | (components.g << 16) | (components.r << 8) | components.a);
       #endif
    }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent. */
    forcedinline uint32 getEvenBytes() const noexcept { return 0x00ff00ff & internal; }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent. */
    forcedinline uint32 getOddBytes() const noexcept  { return 0x00ff00ff & (internal >> 8); }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept      { return components.a; }
    forcedinline uint8 getRed()   const noexcept      { return components.r; }
    forcedinline uint8 getGreen() const noexcept      { return components.g; }
    forcedinline uint8 getBlue()  const noexcept      { return components.b; }

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        internal = src.getNativeARGB();
    }

    //==============================================================================
    /** Sets the pixel's colour from individual components. */
    void setARGB (uint8 a, uint8 r, uint8 g, uint8 b) noexcept
    {
        components.b = b;
        components.g = g;
        components.r = r;
        components.a = a;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        auto rb = src.getEvenBytes();
        auto ag = src.getOddBytes();

        const auto alpha = 0x100 - (ag >> 16);

        rb += maskPixelComponents (getEvenBytes() * alpha);
        ag += maskPixelComponents (getOddBytes() * alpha);

        internal = clampPixelComponents (rb) | (clampPixelComponents (ag) << 8);
    }

    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    forcedinline void blend (PixelRGB src) noexcept;


    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        auto rb = maskPixelComponents (extraAlpha * src.getEvenBytes());
        auto ag = maskPixelComponents (extraAlpha * src.getOddBytes());

        const auto alpha = 0x100 - (ag >> 16);

        rb += maskPixelComponents (getEvenBytes() * alpha);
        ag += maskPixelComponents (getOddBytes() * alpha);

        internal = clampPixelComponents (rb) | (clampPixelComponents (ag) << 8);
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, uint32 amount) noexcept
    {
        auto dEvenBytes = getEvenBytes();
        dEvenBytes += (((src.getEvenBytes() - dEvenBytes) * amount) >> 8);
        dEvenBytes &= 0x00ff00ff;

        auto dOddBytes = getOddBytes();
        dOddBytes += (((src.getOddBytes() - dOddBytes) * amount) >> 8);
        dOddBytes &= 0x00ff00ff;
        dOddBytes <<= 8;

        dOddBytes |= dEvenBytes;
        internal = dOddBytes;
    }

    //==============================================================================
    /** Replaces the colour's alpha value with another one. */
    forcedinline void setAlpha (uint8 newAlpha) noexcept
    {
        components.a = newAlpha;
    }

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int multiplier) noexcept
    {
        // increment alpha by 1, so that if multiplier == 255 (full alpha),
        // this function will not change the values.
        ++multiplier;

        internal = ((((uint32) multiplier) * getOddBytes()) & 0xff00ff00)
                | (((((uint32) multiplier) * getEvenBytes()) >> 8) & 0x00ff00ff);
    }

    forcedinline void multiplyAlpha (float multiplier) noexcept
    {
        multiplyAlpha ((int) (multiplier * 255.0f));
    }


    inline PixelARGB getUnpremultiplied() const noexcept
    {
        PixelARGB p (internal);
        p.unpremultiply();
        return p;
    }

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept
    {
        const auto alpha = components.a;

        if (alpha < 0xff)
        {
            if (alpha == 0)
            {
                components.b = 0;
                components.g = 0;
                components.r = 0;
            }
            else
            {
                components.b = (uint8) ((components.b * alpha + 0x7f) >> 8);
                components.g = (uint8) ((components.g * alpha + 0x7f) >> 8);
                components.r = (uint8) ((components.r * alpha + 0x7f) >> 8);
            }
        }
    }

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept
    {
        const auto alpha = components.a;

        if (alpha < 0xff)
        {
            if (alpha == 0)
            {
                components.b = 0;
                components.g = 0;
                components.r = 0;
            }
            else
            {
                components.b = (uint8) jmin ((uint32) 0xffu, (components.b * 0xffu) / alpha);
                components.g = (uint8) jmin ((uint32) 0xffu, (components.g * 0xffu) / alpha);
                components.r = (uint8) jmin ((uint32) 0xffu, (components.r * 0xffu) / alpha);
            }
        }
    }

    forcedinline void desaturate() noexcept
    {
        if (components.a < 0xff && components.a > 0)
        {
            const auto newUnpremultipliedLevel = (0xff * ((int) components.r + (int) components.g + (int) components.b) / (3 * components.a));

            components.r = components.g = components.b
                = (uint8) ((newUnpremultipliedLevel * components.a + 0x7f) >> 8);
        }
        else
        {
            components.r = components.g = components.b
                = (uint8) (((int) components.r + (int) components.g + (int) components.b) / 3);
        }
    }

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
  #if JUCE_ANDROID
   #if JUCE_BIG_ENDIAN
    enum { indexA = 0, indexR = 3, indexG = 2, indexB = 1 };
   #else
    enum { indexA = 3, indexR = 0, indexG = 1, indexB = 2 };
   #endif
  #else
   #if JUCE_BIG_ENDIAN
    enum { indexA = 0, indexR = 1, indexG = 2, indexB = 3 };
   #else
    enum { indexA = 3, indexR = 2, indexG = 1, indexB = 0 };
   #endif
  #endif

private:
    //==============================================================================
    PixelARGB (uint32 internalValue) noexcept
        : internal (internalValue)
    {
    }

    //==============================================================================
    struct Components
    {
      #if JUCE_ANDROID
       #if JUCE_BIG_ENDIAN
        uint8 a, b, g, r;
       #else
        uint8 r, g, b, a;
       #endif
      #else
       #if JUCE_BIG_ENDIAN
        uint8 a, r, g, b;
       #else
        uint8 b, g, r, a;
       #endif
      #endif
    } JUCE_PACKED;

    union
    {
        uint32 internal;
        Components components;
    };
}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;


//==============================================================================
/**
    Represents a 24-bit RGB pixel, and can perform compositing operations on it.

    This is used internally by the imaging classes.

    @see PixelARGB

    @tags{Graphics}
*/
class JUCE_API  PixelRGB
{
public:
    /** Creates a pixel without defining its colour. */
    PixelRGB() noexcept = default;

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format which is compatible
        with the native format of a PixelARGB.

        @see PixelARGB::getNativeARGB */
    forcedinline uint32 getNativeARGB() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((0xffu << 24) | r | ((uint32) g << 8) | ((uint32) b << 16));
       #else
        return (uint32) ((0xffu << 24) | b | ((uint32) g << 8) | ((uint32) r << 16));
       #endif
    }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((0xffu << 24) | b | ((uint32) g << 8) | ((uint32) r << 16));
       #else
        return getNativeARGB();
       #endif
    }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept
    {
       #if JUCE_BIG_ENDIAN
        return getInARGBMaskOrder();
       #else
        return (uint32) ((b << 24) | (g << 16) | (r << 8) | 0xff);
       #endif
    }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getEvenBytes of the PixelARGB class.

        @see PixelARGB::getEvenBytes */
    forcedinline uint32 getEvenBytes() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) (r | (b << 16));
       #else
        return (uint32) (b | (r << 16));
       #endif
    }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getOddBytes of the PixelARGB class.

        @see PixelARGB::getOddBytes */
    forcedinline uint32 getOddBytes() const noexcept       { return (uint32) 0xff0000 | g; }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept    { return 0xff; }
    forcedinline uint8 getRed()   const noexcept    { return r; }
    forcedinline uint8 getGreen() const noexcept    { return g; }
    forcedinline uint8 getBlue()  const noexcept    { return b; }

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
        Because PixelRGB has no alpha channel, any alpha value in the source pixel
        is thrown away.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        b = src.getBlue();
        g = src.getGreen();
        r = src.getRed();
    }

    /** Sets the pixel's colour from individual components. */
    void setARGB (uint8, uint8 red, uint8 green, uint8 blue) noexcept
    {
        r = red;
        g = green;
        b = blue;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        const auto alpha = (uint32) (0x100 - src.getAlpha());

        // getEvenBytes returns 0x00rr00bb on non-android
        const auto rb = clampPixelComponents (src.getEvenBytes() + maskPixelComponents (getEvenBytes() * alpha));
        // getOddBytes returns 0x00aa00gg on non-android
        const auto ag = clampPixelComponents (src.getOddBytes() + ((g * alpha) >> 8));

        g = (uint8) (ag & 0xff);

       #if JUCE_ANDROID
        b = (uint8) (rb >> 16);
        r = (uint8) (rb & 0xff);
       #else
        r = (uint8) (rb >> 16);
        b = (uint8) (rb & 0xff);
       #endif
    }

    forcedinline void blend (PixelRGB src) noexcept
    {
        set (src);
    }

    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        auto ag = maskPixelComponents (extraAlpha * src.getOddBytes());
        auto rb = maskPixelComponents (extraAlpha * src.getEvenBytes());

        const auto alpha = 0x100 - (ag >> 16);

        ag = clampPixelComponents (ag + (g * alpha >> 8));
        rb = clampPixelComponents (rb + maskPixelComponents (getEvenBytes() * alpha));

        g = (uint8) (ag & 0xff);

       #if JUCE_ANDROID
        b = (uint8) (rb >> 16);
        r = (uint8) (rb & 0xff);
       #else
        r = (uint8) (rb >> 16);
        b = (uint8) (rb & 0xff);
       #endif
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, uint32 amount) noexcept
    {
        auto dEvenBytes = getEvenBytes();
        dEvenBytes += (((src.getEvenBytes() - dEvenBytes) * amount) >> 8);

        auto dOddBytes = getOddBytes();
        dOddBytes += (((src.getOddBytes() - dOddBytes) * amount) >> 8);

        g = (uint8) (dOddBytes & 0xff);  // dOddBytes =  0x00aa00gg

       #if JUCE_ANDROID
        r = (uint8) (dEvenBytes & 0xff); // dEvenBytes = 0x00bb00rr
        b = (uint8) (dEvenBytes >> 16);
       #else
        b = (uint8) (dEvenBytes & 0xff); // dEvenBytes = 0x00rr00bb
        r = (uint8) (dEvenBytes >> 16);
       #endif
    }

    //==============================================================================
    /** This method is included for compatibility with the PixelARGB class. */
    forcedinline void setAlpha (uint8) noexcept {}

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int) noexcept {}

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (float) noexcept {}

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept {}

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept {}

    forcedinline void desaturate() noexcept
    {
        r = g = b = (uint8) (((int) r + (int) g + (int) b) / 3);
    }

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
   #if JUCE_MAC
    enum { indexR = 0, indexG = 1, indexB = 2 };
   #else
    enum { indexR = 2, indexG = 1, indexB = 0 };
   #endif

private:
    //==============================================================================
    PixelRGB (uint32 internal) noexcept
    {
      #if JUCE_ANDROID
        b = (uint8) (internal >> 16);
        g = (uint8) (internal >> 8);
        r = (uint8) (internal);
      #else
        r = (uint8) (internal >> 16);
        g = (uint8) (internal >> 8);
        b = (uint8) (internal);
      #endif
    }

    //==============================================================================
   #if JUCE_MAC
    uint8 r, g, b;
   #else
    uint8 b, g, r;
   #endif

}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;

forcedinline void PixelARGB::blend (PixelRGB src) noexcept
{
    set (src);
}

//==============================================================================
/**
    Represents an 8-bit single-channel pixel, and can perform compositing operations on it.

    This is used internally by the imaging classes.

    @see PixelARGB, PixelRGB

    @tags{Graphics}
*/
class JUCE_API  PixelAlpha
{
public:
    /** Creates a pixel without defining its colour. */
    PixelAlpha() noexcept = default;

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format which is compatible
        with the native format of a PixelARGB.

        @see PixelARGB::getNativeARGB */
    forcedinline uint32 getNativeARGB() const noexcept      { return (uint32) ((a << 24) | (a << 16) | (a << 8) | a); }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept { return getNativeARGB(); }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept     { return getNativeARGB(); }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getEvenBytes of the PixelARGB class.

        @see PixelARGB::getEvenBytes */
    forcedinline uint32 getEvenBytes() const noexcept      { return (uint32) ((a << 16) | a); }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getOddBytes of the PixelARGB class.

        @see PixelARGB::getOddBytes */
    forcedinline uint32 getOddBytes() const noexcept       { return (uint32) ((a << 16) | a); }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept    { return a; }
    forcedinline uint8 getRed()   const noexcept    { return 0; }
    forcedinline uint8 getGreen() const noexcept    { return 0; }
    forcedinline uint8 getBlue()  const noexcept    { return 0; }

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        a = src.getAlpha();
    }

    /** Sets the pixel's colour from individual components. */
    forcedinline void setARGB (uint8 a_, uint8, uint8, uint8) noexcept
    {
        a = a_;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        const auto srcA = src.getAlpha();
        a = (uint8) ((a * (0x100 - srcA) >> 8) + srcA);
    }

    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        ++extraAlpha;
        const auto srcAlpha = (int) ((extraAlpha * src.getAlpha()) >> 8);
        a = (uint8) ((a * (0x100 - srcAlpha) >> 8) + srcAlpha);
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, uint32 amount) noexcept
    {
        a += ((src.getAlpha() - a) * amount) >> 8;
    }

    //==============================================================================
    /** Replaces the colour's alpha value with another one. */
    forcedinline void setAlpha (uint8 newAlpha) noexcept
    {
        a = newAlpha;
    }

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int multiplier) noexcept
    {
        ++multiplier;
        a = (uint8) ((a * multiplier) >> 8);
    }

    forcedinline void multiplyAlpha (float multiplier) noexcept
    {
        a = (uint8) (a * multiplier);
    }

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept {}

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept {}

    forcedinline void desaturate() noexcept {}

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
    enum { indexA = 0 };

private:
    //==============================================================================
    PixelAlpha (uint32 internal) noexcept
        : a ((uint8) (internal >> 24)) { }

    //==============================================================================
    uint8 a;
}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;

#if JUCE_MSVC
 #pragma pack (pop)
#endif

} // namespace juce